Lentes intraoculares trifocales versus lentes intraoculares bifocales después de la extracción de cataratas en participantes con presbicia
Resumen
Antecedentes
La presbiopía (presbicia) se produce cuando el cristalino de los ojos pierde su elasticidad, lo que lleva a la pérdida de acomodación. La lente también puede progresar hasta desarrollar cataratas, afectando la agudeza visual y la sensibilidad al contraste. Una opción de atención para los pacientes con presbiopía y cataratas es el uso de lentes intraoculares (LIO) multifocales o de profundidad de foco extendida después de la cirugía de cataratas. Aunque las LIO trifocales y bifocales están diseñadas para restaurar tres y dos puntos focales respectivamente, la lente trifocal puede ser preferible porque restaura la visión cercana, intermedia y lejana, y también podría proporcionar un mayor campo de visión útil y permitir una mayor independencia de las gafas en las personas con presbiopía.
Objetivos
Evaluar la efectividad y la seguridad de implantar LIO trifocales versus bifocales durante la cirugía de cataratas en personas con presbiopía.
Métodos de búsqueda
Se realizaron búsquedas en el Registro Cochrane central de ensayos controlados (Cochrane Central Register of Controlled Trials, CENTRAL) (que contiene el registro de ensayos del Grupo Cochrane de Salud ocular y de la visión [Cochrane Eyes and Vision]) (2022, número 3); Ovid MEDLINE; Embase.com; PubMed; ClinicalTrials.gov, y en la Plataforma de registros internacionales de ensayos clínicos (ICTRP) de la Organización Mundial de la Salud (OMS). No se utilizaron restricciones de fecha ni de idioma en la búsqueda electrónica de los ensayos. El 31 de marzo de 2022 se realizó la última búsqueda en las bases de datos electrónicas.
Criterios de selección
Se incluyeron ensayos controlados aleatorizados que compararon las LIO trifocales y bifocales en participantes de 30 años o más con presbiopía sometidos a una cirugía de cataratas.
Obtención y análisis de los datos
Se utilizó la metodología estándar de Cochrane y la certeza del conjunto de evidencia según el método GRADE.
Resultados principales
Se identificaron siete estudios realizados en Europa y Turquía con un total de 331 participantes. Todos los estudios incluidos evaluaron la agudeza visual mediante un logaritmo del ángulo mínimo de resolución (gráfico LogMAR). De ellos, seis (86%) estudios evaluaron la agudeza visual de lejos sin corrección (desenlace principal de esta revisión). Algunos estudios también examinaron los desenlaces secundarios de esta revisión, entre ellos la agudeza visual de cerca e intermedia sin corrección, la agudeza visual de lejos con la mejor corrección y la sensibilidad al contraste.
Características de los estudios
Todos los participantes tenían cataratas bilaterales sin patologías oculares ni cirugía ocular preexistentes. La media de edad de los participantes varió entre 55 y 74 años. Tres estudios informaron sobre el género de los participantes, y fueron en su mayoría mujeres. Se evaluaron todos los estudios incluidos como de riesgo incierto de sesgo para la mayoría de los dominios. Dos estudios recibieron financiación de los fabricantes de lentes evaluados en esta revisión y al menos un autor de otro estudio declaró haber recibido pagos por impartir conferencias con los fabricantes de lentes.
Hallazgos
Todos los estudios compararon la implantación de LIO trifocales versus bifocales en desenlaces de agudeza visual medidos en una escala LogMAR. Al año, la LIO trifocal no mostró evidencia de efecto sobre la agudeza visual de lejos sin corrección (diferencia de medias [DM] 0,00; intervalo de confianza [IC] del 95%: ‐0,04 a 0,04; I2 = 0%; dos estudios, 107 participantes; evidencia de certeza baja) ni la agudeza visual de cerca sin corrección (DM 0,01; IC del 95%: ‐0,04 a 0,06; I2 = 0%; dos estudios, 107 participantes; evidencia de certeza baja). El implante de LIO trifocales podría mejorar la agudeza visual intermedia sin corrección al año (DM ‐0,16; IC del 95%: ‐0,22 a ‐0,10; I2 = 0%; dos estudios, 107 participantes; evidencia certeza baja), pero no mostró evidencia de un efecto sobre la agudeza visual de lejos con la mejor corrección al año (DM 0,00; IC del 95%: ‐0,03 a 0,04; I2 = 0%; dos estudios, 107 participantes; evidencia de certeza baja). Ningún estudio informó sobre la sensibilidad al contraste ni la calidad de vida al año de seguimiento. Los datos de un estudio a los tres meses indican que la sensibilidad al contraste no difirió entre los grupos bajo condiciones fotópicas, pero podría ser peor en el grupo trifocal en una de las cuatro frecuencias bajo condiciones mesópicas (DM ‐0,19; IC del 95%: ‐0,33 a ‐0,05; un estudio; I2 = 0%, 25 participantes; evidencia de certeza baja). Un estudio examinó la calidad de vida relacionada con la visión mediante el cuestionario 25‐item National Eye Institute Visual Function Questionnaire (NEI‐VFQ‐25) a los seis meses, y apuntó a que no había evidencia de una diferencia entre las LIO trifocales y las bifocales (DM 1,41; IC del 95%: ‐1,78 a 4,60; un estudio, 40 participantes; evidencia de certeza baja).
Eventos adversos
La información acerca de los eventos adversos varió de un estudio a otro. De los cinco estudios que proporcionaron información sobre eventos adversos, dos no observaron complicaciones intraoperatorias ni posoperatorias ni opacificación capsular posterior a los seis meses. Un estudio informó de que el resplandor y los halos eran similares a las mediciones preoperatorias. Un estudio informó de que 4 (20%) y 10 (50%) participantes presentaron molestias por deslumbramiento a los seis meses en el grupo trifocal y bifocal, respectivamente (razón de riesgos 0,40; IC del 95%: 0,15 a 1,07; 40 participantes). Un estudio informó de que cuatro ojos (11,4%) del grupo bifocal y tres (7,5%) del grupo trifocal presentaron una opacificación capsular posterior significativa que requirió capsulotomía YAG al año. La certeza de la evidencia para los eventos adversos fue baja.
Conclusiones de los autores
Se observó evidencia de certeza baja de que, en comparación con la LIO bifocal, la implantación de la LIO trifocal podría mejorar la agudeza visual intermedia sin corrección al año. Sin embargo, no hay evidencia de que exista una diferencia entre las lentes intraoculares trifocales y bifocales para la agudeza visual de lejos sin corrección, la agudeza visual de cerca sin corrección ni la agudeza visual con la mejor corrección al año. Las investigaciones futuras deben incluir la comparación de las LIO trifocales y las bifocales concretas que corrijan la agudeza visual intermedia para evaluar desenlaces importantes como la sensibilidad al contraste, la calidad de vida y los efectos adversos relacionados con la visión.
PICO
Resumen en términos sencillos
Implantación de lentes trifocales frente a bifocales después de la cirugía de cataratas
¿Qué se quería averiguar?
Se deseaba averiguar si existe alguna diferencia en la eficacia y la seguridad de la implantación en los ojos durante la cirugía de cataratas de una lente que contiene tres regiones que corrigen la visión de lejos, intermedia y de cerca (trifocal) en comparación con una lente que contiene dos regiones que corrigen la visión de lejos y de cerca (bifocal) en personas con cataratas.
Mensajes clave
Se observó que las personas que reciben lentes trifocales después de la cirugía de cataratas podrían experimentar una mejora en la agudeza visual intermedia sin corrección (agudeza visual) al año en comparación con las que recibieron lentes bifocales, pero se tiene poca confianza en las pruebas. No hay evidencia de que exista una diferencia entre las lentes trifocales y bifocales para la agudeza visual sin corrección de lejos, de cerca o para la agudeza visual con la mejor corrección de lejos al año. Los efectos de estas lentes sobre la calidad de vida y la capacidad de distinguir entre los sutiles aumentos de luz y oscuridad (sensibilidad al contraste) siguen sin conocerse.
¿Qué es la presbicia y cómo se trata?
La presbicia es una enfermedad del cristalino del ojo relacionada con la edad que causa una pérdida gradual de la capacidad de enfocar los objetos cercanos. Otras alteraciones del cristalino relacionadas con la edad pueden llevar a la pérdida de claridad del cristalino (catarata), causando la pérdida de la agudeza visual y la sensibilidad al contraste. Las lentes con tres o dos regiones (trifocales o bifocales, respectivamente) son una nueva tecnología que pretende reducir la dependencia de las gafas después de la cirugía de cataratas.
¿Qué se hizo?
Se buscaron estudios que examinaran lentes trifocales frente a bifocales en personas con presbicia. Se compararon y resumieron los resultados de los estudios y la confianza en la evidencia se evaluó sobre la base de factores como la metodología y el tamaño de los estudios.
¿Qué se encontró?
Se encontraron siete estudios relevantes realizados en Europa y Turquía con un total de 331 personas con presbicia.
Se observó que implantar la lente trifocal en el momento de la cirugía de cataratas podría mejorar la agudeza visual intermedia al año. No se observaron evidencias de que exista una diferencia entre la lente trifocal y bifocal para la agudeza visual sin corrección de lejos, de cerca ni para la agudeza visual de lejos con la mejor corrección al año. No se sabe si el implante de lentes trifocales comparado con el de lentes bifocales tiene algún efecto en la calidad de vida o la sensibilidad al contraste.
¿Cuáles son las limitaciones de la evidencia?
Se tiene poca confianza en la evidencia porque la realización de los estudios no estuvo clara y solo se encontraron pocos estudios relevantes.
¿Cuál es el grado de actualización de esta revisión?
Se buscaron estudios publicados hasta el 31 de marzo de 2022.
Authors' conclusions
Summary of findings
| Trifocal intraocular lenses versus bifocal intraocular lenses after cataract extraction among participants with presbyopia | ||||||
| Patient or population: people (> 30 years) with cataract and presbyopia | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with bifocal IOL | Risk with trifocal IOL | |||||
| Mean uncorrected distance visual acuity (LogMAR (1 year) | The mean uncorrected distance visual acuity (LogMAR) at 1 year was −0.01 to 0.01 LogMAR. | MD 0 LogMAR | ‐ | 107 | ⊕⊕⊝⊝ |
|
| Mean uncorrected near visual acuity (LogMAR) (1 year) | The mean uncorrected near visual acuity (LogMAR) at 1 year was 0.13 to 0.19 LogMAR. | MD 0.01 LogMAR | ‐ | 107 | ⊕⊕⊝⊝ |
|
| Mean uncorrected intermediate visual acuity (LogMAR) (1 year) | The mean uncorrected intermediate visual acuity (LogMAR) at 1 year was 0.25 to 0.26 LogMAR. | MD −0.16 LogMAR | ‐ | 107 | ⊕⊕⊝⊝ |
|
| Mean best‐corrected distance acuity (LogMAR) (1 year) | The mean best‐corrected distance acuity (LogMAR) at 1 year was −0.03 to −0.01 LogMAR. | MD 0.00 LogMAR | ‐ | 107 | ⊕⊕⊝⊝ |
|
| Mean contrast sensitivity (1 year) | No study reported this outcome at 1 year.
| ‐ | ‐ | 1 study reported that contrast sensitivity did not differ between groups under photopic conditions, but may be worse in the trifocal group in 1 of the 4 frequencies under mesopic conditions at 3 months (MD −0.19, 95% CI −0.33 to −0.05; n = 25). | ||
| Mean quality of life or visual function (measured using Visual Function Index‐14 tool) (1 year) | No study reported this outcome at 1 year. | ‐ | ‐ | 1 study examined vision‐related quality of life using the NEI‐VFQ‐25 at 6 months and found no evidence of a difference between trifocal and bifocal IOLs (MD 1.41, 95% CI −1.78 to 4.60; 40 participants). | ||
| Adverse events (1 year) | See comment | ‐ | ‐ | 129 (2 RCTs) | ⊕⊕⊝⊝ | 1 study reported no intraoperative or postoperative complications; in the other study, 4 eyes (11.4%) in the bifocal group and 3 eyes (7.5%) in the trifocal group developed significant posterior capsular opacification requiring YAG capsulotomy. |
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; IOL: intraocular lens; LogMAR: logarithm of the minimum angle of resolution; MD: mean difference; NEI‐VFQ‐25: 25‐item National Eye Institute Visual Function Questionnaire; RCT: randomized controlled trial | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1Downgraded for risk of bias (one level), as most domains were judged as at unclear risk of bias. | ||||||
Background
Description of the condition
The lens is one of the most important tissues in the human eye. Located in the posterior chamber, it is the second most powerful refractive structure, and contributes 20% to 30% of the total refractive power. It is an elastic and transparent tissue that helps focus images onto the retina. The accommodation process causes the lens to change its anterioposterior length and is associated with convergence and miosis (Glasser 1999). This process allows adequate intermediate and near vision.
The broadly accepted theory of accommodation is the Helmholtz theory, in which accommodation is the result of elastic properties of the human lens and possibly the vitreous which allows the lens to increase its negative power when zonular tension is relieved, and vice versa. This movement is performed by the ciliary muscle. This property of the human lens is lost in a progressive manner during aging until the accommodation range is practically none (Glasser 1999; Torricelli 2012).
Accommodation decreases with aging in a process known as presbyopia. In individuals with presbyopia, the ability of the lens to accommodate is insufficient for near vision. This process generally occurs between age 40 and 50 years (Glasser 1999; Papadopoulos 2014), and if not corrected has a significant impact on quality of life (Torricelli 2012).
As presbyopia develops and elasticity is lost, the lens may become opaque. The loss of transparency of the lens is called cataract. There are several types of cataracts. The most common type is the senile (age‐related) cataract. There are several well‐known risk factors for developing this type of vision‐impairing lens opacity, including high sodium intake (Bae 2015), some systemic diseases such as diabetes mellitus (Li 2014), high body mass index (WHO 2015), exposure to ultraviolet B radiation, and smoking (Hodge 1995).
According to the World Health Organization, cataract accounts for 51% of worldwide blindness and affects about 20 million people around the world (WHO 2015).
Symptoms associated with this condition are myopia and decrease in contrast sensitivity and visual acuity. Cataract extraction by phacoemulsification followed by capsular bag implantation of an artificial intraocular lens (IOL) is one option of care for individuals with presbyopia and cataract (Carson 2014). Intraocular lens implantation does reduce spectacle dependence compared with aphakia, but many individuals may still need spectacle correction for near vision following cataract surgery.
Description of the intervention
Cataract surgery is performed to extract the cloudy lens material, while preserving some structures such as the capsular bag. An artificial IOL is then placed to restore vision in the eye (Kohnen 2009). The standard practice is usually the implantation of a monofocal IOL, which confers only one focal point on the retina (Carson 2014), typically to provide good distance vision. With a monofocal IOL, a pseudophakic patient thus continues to be presbyopic, and spectacles may still be needed after phacoemulsification surgery to restore vision at other distances. With the advancement of technology and increased expectations of better vision, the goal of cataract surgery is no longer only limited to restoring vision, but management of the refractive component is also important prior, during, and after surgery (Torricelli 2012). Multifocal lenses were therefore designed to give more than one focal point and provide spectacle independence to the patient.
With changes in social and work environments, especially with the use of computers, tablets, smartphones, etc., excellent intermediate distance vision has become more important. New types of IOL design feature a refractive and diffractive component and confer three focal points within the eye. These trifocal IOLs restore near, far, and intermediate vision (Gatinel 2013). Intraocular lenses with this design have been shown to achieve better patient satisfaction (Kretz 2015b).
How the intervention might work
Unlike monofocal IOLs, diffractive IOLs were originally designed using apodization and convolution technologies that cause light to divide, and produce two or more focal points. To restore near, intermediate, and far vision, three focal points may be preferable in an IOL.
Multifocal acrylic IOLs come in several designs. The goal of the first generation of multifocal lens design (bifocal IOL) was to restore two focal points: far and near vision (Voskresenskaya 2010). These bifocal IOLs, known by convention as a multifocal lens, have acceptable visual outcomes and give spectacles independence to many pseudophakic people (Calladine 2012; Torricelli 2012). The latest generation of multifocal IOLs are based on a diffractive/refractive technology design with the main objective of restoring intermediate vision (Papadopoulos 2014).
Different bifocal IOLs have different visual outcomes, mainly because of the different added power placed in the IOL to adjust for different near vision distances. Besides near and distance vision, good intermediate vision is needed to increase patient satisfaction with IOLs (Kretz 2015a; Kretz 2015b). A few trifocal IOLs are available. Excellent visual outcomes and high patient satisfaction scores have been reported with these lenses (Cochener 2012; Law 2014; Lesieur 2012; Sheppard 2013; Torricelli 2012; Voskresenskaya 2010; Vryghem 2013).
However, the most common adverse visual effects in a multifocal IOL are glare, halos, and loss of contrast sensitivity, which result in poor quality of vision during mesopic conditions (Carson 2014). These effects could be related to neuroadaptation when the brain and visual system adapt to the new way of vision. As this process evolves, patients become more comfortable with their new vision, and their perception of side effects decreases (Voskresenskaya 2010).
Why it is important to do this review
It is important to restore visual acuity at all distances in order to treat cataract and presbyopia satisfactorily. Adverse effects such as halos, glare, lowered contrast sensitivity, and dissatisfaction associated with IOLs seem to be inherent with the multifocal designs (bifocal or trifocal IOL). However, other visual and patient‐important benefits have been reported for both bifocal and trifocal IOLs (Cochener 2012; Law 2014; Lesieur 2012; Sheppard 2013; Voskresenskaya 2010; Vryghem 2013). Another Cochrane Review comparing multifocal and monofocal IOLs after cataract extraction was published in 2012 (Calladine 2012), but to our knowledge no high‐quality systematic review of evidence for the comparison of trifocal and bifocal IOLs has been published.
Objectives
To assess the effectiveness and safety of implantation with trifocal versus bifocal intraocular lenses (IOLs) during cataract surgery among people with presbyopia.
Methods
Criteria for considering studies for this review
Types of studies
We only included randomized controlled trials (RCTs). We included all eligible trials regardless of their publication status or language of publication.
Types of participants
We included studies in which the participants were 30 years of age or older with cataract and presbyopia. We documented studies that included participants with other ocular comorbidities, such as pseudoexfoliation syndrome, glaucoma, diabetes mellitus, age‐related macular degeneration, retinal disease, optic nerve disease, or amblyopia in the eye undergoing cataract surgery or a history of intraocular surgery, pediatric cataract, or ocular trauma.
Types of interventions
We included studies in which implantation of trifocal IOLs was compared with implantation of bifocal IOLs during cataract surgery.
Types of outcome measures
Primary outcomes
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Mean uncorrected (without the aid of spectacles or contact lenses) distance visual acuity measured by logarithm of the minimum angle of resolution (LogMAR) chart at one‐year follow‐up.
Secondary outcomes
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Mean uncorrected distance visual acuity measured by LogMAR chart at three‐ and six‐month follow‐up.
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Mean uncorrected near visual acuity at three‐month, six‐month, and one‐year follow‐up.
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Mean uncorrected intermediate visual acuity at three‐month, six‐month, and one‐year follow‐up.
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Mean best‐corrected distance visual acuity at three‐month, six‐month, and one‐year follow‐up.
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Mean contrast sensitivity, measured by the FACT (Functional Acuity Contrast Test) chart (Pesudovs 2004), or by the Pelli‐Robson contrast sensitivity test (Mantyjarvi 2001), noted in logarithm of the contrast sensitivity (LogCS) at different cycles per grade in spatial frequencies at three‐month, six‐month, and one‐year follow‐up.
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Mean quality of life or visual function evaluated by validated and comparable instruments (e.g. 25‐item National Eye Institute Visual Function Questionnaire (NEI‐VFQ‐25)) noted in numeric scores at three‐month, six‐month, and one‐year follow‐up.
Adverse outcomes
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Visual disturbances such as glare, experienced when a source of light other than the main target image illuminates the retina, and halos, defined as visual disturbances related to the main target image that lower contrast sensitivity; these visual disturbances are only noted by proportions at three months, six months, and one year after surgery.
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Opacification of the posterior capsule (proliferation of epithelial lens cells in the main visual axis that lowers visual acuity), with or without YAG laser capsulotomy, at three months, six months, and one year after surgery.
We assessed additional adverse effects related to IOLs mentioned in any of the included studies.
Search methods for identification of studies
Electronic searches
The Cochrane Eyes and Vision Information Specialist searched the following electronic databases for RCTs and controlled clinical trials. There were no restrictions on language or year of publication. The electronic databases were last searched on 31 March 2022.
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Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) in the Cochrane Library (2022, Issue 3) (Appendix 1).
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MEDLINE Ovid (1946 to 31 March 2022) (Appendix 2).
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Embase.com (1980 to 31 March 2022) (Appendix 3).
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PubMed (1948 to 31 March 2022) (Appendix 4).
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LILACS (Latin American and Caribbean Health Science Information database) (1982 to 31 March 2022) (Appendix 5).
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US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov (www.clinicaltrials.gov; searched 31 March 2022) (Appendix 6).
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World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp; 31 March 2022) (Appendix 7).
Searching other resources
We searched the reference lists of included studies to identify additional relevant studies. We did not conduct specific searches on conference proceedings for this review because CENTRAL covers those abstracts. We did not contact any institution or personnel to identify potentially eligible trials.
Data collection and analysis
Selection of studies
Two review authors independently assessed the titles and abstracts of all records identified by the electronic and manual searches. Each review author reviewed and labeled each record as 'definitely relevant,' 'possibly relevant,' or 'definitely not relevant.' We retrieved the full‐text report for all records labeled as 'definitely relevant' or 'possibly relevant.' Two review authors independently assessed each full‐text report, classifying each as 'include,' 'exclude,' or 'awaiting classification.' Any differences between the two review authors at title, abstract, and full‐text screening stage were resolved by discussion. We documented the studies excluded after full‐text review and noted their reasons for exclusion.
Data extraction and management
Two review authors independently extracted the data from reports of the included studies using a data collection form developed by Cochrane Eyes and Vision and implemented in Covidence software (Covidence). Two review authors independently checked the data before entry into Review Manager 5 or Review Manager Web software (Review Manager 2020; RevMan Web 2022). We recorded the following characteristics of the included studies: study methods, participants, interventions, and outcomes. Where information about (or outcome data from) included studies was missing or unclear, we contacted the study investigators or organizations involved for additional data, confirmation, or clarification. We collected and used the most detailed numerical data available from the included studies to facilitate analyses. We attempted to obtain data from available reports, investigators, or organizations in preference to less precise methods such as extracting numeric data from graphs. When it was necessary to extract data available only in graphical displays, two review authors independently extracted the data, resolving any disagreements or discrepancies by discussion or by consulting a third review author.
Assessment of risk of bias in included studies
We used the Cochrane risk of bias tool as described in Chapter 8 of the Cochrane Handbook for Systematic Reviews of Interventions to assess the risk of bias in the included studies (Higgins 2017). Two review authors independently assessed risk of bias for each included study, grading each risk of bias domain as low, high, or unclear. We evaluated the following risk of bias domains: selection bias (sequence generation and allocation concealment before assignment), performance bias (masking of participants and study personnel), detection bias (masking of outcome assessors), attrition bias (loss to follow‐up), reporting bias (selective outcome reporting), and other sources of bias. Any disagreements between review authors were resolved by discussion until consensus was reached or by consulting another review author.
Measures of treatment effect
Continuous outcomes
We had planned to use standardized mean differences (SMDs) and 95% confidence intervals (CIs) calculated for continuous data outcomes in anticipation of the use of different instruments of measurement in different studies. This statistic is used, for example, when distance and near visual acuity are reported on different scales (LogMAR, decimal, or Snellen fraction) in different studies to permit the analysis of effects on a uniform scale (Deeks 2017). However, because all visual acuity was reported as LogMAR in all studies that contributed data to the meta‐analysis, we estimated the overall effects as mean differences (MDs) and 95% CIs. Where possible, we checked for skewness using the methods outlined in Chapter 9 of the Cochrane Handbook for Systematic Reviews of Interventions (Deeks 2017).
Dichotomous outcomes
When data on adverse outcome such as 'glare,' 'halos,' 'spectacle independence,' 'posterior capsular opacification' (PCO), and 'glistenings' were available, we analyzed them as dichotomous outcomes, and calculated risk ratios (RRs) along with their 95% CIs to estimate effects.
Unit of analysis issues
The participant was the primary unit of analysis when only one eye per participant was enrolled in the study. We determined whether the included studies included one or both eyes from each participant and whether the study investigators randomized and analyzed data at the participant or eye level. We planned that when both eyes were randomized to the same treatment group (two‐eye design) or to different treatment groups (paired‐eye design), we would extract the results that had accounted for the correlation and refer to Chapter 23 of the Cochrane Handbook for Systematic Reviews of Interventions for guidelines regarding considerations of including variants on randomized trials (Higgins 2019). When studies with more than two arms were included (e.g. two or more IOLs), we evaluated each relevant comparison separately, and selected one pair of intervention and comparison that were relevant to the review without double counting them in the analysis (Higgins 2019).
Dealing with missing data
We analyzed outcomes on an intention‐to‐treat basis. We contacted study authors when outcome data were missing. When no response was received within two weeks, we used the best information available to analyze the data. We only analyzed available data, and did not impute missing data for the purposes of this review.
Assessment of heterogeneity
We investigated clinical or methodological heterogeneity among studies by evaluating differences with respect to characteristics of participant populations, interventions, and outcome assessment. We evaluated statistical heterogeneity among outcomes by examining the overlap in CIs of forest plots and by using the Chi2 and the I2 statistic, as described in Chapter 9 of the Cochrane Handbook for Systematic Reviews of Interventions (Deeks 2017). We used the I2 statistic to assess the proportion of total variability explained by heterogeneity among studies. If we observed substantial heterogeneity (I2 > 60%) or inconsistency among effect sizes estimated from individual studies contributing data to a meta‐analysis, we did not report a pooled analysis, and instead provided a narrative summary of the intervention effects estimated from the individual studies. However, if all estimates were in the same direction, we performed a meta‐analysis despite substantial statistical heterogeneity, and interpreted the findings taking account of the heterogeneity.
Assessment of reporting biases
We assessed selective outcome reporting for each study by comparing the outcomes specified in a protocol or clinical trial registry with the reported results. When protocols or clinical trial registry records were not available, we assessed selective outcome reporting based on the outcomes specified in the methods section of the study reports and on data collected and reported in the study. We planned to use funnel plots to assess small‐study effects that could result in publication bias when a sufficient number of trials (more than 10) were included in the review. However, we did not assess publication bias because the number of studies included in the review was less than 10.
Data synthesis
We analyzed data according to the guidelines in Chapter 9 of the Cochrane Handbook for Systematic Reviews of Interventions (Deeks 2017). If there was no statistical or clinical heterogeneity, or fewer than three trials contributed data to a meta‐analysis, we used a fixed‐effect model to estimate intervention effects; otherwise we used random‐effects models. When we detected substantial statistical heterogeneity (I2 > 50%), and the direction of treatment effects was not consistent across studies, we did not perform a meta‐analysis and instead presented a narrative summary.
Subgroup analysis and investigation of heterogeneity
We had planned to conduct subgroup analysis to investigate the reasons for any clinical or statistical heterogeneity according to outcomes within subgroups of participants defined by such factors as unilateral versus bilateral surgery and optical design in the IOLs. However, we did not conduct these analyses due to insufficient numbers of studies.
Sensitivity analysis
We had planned to conduct sensitivity analysis to examine the impact of excluding studies with high risk of bias, unpublished data, and industry‐funded studies to assess the robustness of estimates with respect to these factors. Due to insufficient numbers of included studies and the absence of unpublished studies, we did not perform these analyses. Although we had not planned at the protocol stage to conduct sensitivity analysis based on unit of analysis (participants versus eyes), we had planned post hoc to conduct additional sensitivity analyses to examine the impact of restricting our analyses to studies for which analysis was performed at the participant level. However, we did not conduct this analysis because only one study analyzed data at the participant level.
Summary of findings and assessment of the certainty of the evidence
We prepared a summary of findings table according to the methods described in Chapters 11 and 12 of the Cochrane Handbook for Systematic Reviews of Interventions (Schünemann 2011a; Schünemann 2011b), and presented the estimated effects of trifocal IOLs versus bifocal IOLs at one‐year follow‐up. We included the following outcomes in the summary of findings table.
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Mean uncorrected distance visual acuity
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Mean uncorrected near visual acuity
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Mean uncorrected intermediate visual acuity
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Mean best‐corrected distance visual acuity
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Mean contrast sensitivity
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Mean quality of life or visual function scores
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Adverse events
Using the GRADE approach, two review authors independently judged the certainty of the evidence for each outcome as high, moderate, low, or very low (Langendam 2013). Any differences between review authors were resolved by discussion.
Results
Description of studies
Results of the search
Detailed results of the previous search were published in the original version of this review (Zamora‐de La Cruz 2020). Briefly, we included five studies (six reports), excluded 21 studies (21 reports), and categorized one study (one report) as awaiting classification from 8787 records identified by the database searches in September 2019.
We performed an updated electronic database searches on 31 March 2022, which yielded 1030 unique records. After title and abstract screening of 1030 records, we retrieved 21 full‐text reports for further review. We included two studies (two reports) and excluded 17 studies (17 reports). We listed two studies as awaiting classification because we were unclear about study design (Nava 2019; Song 2020). In addition, after review of the one study awaiting classification in the previous version of this review, we decided to exclude it because it was not an RCT (de Carneros‐Llorente 2019).
Overall, we included seven studies (eight reports), excluded 40 studies (40 reports), and categorized two studies (two reports) as awaiting classification. A study flow diagram is shown in Figure 1.
Study flow diagram.
Included studies
Study design
Six included studies were conducted in Europe: two in the Czech Republic (Mojzis 2014; Mojzis 2017), one in France (Cochener 2016), one in the Netherlands (Jonker 2015), one in Spain (Gil 2019), and one multicenter study was conducted in Spain, Germany, and France (Kaymak 2017). The remaining study was conducted in Turkey (Bozkurt Gencer 2021). Further details of the included studies can be found in the Characteristics of included studies table. The included studies were published between 2014 and 2021. Follow‐up duration ranged from three months in Mojzis 2014 to one year in Kaymak 2017 and Mojzis 2017. All of the included studies randomized both eyes of the same participant to the same intervention. Two studies analyzed data at the participant level (Cochener 2016; Gil 2019). In one study it was unclear if the unit of analysis was the eye or individual, and the remaining four studies analyzed data at the eye level, but the investigators did not report whether they had accounted for the correlation between eyes in their analysis. Two studies were of multi‐arm design (Gil 2019; Kaymak 2017), and we included only the comparison relevant to this review. We included all seven studies in meta‐analysis. The authors of two studies reported receiving funding from manufacturers of the lens examined in this review (Jonker 2015; Kaymak 2017). In one study at least one author reported a conflict of interest with manufacturers of the lens examined (Jonker 2015).
Participants
The seven included studies enrolled a total of 331 participants. The studies varied in size from 27 in Cochener 2016 to 116 participants in Gil 2019. The mean age of participants ranged from 55 to 74 years. Three studies reported information on the gender of participants, and participants were predominantly women, ranging from 60% in Kaymak 2017 to 71% in Gil 2019. Diagnosis of cataract varied among participants, highlighting clinical heterogeneity. All studies involved participants with bilateral cataracts and no pre‐existing ocular pathologies or ocular surgery. Cochener 2016 included participants who had started to show clouding of the crystalline lens (Lens Opacities Classification System III classification global score 2 or greater) and corneal astigmatism of 1.00 diopter (D) or less. Jonker 2015 and Kaymak 2017 included participants with bilateral cataracts with less than 1.0 D corneal astigmatism in both eyes. The remaining two studies enrolled participants with cataracts and presbyopic or pre‐presbyopic requiring refractive lenses (Mojzis 2014; Mojzis 2017). Gil 2019 included participants with bilateral cataracts, good motivation for spectacle independence potential visual acuity (20/25 of better), and preoperative corneal astigmatism less or equal to 1.25D. Bozkurt Gencer 2021 included participants with low vision in both eyes and best‐corrected visual acuity of less than 0.5 and astigmatism > 1.0 D. They used the Verion digital system and the conventional corneal marking method.
Interventions
All seven included studies evaluated trifocal versus bifocal IOLs.
Outcomes
All seven included studies assessed visual acuity measured using a LogMAR chart, and three studies assessed contrast sensitivity (Bozkurt Gencer 2021; Jonker 2015; Mojzis 2017). Five studies examined vision‐related quality of life; Bozkurt Gencer 2021 used the 25‐item National Eye Institute Visual Function Questionnaire (NEI‐VFQ‐25); Gil 2019 evaluated patient satisfaction and quality of life using the Visual Function 14 (VF‐14) questionnaire; three studies assessed other visual functions such as spectacle independence, Cochener 2016; Jonker 2015, and reading performance (Jonker 2015; Kaymak 2017). Five studies reported adverse events (Bozkurt Gencer 2021; Cochener 2016; Gil 2019; Jonker 2015; Mojzis 2017).
Excluded studies
We excluded 40 studies after full‐text review. Seventeen of these studies did not address the comparisons of interest, and the remaining 23 studies were not reports of RCTs (see Characteristics of excluded studies table).
Ongoing studies and studies awaiting classification
We listed two studies as awaiting classification because it was unclear if participants had been randomly assigned to intervention groups (see Characteristics of studies awaiting classification table). We identified no ongoing studies.
Risk of bias in included studies
Risk of bias assessment for all seven studies is summarized in Figure 2.
Risk of bias summary: review authors' judgements about each risk of bias item for each included study.
Allocation
Random sequence generation
Randomization sequence was adequately generated in three studies: participants were assigned to treatment groups using web‐based software in Cochener 2016, computer‐generated random sequence in Gil 2019, and by randomization code administered centrally using a vocal server in Kaymak 2017. We judged these three studies to be at low risk of bias for this domain. Four studies did not report the method of randomization (Bozkurt Gencer 2021; Jonker 2015; Mojzis 2014; Mojzis 2017), and were therefore judged as at unclear risk of bias.
Allocation concealment
We judged Kaymak 2017 to be at low risk of bias as the treatment allocation was accomplished centrally. The method of treatment allocation concealment was not reported in the remaining six studies, therefore they were judged as at unclear risk of bias.
Blinding
We judged most of the included studies as at unclear risk of performance and detection bias. Only one study masked both participants and investigators to the IOL implanted, and was judged as at low risk of performance bias (Jonker 2015). We judged Bozkurt Gencer 2021 as at high risk of bias because masking could not be done due to the nature of interventions (i.e. digital versus manual marking). We judged the remaining five studies as at unclear risk of bias for various reasons. Gil 2019 reported that their study was "double‐masked," but it was unclear who was masked and how th masking was conducted. Mojzis 2014 and Mojzis 2017 masked participants to IOL but did not report whether study personnel were masked. Cochener 2016 and Kaymak 2017 did not report if participants or study personnel were masked.
The primary outcome of this review was mean uncorrected distance visual acuity at one‐year follow‐up. Only one study reported that all postoperative outcome assessments were performed by an independent observer who was masked to the intervention (Kaymak 2017); we judged this study to be at low risk of detection bias. The remaining six studies did not report masking outcome assessors and were therefore judged as at unclear risk of detection bias.
Incomplete outcome data
There were no missing outcome data in Bozkurt Gencer 2021; we judged this study as at low risk of bias. Kaymak 2017 excluded six eyes, three (9%) of participants from the analysis, because participants withdrew after IOL implantation. Given that this proportion of the total eyes/participants was small, we judged Kaymak 2017 as at low risk of attrition bias. The remaining five studies did not report attrition information and were therefore judged as at unclear risk of attrition bias.
Selective reporting
In two studies some outcomes were reported incompletely (Bozkurt Gencer 2021; Gil 2019). We judged these studies as having unclear risk of reporting bias. Although the remaining five studies had no trial registration or published protocol, the authors reported all outcomes specified in the methods section of the study, therefore we judged these studies as at low risk of reporting bias.
Other potential sources of bias
In two of the seven included studies, at least one study investigator had a financial relationship with manufacturers of one of the intervention devices (Jonker 2015; Kaymak 2017). The remaining five studies appeared to be free from other sources of bias.
Effects of interventions
The only comparison in this review was trifocal compared with bifocal IOL implantation during cataract surgery for visual acuity among presbyopic participants. All seven included studies reported data on at least one of our prespecified outcomes.
Mean uncorrected distance visual acuity (UDVA)
At three months, data were available from only two studies. Participants treated with trifocal IOL implantation probably experienced more of an improvement in UDVA than in those treated with bifocal IOL (mean difference (MD) −0.04, 95% confidence interval (CI) −0.08 to 0.00; I2 = 0%; 2 studies, 92 participants; Analysis 1.1; Figure 3). The certainty of the evidence was moderate, downgraded for risk of bias. The beneficial effect of trifocal IOL for this outcome persisted at six months (MD −0.04, 95% CI −0.07 to 0.00; I2 = 53%; 5 studies, 257 participants; Analysis 1.1; Figure 3). The certainty of the evidence was moderate, downgraded for risk of bias. However, the observed beneficial effect of trifocal IOL disappeared at one year (MD 0.00, 95% CI −0.04 to 0.04; I2 = 0%; 2 studies, 107 participants; Analysis 1.1; Figure 3), the primary outcome of our review. The certainty of the evidence was low, downgraded for imprecision and risk of bias.
Forest plot of comparison: 1 Trifocal versus bifocal intraocular lenses after cataract extraction, outcome: 1.1 Mean uncorrected distance visual acuity (LogMAR).
Mean uncorrected near visual acuity (UNVA)
At three months, pooled data from two studies suggested that trifocal IOL implantation had no effect on UNVA compared with bifocal IOL (MD −0.08, 95% CI −0.20 to 0.03; I2 = 84%; 2 studies, 92 participants; Analysis 1.2; Figure 4). There was considerable statistical heterogeneity, and the certainty of the evidence was very low, downgraded for risk of bias, imprecision, and inconsistency. We observed similar findings at six months (MD −0.01, 95% CI −0.05 to 0.02; I2 = 50%; 5 studies, 257 participants; Analysis 1.2; Figure 4) and at one year (MD 0.01, 95% CI −0.04 to 0.06; I2 = 0%; 2 studies, 107 participants; Analysis 1.2; Figure 4). Estimates at both time points were imprecise. The certainty of the evidence was very low at six months (downgraded for risk of bias, imprecision, and inconsistency) and low at one year (downgraded for imprecision and risk of bias).
Forest plot of comparison: 1 Trifocal versus bifocal intraocular lenses after cataract extraction, outcome: 1.2 Mean uncorrected near visual acuity (LogMAR).
Mean uncorrected intermediate visual acuity (UIVA)
At three months, data were available for two studies. Participants treated with trifocal IOL implantation may experience more improvement in UIVA than those treated with bifocal IOL (MD −0.19, 95% CI −0.29 to −0.09; I2 = 52%; 2 studies, 92 participants; Analysis 1.3; Figure 5). The certainty of the evidence was low, downgraded for risk of bias and imprecision. Although the observed beneficial effect of trifocal IOL implantation disappeared at six months (MD −0.15, 95% CI −0.31 to 0.01; I2 = 97%; 5 studies, 256 participants; Analysis 1.3; Figure 5), the data should be interpreted with caution, as the I2 statistic indicates substantial heterogeneity. Data from two studies suggest that trifocal IOL implantation may improve UIVA more than bifocal IOL at one year (MD −0.16, 95% CI −0.22 to −0.10; I2 = 0%; 2 studies, 107 participants; Analysis 1.3; Figure 5). The certainty of the evidence was very low at six months (downgraded for risk of bias, imprecision, and inconsistency) and low at one year (downgraded for risk of bias and imprecision).
Forest plot of comparison: 1 Trifocal versus bifocal intraocular lenses after cataract extraction, outcome: 1.3 Mean uncorrected intermediate visual acuity (LogMAR).
Mean best‐corrected distance visual acuity (BCDVA)
At three months, available data from two studies suggested that trifocal IOL implantation had no effect on BCDVA compared to bifocal IOL (MD −0.03, 95% CI −0.06 to 0.01; I2 = 0%; 2 studies, 92 participants; Analysis 1.4; Figure 6). Pooled analysis of six studies suggested that trifocal IOL implantation may have a slight effect on BCDVA at six months compared with bifocal IOL (MD −0.01, 95% CI −0.02 to 0.00; I2 = 2%; 6 studies, 352 participants; Analysis 1.4; Figure 6). The estimates at both time points were also imprecise. The certainty of the evidence at both three months and six months was low, downgraded for risk of bias and imprecision. At one year, available data from two studies suggested no evidence of an effect of trifocal IOL compared with bifocal IOL (MD 0.00, 95% CI −0.03 to 0.04; I2 = 0%; 2 studies, 107 participants; Analysis 1.4; Figure 6). The certainty of the evidence was low, downgraded for risk of bias and imprecision.
Forest plot of comparison: 1 Trifocal versus bifocal intraocular lenses after cataract extraction, outcome: 1.4 Mean best‐corrected distance visual acuity (LogMAR).
Contrast sensitivity
Three studies assessed contrast sensitivity. However, at three months only one study reported data on mean contrast sensitivity in log contrast sensitivity function (logCSF) scale under both photopic and mesopic conditions at four spatial frequencies: 3, 6, 12, and 18 cycles per degree (Jonker 2015). Point estimates suggested no evidence of a difference in contrast sensitivity between groups under photopic conditions at all four spatial frequencies. The certainty of the evidence was very low, downgraded for risk of bias and imprecision (−2). However, when contrast sensitivity was measured under mesopic conditions, point estimates suggested that trifocal IOL implantation showed no evidence of a difference in contrast sensitivity at all spatial frequencies (data not shown), except one (6 cycles per degree), where participants treated with trifocal IOL did worse compared with those in the bifocal IOL group (MD −0.19, 95% CI −0.33 to −0.05; 1 study, 25 participants; Analysis 1.5). The certainty of the evidence was low, downgraded for risk of bias and imprecision. At three months, Mojzis 2014 observed no evidence of a difference between groups for contrast sensitivity for most frequencies analyzed. The authors of Mojzis 2017 reported observing minimal difference in contrast sensitivity between groups, which was significant only for low to medium spatial frequencies, at six months but not at one year.
Quality of life
One study examined vision‐related quality of life using the NEI‐VFQ‐25 at six months (Bozkurt Gencer 2021). Analysis suggested no evidence of a difference between trifocal and bifocal IOLs (MD 1.41, 95% CI −1.78 to 4.60; 1 study, 40 participants; Analysis 1.6). One study evaluated patient satisfaction and quality of life using the VF‐14 questionnaire (Gil 2019), and three studies assessed other visual function such as reading speed (Jonker 2015), reading performance (Kaymak 2017), and spectacle independence (Cochener 2016; Jonker 2015). However, none of these studies provided data in a format that permitted formal analysis. In Jonker 2015, reading speed was assessed at six months using the Radner reading chart. Investigators found no evidence of a difference between groups in mean reading distance, mean reading speed, or maximum reading speed under 70% and 100% contrast. At six months, Kaymak 2017 observed no evidence of a difference between groups in reading performance. Similarly, investigators found no evidence of a difference between groups in spectacle dependence score at all distances (P ≥ 0.296) (Kaymak 2017). At six months, Cochener 2016 found that spectacle independence and patient satisfaction may be higher in the trifocal compared with the bifocal IOL group. In addition, Jonker 2015 observed that at six months all participants were spectacle‐free for distance, and 80% of participants in the trifocal group (12 participants) reported complete spectacle independence at six months compared to 50% (6 participants) in the bifocal group, suggesting good‐quality vision. The certainty of the evidence for these outcomes in each study at the time points examined was low, downgraded for risk of bias and imprecision.
Adverse events
One study reported that no intraoperative or postoperative complications had occurred (Cochener 2016). Jonker 2015 reported that "side effects of trifocal IOLs such as glare and halos was similar to preoperative measurements." Another study reported that four eyes (11.4%) in the bifocal group and three eyes (7.5%) in the trifocal group developed significant posterior capsular opacification requiring YAG capsulotomy (Mojzis 2017). In Bozkurt Gencer 2021, four (20%) participants in trifocal group and 10 (50%) participants in bifocal group had glare complaints (risk ratio 0.40, 95% CI 0.15 to 1.07; 40 participants; Analysis 1.7). Gil 2019 reported that no posterior capsular opacification was observed at six months. The remaining two studies did not report on adverse events such as glare/halos. The certainty of the evidence for adverse events was low, downgraded for risk of bias and imprecision.
Discussion
Summary of main results
We identified two new trials in this update, for a total of seven studies with 331 participants that compared trifocal versus bifocal IOLs implantation during cataract surgery among participants 30 years or older with cataract and presbyopia. After reviewing the available evidence, we summarized our findings in summary of findings Table 1 for the main comparison.
The evidence was not consistent across outcomes and time points. Moderate‐certainty evidence shows that trifocal IOL implantation probably results in more improvement in UDVA at three and six months after surgery than bifocal IOL, but with no evidence of an effect at one year. We found no evidence of a difference in UNVA between trifocal and bifocal IOL implantation at three months, six months, and one year after surgery. Trifocal IOL implantation may improve UIVA compared with bifocal IOL at three months and one year, but the evidence is very uncertain at six months after surgery. Trifocal IOL implantation showed a slight effect on BCDVA compared with bifocal IOL at six months, but not at three months and one year. There was also no evidence of a difference between trifocal and bifocal IOL implantation for contrast sensitivity, although the data from one study suggested that contrast sensitivity may be worse in the trifocal group at three months in one of the four spatial frequencies under mesopic conditions. There was no evidence of an important difference in vision‐related quality of life or visual function, except spectacle independence and patient satisfaction, which favored the trifocal IOL group. Treatment with trifocal IOL appears to be well tolerated, as fewer eyes in the trifocal compared with the bifocal IOL group developed complications such as glare complaints and significant posterior capsular opacification requiring YAG capsulotomy.
Overall completeness and applicability of evidence
The included studies differed in a number of characteristics. Participants were recruited predominantly in Europe, and most participants were women. The evidence from this review may not be applicable to certain racial groups or genders, as well as people with certain ocular pathologies, as these groups were either underrepresented or excluded in the primary studies that contributed data to the review.
Quality of the evidence
The certainty of the evidence was mostly low across the outcomes examined in this review. Most studies did not report how the random sequence was generated or the method of concealing treatment allocation. We assessed most studies as at unclear risk of performance and detection bias. Attrition bias was unclear for most studies. However, risk of bias for selective outcome reporting was low for most studies. Other limitations to the certainty of the evidence included wide confidence interval of the effect estimates, resulting in downgrading for risk of bias and imprecision. In addition to aspects of study design, we considered financial support as a potential source of bias. Two of the seven included studies were sponsored by manufacturers of one of the study lenses under investigation, and some study investigators reported that they had a financial relationship with industry that marketed the study lens.
Potential biases in the review process
We performed a very broad literature search of multiple electronic databases with the help of an Information Specialist. To reduce potential bias arising during study selection, risk of bias assessment, and data extraction, two review authors, working independently, completed all steps of the review process outlined in the Methods section of this review. We decided post hoc to include studies with a two‐eye design; none of these studies reported on how correlation between eyes from the two‐eye design was accounted for in their analysis. Analyses that do not account for the correlation between eyes may appear to have more information than there actually is, and can overestimate the treatment effect with a false increase in precision (Murdoch 1998). Our post hoc decision to include data from studies with a two‐eye design may have artificially overestimated the magnitude of the effect estimate, since four of the seven included studies in this review used a two‐eye design.
Agreements and disagreements with other studies or reviews
Our review is generally in agreement with other systematic reviews comparing bifocal and trifocal IOL. Jin 2019 included four RCTs and four cohort studies (489 eyes, 245 participants) that compared trifocal with bifocal IOL implantation among participants undergoing cataract surgery. The study authors found that trifocal IOLs improve intermediate visual acuity, but that there was no difference between groups in distance or near visual acuity. Similar results were reported by Xu and colleagues (Xu 2017), who found improvement in intermediate vision in favor of trifocal compared with bifocal IOL. They observed that distant and near vision did not differ between groups at six months postoperatively (Xu 2017). Yoon 2018 also reported improvement in intermediate vision and no evidence of a difference between trifocal and bifocal IOL implantation for distance and near vision. Additionally, evidence from Yang 2018 supported no evidence of a difference between trifocal and bifocal IOL in distance and near vision. Shen 2017 also observed results in favor of trifocal IOL implantation for intermediate vision.
Zhang 2021 included nine studies with 440 participants undergoing cataract surgery in a recent systematic review. They reported that the trifocal IOL group showed improvement compared with the bifocal IOL group in near and intermediate vision, but not distance vision (time points varied from three to 12 months). The difference in findings from our review was due to study selection. We excluded Postolache 2015 because it was not a RCT, and did not include Bilbao‐Calabuig 2016 because it applied mix‐and‐match implantation in the bifocal group (different bifocal in the same participant). Additionally, Zhang 2021 separately included Kaymak 2017 and Alió 2018 (under the study references of Kaymak 2017) in the meta‐analyses, although these two studies used the same cohorts.
Study flow diagram.
Risk of bias summary: review authors' judgements about each risk of bias item for each included study.
Forest plot of comparison: 1 Trifocal versus bifocal intraocular lenses after cataract extraction, outcome: 1.1 Mean uncorrected distance visual acuity (LogMAR).
Forest plot of comparison: 1 Trifocal versus bifocal intraocular lenses after cataract extraction, outcome: 1.2 Mean uncorrected near visual acuity (LogMAR).
Forest plot of comparison: 1 Trifocal versus bifocal intraocular lenses after cataract extraction, outcome: 1.3 Mean uncorrected intermediate visual acuity (LogMAR).
Forest plot of comparison: 1 Trifocal versus bifocal intraocular lenses after cataract extraction, outcome: 1.4 Mean best‐corrected distance visual acuity (LogMAR).
Comparison 1: Trifocal versus bifocal intraocular lenses after cataract extraction, Outcome 1: Mean uncorrected distance visual acuity (LogMAR)
Comparison 1: Trifocal versus bifocal intraocular lenses after cataract extraction, Outcome 2: Mean uncorrected near visual acuity (LogMAR)
Comparison 1: Trifocal versus bifocal intraocular lenses after cataract extraction, Outcome 3: Mean uncorrected intermediate visual acuity (LogMAR)
Comparison 1: Trifocal versus bifocal intraocular lenses after cataract extraction, Outcome 4: Mean best‐corrected distance acuity (LogMAR)
Comparison 1: Trifocal versus bifocal intraocular lenses after cataract extraction, Outcome 5: Mean contrast sensitivity
Comparison 1: Trifocal versus bifocal intraocular lenses after cataract extraction, Outcome 6: Mean quality of life
Comparison 1: Trifocal versus bifocal intraocular lenses after cataract extraction, Outcome 7: Adverse outcomes
| Trifocal intraocular lenses versus bifocal intraocular lenses after cataract extraction among participants with presbyopia | ||||||
| Patient or population: people (> 30 years) with cataract and presbyopia | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with bifocal IOL | Risk with trifocal IOL | |||||
| Mean uncorrected distance visual acuity (LogMAR (1 year) | The mean uncorrected distance visual acuity (LogMAR) at 1 year was −0.01 to 0.01 LogMAR. | MD 0 LogMAR | ‐ | 107 | ⊕⊕⊝⊝ |
|
| Mean uncorrected near visual acuity (LogMAR) (1 year) | The mean uncorrected near visual acuity (LogMAR) at 1 year was 0.13 to 0.19 LogMAR. | MD 0.01 LogMAR | ‐ | 107 | ⊕⊕⊝⊝ |
|
| Mean uncorrected intermediate visual acuity (LogMAR) (1 year) | The mean uncorrected intermediate visual acuity (LogMAR) at 1 year was 0.25 to 0.26 LogMAR. | MD −0.16 LogMAR | ‐ | 107 | ⊕⊕⊝⊝ |
|
| Mean best‐corrected distance acuity (LogMAR) (1 year) | The mean best‐corrected distance acuity (LogMAR) at 1 year was −0.03 to −0.01 LogMAR. | MD 0.00 LogMAR | ‐ | 107 | ⊕⊕⊝⊝ |
|
| Mean contrast sensitivity (1 year) | No study reported this outcome at 1 year.
| ‐ | ‐ | 1 study reported that contrast sensitivity did not differ between groups under photopic conditions, but may be worse in the trifocal group in 1 of the 4 frequencies under mesopic conditions at 3 months (MD −0.19, 95% CI −0.33 to −0.05; n = 25). | ||
| Mean quality of life or visual function (measured using Visual Function Index‐14 tool) (1 year) | No study reported this outcome at 1 year. | ‐ | ‐ | 1 study examined vision‐related quality of life using the NEI‐VFQ‐25 at 6 months and found no evidence of a difference between trifocal and bifocal IOLs (MD 1.41, 95% CI −1.78 to 4.60; 40 participants). | ||
| Adverse events (1 year) | See comment | ‐ | ‐ | 129 (2 RCTs) | ⊕⊕⊝⊝ | 1 study reported no intraoperative or postoperative complications; in the other study, 4 eyes (11.4%) in the bifocal group and 3 eyes (7.5%) in the trifocal group developed significant posterior capsular opacification requiring YAG capsulotomy. |
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; IOL: intraocular lens; LogMAR: logarithm of the minimum angle of resolution; MD: mean difference; NEI‐VFQ‐25: 25‐item National Eye Institute Visual Function Questionnaire; RCT: randomized controlled trial | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1Downgraded for risk of bias (one level), as most domains were judged as at unclear risk of bias. | ||||||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1.1 Mean uncorrected distance visual acuity (LogMAR) Show forest plot | 6 | Mean Difference (IV, Random, 95% CI) | Subtotals only | |
| 1.1.1 3 months | 2 | 92 | Mean Difference (IV, Random, 95% CI) | ‐0.04 [‐0.08, ‐0.00] |
| 1.1.2 6 months | 5 | 257 | Mean Difference (IV, Random, 95% CI) | ‐0.04 [‐0.07, ‐0.00] |
| 1.1.3 12 months | 2 | 107 | Mean Difference (IV, Random, 95% CI) | ‐0.00 [‐0.04, 0.04] |
| 1.2 Mean uncorrected near visual acuity (LogMAR) Show forest plot | 6 | Mean Difference (IV, Random, 95% CI) | Subtotals only | |
| 1.2.1 3 months | 2 | 92 | Mean Difference (IV, Random, 95% CI) | ‐0.08 [‐0.20, 0.03] |
| 1.2.2 6 months | 5 | 257 | Mean Difference (IV, Random, 95% CI) | ‐0.01 [‐0.05, 0.02] |
| 1.2.3 12 months | 2 | 107 | Mean Difference (IV, Random, 95% CI) | 0.01 [‐0.04, 0.06] |
| 1.3 Mean uncorrected intermediate visual acuity (LogMAR) Show forest plot | 6 | Mean Difference (IV, Random, 95% CI) | Subtotals only | |
| 1.3.1 3 months | 2 | 92 | Mean Difference (IV, Random, 95% CI) | ‐0.19 [‐0.29, ‐0.09] |
| 1.3.2 6 months | 5 | 256 | Mean Difference (IV, Random, 95% CI) | ‐0.15 [‐0.31, 0.01] |
| 1.3.3 12 months | 2 | 107 | Mean Difference (IV, Random, 95% CI) | ‐0.16 [‐0.22, ‐0.10] |
| 1.4 Mean best‐corrected distance acuity (LogMAR) Show forest plot | 7 | Mean Difference (IV, Random, 95% CI) | Subtotals only | |
| 1.4.1 3 months | 2 | 92 | Mean Difference (IV, Random, 95% CI) | ‐0.03 [‐0.06, 0.01] |
| 1.4.2 6 months | 6 | 352 | Mean Difference (IV, Random, 95% CI) | ‐0.01 [‐0.02, 0.00] |
| 1.4.3 12 months | 2 | 107 | Mean Difference (IV, Random, 95% CI) | 0.00 [‐0.03, 0.04] |
| 1.5 Mean contrast sensitivity Show forest plot | 1 | Mean Difference (IV, Random, 95% CI) | Totals not selected | |
| 1.5.1 Mesopic: 6 months | 1 | Mean Difference (IV, Random, 95% CI) | Totals not selected | |
| 1.6 Mean quality of life Show forest plot | 1 | Mean Difference (IV, Fixed, 95% CI) | Subtotals only | |
| 1.7 Adverse outcomes Show forest plot | 1 | Risk Ratio (M‐H, Fixed, 95% CI) | Totals not selected | |
| 1.7.1 Visual disturbance | 1 | Risk Ratio (M‐H, Fixed, 95% CI) | Totals not selected | |
