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Study flow diagram.
Figures and Tables -
Figure 1

Study flow diagram.

Summary of findings for the main comparison. Low‐ versus high‐energy diode trans‐scleral cyclophotocoagulation for non‐refractory glaucoma

Low‐ versus high‐energy diode transscleralcyclophotocoagulation for non‐refractory glaucoma

Population: people with primary open‐angle glaucoma and no previous glaucoma surgery

Settings: ophthalmology clinics

Intervention: low energy; 1.5 watts for 1.5 seconds x 20 spots over 360 ° (45.0 J)

Comparison: high energy; 1.25 watts for 2.5 seconds x 20 spots over 360 ° (62.5 J)

Outcomes*

Illustrative comparative risks** (95% CI)

Relative effect
(95% CI)

No of participants
(studies)

Quality of the evidence
(GRADE)

Comments

Assumed risk

Corresponding risk

High‐energy diode transscleralcyclophotocoagulation

Low‐energy diode transscleralcyclophotocoagulation

Control of intraocular pressure

462 per 1000

475 per 1000
(295 to 762)

RR 1.03 (0.64 to 1.65)

79
(1 study)

⊕⊕⊝⊝
low1, 2

Control of intraocular pressure defined as a decrease in IOP by 20% from baseline value

Mean change in intraocular pressure

On average intraocular pressure in the high energy group dropped by 3 mmHg

On average intraocular pressure in the low‐energy group was 0.5 mmHg lower than the IOP in the high‐energy group (5.79 mmHg lower to 4.79 mmHg higher)

79
(1 study)

⊕⊕⊝⊝
low1, 2

Decrease in visual acuity

205 per 1000

250 per 1000
(111 to 566)

RR 1.22 (0.54 to 2.76)

79
(1 study)

⊕⊕⊝⊝
low1, 2

Decrease in visual acuity defined as a decrease of 2 or more lines on the Snellen chart or one or more categories of visual acuity if unable to read the eye chart

Mean visual field

No visual field outcomes reported

Number of glaucoma medications after treatment

The mean number of glaucoma medications in the high energy group was 1.3

The mean number of glaucoma medications in the low energy group was 0.10 more (0.43 fewer to 0.63 more)

79
(1 study)

⊕⊕⊕⊝
moderate1

Additional glaucoma surgery

231 per 1000

175 per 1000
(72 to 425)

RR 0.76 (0.31 to 1.84)

79
(1 study)

⊕⊕⊝⊝
low1, 2

Additional glaucoma surgery defined as retreatment with cyclophotocoagulation according to randomized assignment

Adverse events: atonic pupil

311 per 1000

277 per 1000
(146 to 523)

RR 0.89 (0.47 to 1.68)

92
(1 study)

⊕⊕⊝⊝
low1, 2

Atonic pupil was the only adverse event reported by treatment group. Trial authors noted that most participants had mild to moderate pain for a few days following the procedure and many also had transient conjunctival burns (number not reported). Severe iritis occurred in 2 eyes and hyphema occurred in 3 eyes. No instances of hypotony or phthisis bulbi were reported

*All outcomes are reported for participants with at least 3 months follow‐up; mean follow‐up was 13.2 months.
**The basis for the assumed risk is the risk in the comparison group. The corresponding risk (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).
J: joule; CI: confidence interval; RR: risk ratio; mmHg: millimeter of mercury

GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

1Downgraded for risk of bias in the trial (unmasked outcome assessors and 14% attrition).
2Downgraded for imprecision in the effect estimate (wide confidence interval).

Figures and Tables -
Summary of findings for the main comparison. Low‐ versus high‐energy diode trans‐scleral cyclophotocoagulation for non‐refractory glaucoma