- Design
- prospective comparative multicentre study, non-randomised group assignment, 19 centres
- Population
- 126 eyes of 98 patients with juvenile open-angle glaucoma, mean age 22.9 years (SD 8.7)
- Primary outcome
- complete and qualified surgical success at 12 months (pressure 21 mmHg or less)
- Effect
- complete success 13.3% (120°), 55.3% (240°), 64.7% (360°); hyphema 31.1%, 34.0%, 64.7% (P = 0.003)
Nineteen Chinese centres prospectively followed 126 eyes of 98 patients with juvenile open-angle glaucoma, grouped by the arc of goniotomy performed: 120, 240 or 360 degrees. Mean age was 22.9 years. Success was defined as a pressure of 21 mmHg or less, complete without medication and qualified with it.
At 12 months, complete success was 13.3% at 120 degrees, 55.3% at 240 and 64.7% at 360. The two larger arcs did not differ from each other (P = 0.447) and both were clearly better than 120 degrees (both P < 0.001). Qualified success did not separate at all (80.0%, 93.6%, 91.2%; P = 0.302), which means medication rescued most of the 120-degree failures. The 360-degree group needed fewer medications at 6 months but not at 12.
Hyphema is where the arcs diverge in the other direction: 64.7% after 360 degrees against 34.0% at 240 and 31.1% at 120 (P = 0.003). Nearly two-thirds of the largest-arc group bled.
So the case the authors make for 240 degrees is about the ratio rather than either number alone — equivalent observed efficacy to a full circumferential procedure, roughly half the hyphema, technical simplicity, and no consumable required. That last point is not incidental in settings where cost determines what is offered, and juvenile open-angle glaucoma is a significant burden in India. The design is prospective but not randomised — surgeons chose the arc — so the comparison carries the usual caveat, and the authors themselves call for randomised validation.
- Consider 240 degrees rather than 360 for goniotomy in juvenile open-angle glaucoma; observed efficacy was similar with about half the hyphema
- Do not use a 120-degree arc where the aim is medication-free control — complete success was 13.3%
- Counsel specifically about hyphema, which affected about a third at 240 degrees and two-thirds at 360
- Note that qualified success did not differ between arcs, so medication rescued most smaller-arc failures
- Treat this as a non-randomised comparison with surgeon-chosen arc size, pending randomised evidence
Why it matters
The assumption that a fuller circumferential procedure must work better does not survive the complication count.
Don't overread it
Arc size was chosen by the surgeon, not randomised, so this cannot establish that 240 degrees is as effective as 360.
The statistics, in plain English
Complete success of 55.3% against 64.7% with P = 0.447 means no difference was detected, not that the two are equal — with these group sizes a genuine 9-point difference could easily go undetected. The hyphema comparison is the more secure finding, with a large gap and P = 0.003. Because surgeons chose the arc rather than randomising it, eyes judged more severe may have received larger arcs, which would bias efficacy in favour of the smaller arcs and complications against the larger ones.
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