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Randomized clinical trials on medical treatment of glaucoma. Are they appropriate to guide clinical practice?
L Rossetti1, I Marchetti, N Orzalesi
1Eye Clinic, University of Milan, Italy.
Abstract:
A systematic quantitative and qualitative overview of published randomized clinical trials was undertaken to assess the yield of medical treatment on the outcome of patients with primary open angle glaucoma. Reports of 102 randomized clinical trials were published between 1975 and 1991, totalling about 5000 patients. Only 16% (16/102) of the trials were, however, properly designed (ie, comparing an active treatment with a placebo-treated or untreated control group) to answer the question of whether any medical treatment can effectively cure patients with primary open angle glaucoma. Pooled analysis showed a moderate yet statistically significant reduction in mean intraocular pressure (-4.9 mm Hg; 95% confidence interval [CI], -7.3 to -2.5 mm Hg); however, data on long-term visual field changes were available in only three randomized clinical trials, and their statistical combination failed to show a significant protective effect of active treatment (odds ratio, 0.75; 95% CI, 0.42 to 1.35). All of the remaining 86 randomized clinical trials looked at the effectiveness of one drug vs another in lowering intraocular pressure and were thus of no use in the overview. Practicing ophthalmologists should be aware that the effectiveness of pressure-lowering agents in the treatment of primary open angle glaucoma is still to be determined and that the vast majority of published trials are not appropriate to guide clinical practice. It is urgent to plan trials with end-point and follow-up duration that is fully relevant for the health of patients.
Insights
Medical treatments for primary open-angle glaucoma show a moderate reduction in intraocular pressure but lack evidence for long-term visual field improvement. More rigorous trials are needed to determine true treatment effectiveness.
Area of Science:
- Ophthalmology
- Clinical Trials
- Glaucoma Research
Background:
- Primary open-angle glaucoma (POAG) is a leading cause of irreversible blindness.
- Medical treatments aim to lower intraocular pressure (IOP) to prevent vision loss.
- The efficacy of current medical treatments for POAG requires robust evaluation.
Purpose of the Study:
- To systematically review randomized clinical trials (RCTs) assessing medical treatments for POAG.
- To evaluate the impact of medical interventions on patient outcomes, including IOP and visual fields.
- To identify the quality and relevance of published RCTs in guiding clinical practice.
Main Methods:
- A systematic quantitative and qualitative overview of published RCTs from 1975 to 1991.
- Inclusion criteria focused on trials assessing medical treatment for POAG.
- Analysis included pooled data on IOP and visual field changes, and trial design quality.
Main Results:
- Only 16% of 102 reviewed RCTs were properly designed to assess treatment efficacy against a control.
- Pooled analysis revealed a statistically significant reduction in mean IOP (-4.9 mm Hg).
- Data on long-term visual field changes were limited, with no significant protective effect found for active treatments.
Conclusions:
- Current evidence on the effectiveness of medical treatments for POAG is limited due to trial design.
- While IOP reduction is observed, long-term visual field preservation remains unproven by existing high-quality trials.
- There is an urgent need for well-designed RCTs with relevant endpoints and follow-up durations to guide POAG management.