Primary angle-closure glaucoma (PACG) is a leading cause of irreversible blindness worldwide. In its early stage, primary angle-closure (PAC), there is increased intraocular pressure (IOP) but no visual loss. Because the crystalline lens has a major mechanistic role, lens extraction as initial treatment may be more effective than standard treatment, laser peripheral iridotomy.
In this randomized controlled trial we compared lens extraction versus laser peripheral iridotomy (1:1). We enrolled 419 participants from 30 hospital eye services in five countries. A web-based randomization application was used. Participants were ≥ 50 years, without cataract, and newly diagnosed with (1) PAC with IOP above 30 mmHg (n=155) or (2) PACG (n=263). The primary outcome was multidimensional measuring, at three years, patient reported health status (EQ-5D), clinical efficacy (IOP) and efficiency (incremental cost effectiveness ratio [ICER] per Quality Adjusted life year [QALY] gained, from a UK health service perspective). IOP measurements were masked. An intent-to-treat analysis was conducted. (ISRCTN 44464607).
EQ-5D and IOP data at three years were complete in 351 (83.8%) and 366 (87.4%) participants, respectively. After lens extraction (n=208) EQ-5D (0·87, SD 0·12) was 0·052 higher (95% CI 0·015, 0·088, p=0·005) and IOP (16·6 mmHg, SD 3·5) was 1·18 lower (95% CI -1·99, -0·38, p = 0.004) than after laser iridotomy (n=211); ICER £14,284 for initial lens extraction versus standard care (n=285). Irreversible loss of vision was rare and occurred in one participant in the lens extraction and three in the laser iridotomy group. Ethnicity, status of fellow eye, and diagnosis did not influence the results.
Initial treatment with lens extraction for PACG and PAC (with IOP above 30 mmHg) is more effective and cost-effective than laser iridotomy after three years and should be considered as an alternative to current practice.