Effects of lens extraction versus laser peripheral iridotomy on anterior segment morphology in primary angle closure suspect

Abstract

PurposeTo compare the anatomical effects on anterior segment by lens extraction (LE, phacoemulsification with posterior chamber intraocular lens implantation) and laser peripheral iridotomy (LPI) in primary angle closure suspect (PACS) eyes.MethodsThis prospective comparative cohort trial included a total of 122 consecutive patients identified as PACS aged 52 to 80\xa0years. LE or LPI was performed based on each patient’s choice. The anterior segment optical coherence tomography (ASOCT) and gonioscopy were conducted at baseline and 4\xa0weeks post-operation. Outcome measures include percentage of residual angle closure, mean angle width (modified Shaffer grade), angle opening distance (AOD), trabecular iris angle (TIA), trabecular iris space area (TISA), anterior chamber depth (ACD), iris curvature (I-Curve), lens vault (LV), intraocular pressure (IOP), and best-corrected visual acuity (BCVA).ResultsAll anterior angle parameters (AOD, TIA, and TISA) were significantly greater after LE than LPI (P\u2009<\u20090.001 for all). ACD (P\u2009<\u20090.001) increased, LV (P\u2009<\u20090.001) decreased, IOP (P\u2009<\u20090.001) decreased, and BCVA (P\u2009<\u20090.001) increased after LE. However, no significant changes were found in ACD (P\u2009=\u20090.782), LV (P\u2009=\u20090.616), IOP (P\u2009=\u20090.112), and BCVA (P\u2009=\u20090.131) after LPI. In both groups, I-Curve decreased after the operation, but the iris was flatter after LE than LPI (P\u2009<\u20090.001). Gonioscopically, the LE group achieved a larger post-operative angle width (modified Shaffer grade) than LPI (P\u2009<\u20090.001) and all anterior chamber angles were open (defined as posterior pigmented trabecular meshwork (PTM) visible with static gonioscopy) after operation. Nevertheless, after LPI, 12 eyes (20.0%) still had two or more quadrants and 32 eyes (53.3%) still had at least one quadrant in which the posterior PTM could not be observed.ConclusionsCompared with LPI, LE resulted in a wider anterior chamber angle, a deeper anterior chamber, and a lower IOP in PACS eyes. Moreover, no residual angle closure was observed after LE, which could morphologically prevent the progress of angle closure.Trial registrationChiCTR1800016511