Abstract
Purpose: :
To assess the effect of prophylactic laser iridotomy (LI) on corneal endothelial cell density in a cohort of primary angle closure suspects (PACS) over a 3-year period.
Methods: :
As part of a randomized controlled trial, subjects over the age of 50 years and diagnosed as PACS in both eyes underwent prophylactic LI in one eye, while the fellow eye served as a control. PACS was defined as an eye in which the posterior trabecular meshwork was not visible for at least 180º on non-indentation gonioscopy, with intraocular pressure ≤ 21 mm Hg, and absence of peripheral anterior synechiae, glaucomatous optic neuropathy or visual field changes compatible with glaucoma. The central corneal endothelial cell density of both eyes of all subjects was measured using non-contact specular microscope (Konan Noncon Robo SP-9000LC) at baseline and at 1 and 3 year follow-up. Inter-observer reliability was determined using intra-class correlation.
Results: :
A total of 147 PACS subjects were included. The mean age was 62.6 ± 6.6 years (50-86 years). The majority of subjects were Chinese (90.6%) and female (74.1%). In eyes that underwent LI, the endothelial cell density was significantly lower at year 1 (2451, 95% C.I, 2388-2513) (p<0.0001) and year 3 (2520 cells/mm2, 95% C.I, 2460-2580) (p<0.0001), when compared to baseline (2748 cells/mm2, 95% C.I, 2684-2811). There was also a significant decrease in endothelial cell density in fellow untreated eyes from baseline (2719 cells/mm2, 95% C.I, 2652-2785) to year 1 (2426 cells/mm2, 2363-2489) (p<0.0001) and year 3 (2517 cells/mm2, 95% C.I, 2457-2577) (p<0.0001). There was no difference in the percentage decrease in cell density at year 3, in eyes that underwent LI (8.3%) when compared to fellow eyes (7.4%) (p=0.33). Intra-class correlation for inter-observer reliability was 0.88 (95% C.I, 0.72-0.95).
Conclusions: :
In this cohort of PACS eyes, there was a decrease in endothelial cell counts in both LI treated and control eyes after 3 years, but the percentage reduction was comparable in both groups.
Clinical Trial: :
www.clinicaltrials.gov NCT00347178
Keywords: laser • cornea: endothelium • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials