Laser iridotomy and the corneal endothelium: a systemic review.

This study aims to systemically review the effect of laser iridotomy on the corneal endothelium. Searches were performed for studies that either compared corneal endothelial cell density/count, corneal thickness and morphology pre- and postiridotomy, or evaluated the postiridotomy development of corneal decompensation. There were 26 eligible studies. Our review shows that the effect of laser iridotomy on the corneal endothelium has been investigated with varying results. Although it has been demonstrated to be a relatively safe procedure, there is still the potential long-term risk of corneal decompensation, for which a corneal transplantation may be indicated eventually. The longest interval between laser iridotomy and corneal decompensation reported was 8 years. Mechanisms proposed for endothelial damage include direct focal injury, thermal damage, mechanical shock waves, iris pigment dispersion, transient rise in intraocular pressure, inflammation, turbulent aqueous flow, time-dependent shear stress on endothelium, chronic breakdown of blood-aqueous barrier and damage from bubbles that settled onto the endothelium. Inherent risk factors identified were iridotrabecular contact, current or prior acute angle closure, pigmented irides, small iris-to-endothelium distance, pre-existing endothelial disease and diabetes. Intervention-related risk factors include laser type, delivery and quantity. The significance of the risk factors and their direct association with the development of corneal decompensation remain to be determined. Understanding these risk factors may allow physicians to counsel their patients better. They may offer opportunities for preventive strategies, allowing us to ensure that a procedure performed to prevent disease progression and visual loss does not cause further morbidity.

The epidemiology and incidence of cytomegalovirus retinitis in the HIV population in Singapore over 6 years.

PURPOSE: We report the epidemiologic trend of cytomegalovirus (CMV) retinitis among human immunodeficiency virus (HIV) patients in Singapore. METHODS: Our study included a retrospective case series of HIV patients with newly diagnosed CMV retinitis (CMVR) at the Singapore CDC between 2005 and 2010. Demographics, symptoms, signs, and laboratory results, including CD4 counts, were collected. Prevalence and disease trends over time were measured. RESULTS: Of 224 new patients, 92.9% were male and 96.0% were on antiretroviral therapy (ART). Median age was 43.0 years, with a median CD4 count of 38.0 cells/µL at HIV diagnosis. There was a decline in CD4 counts at diagnosis, and median duration of ART initiation from HIV diagnosis generally was earlier. Overall incidence rate was 10.4 cases per 1000 person-years (PY) and the mortality rate was 19.4 per 1000 PY. Mean survival time was 160.2 months (95% confidence interval [CI] 150.3-170.2). The 25 patients who died during the study period were older at the time of CMVR diagnosis (P = 0.003) and had lower CD4 counts (P = 0.030). Worse prognoses were associated with older age (hazard ratio [HR] 1.06, 95% CI 1.02-1.10) and shorter time lag from HIV to CMVR diagnosis (HR 0.97, 95% CI 0.95-0.99). Patients who did not receive highly active antiretroviral treatment (HAART) had a higher mortality risk (HR 4.70, 95% CI 1.54-14.33). CONCLUSIONS: The incidence rate of CMVR was decreasing with earlier initiation of ART and lower CD4 counts at HIV diagnosis. Poor prognostic factors included older age, shorter time lag from HIV to CMVR diagnosis, and the absence of HAART. Constant ophthalmologic surveillance until immune reconstitution is recommended.