Laser iridotomy and the corneal endothelium: a systemic review

Abstract

ABSTRACT. 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.

Changes in Corneal Endothelial Cell after Ahmed Glaucoma Valve Implantation and Trabeculectomy: 1-Year Follow-up

“…Glaucoma drainage device implantation is currently comparable to trabeculectomy in terms of success rate and the possibility of complications [30]. However, glaucoma drainage device implantation is associated with persistent damage to the corneal endothelium [1011121631], contrary to other intraocular procedures including trabeculectomy, in which corneal damage is thought to occur only during the treatment [6789131432]. Lee et al [11] reported that the endothelial cell density of the central cornea was reduced by 12.6% at 12 months and by 15.4% at 24 months after AGV implantation.…”

Quantitative study of the microvasculature and its endothelial cells in the porcine iris

“…Considering recent evidence from both clinical and experimental studies demonstrating the increased development of nuclear cataract as a consequence of disturbed ocular oxygen gradients caused by vitrectomy (Barbazetto et al, 2004;Holekamp et al, 2005), any iris vascular abnormality would probably affect the oxygen gradients in anterior chamber with pathological consequences. Moreover, there is added potential risk of corneal decompensation after traumatic procedures such as laser iridotomy (Szumny and Szelag, 2014;Wang et al, 2014;Youm et al, 2014).…”

Changes in corneal endothelial cell density and the cumulative risk of corneal decompensation after Ahmed glaucoma valve implantation

“…To perform this function, the corneal endothelium must consist of healthy cells above a given minimum cell density. Corneal endothelial cell loss is induced by various ocular interventions, including cataract surgery,1 trabeculectomy,2 laser iridotomy,3 cyclophotocoagulation,4 pars plana vitrectomy5 and glaucoma implant surgery 6–8. Endothelial cell loss after glaucoma implant surgery is a particularly significant factor, especially with respect to its continuity 6–8…”