Assessment of Corneal Endothelial Function
In patients with a history of endothelial dystrophy, previous ocular surgery, or trauma, additional corneal measurements may be useful. These data may aid the surgeon in counseling the patient regarding the possibility of postoperative corneal decompensation. In some cases, consideration of a combined surgery incorporating removal of the cataract and transplantation of corneal tissue may be in order.
Corneal pachymetry, a method employed to measure corneal thickness, is useful for indirectly assessing the function of the endothelium. Significantly increased central corneal thickness (>640 μm) in patients with endothelial dysfunction is associated with a greater risk of postoperative corneal decompensation.
Specular microscopy is used to determine corneal endothelial cell density per square millimeter and evaluate these cells' regularity. Because cataract surgery results in some loss of endothelial cells, the risk of postoperative corneal decompensation is increased if the preoperative endothelial cell count is low. Abnormal endothelial cell morphology, including enlargement (polymegathism) and irregularity (pleomorphism), may limit the cornea’s ability to maintain its clarity after the stress of cataract surgery. (See also BCSC Section 8, External Disease and Cornea.)
Excerpted from BCSC 2020-2021 series: Section 11 - Lens and Cataract. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.