Central Corneal Thickness Change with Intraocular Pressure Lowering

Abstract

Abstract: : Purpose:Central corneal thickness (CCT) has been proven an important clinical predictor of development and progression of glaucoma. Prior studies have also shown that prolonged increase in intraocular pressure (IOP) results in corneal endothelial cell loss with resultant increase in corneal thickness. We wished to investigate CCT and endothelial cell count change in response to IOP lowering by trabeculectomy. Methods: We prospectively evaluated patients undergoing primary or repeat trabeculectomy. IOP, mean CCT and endothelial cell count by specular microscopy were obtained on both eyes, with the non–operative eye serving as a control. IOP, CCT and endothelial cell counts were repeated approximately 4–6 weeks after trabeculectomy. Patients undergoing primary or repeat trabeculectomy surgery were included, while patients with pre–existing corneal pathology or those undergoing combined surgery were excluded. Variables analyzed were age, race, gender, type of glaucoma, severity of glaucoma, medications prior to and after surgery, and presence of hypertension and diabetes. Results: In the patients evaluated thus far, the mean presurgical IOP was 28 mm Hg, and mean postsurgical IOP was 7.7 mm Hg. Mean presurgical CCT was 590 microns while the postsurgical mean CCT was 565 microns, a 4.2% CCT reduction (p=0.5). Mean presurgical endothelial cell count was 2419, while mean postsurgical endothelial cell count was 2643, a 9.2% increase (p=0.5). Non–surgical eyes did not show significant changes in IOP, CCT or endothelial cell count. These findings were consistent among the demographic variables analyzed. Conclusions: Our results thus far have shown that neither CCT nor endothelial cell counts change to a statistically significant degree as compared to their preoperative values. Further study and analysis is ongoing, and is required to predict the definitive response of CCT and endothelial cell counts in eyes that have undergone trabeculectomy.

Keywords: intraocular pressure • cornea: endothelium • trabecular meshwork