Comparison of Morphological and Functional Corneal Endothelial Changes after Cataract Surgery under DBCS Program at a Tertiary Care Centre

Abstract

Introduction: Cataract extraction constitutes the largest workload through DBCS program in ophthalmic units in India. Both SICS & Phacoemulsification surgery are performed in a limited, confined space; however, securing adequate surgical space during cataract surgery can decrease the risk of corneal endothelial cell loss.1 Thus, anatomical and surgical factors, such as adequate Anterior Chamber Depth (ACD), are important for preserving these cells from the mechanical and thermal damage that can occur during the procedure. Under normal circumstances, corneal endothelial cells do not proliferate because they are stuck in G1 phase of cell cycle. The central corneal endothelial cell density gradually decreases at an average of about 0.6% per year, reducing approximately from 3400 cells/mm2 at age 15 to 2300 cells at age 80 years. Two important factors in maintaining corneal transparency are the number and the integrity of the corneal endothelial cells.3 Corneas with cell densities as low as 500 cells/mm2 and average cell area of approximately 2000-3000 μm2 can remain clear. Protection of corneal endothelium during cataract surgery is critical for achieving good visual outcomes. Objectives: To study the endothelial cell loss in SICS and Phacoemulsification and compare the cell loss between two surgeries and to compare morphological and functional changes in corneal endothelium between the two surgeries. Materials and methods: A comparative prospective study is performed in 200 eyes of 200 patients attending DBCS Camp at Babuji Eye Hospital and Chigateri General Hospital attached to JJM Medical College Hospital, Davanagere from July 2018 to October 2019 for cataract surgery. Patients were randomly allocated to two groups. One group underwent small incision cataract surgery and the other group underwent phacoemulsification. Corneal endothelial assessment was done for patients undergoing both the surgeries using non-contact specular microscopy Tomey EM 3000 preoperatively and postoperatively at 1 week and 6 weeks. Results: In SICS group, corneal endothelial count was 2303.0 ± 329.1 preoperatively, postoperatively it was reduced to 2068.9 ± 381.1 at 1 week and 1980.3 ± 401.5 at 6 weeks. In phacoemulsification group, it was found to be 2213.9 ± 442.3 preoperatively and which reduced to 1878.7 ± 458.3 at 1 week and 1796.4 ± 467.3 at 6 weeks postoperatively. Cases in SICS group showed 10.2% loss at 1 week and 14% cell loss at 6 weeks while phacoemulsification group showed 15.1% cell loss at 1 week and 18.9% cell loss at 6 weeks. Polymegathism was increased in both the groups while hexagonality was decreased in both groups. No significant difference in functional parameters like central corneal thickness (CCT) and best corrected visual acuity (BCVA) was observed in both SICS and Phacoemulsification group at the end of 6 weeks. Conclusion: The study shows that phacoemulsification is safe procedure in experienced hands. Compared to phacoemulsification, small incision cataract surgery is associated with lower post-operative endothelial damage. It is suggested that SICS should be used in patients at risk for endothelial damage in cataract surgery.