Evaluation of Corneal Endothelial Cell Density Changes in Eyes with Silicone Oil Tamponade after Pars Plana Vitrectomy

Abstract

Aim To assess the changes in corneal endothelium by non-contact specular microscopy in eyes treated by pars plana vitrectomy (PPV) with temporary silicone oil (SO) tamponade with or without phacoemulsification. Patients and Methods We enrolled 24 patients, assigned into two groups: 12 patients underwent pars plana vitrectomy with SO injection (group 1) and 12 patients underwent combined phaco-vitrectomy with SO injection (group 2). All of them underwent an ophthalmological examination, which included: best corrected visual acuity (BCVA), intraocular pressure measurement, fundus examination and specular microscopy follow ups at the 1st week,1st month and 3rd month visits. Results The initial count of endothelial cell density (ECD) in group 1 was 2543.58 ± 759.62 cell/mm2 which decreased at 3rd month visit to 2299.33 ± 729.87 cell/mm2, while in group 2 was 2621.08 ± 514.50 & 2307.50 ± 575.55 cell/mm2 respectively. We found statistically significant decrease in the mean cell density (MCD) in group 1 and group 2, at the 3rd month than at the 1st week. Three months after operation, coefficient of variation (CV) was 34.58 ± 4.29 % and 35.75 ± 4.16%, hexagonality (HEX) was 46.83 ± 8.67 % and 47.83 ± 10.50%, while mean central corneal thickness (CCT) was 553.08 ± 22.13 μm and 548.17 ± 33.12 for group 1 and 2 respectively, and no corneal edema reported at the study end. Conclusion The pars plana vitrectomy (PPV) with silicone oil (SO) injection procedure caused changes in corneal endothelial cells in varying between pleomorphism (decreased HEX), polymegathism (increased CV) and endothelial cell loss. A higher incidence of CV increase (polymegathism) reported after combined phaco-vitrectomy than pars plana vitrectomy alone with silicone tamponade. We recommend SO removal after achieving the proposed tamponading action of SO to avoid SO keratopathy.