Abstract
Purpose :
Morphologically, the cornea has 3 zones: Central (CZ), Mid Peripheral (MPZ) and Peripheral (PZ).
Excrescences of Descemet's membrane (EDM) characterize FED, and with their progression increase in quantity and size and initially affect the CZ endothelial mosaic (EM) to later the MPZ and PZ. Different profiles of EM involvement at different corneal zones indicate the need to grade these areas, from most to least affected. Non-contact specular microscopes (SM) evaluate the CZ, central part of the MPZ, and never the PZ.
Purpose: To study EM deterioration using an objective CESSS for FED with SM to confirm previous studies which shows that exposed areas of the cornea can show worse endothelial patterns; Identify EM zones where it is possible and not to calculate corneal endothelial density.
Methods :
Retrospective cross-sectional study, 372 eyes, 186 patients with FED. Age range 25-88 years old and average of 59±12 years old, Female 140 (75.26%) and male 46 (24.76%).
Contact specular microscopy (2013-2022) at Clínica de Olhos Prof. Dr. Fernando Abib, Curitiba, Brazil with a BioOptics CSM, Oregon, USA and Cells Analyzer – Corneal Endothelial Lab, Technicall, Brazil.
EM involvement by EDM was scoring into six categories (FIGURE 1) to describe the studied zones:
Central (CZ), superior mid-periphery (SMPZ), superior (SZ), temporal (TZ), inferior (IZ), and nasal (NZ), and determine which EM zones can be included in a sampling process to calculate corneal endothelial density (CED). Results are presented by descriptive statistics.
Results :
The percentages of EM involvement in FED examined by contact SM in all studied zones (CZ, SMPZ, SZ, TZ, IZ, and NZ) are shown - Figure 2.
Corneas with zones that can be used to integrate the EM sampling process for calculating the ECD were classified as grades 1, 2 and 3: CZ 141 (37.9%), SMPZ 243 (65.32%), SZ 350 (94.08%), TZ 312 (83.87%), IZ 298 (80.1%), and NZ 323 (86.82).
Conclusions :
The most affected EM zone in the FED was the central one, the least affected were the peripheral ones and however the superior peripheral zone was much less affected than all other zones. Examining the central zone only 38% of exams be able to calculate ECD, including peripheral zones, calculate until 80 to 94% of exams. Unfortunately, non-contact specular microscopes don’t examine corneal peripheral zones.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.