Lens Epithelial Surface Disorders in Exfoliation Syndrome: A Scanning and Transmission Electron Microscopy Study

Abstract

Background: Hydrodissection was recently reported to occur more easily in patients with exfoliation syndrome (XFS). Transmission electron microscopy (TEM) studies have already revealed alterations of the lens epithelial cells (LECs) and their apical membrane towards the lens fibers. Objective: The aim of this work was to examine the three-dimensional appearance of the lens epithelium in patients with XFS. Methods: Fourteen patients with senile cataract, 7 of whom had XFS, were included. Anterior lens capsules (aLCs) were obtained with continuous curvilinear capsulorrhexis (CCC) during phacoemulsification and were examined with scanning electron microscopy (SEM) and TEM. Results: Exfoliation samples exhibited an overall more irregular apical surface of the lens epithelium compared to control aLCs. The height of LECs varied extensively. On the apical surface of LECs, amorphous, crystalline-like, or microgranular extracellular material and membranous, oval-shaped structures were documented with SEM. All findings were connected to corresponding observations with TEM and were not correlated to the type of cataract. Conclusions: In XFS patients, the lens epithelial surface exhibited a highly irregular margin, with extracellular material covering the apical membrane of LECs. We suggest that XFS probably causes both epithelial and lens fiber degeneration which, during CCC and mechanical extraction of the aLC from the lens cortex, result in diverse alterations.

Structural Characteristics of the Lens in Presenile Cataract

“…Very often there was more than one layer of cells ( 21 ). However, in exfoliation syndrome, SEM did not show the dents on the aLECs as described in our studies ( 20 ). Large intercellular and a few intracellular vacuoles were also seen in the anterior part of the epithelium, both light- and electron-microscopically in senile cataract lenses ( 23 ).…”

“…However, there are very few recent research that studied SEM and TEM features of the lens epithelium in senile cataracts and they do not distinguish cortical from nuclear senile cataracts, whereas cortical cataracts would be more relevant to compare. These document irregular apical surfaces of the lens epithelium ( 20 – 22 ). TEM examination revealed ultrastructural abnormalities, such as transparent vacuoles of various sizes that were detected between the cells and between cells and the basal membrane, influencing the appearance of both the nucleus and the whole cell, and were detected in all patients with age-related cataracts.…”