LONG-TERM MORPHOLOGICAL CHANGES IN THE HUMAN CORNEA LAYERS

Purpose: To describe and compare the morphology of the corneal layers from adults and aging individuals. Methods: The study was conducted with normal corneas (n = 15) of predominantly male individuals grouped into two classes (group I: < 40 years; group II: [≥] 40 years). To describe and to compare the corneas, the thickness of the layers, the integrity of the stromal lamellae and the endothelial lesions, SEM images of the central and peripheral regions of each cornea were quantified. Results: The total thickness of the cornea was largest in the periphery only for group I. The Bowman, Descemet and endothelium layers of group I were thicker at the periphery of the corneas than their respective central regions, while for group II, this difference was observed only in the Bowman layer. Comparison between groups showed that the Bowman layer was thicker (central region), while the Descemet membrane and endothelium were thinner in group II; A greater number of endothelial lesions in both regions of the corneas was observed in group II, but no difference in the total number of interlamellar slits. Conclusions: The morphological changes observed in group II could be related to the reduction in the pool of stem cell of limbus and, despite the corneas being from healthy individuals, these changes could compromise the success of transplantation. Our results point to an update of corneal uptake protocols and they may aid in the refractive surgeries interventions in individuals from different age groups.