Abstract
Abstract: :
Purpose:This study is proposed to verify the existence between retinitis pigmentosa and corneal alterations. Materials and Methods: Have been examined twenty corneas of 10 patients (7 males and 3 females) diagnosed whit retinite pigmentosa (based on the criteria of Fishman and Marmor), from 24 to 63 years old. The corneal examination were performed whit Confoscan Microscopy (Confoscan 3.0; Nidek Technologies). All corneal layer were examined in particular the endothelium parameters (cellular density, of polimorfismo and polimegatismo). Results: The confoscal Microscopy analysis it did not evidence no epithelial alteration; no alterations in complex Bowman’s membrane and nerve plexus. No alteration was found in stroma in both eyes; posterior stroma was examined whit more care and it did not evidence lesions. Only one patient was found to have folds in posterior stroma and microdots iper reflecting in both eyes. The nerve fibers in the middle and anterior stroma were normal with passed linear and normal thickness (4–14m); only one patient was found to have a nerve fibers with diminished thickness and course tortuous with no folds in posterior stroma and microdots iper reflecting. The average cell density of endothelium was 2850 cell/mm, the average polymegathism was 26.3% and the average pleomorphism was 64.95%. Conclusions: The corneal involvement in the patients with retinitis pigmentosa, would seem to depend directly from the progressive degeneration of the photoreceptor cells that characterizes the RP. We believe that the corneal alterations depend on the spread in the vitreo of toxic aldehydes, peroxides and lipid radicals of coming from fat acids polinsaturi from the degeneration of the photoreceptor cells, and in particular way of their external segments. The corneal metabolic enzymes (superoxide dismutase,catalase, glutathione peroxidase) have a protecting role in comparisons of toxic substances. However defense mechanisms are not sufficient in the comparisons of elevate levels of toxic substances, that act the endothelium, altering the permeability and the mechanisms of transport of the cellular membrane of endothelium cells. This study does not agree with other study that describe the corneal alteration and retinitis pigmentosa However that does not exclude that the retinitis pigmentosa can be correlated to the insorgence of corneal alterations: it must consider the genetic and phenotypic variability of this pathology, it is necessary to emphasize that in our study we have considered a reduced number of patients.
Keywords: cornea: endothelium • retinal degenerations: hereditary • photoreceptors