Examination of the Corneal Endothelium in Patients With Congenital Aniridia With a PAX6 Mutation Using In Vivo Confocal Laser Scanning Microscopy

Purpose: In PAX6 syndrome, it is still not clear, whether prenatally, parallel to the iris tissue developmental anomaly, there is neural ectodermal, neural crest, or mesodermal cell deposition at the corneal endothelium, affecting endothelial structure and function. In addition, because of the postnatal corneal inflammation and commonly appearing secondary glaucoma, progressive endothelial changes are expected. Our purpose was to study the corneal endothelium in subjects with PAX6 aniridia, using in vivo confocal laser scanning microscopy. Methods: Twenty-seven eyes of 16 subjects with congenital aniridia (age 28.25 +/- 16.32 [11-59] years, 8 [50%] female) and 40 eyes of 26 healthy subjects (age 33.8 +/- 15.2 [14-67] years, 17 [58.6%] females) were examined. Aniridia-associated keratopathy and iris malformation were graded, and means of endothelial cell density, cell area, cell diameter, spatial pattern of cell centroids (Clark-Evans index), polygonality, neighbor count, percentage of hexagonal cells, and endothelial deposit number were determined by in vivo confocal laser scanning microscopy. Results: Mean cell diameter and mean Clark-Evans index were significantly lower (P = 0.049; P = 0.008) in congenital aniridia eyes than in controls. There were hyperreflective endothelial deposits in congenital aniridia eyes but not in controls (P < 0.001). Only aniridia-associated keratopathy grade correlated positively with mean endothelial deposit number (P = 0.017). Conclusions: In congenital aniridia, the corneal endothelium might possess a slightly better quality and greater reserves than in healthy subjects. Corneal endothelial deposition seems to be independent from developmental abnormalities but may be related to up to date undescribed endothelial inflammatory or metabolic changes.