Corneal endothelial iayer changes in various stages of keratoconus and their correlation with topographic findings: a cross-sectional study

Background. Keratoconus (KCN) is a multifactorial progressive corneal disease that leads to significant disturbances in visual function. Various layers of the cornea, such as the endothelium, are affected by this condition. This study aimed to evaluate the corneal endothelial layer in different stages of the KCN and its correlation to topographic findings. Methods. It is a cross-sectional study of 110 eyes of 70 patients (28 females and 42 males) with KCN. The KCN severity staging in this study was based on the Amsler-Krumeich criteria and topographic findings. Specular microscopy was used to evaluate and compare the condition of the endothelial layer in different stages of KCN. Results. The prevalence of the various stages of KCN was 10%, 33.6%, 13.6%, and 42.8%, respectively, for stages I to IV. There was no significant difference between various stages of OCN regarding endothelial cell density and polymegethism (P=0.759 and P=0.052, respectively). However, the mean frequency of the hexagonal endothelial cells (6A) in stage IV was 7.8% lower than in stage II eyes (P=0.025). In addition, the Kmax had a positive correlation with polymegethism (P<0.001, r2=0.110) and a negative correlation with 6A (P=0.007, r2 =0.066). Conclusion. According to our findings, the progression of KCN could be associated with increased endothelial cell pleomorphism, and higher Kmax could be associated with polymegethism. However, there was no significant difference in endothelial cell density or polymegethism between the various stages of KCN. Practical Implications. Regarding the possible changes in the corneal endothelial layer with KCN progression, the pre-operative endothelial evaluations could improve the surgical plans in these patients.