Purpose The present study systematically investigated and quantified histopathological changes in a series of keratoconic (Kc) corneas utilizing a physiologically formulated fixative to not further distort the already distorted diseased corneas. Methods Twelve surgically removed Kc corneal buttons were immediately preserved and processed for light and transmission electron microscopy using an established corneal protocol. Measurements were taken from the central cone and peripheral regions of the host button. The sample size examined ranged in length from 390–2608um centrally and 439–2242um peripherally. Results The average corneal thickness was 437um centrally and 559um peripherally. Epithelial thickness varied centrally from 14–92um and peripherally from 30–91um. A marked thickening of the epithelial basement membrane was noted in 58% of corneas. Centrally, anterior limiting lamina (ALL) was thinned or lost over 60% of the area examined, while peripheral cornea was also affected, but to a lesser extent. Histopathologically, posterior cornea remained undisturbed by the disease. Anteriorly in the stroma, an increased number of cells and tissue debris were encountered and some of these cells were clearly not keratocytes. Conclusions It is concluded that Kc pathology, at least initially, has a distinct anterior focus involving the epithelium, ALL and anterior stroma. The epithelium had lost its cellular uniformity and was compromised by the loss or damage to the ALL. The activity of the hitherto unreported recruited stromal cells may be to break down and remove ALL and anterior stromal lamellae leading to the overall thinning that accompanies this disease.

TCLs are a good option when trying to improve the vision of patients with low-to-moderate astigmatism given the subjective improvements in outcomes.