Abstract
Purpose :
Keratoconus is a bilateral and asymmetrical corneal ectasia. The pathophysiology of this particular disease has yet to be elucidated. The most common morphological features of keratoconus have been previously described. The aim of this study is to characterize histopathologic changes in cornea with keratoconus following a novel technique to reshape the ectatic cornea by means of crescent keratectomy performed with an excimer laser.
Methods :
A total of 36 corneal specimens obtained post remodeling procedure in eyes diagnosed with keratoconus were evaluated. A crescent-shaped perforation at the base allowed the laser ablation to be directed to the superficial layers of the cornea. The surgical specimens were obtained from an 8 mm diameter 360-degree keratectomy procedure. The corneas were bisected at their center, embedded in paraffin, and stained with haematoxylin and eosin (H&E) and periodic acid-Schiff (PAS). A histopathological study of the corneal epithelium, Bowman’s layer, and stromal collagen fibers was conducted.
Results :
Breaks in Bowman’s layer were the most frequent finding (89%), followed by epithelial thinning (30%), and compaction of the anterior stromal collagen fibers (19%). Superficial iron deposition and epithelial scarring, previously associated with keratoconus, were not seen in any of the specimens. Given the nature of the collecting technique (thin keratectomy), histopathological characteristics of the deeper stroma, the Descemet’s membrane, and the endothelium layer were not evaluated.
Conclusions :
The remodeling technique used in this study limited the findings to the epithelium, Bowman’s layer, and the anterior stroma of the cornea; however these findings are similar of those previously described for these areas in penetrating keratoplasty. Therefore, both corneal buttons are comparable histopathologically. The use of immunohistochemistry in this particular cohort of corneal specimens may allow the development of predictive markers of disease prognosis and response to treatment.
This is a 2020 ARVO Annual Meeting abstract.