Morphological Characterization of Human Keratoconic Corneas by SHG Microscopy

Keratoconus is an ophthalmic disease in which the cornea acquires an abnormal conical shape that prevents the correct focusing on the retina, causing visual impairment. The late diagnosis of keratoconus is among the principal causes of corneal transplantation surgery. In several previous studies, a different organization sutural lamellae was observed in keratoconic corneas compared to healthy corneas. This study is intended to investigate this anomaly by means of Second Harmonic Generation (SHG) microscopy, using an optical scheme relevant for clinical applications. In particular, we propose a method based on 3D correlation of SHG image stacks, able to appreciate statistical differences in the orientation distribution of sutural lamellae between healthy and keratoconic corneas. The proposed method offers the potential for diagnosing keratoconus in an early stage.