Keratoconus diagnosis based on macro-micro corneal characteristics via optical coherence tomography.

Keratoconus is an ophthalmopathy characterized by a central thinning that commonly causes irregular astigmatism and high myopia. However, the diagnostic standards of keratoconus have not yet been well established clinically and mainly rely on macro characteristics measured through corneal topography. To describe the micro changes conveyed by collagen microstructures in the corneal stroma and provide a new insight for keratoconus, we developed a quantitative diagnostic method combining macro-micro information via in vivo optical coherence tomography (OCT). A comparison experiment was designed to confirm the feasibility of characterizing collagen organization using OCT. Macro variables, including heterogeneity in curvature and thickness of cornea, and micro variables of collagen fiber alignment, were calculated and weighted to define the keratoconus potential index (KPI) as a quantitative measure for diagnosing keratoconus and mapping disease risks of 104 participants, which showed excellent diagnostic power (with an area under the curve of 0.991) in keratoconus detection.