Fibril density reduction in keratoconic corneas

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Corneal Science

Background:

• Keratoconus is a progressive eye condition characterized by thinning and irregular bulging of the cornea.
• Understanding changes in corneal microstructure, specifically collagen fibril density, is crucial for diagnosing and managing keratoconus.
• Current methods may not fully capture the localized microstructural alterations within the keratoconic cone.

Purpose of the Study:

• To quantify the reduction in collagen fibril density within the central cone of keratoconic corneas.
• To develop a method for estimating collagen fibril density changes using microstructure and videokeratography data.
• To correlate the degree of collagen reduction with clinical parameters like cone area, corneal thickness, and refractive power.

Main Methods:

• Acquired collagen fibril distribution and topography maps from keratoconic and healthy corneas.
• Identified and calculated the area of the cone in keratoconic eyes using topographic features.
• Estimated collagen fibril density reduction by comparing keratoconic cones to healthy cornea reference maps.
• Developed a linear model correlating cone area, minimum thickness, and refractive power with fibril density reduction.

Main Results:

• Keratoconic cones exhibited a reduction in collagen fibril density by up to 35%, with a mean reduction of 17 ± 10%.
• A strong linear correlation (R² = 0.95, p < 0.001) was found between the magnitude of density reduction and clinical parameters.
• No significant differences in fibril arrangement were observed outside the cone area between healthy and keratoconic corneas.

Conclusions:

• The study presents a reliable method to predict mean collagen fibril density in the keratoconic cone area.
• The findings highlight significant localized microstructural changes in keratoconus.
• The developed technique can be integrated into finite-element models for simulating corneal biomechanics and stiffness in keratoconus.