Ultrastructural analysis of collagen fibrils and proteoglycans in keratoconus.

Purpose: To investigate ultrastructural alterations in the distribution of collagen fibrils (CFs) and proteoglycans (PGs) in the keratoconus cornea.

Methods: Four normal corneas (donor age 24-75 years) and four severe and one mild keratoconus corneas (donor age 24-47 years) were fixed in 2.5% glutaraldehyde containing 0.