Abstract
Purpose: :
To compare epithelial, stromal, and total corneal volume in normal and keratoconic eyes.
Methods: :
OCT Pachymetry scans of 8 eyes from keratoconus patients and 8 eyes from normal patients were collected using the OptoVue RTVue® scanner. Each image covers a diameter of 6mm. Each set of images was segmented to determine the anterior corneal boundary, epithelial-Bowman’s boundary, and posterior corneal boundary and analyzed to calculate epithelial, stromal, and total corneal volume using a custom-written computer algorithm.
Results: :
Eight eyes of eight patients were scanned in preparation for UV cross-linking procedure (3 eyes OD, 5 eyes OS). Eight eyes of four patients served as normal controls (4 eyes OD, 4 eyes OS). Epithelial volume for keratoconus eyes was a mean ± SD of 3.3 ± 0.1mm3 and for normal eyes was a mean ± SD of 3.4 ± 0.05mm3(p=0.40). Stromal volume for keratoconus eyes was a mean ± SD of 30.8 ± 6.8mm3 and for normal eyes was a mean ± SD of 34.5 ± 15.9mm3. Stromal volume was significantly lower in keratoconus eyes (p= 0.04). Stromal volume for keratoconus eyes was a mean ± SD of 34.1 ± 6.6 mm3 and for normal eyes was a mean ± SD of 37.9 ± 17.0 mm3. Total cornea volume was also significantly lower for keratoconic eyes (p=0.04).
Conclusions: :
Stromal and total corneal volumes were both significantly decreased in keratoconic eyes. Epithelial volume was conserved in keratoconus but demonstrated less consistent thickness pattern. These differences can affect interpretation of anterior surface topography and may bear pathologic and diagnostic significance.
Keywords: keratoconus • cornea: stroma and keratocytes