Purchase this article with an account.
Karolinne M. Rocha, David Xu, Chen Yan, George O. Waring IV, R Doyle Stulting, William J. Dupps, Jr.; Three Dimensional Spectral Domain Oct Analysis Of Corneal Architecture And Epithelial Thickness Profile In Corneal Collagen Crosslinking. Invest. Ophthalmol. Vis. Sci. 2012;53(14):95.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To assess the corneal architecture and epithelial thickness profile of eyes with keratoconus after corneal collagen crosslinking (CXL) using a spectral domain optical coherence tomography (OCT).
Anterior segment OCT (Optovue RTVue) was used to analyze the corneal morphology of eyes with keratoconus preoperatively, 1 and 3 months after CXL. Patients were imaged using the Anterior Segment Corneal 8 mm Cross Line and 6 mm Pachymetry scans. Scans were exported for image custom analysis to measure the topography of the anterior corneal surface, the epithelial-Bowman's transition, and the posterior corneal surface. A custom-written automated algorithm was used to automatically segment images based on intensity and gradient cues to produce 3D thickness profiles of the epithelial and stromal layers. Dewarping of scans to adjust for corneal refraction was performed; all thickness measurements were performed along the axis perpendicular to the corneal surface. Averaged epithelial thickness measurements were made at the corneal apex and 1.5 mm and 2 mm offset from the corneal apex.
17 patients with keratoconus were enrolled in a prospective, randomized, clinical trial performed under the guidelines of the U.S. Food and Drug administration. Epithelial thickness in the keratoconus showed a standard deviation in the vertical and horizontal axis ranging from 3.25 to 22.55µm and from 2.72 to 15.98µm, respectively. Epithelium was significantly thickened 1.5 to 2.5 mm below the corneal apex (p<0.001). Epithelial thickness at the corneal apex was a mean +/- STD of 49 +/- 13 um pre-operatively, 51 +/- 5.0 um 1 month post-operatively, and 50 +/- 7.7 um 3 months post-operatively. Pre-operative averaged epithelial thickness measurements were statistically thinner at the corneal apex and in the 1.5 mm and 2 mm offset locations compared to 1 month after CXL (p = .017, p=0.001, p=0.007 respectively). At 3 months postoperatively significant epithelial thickness were found at 2mm from the corneal apex.
Analysis of the epithelial thickness profile can aid interpretation of corneal curvature changes after CXL.
This PDF is available to Subscribers Only