Purpose: To evaluate the repeatability of Fourier domain optical coherence tomography (OCT) pachymetric mapping in patients with corneal opacities and to assess the reliability of Fourier domain OCT with 830 nm wavelength as a pachymetric measurement tool in opaque corneas.
Methods: A Fourier domain OCT system was used to map the corneal thickness of patients with corneal scars or dystrophy. A retrospective study of a consecutive series was conducted. The repeatability was measured using pooled standard deviation of repeated measurements. A slit-scanning tomography device provided pachymetric mapping for comparison.
Results: Seventeen eyes of 12 patients with corneal scars (7 trauma and 3 post infection) or dystrophy (2 Reis–Bucklers and 5 granular dystrophy) were included. The posterior corneal boundary was detectable in all cases. The average corneal thickness measured by OCT was 536 ± 89 μm in central 2 mm area, 553 ± 76 μm in pericentral 2- to 5-mm area, and 508 ± 93 μm for the minimum corneal thickness. The slit-scanning tomography central corneal thickness, 433 ± 111 μm, was significantly lower than OCT readings (mean difference −91.1 ± 33.3 μm, P = 0.002). Repeatability of the OCT measurements was 2.1 μm centrally and 1.2 μm pericentrally.
Conclusion: Pachymetric mapping with Fourier domain OCT was highly repeatable. Fourier domain OCT is a reliable pachymetric tool in opaque corneas. In comparison, corneal thickness measured by the slit-scanning tomography is significantly thinner than those measured by the Fourier domain OCT in the presence of corneal opacities.
*Department of Ophthalmology, Doheny Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA
†Ophthalmology Department, Kaser Al Aini Medical School, Cairo University, Cairo, Egypt
Reprints: David Huang, MD, PhD, Casey Eye Institute, 3375 SW Terwilliger Boulevard, Portland, OR (e-mail: email@example.com).
Supported by National Institutes of Health grant R01EY018184, research grant from Optovue, Inc (Freemont, CA), and Charles C. Manger III, MD, Chair in Corneal Laser Surgery Endowment.
D. Huang received stock options, patent royalty, speaker royalty, and travel support from Optovue, Inc (Fremont, CA). D. Huang and Y. Li received research grant support from Optovue. D. Huang received a royalty from an optical coherence tomography–related patent licensed to Carl Zeiss Meditec, Inc (Dublin, CA) by the Massachusetts Institute of Technology. Other authors have no proprietary interest in the topic of this article.
Received June 14, 2011
Accepted October 14, 2011