High-speed Optical Coherence Tomography of Corneal Opacities
Presented in part at: Association for Research in Vision and Ophthalmology Annual Meeting, May 2006, Fort Lauderdale, Florida.
Received 13 July 2006; accepted 20 October 2006. published online 16 February 2007.
Purpose
To evaluate corneal opacities with optical coherence tomography (OCT).
Design
Prospective observational case series.
Participants
Twenty-three eyes of 19 patients with corneal opacities referred to a tertiary medical center.
Methods
Twenty-three consecutive eyes with corneal opacities were imaged with a high-speed corneal OCT prototype (Carl Zeiss Meditec, Inc., Dublin, CA). The OCT system operates at a speed of 2000 axial scans per second and a wavelength of 1.3 μm. Slit-scanning tomography (Orbscan II, software version 3.12; Bausch & Lomb, Inc., Rochester, NY) and ultrasound pachymetry (Corneo-Gage Plus; Sonogage, Cleveland, OH) also were performed.
Main Outcome Measures
Central cornea thickness was measured by the 3 instruments.
Results
In eyes with central opacities (n = 17), OCT central cornea thickness measurements were statistically equivalent to ultrasound pachymetry, whereas Orbscan II measurements were significantly less than ultrasound pachymetry (difference, −132.7±143 μm; P = 0.006). The OCT and ultrasound pachymetry results were obtained for all eyes, whereas Orbscan was unable to provide readings in 4 eyes. In eyes with off-center opacities (n = 6), OCT and Orbscan II central cornea thickness measurements were statistically equivalent to ultrasound pachymetry. The OCT measurements of epithelial thickness and scar depth also were demonstrated.
Conclusions
Optical coherence tomography provides consistent pachymetry mapping, whereas Orbscan II significantly underestimates corneal thickness in the presence of central corneal scars. Optical coherence tomography could be valuable in the planning of surgical treatment of corneal scars.
Doheny Eye Institute, Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, California.
Correspondence to David Huang, MD, PhD, Doheny Eye Institute, Department of Ophthalmology, Keck School of Medicine, University of Southern California,1450 San Pablo Street, DEI 5702, Los Angeles, CA 99033.
Manuscript no. 2006-776.
Supported by the National Institutes of Health, Bethesda, Maryland (grant no. P30 EY03040), and Carl Zeiss Meditec, Inc., Dublin, California.
Dr Huang receives patent royalties for optical coherence tomography technology. Drs Huang, Li, and Tang receive research grant support from Carl Zeiss Meditec. The other authors do not have proprietary interests in the article’s topic.
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