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A. Rothstein, J. Wang, S. Ching, S. Chung; Corneal Front And Back Curvatures And Thickness By Optical Coherence Tomography And Orbscan . Invest. Ophthalmol. Vis. Sci. 2006;47(13):1351.
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Optical coherence tomography has been used clinically to image the retina and optic nerve. The use of this technique is being explored for the cornea and anterior segment. In this preliminary study, we evaluated the relationship between corneal optical coherence tomography (OCT) and Orbscan in measuring corneal front curvature, back curvature and central corneal thickness .
The method using our custom built anterior segment OCT in measuring front and back curvatures and central thickness was validated using a PMMA lens with known front and back curves and thickness. OCT and Orbscan were then used to measure corneal front and back curvatures and central thickness of 7 post–LASIK (46–53 months) eyes and 9 normal control eyes. Custom software was used to process the OCT images (10 mm scan width at horizontal meridian) to yield the results, which were compared with the best fit sphere (BFS) obtained with Orbscan.
For the purposes of statistical analysis, control and post–LASIK eyes were analyzed as one group due to the small sample size. Mean front surface curvatures with OCT and Orbscan were 8.01mm (SD 0.33) and 8.05mm (SD 0.21), respectively, with a correlation of 0.76. Mean back surface curvatures with OCT and Orbscan were 6.71mm (SD 0.40) and 6.45mm (SD 0.16), respectively, with a correlation of 0.65. Central corneal thicknesses were 525.5um (SD 32.0) with OCT and 509.3um (SD 34.2) with Orbscan (correlation of 0.83).
The preliminary data suggests that corneal OCT may be useful in providing measurements of corneal front curvature, back curvature, and central corneal thickness. The OCT results correlate well with Orbscan values. A large sample size is needed to further study the relationship between these two modalities.
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