title: Extended scan depth optical coherence tomography for evaluating ocular surface shape.
abstract: Spectral domain optical coherence tomography (SD-OCT) with extended scan depth makes it possible for quantitative measurement of the entire ocular surface shape. We proposed a novel method for ocular surface shape measurement using a custom-built anterior segment SD-OCT, which will serve on the contact lens fitting. A crosshair alignment system was applied to reduce the misalignment and tilting of the eye. An algorithm was developed to automatically segment the ocular surface. We also described the correction of the image distortion from the segmented dataset induced by the nontelecentric scanning system and tested the accuracy and repeatability. The results showed high accuracy of SD-OCT in measuring a bicurved test surface with a maximum height error of 17.4 μm. The repeatability of in vivo measurement was also good. The standard deviations of the height measurement within a 14-mm wide range were all less than 35 μm. This work demonstrates the feasibility of using extended depth SD-OCT to perform noninvasive evaluation of the ocular surface shape.
authors.affiliation: Department of Ophthalmology, University of Miami, Bascom Palmer Eye Institute, 1638 NW 10th Avenue, Miami, Florida 33136, USA.
authors.forename: Meixiao
authors.initials: M
authors.lastname: Shen
authors.forename: Lele
authors.initials: L
authors.lastname: Cui
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Dexi
authors.initials: D
authors.lastname: Zhu
authors.forename: Michael R
authors.initials: MR
authors.lastname: Wang
authors.forename: Jianhua
authors.initials: J
authors.lastname: Wang
mesh_terms: D000465:Algorithms; D003315:Cornea / Q000033:anatomy & histology*; D019781:Corneal Topography / Q000295:instrumentation*; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation*; D021621:Imaging, Three-Dimensional / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence / Q000295:instrumentation*