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Christine Shieh, S. Tammy Hsu, Perry Isaac, Sandra Stinnett, Anthony N Kuo; Corneal Donor Tissue Evaluation with Optical Coherence Tomography Compared to Slit Lamp Examination. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4350.
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© ARVO (1962-2015); The Authors (2016-present)
A component of donor cornea evaluation is slit lamp examination (SLE). However, SLE requires subjective interpretation, especially when estimating the depth of cornea scars or lesions. More precise localization of lesion depth by optical coherence tomography (OCT) may allow corneas with small lesions to be used for lamellar procedures instead of being discarded (Figure A). In this study, we compared the characterization of lesions in donor corneas by OCT vs. SLE, particularly in regards to depth of the lesions.
92 donor corneas from Miracles in Sight Eye Bank were identified by eye bank technicians on SLE to have cornea lesions, defined as scars or pathologic findings affecting stroma. Lesion depth was estimated by SLE as 1-25%, 25-50%, 50-75%, or 75-100% of total cornea thickness. OCT scans (1000 A scans x 100 radial B scans) were then taken of these same corneas in their storage containers. A masked grader identified findings on OCT and excluded non-pathologic findings (e.g., cataract incision) (Figure B). The grader then measured the depth of the lesions on the OCT image. OCT lesions were then compared to the recorded SLE lesions. A test of symmetry, percent agreement, and kappa were used to assess for agreement between the depth of cornea lesions detected on OCT vs. SLE.
Estimation of lesion depth was significantly different between SLE and OCT (p< 0.0001 by test of symmetry, kappa=0.1372, percent agreement=44%). SLE was more likely to grade lesions as being deeper than OCT (48% vs. 7%, respectively). Percent agreement between SLE and OCT on the presence of lesions was 49% and Kappa = 0.129. In the 92 corneas, SLE detected 98 lesions, whereas OCT detected 149 cornea findings, 24 of which were classified as cornea lesions.
Compared to OCT, SLE is more likely to estimate lesions as extending deeper into the cornea than OCT. As OCT has higher depth resolution to better localize and characterize lesions, determination of cornea tissue suitability for lamellar procedures may be helped using OCT. Further studies are needed to determine the reason for differences between OCT and SLE for lesion depth and presence; disparities in sensitivity and specificity for OCT and SLE respectively are potential sources for the disparity.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
OCT images of two different donor corneas: (A) mid-stromal cornea lesion. (B) cataract incision scar.
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