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PURPOSE: To determine whether optical coherence tomography (OCT) is useful for quantitative evaluation of the thickness of the rat retinal nerve fiber layer (RNFL) in an optic nerve crush model. METHODS: An OCT system was developed with a modified commercial time-domain OCT and a superluminescent diode with a bandwidth of 150 nm. Optical components were optimized to acquire rat retinal images. The right optic nerve was crushed intraorbitally with a clip. The left eye served as the untreated control. Circumpapillary OCT scans with a circle diameter of 500 microm centered on the optic disc were performed before and 1, 2, and 4 weeks after the crush. Repeatability and reproducibility of RNFL thickness measurements were evaluated. The RNFL thicknesses at 400, 500, and 600 microm from the center of the optic disc determined by linear vertical OCT scans were compared with thicknesses in retinal sections. RESULTS: The mean RNFL thicknesses in circumpapillary OCT scans were 27.9 ± 1.8, 29.2 ± 2.4, 19.9 ± 2.3, and 4.5 ± 3.6 microm before and 1, 2, and 4 weeks after the crush, respectively. RNFL thickness was unchanged 1 week after the crush, but then decreased significantly and progressively after the second week (P < 0.01). Coefficients of repeatability and reproducibility were less than 10% except for the crushed eyes at 4 weeks. RNFL thicknesses in OCT images correlated significantly with thicknesses determined histologically (r = 0.90, P < 0.001). CONCLUSIONS: OCT is a useful and valuable tool for quantitative evaluation of rat RNFL thickness.
Department of Ophthalmology and Visual Science, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan.
5.1 Rodent (Part of: 5 Experimental glaucoma; animal models)
6.9.2.2 Posterior (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis > 6.9.2 Optical coherence tomography)