Progressive change of optical coherence tomography scans in retinal degeneration slow mice

Objective: To study whether optical coherence tomography (OCT) scans correl ate retinal histologic findings with the progression of retinal degeneratio n in retinal degeneration slow (rds) mice. Methods: Sensory retinal thickness (SRT) and outer retinal thickness (ORT), representing photoreceptor cell layer, in temporal retina at a distance 1 to 2 disc diameters from the optic disc were measured using scan profile in OCT from 6 healthy mice (16 weeks old) and 2-week-old (n=6), 6-week-old (n =4), and 60-week-old (n=2) rds mice. Histologic sections were obtained from Epon-embedded retinas from the corresponding location. Results: Cross-sectional OCT images correlated to the corresponding histolo gic sections in each mouse. Both SRT and ORT of 2-week-old rds mice (150 +/ - 4 mum and 28 +/- 4 mum, respectively) lacking photoreceptor outer segment s were already shorter than those of healthy mice (174 +/- 5 mum and 37 +/- 6 mum, respectively) (P<.001). In 6-week-old mice, microscopic findings re vealed a decreased number of nuclei in the outer nuclear layer, and SRT and ORT (136 +/- 2 <mu>m and 20 +/- 1 mum, respectively) were shorter than tho se of 2-week-old rds mice (P<.001). The SRT of 60-week-old rds mice without a photoreceptor layer was remarkably reduced (120 +/- 7 <mu>m), and no ORT could be measured. Conclusion: Our findings suggest a possible relationship between SRT and OR T, as measured by OCT, and histologic change in retinal degenerative diseas es. Clinical Relevance: The quantitative analysis obtained by OCT scans may hav e potential to detect progressive change in degenerative retina and may be used in studying human retinal degeneration.