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M Miura, AE Elsner, M Osako, T Iwasaki, T Okano, M Usui; Reflection from the Internal Limiting Membrane in Scanning Laser Ophthalmoscope Images . Invest. Ophthalmol. Vis. Sci. 2002;43(13):2539.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To evaluate the internal limiting membrane (ILM) using imaging with a scanning laser ophthalmoscope. Methods: In a prospective study, six eyes of six patients with idiopathic macular holes were tested. All eyes underwent vitrectomy with ILM peeling. Retinal images of 40 deg were taken with a scanning laser ophthalmoscope (Rodenstock) using a 4 mm confocal aperture and 488, 514, 633, or 780 nm. We calculated the Michelson contrast between the area of ILM peeling and the area adjacent to ILM peeling. Michelson contrast = ( Ladj- Lilm) / ( Ladj + Lilm) Lilm: intensity at the area of ILM peeling, Ladj: intensity at the adjacent area. To avoid the influence of macular holes, the area within 5 deg from the foveola was omitted from each evaluation. Any area with manifest surgical damage, such as retinal hemorrhage, was also omitted. We compared data for corresponding areas from one month after ILM peeling to before ILM peeling. Results: Before ILM peeling, the Michelson contrasts (mean SD) were 0.059 0.078 for 488 nm, 0.017 0.086 for 514 nm, 0.009 0.052 for 633nm, and -0.016 0.041 for 780nm. After ILM peeling, the Michelson contrasts were 0.082 0.091 for 488 nm, 0.085 0.081 for 514 nm, 0.036 0.074 for 633 nm, and 0.012 0.068 for 780 nm. The Michelson contrasts after ILM peeling were significantly larger than before at 488, 514, and 633 nm (paired-t, P < 0.05). Images at 780 nm visualized deeper structures, more than ILM changes (paired-t, P = 0.88). Among the Michelson contrasts after ILM peeling, the contrast for 488 nm was significantly larger than the contrasts with 633 or 780 nm (paired-t, P < 0.05), and the contrast with 514 nm was significantly larger than the contrast with 780 nm (paired-t, P = 0.005). Conclusion: The reflection at the ILM significantly contributes to a retinal image for a large confocal aperture and 488, 514, and 633. Its contribution was relatively small with for a longer wavelength.
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