Kazunori Hirasawa1, Nobuyuki Shoji2. 1. Department of Orthoptics and Visual Science, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan. 2. Department of Ophthalmology, School of medicine, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan.
Abstract
AIM: To evaluate the influence of corneal power on circumpapillary retinal nerve fiber layer (cpRNFL) and optic nerve head (ONH) measurements by spectral-domain optical coherence tomography (SD-OCT). METHODS: Twenty-five eyes of 25 healthy participants (mean age 23.6±3.6y) were imaged by SD-OCT using horizontal raster scans. Disposable soft contact lenses of different powers (from -11 to +5 diopters including 0 diopter) were worn to induce 2-diopter changes in corneal power. Differences in the cpRNFL and ONH measurements per diopter of change in corneal power were analyzed. RESULTS: As corneal power increased by 1 diopter, total and quadrant cpRNFL thicknesses, except for the nasal sector, decreased by --0.19 to -0.32 µm (P<0.01). Furthermore, the disc, cup, and rim areas decreased by -0.017, -0.007, and -0.015 mm2, respectively (P<0.001); the cup and rim volumes decreased by -0.0013 and -0.006 mm3, respectively (P<0.01); and the vertical and horizontal disc diameters decreased by -0.006 and -0.007 mm, respectively (P<0.001). CONCLUSION: For more precise OCT imaging, the ocular magnification should be corrected by considering both the axial length and corneal power. However, the effect of corneal power changes on cpRNFL thickness and ONH topography are small when compare with those of the axial length.
AIM: To evaluate the influence of corneal power on circumpapillary retinal nerve fiber layer (cpRNFL) and optic nerve head (ONH) measurements by spectral-domain optical coherence tomography (SD-OCT). METHODS: Twenty-five eyes of 25 healthy participants (mean age 23.6±3.6y) were imaged by SD-OCT using horizontal raster scans. Disposable soft contact lenses of different powers (from -11 to +5 diopters including 0 diopter) were worn to induce 2-diopter changes in corneal power. Differences in the cpRNFL and ONH measurements per diopter of change in corneal power were analyzed. RESULTS: As corneal power increased by 1 diopter, total and quadrant cpRNFL thicknesses, except for the nasal sector, decreased by --0.19 to -0.32 µm (P<0.01). Furthermore, the disc, cup, and rim areas decreased by -0.017, -0.007, and -0.015 mm2, respectively (P<0.001); the cup and rim volumes decreased by -0.0013 and -0.006 mm3, respectively (P<0.01); and the vertical and horizontal disc diameters decreased by -0.006 and -0.007 mm, respectively (P<0.001). CONCLUSION: For more precise OCT imaging, the ocular magnification should be corrected by considering both the axial length and corneal power. However, the effect of corneal power changes on cpRNFL thickness and ONH topography are small when compare with those of the axial length.
Authors: Carol Yim Lui Cheung; Christopher Kai Shun Leung; Dusheung Lin; Chi-Pui Pang; Dennis Shun Chiu Lam Journal: Ophthalmology Date: 2008-02-21 Impact factor: 12.079
Authors: Delia Bendschneider; Ralf P Tornow; Folkert K Horn; Robert Laemmer; Christopher W Roessler; Anselm G Juenemann; Friedrich E Kruse; Christian Y Mardin Journal: J Glaucoma Date: 2010-09 Impact factor: 2.503