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Y. Tian, J.M. Tarrant, C.F. Wildsoet; Optical and Biometric Bases of Anisomyopia . Invest. Ophthalmol. Vis. Sci. 2006;47(13):3677.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate the interocular differences in ocular dimensions, corneal shape, higher order aberrations (HOA) and visual acuity in human anisomyopes.
Ten anisometropic myopes (ANISO, interocular differences in spherical equivalent refractive error (SERE) > 1.0D; SERE range: –0.25 to –5.25D, less myopic eyes; –1.75 to –7.0D, more myopic eyes) were compared with 12 isometropes (ISO, interocular differences in SERE < 0.5D; SERE range: 0.5 to –6D). All subjects were free of ocular pathology. Refractive errors were measured both subjectively and objectively (auto–refractometer), anterior chamber depth, lens thickness, vitreous chamber depth and their sum (optical axial length), by A–scan ultrasonography, corneal shape by topography and ocular aberrations by aberrometry (under cycloplegia in dark). Monocular best–corrected visual acuities (BCVA) were recorded in logMAR units. Aberrations were analyzed with Zernike polynomials for a 5 mm pupil diameter. The two groups were compared in terms of interocular differences for all measured parameters (unpaired t–test, significance level 0.05), and interocular correlations also were analyzed. Since subjective and objective refractive error measurements were highly correlated with aberrometry data (SERE: r = 0.98 and 0.98), the latter were used in analyses.
For the ANISO group but not the ISO group, there are significant interocular differences in SERE, BCVA, vitreous chamber depth, optical axial length and corneal asphericity (Table.1, Part A), and these intergroup differences are also significant (p<0.02 or less). For corneal asphericity, spherical aberration and coma, interocular correlations for the ANISO group were poor, but for the ISO group, strong (Table.1, Part B). However, neither group showed significant interocular differences in the RMSs for 3rd, 4th, 5th and total HOAs.
Analyses confirmed the axial nature of both the refractive errors and the anisomyopia. Observed differences between the ANISO and ISO groups – larger interocular differences of BCVA and corneal asphericity in ANISOs and the stronger interocular correlations in spherical aberration and coma C(3,–1) in ISOs, warrant further investigation.
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