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Refractive symmetry analysis of fellow eyes

sankha Jyoti Saha, Dr Kapil Dev, Pratyay Ranjan Dutta


The biological structure of human body frequently exhibit symmetry. The hypothesis of refractive symmetry assumes that the two eyes of an individual should have homogeneous refractive properties. Optometry clinical management mostly rely upon meridional magnification effect, spatial distortion, and binocular spatial perception while prescribing refractive correction. Additionally, bilateral symmetry analysis approach has proven very informative for better diagnosis. This study was multi-centered, cross-sectional, analytical, and retrospective, where we studied refractive errors with conventional clinical notation using the sphere, cylinder, and axis. The collected data were scrutinized using the SPSS, Minitab Statistical Software. In inter-ocular symmetry analysis, if the numerical difference between both axes is zero, Equal Octant or Direct Symmetry is to be considered. While, with Mirror Octants or Mirror Symmetry or Enantiomorphism, the axes difference is not zero, but the portrayal of the figures are reverberatory. 53.23% and 70.15% of the cases rooted in the Equal Octant and Mirror Octant pattern respectively, within 15° of absolute symmetry. Analysis showed that age between 7 to 14 years has the lowest inter-ocular axis difference with both the models. The average difference in inter-ocular axis was significantly reduced in the isorule group compared to the anisorule group, as observed in both direct and mirror symmetry models. Interval plot shows a lower interval proximity for Mirror Octant, in compare to Equal Octant. We tracked down that isorule bilateral astigmatism dominates the study population. Whereas, Mirror Octant is more periodic than Equal Octant.

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