Symmetries in peripheral ocular aberrations

Abstract

A mirror symmetry in the aberrations between the left and right eyes has previously been found foveally, but while a similar symmetry for the peripheral visual field is likely, it has not been investigated. Nevertheless, the peripheral optical quality is often evaluated in only one eye, because it is more time efficient than analyzing the whole visual field of both eyes. This study investigates the correctness of such an approach by measuring the peripheral wavefront aberrations in both eyes of 22 subjects out to AE40horizontally. The largest aberrations (defocus, astigmatism, and coma) were found to be significantly correlated between the left and right eyes when comparing the same temporal or nasal angle. The slope of the regression line was close to AE1 (within 0.05) for these aberrations, with a negative slope for the horizontally odd aberrations, i.e. the left and right eyes are mirror symmetric. These findings justify that the average result, sampled in one of the two eyes of many subjects, can be generalized to the other eye as well.

Myopic anisometropia: ocular characteristics and aetiological considerations

“…A high degree of interocular symmetry also exists for the total higher-order aberrations of the eye after correcting for enantiomorphism (between eye mirror symmetry) in various isometropic populations during distance [171][172][173][174][175] and near fixation. 176 Studies of chicks 177,178 have reported a significant increase in higher-order aberrations following monocular form deprivation and the development of myopia, and recently Colletta, Marcos and Troilo 179 observed that experimentally form-deprived eyes of marmosets had significantly higher levels of the asymmetric aberration trefoil compared to the fellow control eye. These animal models suggest that interocular asymmetries in higher-order aberrations may be a result of asymmetric visual experience and/or ocular growth, rather than a cause.…”

Mirror Symmetry of Peripheral Monochromatic Aberrations in Fellow Eyes of Isomyopes and Anisomyopes

“…8,11,15,35 The aberration coefficients with negative, even m indices or positive, odd m indices had negative fellow eye correlations across the visual field because the coefficients had opposite signs at corresponding temporal or nasal visual field locations of fellow eyes. Supporting previous studies for aberrations at fixation or along the horizontal meridian of the visual field, 14,[16][17][18][19][20][21][22][23][24][25][26][27][28]32 in a pooled data set the sign of these coefficients should be altered for left eye data. 36 Mirror symmetry was found between fellow eyes across the visual field for most peripheral aberration coefficients.…”

“…A requirement for mirror symmetry between eyes is an absolute slope of 1.0. Across all visual field angles and participants, absolute slopes of 0.90 to 1.10 occurred in regressions for all second-order terms (C 16 and for C , 32 indicating mirror symmetry for these coefficients, although the significances were not tested. The studies did not mention whether any of the participants had anisometropia.…”

“…30,31 Two studies failed to find significant differences of higherorder aberration coefficients between fellow eyes of anisometropes, 23,27 but another two studies found significantly more positive spherical aberration coefficient (C 0 4 ) in the less myopic eyes than in the more myopic eyes of anisomyopes. 22,28 In a study of more than 20,000 patients, Hartwig and Atchison 25 attempted to separate the effects of anisometropia from those of refraction, and were able to identify significant, but minor, iovs.arvojournals.org j ISSN: 1552-5783 effects of anisometropia for vertical coma (C One study compared peripheral ocular aberrations of fellow eyes at a few angles along the horizontal meridian out to 6408 16 and another considered many angles along the horizontal meridian out to 6358. 32 From linear regression analysis at corresponding temporal or nasal visual field locations, 10 of 12 second-to fourth-order aberration coefficients 16 and all 12 aberration coefficients 32 had significant correlations between fellow eyes and showed a degree of mirror symmetry because the correlations between the corresponding locations were negative only for ''odd over the horizontal meridian'' coefficients having either negative, even m indices or positive, odd m indices.…”

“…Peripheral aberration coefficients have been measured in only one eye of participants in most studies [5][6][7][8][9][10][11][12][13][14][15] for reasons of time efficiency, 16 with the assumption that they change similarly across the visual fields of fellow eyes. Comparisons of ocular aberration coefficients of fellow eyes have been made for central vision, [17][18][19][20][21][22][23][24][25][26][27][28] in both isometropes (similar refraction in fellow eyes) [17][18][19][20][21][22][24][25][26][27] and anisometropes (dissimilar refraction in fellow eyes).…”