A Prospective Study of Anterior Segment Ocular Parameters in Anisometropia

Abstract

PurposeThe aim of this study was to investigate the differences in anterior segment ocular parameters in anisometropia >1 D.MethodsThis study included 202 eyes of 101 subjects ranging from 10 to 40 years of age with anisometropia of 1 D or more. The subjects were divided into groups according to anisomyopia, anisoastigmatism, and anisohypermetropia. After providing informed consent, each patient underwent a detailed ophthalmological examination including cycloplegic refraction, best-corrected visual acuity, cover test, axial length (AL) measurement using A-scan ultrasound biometer, keratometry, anterior chamber depth, and central corneal thickness measurement. For each participant, the eye with greater refractive error was compared to the fellow eye via paired t-tests. Correlations between parameters were studied using the Pearson correlation coefficient.ResultsThe average age of subjects was 21.7 ± 9.3 years. Of 101 subjects, 31 had anisomyopia; 42 had anisohypermetropia; and 28 had anisoastigmatism. A predisposition toward greater myopia in right eyes was noted in anisomyopia (24 of 31 subjects, 77%). The inter-ocular acuity difference was significant in all three groups (p < 0.01). As the degree of anisometropia increased, there was significant positive correlation in the difference in AL in myopes (r = 0.863, p < 0.01) and hypermetropes (r = 0.669, p < 0.01) and the difference in corneal curvature in anisoastigmatism (r = 0.564, p = 0.002) and hypermetropes (r = 0.376, p = 0.014). A significant positive correlation was also present between the anterior chamber depth difference and refractive difference in hypermetropes (r = 0.359, p = 0.020).ConclusionsThis study showed that anisomyopia is correlated only with anterior chamber differences. Anisohypermetropia is correlated with AL differences as well as corneal curvature difference and anterior chamber depth difference. The amount of anisoastigmatism correlates only with corneal curvature difference.

Eyes of Aniso-Axial Length Individuals Share Generally Similar Corneal Biometrics with Normal Eyes in Cataract Population

“…Among all the aniso-axial length patients, we detected greater tendencies for female patients to develop aniso-axial length and for the right eye to be the longer one, which are consistent with the findings of Linke et al [ 25 ] and Singh et al [ 9 ], respectively. Many studies support the proposition that the dominant eye is the more myopic in patients with myopic anisometropia [ 26 – 29 ].…”

“…The comparison of binocular parameters in the anisometropic eye was studied previously, indicating that axial length (AL) was the most important factor in anisometropia [ 7 ]. Whether or not other anterior segmental parameters such as corneal power, lens power, and anterior chamber resulting in or related to anisometropia is under debate [ 7 – 9 ].…”

The biometric parameters of aniso-astigmatism and its risk factor in Chinese preschool children: the Nanjing Eye Study

“…The difference between non-vectorial aniso-TA prevalence and vectorial aniso-TA prevalence was reasonable as the later one took astigmatic axis into consideration Whatever de nition was used, aniso-TA was associated not only with increased interocular differences in CR, but also with AL, possibly due to the relationship among aniso-TA and anisometropia. A similar correlation was reported by Huynh et al [14], O'Donoghue et al [24], Singh et al [29], and Hameshi et al [30]. These studies showed non-vectorial aniso-CA was associated with non-vectorial aniso-TA.…”

The biometric parameters of aniso-astigmatism and its risk factor in Chinese preschool children: the Nanjing Eye Study

“…Whatever de nition was used, aniso-TA was associated not only with increased interocular differences in CR, but also with AL, possibly due to the relationship among aniso-TA and anisometropia. A similar correlation was reported by Huynh et al [14], O'Donoghue et al [26], Singh et al [31], and Hameshi et al [32]. These studies showed non-vectorial aniso-CA was associated with non-vectorial aniso-TA.…”