Objective:

Prospective cross-sectional study designed to find out the ocular bio-metrics and parametric changes between identical and non-identical twins in the Indian population as these have not been studied earlier despite several twin studies present globally.

Methods:

A cluster sample of twin populations from the Kodinhi village, India, was identified. Various ocular and biometric parameters were measured in identical and non-identical twin groups.

Results:

A total of 19 twin pairs participated in the study, 7 of whom were identical twins, and 12 non-identical. The prevalence of refractive errors among all 19 twin pairs was 10.5%, with 7.9% myopia and 2.6% hyperopia. Among non-identical twins, the prevalence of myopia was 12.5%, hyperopia 4.2%, and emmetropia 83.3%. There was no statistical significance for all the parameters among non-identical twins or between the first and second twin with p > 0.05. The punto próximo de convergencia (PPC) break, PPC recovery, and contrast sensitivity of both eyes revealed a statistical significance of p < 0.05 between the eyes of 7 identical twins. The near point of accommodation of the right eye, the anterior chamber depth (ACD) of the left eye, contrast sensitivity, and the axial length (AL) of both the eyes revealed a statistical significance of p < 0.05 between identical and non-identical twins.

Conclusion:

This study concludes that all refractive errors were seen in non-identical twins only while all identical twins were emmetropic. The parameters that showed statistically significant variation were convergence and contrast sensitivity among identical twins along with accommodation, ACD, contrast sensitivity, and AL between identical and non-identical twins.

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