It is well known that there are differences between the different ethnic groups of the world. Differences in skin color and facial features are obvious, while numerous variations in bones and teeth have also been documented.
Eye structures also vary between different populations, resulting in differences in the prevalence of many eye diseases such as age-related macular degeneration, cataracts, and glaucoma. Racial differences have been observed in cornea, anterior chamber depth, retina, axial length, and optic nerve. However, very little is known in this regard about the lens of the eye, the crystalline. Understanding the possible population differences in lens parameters will help to understand their effect on problems such as cataracts and presbyopia.
The geometric and two-dimensional shape properties of the lens have previously been evaluated using different in vitro and in vivo techniques, but little information is available on possible differences between populations. The only comparative study to date has been that of Augusteyn et al. in 2011 who evaluated ex vivo lenses from India and the US and concluded that there were no differences in lens dimensions, optical power and stiffness.
However, a limited number of in vivo studies have suggested that there may be differences in lens growth patterns due to ethnic, genetic, or dietary variations. These differences could be due to ethnic or environmental influences or differences between experimental procedures.
Therefore the purpose of this study is to compare the central and complete geometric properties of isolated human crystals from Indian and European populations.

Two custom-developed spectral domain optical coherence tomography systems were used to acquire lens geometry: one in India (69 lenses from 59 donors) and the other in Spain (24 lenses from 19 donors). Steps to obtain accurate 3D models from raw optical coherence tomography images include image segmentation, optical and fan distortion correction, tilt removal, and registration. Outcome variables were equatorial lens diameter, lens thickness, anterior and posterior lens thickness and ratio, central curvature radius of anterior and posterior lens surfaces, lens volume, and lens area of the lens surface.

All central geometric parameters and full shape parameters were found to be comparable between the European and Indian populations. Knowledge of these population-based lens parameters is important for making population-specific formulas related to power calculations for designing an intraocular lens and evaluating biomechanical models of accommodation and presbyopia.

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The article is a collaboration between the Institute of Optics, the Ophthalmic Biophysics of the LV Prasad Eye Institute of Hyderabad, the Brien Holden Vision Institute Limited of Sydney, the Ophthalmic Biophysics Center of the Bascom Palmer Eye Institute of the University of Miami, the Department of Biomedical Engineering at the University of Miami and the Anne Bates Leach Eye Center at the Bascom Palmer Eye Institute at the University of Miami