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Ashik Mohamed, Heather Ann Durkee, Fabrice Manns, Arthur Ho, Virender S Sangwan, Jean-Marie A Parel, Robert C Augusteyn; Isolated human lens shape determined by tridimensional digital shadowphotogrammetry: A pilot study. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):6000.
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© ARVO (1962-2015); The Authors (2016-present)
To examine the curvature of the anterior and posterior surfaces of isolated human crystalline lenses using a digital mini-shadowphotogrammetric system.
Crystalline lenses (n = 103, aged 1 month to 88 years, median post-mortem time 26 hours) were isolated from eyes received from the Ramayamma International Eye Bank, Hyderabad, India. Axial thickness, equatorial diameter and surface curvatures (central 3 mm) were calculated from coronal and sagittal profiles of the lenses imaged using a custom-built shadowphotogrammetric system (Mohamed et al, IOVS 2014;55: E-Abstract 747) (Fig. 1). The data were analyzed as a function of age using regression analysis.
For the younger lenses (aged 1 month to 5 years), the anterior (3.99 ± 0.61 mm) and posterior (4.16 ± 0.74 mm) radii of curvature (R) were independent of age (p>0.05). There was no significant difference between the anterior and posterior radii of curvature in young lenses (p = 0.71, Paired t-test). For older lenses (aged 14 to 88 years), the anterior radius (8.74 ± 2.22 mm) was independent of age (p>0.05), whereas the posterior radius showed a significant increase with age (R = 4.94 + 0.02*Age, p = 0.0003). In these lenses, the anterior radius was significantly larger than the posterior radius (p<0.0001, Wilcoxon signed-rank test). The ratio of anterior radius to posterior radius showed no age dependency (p>0.05) in both young (0.99 ± 0.24) and adult (1.51 ± 0.37) lenses, the difference between the two groups being significant (p = 0.001, Mann-Whitney test) (Fig. 2). Thickness (T) decreases from ~5.4 mm during infancy to ~4.2 mm by 5 years, and increases significantly with age from 14 to 88 years (T = 3.79 + 0.01*x, p<0.0001). The diameter shows an exponential relationship with age (y = 7.21x0.07).
The human crystalline lens anterior and posterior surface curvatures are quasi equal in very young isolated lenses. Lens curvatures stabilize around age 14.
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