Abstract
Purpose :
Morphological characteristic of the human eye changes with age, and thus, its optical performance changes accordingly. But the age-related changes in the eye structure and optics have not been well characterized yet. The purpose of this study was to measure wavefront aberrations and biometric parameters by using an advanced wavefront equipped OCT system for a group of adults with different ages in order to study the changes in morphological and optical properties of the eye as a function of the age.
Methods :
A Hartmann-Shack wavefront sensor, integrated with a long-depth OCT system, was used to measure wavefront aberrations and to image anterior segment for 34 subjects aged from 22 to 58 years old. The wavefront sensor measured Zernike aberrations up to 7th order for the left eye, and the 840nm OCT system, co-axially aligned with the wavefront sensor, was used to derive anterior segment parameters including the corneal curvatures, anterior chamber depth (ACD), lens thickness (LT), anterior segment depth (ASD) and the lens surface curvatures.
Results :
Two higher order aberrations were negatively correlated to age: r=-0.62 (p<0.001) for spherical aberration and r=-0.54 (p<0.001) for x-axis coma. Significant age changes were found for several anterior segment parameters including the ACD (r=-0.70, p<0.001), LT (r=0.84, p<0.001), ASD (r=0.36, p<0.05), the anterior lens radius of curvature (ALRC, r=-0.64, p<0.001) and the posterior lens radius curvature (PLRC, r=0.37, p<0.05). While the parameters were significantly decreased with age for the ACD (-0.018mm/year) and ALRC (-0.083mm/year), increases in parameters were found for the LT (0.027mm/year), ASD (0.009mm/year) and PLRC (0.023mm/year). Significant correlation between the spherical aberration and LT was also observed (r=-0.67, p<0.001).
Conclusions :
As the eye ages, the crystalline lens approaches toward a more equiconvex shape because the anterior lens surface becomes more steepened while the posterior surface gets flatter at older ages. An increased lens thickness in the older eye is associated with a shift of the spherical aberration toward more negative direction.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.