Abstract
Purpose: :
To characterize the changes in corneal and natural lens induced monochromatic higher order aberrations (MHOA) with age in the general population.
Methods: :
Prospective observational case series. 300 eyes of 167 subjects ranging in age from 19 to 93 years underwent cycloplegic dilatation and had corneal and internal optics wavefront analysis performed with the iTrace (Tracey Technologies, TX, USA) over a 6mm pupil diameter. No ophthalmic pathology affecting the optical aberrations of the eye was present. Zernike coefficients for the whole eye, cornea and internal optics were obtained to the 6th order. Results of left (OS) and right (OD) eyes were analysed separately.
Results: :
A strong correlation was found between OS and OD for total MHOA, individual total 3rd order and spherical aberration for the whole eye, cornea and lens (p<0.001 for all comparisons). There was a significant increase with age in whole eye total MHOA rms (p<0.001 OD and 0.015 OS), total 3rd order rms (p<0.001 OD), total 4th order rms(p=0.009 OD and 0.031 OS) and total 5th order rms (p=0.01 OD). Group variation per decade in total MHOA increased significantly with age (p<0.01), due to changes in MHOA induced by the internal optics. Mean rms of total internal MHOA rose from 0.30µm in the 4th decade to 0.70µm in the 9th decade in the OD (p=0.052), and from 0.22µm to 0.57µm in the OS (p=0.008). Significant correlations between age and individual MHOA of the internal optics were found, specifically 3rd (p=0.042) and 5th order (p=0.042) in the OD and 4th (p=0.006) and 5th (p=0.034) order in the OS. There was also a significant increase in internal spherical aberration with age in the OS (p=0.006). No significant change with age was found for corneal MHOA.
Conclusions: :
1. The magnitude and population variability of MHOA increases with age. These changes show a strong interocular correlation. 2. The changes in MHOA can be attributed to age-related changes in the internal optical quality of the eye. 3. The functional significance of these changes may be ameliorated by age-related miosis.
Keywords: aberrations • aging: visual performance