Ocular monochromatic aberration statistics in a large emmetropic population

Abstract

The primary objective of this study was to explore the statistics of ocular higher-order aberrations in a nearly emmetropic population. The wavefront aberration of 393 eyes of 218 subjects was obtained under natural conditions using the WaveLight WaveFront Analyser. The spherical equivalent of eyes ranged between +0.75 and − 1.25 D, with the astigmatism being less than 0.75 D. Mean age was 33.0±4.8 years. Analysis was performed for a 6 mm pupil. A significant dispersion in all Zernike coefficients was found. Population average values of Zernike coefficients were almost zero, with the exemption of primary spherical ( µm) and oblique trefoil () aberrations. Mean higher-order RMS error was 0.26 µm, corresponding to an equivalent defocus of 0.20 D. An increase in higher-order RMS with age (at pre-presbyopic range) was found, which was accompanied by changes in coma-like aberrations, while spherical aberration remained unchanged. Emmetropic eyes appear to have on average lower individual and combined higher-order aberrations than previously reported values on myopic eyes. Although aberration levels at fixed pupil diameter increase with age, their effect on retinal image quality is possibly cancelled out by senile miosis.

Keywords:

• ocular aberrations
• emmetropes
• ageing
• spherical aberration
• bilateral symmetry

Acknowledgements

The authors acknowledge Ioannis Aslanides, Sophia Panagopoulou, Dimitris Tsatsaronis and Nikolaos Astyrakakis for their help in data acquisition. Preliminary results of this study were presented at the Association for Research in Vision and Ophthalmology, Ft. Lauderdale, FL, in April 2004.