Abstract

Longitudinal chromatic aberration (LCA) of the human eye has been determined by various investigators [1,2] for foveal vision, usually with subjective methods. Due to low peripheral visual acuities, an accurate subjective determination of off-axis LCA is not possible at large eccentricities. Consequently, no data are available today on the ocular LCA beyond a few degrees away from the fovea. Charman and Jennings [3] determined the foveal LCA objectively using a double pass technique for one observer. They found a basic agreement with subjective data, finding only minor discrepancies between the subjectively determined best focus and the objective best focus criterion (smallest line width at half height). Their objective values were less myopic than subjective data for the shorter wavelengths. In the present study, we measure LCA throughout the visual field also using a double pass method [4]. In addition we have tested for possible discrepancies between objective and subjective data (as reported by Charman and Jennings [3]) for different wavelengths and for eccentricities of 0° and 2.5°, studying possible implications for the suitability of the double pass technique in determining LCA objectively. This objective versus subjective comparison has been done by the method of William's et al. [5] where the focusing target is a purely monochromatic point source.

© 1996 Optical Society of America