Corneal and total optical aberrations in a unilateral aphakic patient

Abstract

Purpose To measure corneal and total optical aberrations in the normal and treated eye of a unilateral aphakic patient to (1) cross-validate techniques in an eye in which corneal and total aberrations should be almost identical (aphakic eye) and (2) compare the interactions of corneal and internal aberrations in the normal eye with those in the aphakic eye. Setting Instituto de Óptica, Consejo Superior de Investigaciones Científicas, Madrid, Spain. Methods Aberrations in both eyes of a unilateral aphakic patient were measured using laser ray tracing. Corneal aberrations were obtained from corneal elevation data measured with a corneal videokeratoscope (Humphrey Instruments) using custom software that performs virtual ray tracing on the measured front corneal surface. Results There was a 98.4% correspondence between the total and corneal aberration pattern in the aphakic eye (6.5 mm pupil). In the normal eye, the total spherical aberration was much lower than the corneal spherical aberration; this did not occur in the aphakic eye. Conclusions The posterior corneal surface contributed slightly to the aberrations in the normal cornea (2% at most). The crystalline lens appears to play a compensatory role in the total spherical aberration in normal eyes.