Abstract

DO.12.09

Influence of the lens/IOL position on image quality – Measurements with a new device using the Purkinje images

Mester U., Hild M., Kaymak H.
Knappschaft's Hospital, Department of Ophthalmology, Sulzbach

Objective: Based on theoretical calculations and in vitro measurements we learned that decentration and tilt of intraocular lenses – particularly with an aspheric optic – lead to significant impairment of image quality.
Methods: With a newly developed device using the Purkinje images, decentration and tilt of the crystalline lens and IOLs can be determined very precisely. With this instrument we investigated the position of the crystalline lens in young and aged individuals as well as the position of different IOLs after cataract surgery. Additionally, internal, corneal, and ocular higher order aberrations were assessed.
Results: Neither the young eye nor the aged eye has a perfectly centered and tilt free position of the crystalline lens. The deviations were symmetric in both eyes. Intraocular lenses in pseudophakic eyes showed excellent centration, but some tilt. Interestingly, the wave front analysis demonstrated a compensation of the horizontal corneal coma by the crystalline lens in the young eye and by the IOL position in the pseudophakic eye.
Conclusions: Our findings demonstrate that, the in vitro measurements of decentration and tilt of IOLs are obviously not according to the situation in the human eye. It is likely that here some mechanisms of compensation exist, comparable to the compensation of spherical aberration in the young eye.

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