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Effect of crystalline lens’ aberrations on AO-simulation of IOLs in phakic eyes


Purpose : Adaptive optics visual simulators (AOVS) allow the prediction of visual outcomes with intraocular lenses (IOL) before the actual cataract surgery is performed. The effective phase profile of the IOL is induced in the phakic eye and visual performance is measured. While in this case the retinal image is affected by the cornea, lens and the induced IOL, after surgery the lens will not be present. In this context, we evaluate the impact of the lens’ aberrations on the AO simulation of IOLs in phakic subjects.

Methods : The experiment was performed monocularly using our AOVS laboratory prototype in 5 subjects. For each eye, the aberrations of the cornea and the whole eye were first measured and the lens’ aberrations estimated by direct subtraction. Visual acuity (VA) at best focus and two different contrasts (100% and 20%) was measured for 5 different conditions. The case with natural lens’ aberrations (case Natural), when the spherical aberration (SA) of the lens was either corrected (case –SA) or doubled (case +SA), and with all high order aberrations of the lens corrected (case –WA) or doubled (case +WA). Through-focus high contrast VA was also measured for a diffractive IOL for the cases ‘Natural’ and ‘-WA’. Three different pupil sizes, 3, 4.5 and 6 mm were tested for all conditions.

Results : In average, for the 4.5 mm pupil high contrast VA was found to be similar for all tested cases. The changes with respect to the Natural case were 0.00±0.20 (case -SA), 0.01±0.22 (case -WA), -0.02±0.17 (case +SA) and 0.04±0.24(case +WA) units of LogMAR. Observed differences were similar for the 3 and 6 mm pupils except for case ‘+WA’ at the largest pupil with a difference of 0.08±0.23 units of LogMAR. For low contrast VA the absolute values of the differences were in average double than those found for high contrast but resulting in p<0.05 only for cases ‘+WA’ (4.5, 6 mm) and ‘-WA’ (3, 4.5 mm pupil). There were no differences in the measurements with the diffractive IOL profile for all the conditions.

Conclusions : Lens’ aberrations in phakic eyes play a minor role in the AO visual simulation of IOLs. AOVS can be accurately used prior to cataract surgery to predict future visual outcomes. In some special cases, the particular aberrations of the lens should be subtracted when inducing the IOL phase for an even better prediction.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

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