Phakic IOL patients report high levels of satisfaction

Implantation of the Artisan IOL (Ophtec), also known as Implantable contact lens (ICL) for treatment of myopia produces high levels of overall satisfaction despite problems with glare and night vision in some patients, suggests a recent study of the iris-claw phakic IOL.

The trial, represented by Rudy MMA Nuijts MD PhD at the XXI Congress of the ESCRS, included 38 patients who underwent bilateral implantation of the Artisan IOL (5.0mm and 6.0mm p[tic models) and four who had the phakic implant in a single eye.
The patients ranged in age from 26-62 years old (mean 44 years) and were followed for three to 51 months (mean 20 months) after implantation.

The researchers assessed satisfaction and quality of vision using a validated questionnaire consisting of seven domains (global satisfaction, quality of uncorrected vision, quality of corrected vision, quality of night vision, glare, daytime driving, and night time driving) and a total of 66 items rated on a scale from 0-5.
The analyses showed the mean global satisfaction score was high, 4.2, and responses to individual questions indicated that 98% of patients were satisfied or very satisfied with their vision, felt their main goal for undergoing the refractive surgery was achieved, believed the surgery was a good choice and indicated they would undergo the surgery again.

In addition, 79% of the subjects had the highest possible satisfaction score of “5” for daytime driving. The mean score for that index was 4.6. However, mean satisfaction for glare, uncorrected vision, night vision, and night driving were all in the 3.1 or 3.2 range.

Furthermore, 24% of patients reported their night vision was worse or much worse than preoperatively and 48% of patients rated their night vision as poor or very poor.

A slight majority (54%) found night driving after Artisan IOL implantation was more difficult than before surgery. A similar proportion (56%) felt they had more bothersome glare postoperatively. More than one third of patients (37%) reported they had more glare from light at night than before surgery and two thirds of the study participants described having glare from oncoming lights.

“ We believe there are a few explanations that can account for the seeming discrepancy between the high overall satisfaction level of these patients and the presence of significant secondary visual effects. First, many of these high myopes might already be accustomed to glare, halos, and night vision problems from having worn rigid gas permeable contact lenses. In addition, previous literature indicates that there is a relationship between the preoperative level of myopia and the level of spherical aberration, and that might be responsible in some of these cases for night vision problems,” Dr. Nuijts said.

The latter observation is consistent with further analyses undertaken to identify correlation’s between satisfaction outcomes for the different quality of vision scales and various clinical and IOL-related parameters. The variables investigated for their relationships with different aspects of quality of vision included UCVA, BCVA, sphere, cylinder, SE, IOL-pupil decentration, optic size, pupil size-IOL diameter disparity, and optical aberrations (measured with the Zywave aberrometer, Bausch & Lomb).

Those analyses showed the UCVA satisfaction score was significantly correlated with logMar UCVA (p=0.019), although there was no significant association between global satisfaction and logMar UCVA. However after testing for multiple possible interactions, the only other statistically significant association was between poorer night driving satisfaction and the presence of a higher amount of higher order aberrations (p=0.037).

“ We would expect a high level of spherical aberration would give a low night driving score. However, since the Zywave aberrometer has a limited range of measurement in highly myopic eyes, we had no preoperative measurements. Therefore, we do not know whether the corneal aberrations in these patients were pre-existing, nor can we differentiate the corneal aberrations from the whole eye aberrations. However, we did look for a relationship between level of spherical aberration and power of the phakic IOL, and found none,” Dr. Nuijts said.

Other analyses showed there was no significant correlation between night vision scores and scotopic pupil-IOL disparity, smaller optic size, or magnitude of higher order aberrations.

“ The lack of a significant association between glare and IOL decentration, pupil-IOL disparity and amount of higher order aberrations were contrary to our expectations, but they may be accounted for by the finding that 90% of eyes had less than 0.5 mm of decentration and an even higher proportion, 92.5%, had less than 0.5 mm of pupil-IOL disparity under low mesopic conditions,” commented Dr. Nuijts.

The mean decentration of the phakic IOL was 0.29 mm. Moreover, the IOL was decentred less than 0.75 mm in all eyes. Mean pupil size under scotopic conditions was 6.00 mm.

Rudy Nuijts
Department of Ophthalmology,
University of Maastricht,

Published in Euro Times November 2003