Diffractive lens offers good intermediate vision

Fresno, CA-Assessments of the intermediate vision and quality of life of patients in whom an apodized diffractive IOL (AcrySof ReSTOR, Alcon Laboratories) was implanted indicate that the lens provides excellent near vision, very good levels of intermediate vision, and uncompromised distance vision compared with a control monofocal IOL (AcrySof, Alcon Laboratories).

Eighty percent of the patients with the diffractive lens were independent of glasses after lens implantation, according to W. Andrew Maxwell, MD.

"The [diffractive] IOL is designed to provide a full range of freedom," said Dr. Maxwell, a private practitioner in Fresno, CA. He and his colleagues evaluated the IOL to determine whether this was the case.

"The results are similar to those of previous studies.

"The thing that is important about our results is that the mean near uncorrected visual acuity (UCVA) was almost 20/20, whereas the control patients had a mean near visual acuity of about 20/50 (logMAR vision, approximately 0.4). The near best-corrected visual acuity was similar between the two groups, the distance UCVA in the clinical trial was very close to 20/20 in most patients with the [diffractive] IOL and 20/20 with the monofocal IOL," Dr. Maxwell said.

The data for the intermediate vision at 50 cm showed that the difference between the control lens and the diffractive lens was significant in favor of the diffractive lens, he reported. "Most patients with the [diffractive] IOL saw 20/32 compared with 20/40 with the control IOL. At 60 and 70 cm, the results were essentially the same for the two IOLs. The vision at 50 cm would allow the patients to perform most visual tasks at the computer or using intermediate vision," he explained.

Considering independence from spectacles, which Dr. Maxwell defined as never having to wear glasses, 80% of the patients who received the diffractive lens had an overall independence from glasses for distance vision, 90% of the patients with the diffractive IOL never wore glasses, and 80% of the patients never wore glasses for near visual tasks.

"Compared with the monofocal controls, interestingly, only 60% of the patients were independent of glasses for distance," he stated.

When asked on the questionnaire whether they were having difficulties with day and night vision, the patients in both groups responded similarly before implantation of the IOLs. The patients used a scale of 0 to 4 to rate their vision, with 0 indicating no trouble and 4 indicating substantial trouble.

"The quality-of-life results showed that patients' day and night vision with the [diffractive] IOL and the near and distance vision activities were statistically significantly better than the controls. In addition, the subjects' overall satisfaction with their vision after [diffractive lens] implantation was statistically significantly better than the control patients," Dr. Maxwell reported.

The patients' expressions of satisfaction with the visual outcomes were virtually identical to the responses on the questionnaire to difficulties with day and night vision. "The patients with the [diffractive] IOL had no subjective vision complaints," he said.

Also, the problems with glare were similar preoperatively in both groups. Postoperatively, the patients with the diffractive lens had slightly fewer problems with glare compared with the control patients. The difference did not reach significance, however.

"When the patients were asked to rate the quality of vision, the results were equal preoperatively between the two groups. However, postoperatively, the patients with the [diffractive] IOL rated their quality of vision better compared with the controls," he said. "This result was highly statistically significant [p = 0.0001]. The overall satisfaction with their vision was the same preoperatively, but postoperatively, the patients were more satisfied with the [diffractive] IOL than with the control IOL [p = 0.0001]," he said.

"The [diffractive] IOL is designed to provide excellent near vision. I think it provides very functional intermediate vision and causes low degrees of visual symptoms with a compromise in the distance vision. The subjective, validated quality-of-life questionnaire showed that there was a high level of satisfaction on the part of the patients with the [diffractive] IOL. In the clinical trial, 80% of the patients did not wear glasses after the study was completed," he concluded.