Contrast sensitivity and depth of focus with aspheric multifocal versus conventional monofocal intraocular lens

Abstract

Background: Laboratoires Domilens, Lyon, France, has introduced a new aspheric multifocal intraocular lens (IOL), the Progress 3. The central portion, measuring 4.7 mm in diameter, has an anterior surface of progressively increasing power, such that there is a central add of +5.00 dioptres. We compared contrast sensitivity and depth of focus in patients who received the Progress 3 and in those who received a conventional monofocal IOL.

Methods: Prospective study. Forty patients with age-related cataract were randomly divided into two groups: 20 patients received the Progress 3 aspheric multifocal IOL, and 20 patients received a conventional monofocal IOL of similar design. Contrast sensitivity was measured with the Pelli-Robson letter-based chart. Depth of focus was determined by dialling a series of overcorrections over the patient's manifest refraction until the patient read 6/12 clearly. The depth of focus was defined as the range over which 6/12 or better acuity was achieved. Quality of vision was evaluated by patient questionnaire.

Results: Mean contrast sensitivity was significantly lower in the patients with a multifocal IOL than in those with a monofocal IOL (1.38 vs. 1.56 log units) (p < 0.001). The mean depth of focus values for the two groups were 3.10 D and 1.65 D respectively (p < 0.001). The prevalence of subjective problems was similar in the two groups.

Interpretation: In our opinion, aspheric multifocal IOLs should be reserved for patients who are willing to trade increased depth of focus for reduced contrast sensitivity postoperatively.