Results of defocus curve testing in eyes with a refractive multifocal IOL implanted as part of a prospective, multicenter comparative trial are better for the +3-D near-add version of the lens compared with the +4-D near-add platform with regard to intermediate visual acuity.
However, overall findings from the study show that distance and near visual acuity are excellent for patients with either IOL implanted, whether the same lens is implanted bilaterally or the different near-add versions are used together in a mix-and-match approach, said Tanja M. Rabsilber, MD, at the annual meeting of the American Society of Cataract and Refractive Surgery.
"Our intention was to investigate the influence of a lower and higher near addition and their combination not only with regard to distance and near visual acuity but also looking at intermediate distances (defocus curve), subjective satisfaction, spectacle independence, as well as photopic phenomena," said Dr. Rabsilber, director of research and development, International Vision Correction Centre (IVCRC), Department of Ophthalmology, University of Heidelberg, Germany.
This particular single-piece, multizoned refractive, distance-dominant multifocal IOL is constructed of a unique hydrophilic acrylic material (Rayacryl). It is available with a near add of +3 or +4 D, and the two lenses were evaluated in a multicenter study enrolling 52 patients undergoing bilateral cataract surgery at the University of Heidelberg and Kaunas University of Medicine, Lithuania.
The study participants had a median age of 65 years. Preoperatively, median logMAR corrected distance visual acuity (CDVA) was 0.34 (range 0.04 to 1) and median SE was 0.63 D (range –6.50 to +5.63 D).
Selection among the three implantation approaches was made to target individual patient needs assuming that bilateral +4-D near add provides better reading visual acuity than +3-D near add that focuses more on intermediate distances. Nineteen patients received the +3-D near-add M-Flex 630F bilaterally, 16 patients had the +4-D near-add M-Flex 630F implanted bilaterally, and there were 17 mix-and-match patients who received the +3-D near-add lens in the distance eye and the +4-D near-add lens in the non-dominant eye.
Patients were seen at a follow-up visit conducted 4 to 6 months postoperatively, and at that time, the refractive and distance uncorrected and corrected visual acuity results were excellent in all groups with no significant differences between groups. For all patients, median logMAR uncorrected distance visual acuity was –0.08 (range –0.22 to 0.16), median logMAR CDVA was –0.12 (range –0.26 to 0.18), and median SE was 0 D (range –0.88 to 1 D).
Near vision endpoints
There were also no significant differences between groups in the endpoints assessed for near vision outcomes, which included uncorrected near visual acuity (UNVA), distance-corrected near visual acuity (DCNVA), near add requirement, and corrected near visual acuity. Median logMAR UNVA was 0.20 (range –0.06 to 0.60), DCNVA was 0.10 (range 0 to 0.50), and median near add requirement was 0 D (range 0 to 2.25 D), Dr. Rabsilber said.
Monocular defocus curves were obtained for 21 eyes with the +3-D near-add M-Flex IOL and for 17 eyes with the +4-D near-add implant. The two lenses were essentially identical for distance, but the +3-D near-add lens was superior in the intermediate range without compromising near visual acuity. The mix-and-match approach was not associated with any advantages comparing binocular defocus curve measurements.