Intraoocular lenses yield good reading performance

August 15, 2010

Two proprietary IOLs can provide good uncorrected distance visual acuity and reading performance in eyes of patients after bilateral IOL implantation.

Boston-Two proprietary IOLs (Acri.Lisa 366D/AT.Lisa, Carl Zeiss Meditec and AcrySof ReSTOR, Alcon Laboratories) can provide good uncorrected distance visual acuity (UDVA) and reading performance in eyes of patients after bilateral IOL implantation, said Max Rasp, MD, at the annual meeting of the American Society of Cataract and Refractive Surgery.

A prospective, randomized, four-arm, multicenter trial was conducted at two European sites that included 240 patients (480 eyes). At the time of the presentation, 106 patients had undergone bilateral implantation and had been followed for at least 1 month, said Dr. Rasp, of the University Eye Clinic, Paracelsus Medical University of Salzburg, Austria.

Patients were randomly assigned to implantation of one of the following four IOLs: a spherical monofocal plate haptic IOL (Acri.Smart 48S, Carl Zeiss Meditec) (58 eyes); a multifocal diffractive plate haptic IOL with +3.75 D of add power (Acri.Lisa 366D/AT.Lisa) (58 eyes); a diffractive multifocal hybrid IOL with +4.0 D of add power (AcrySof ReSTOR) (68 eyes); and a multifocal refractive IOL with +3.5 D of add power (ReZoom, Abbott Medical Optics) (28 eyes).

The primary outcome was the uncorrected bilateral reading performance-reading acuity "at best distance" (logRAD), reading speed (wpm), reading distance (cm), and smallest log-scaled sentence that could be read-1 month after implantation of these lenses, as measured with the Salzburg Reading Desk (SRD). The secondary outcomes were the contrast sensitivity under photopic and scotopic conditions, UDVA, best spectacle-corrected visual acuity, and the refractive spherical equivalent.

Dr. Rasp said that the SRD system consists of a specially designed reading desk, computer, and a dedicated software package. Measurement of reading distance is possible with video-stereo-photogrammetry and additional software processing. In this set-up, patients are able to choose their own subjectively convenient reading distance. A microphone records the time of the reading process. A sentence of a log-scaled reading chart is accepted if it can be read by the patient with a minimum reading speed of 80 wpm, which represents the lower limit for recreational, sense-capturing reading.

Dr. Rasp said that the UDVA increased significantly in all groups postoperatively. No significant difference was found in contrast sensitivity among the groups. The monofocal IOL (Acri.Smart) had the highest scotopic contrast sensitivity with distance correction.

The uncorrected logRAD "at best reading distance" was significantly higher in the diffractive groups (Acri.Lisa 366D/AT.Lisa and ReSTOR) compared with the other groups, with the former performing slightly-but not significantly-better than the multifocal refractive (ReZoom) IOL.

Uncorrected reading distances were significantly longer with the monofocal (Acri.Smart) and multifocal refractive (ReZoom) IOLs. The logRAD values with near add were significantly better with the monofocal (Acri.Smart) and multifocal diffractive (Acri.Lisa 366D/AT.Lisa) IOLs. There were no significant differences among the four IOLs for reading distance with near correction.

"The AT.Lisa and ReSTOR IOLs provide a good uncorrected reading performance despite only a slight limitation in contrast sensitivity," Dr. Rasp said.

"The ReZoom and the Acri.Smart provide a more limited reading performance without near correction," he said. "The ReZoom and the Acri.Smart allow a longer uncorrected reading distance than the AT.Lisa and the ReSTOR IOLs, but the reading distance with near add was similar among all IOL groups. The diffractive and hybrid IOLs can provide good uncorrected reading performance and UDVA."

FYI

Max Rasp, MDE-mail: m.rasp@salk.at

Dr. Rasp has no financial interest in the different IOLs and the SRD technology mentioned in this report. The trial was an ESCRS (European Society of Cataract and Refractive Surgeons)-granted study.