Enhancing toric IOL outcomes

Performing another intraoperative aberrometry (IA) measurement after toric IOL implantation does not seem to improve the refractive outcome compared with obtaining a single measurement in the aphakic state, but it does add significant time to the case, said David Lubeck MD, at the 37th Congress of the ESCRS in Paris, France. He reported results of a prospective, randomised, contralateral eye-controlled study showing that obtaining a second IA measurement in the pseudophakic state added more than three minutes of OR time to each case and did not increase the likelihood of an eye having less than 0.5D of residual refractive astigmatism at one month. “It appears from this study that performing aphakic IA alone is sufficient to provide excellent clinical results with toric IOLs,” said Dr Lubeck. He presented the data on behalf of Satish S Modi, MD, who performed the study at Seeta Eye Centers, Poughkeepsie, NY, USA. The study included 35 patients with a mean age of 73.6 years presenting for uncomplicated bilateral cataract surgery with implantation of a toric IOL. An IA measurement was performed in the aphakic state in each eye and one eye was also measured with IA in the pseudophakic state. The primary outcome of the study analysed the magnitude of residual refractive astigmatism at one month and found no statistically significant difference in this endpoint between the two measurement groups. There were also no statistically significant differences between groups in other refractive outcomes or keratometric data at one month, in mean refractive sphere, MRSE, average keratometry, or average keratometric cylinder. “Impressively, 94% of eyes in both groups had ≤0.50D of residual refractive astigmatism,” Dr Lubeck said of Dr Modi’s study. Based on the aphakic IA measurement alone, 61 of 70 eyes had a spherical equivalent refraction within 0.5D of the intended target, and the refraction was more than 1D from intended in only two eyes. Data on the time required for IA measurement was also noted in each case. The mean time for the aphakic measurement was not significantly different comparing the two study groups, but the overall mean time was significantly shorter than the mean time needed for the pseudophakic measurement. On average, the aphakic measurement took 51 seconds to complete whereas the mean time for one pseudophakic measurement was 71 seconds. In the pseudophakic state, however, each eye was measured an average of 3.4 times, and the mean total pseudophakic measurement time was 226 seconds (3 minutes 46 seconds). The first aphakic measurement was done on both eyes; the eye randomised to just the aphakic measurement had the shown toric axis marked manually on the limbus and the implant was placed at that axis. The contralateral eye was randomised to an additional pseudophakic measurement. Though one pseudophakic measurement took 71 seconds, an average of 3.4 measurements were required to achieve the “NRR”, indicating no further rotation was required.

Tags: intraoperative aberrometry, toric IOLs