Literature review reveals need for prospective, randomized long-term trial to determine phakic IOL safety
NEW ORLEANS — A researcher who investigated the safety of phakic IOLs by reviewing published studies found some positive evidence but was unable to draw precise conclusions due to the study parameters.
Thomas Kohnen, MD, PhD, FEBO, shared results he found from 20 published studies here at Refractive Surgery Subspecialty Day, which was jointly sponsored by the American Academy of Ophthalmology and the International Society of Refractive Surgery.
These studies, which met extensive criteria such as minimum number of patients, trial design, and inclusion and exclusion criteria, involved 2,502 eyes of 1,825 patients. Mean patient age was 36.77 years, he said. Forty-nine percent of patients were female, 31% were male, and the rest were not specified.
There was a mean of 95 patients in each study, with a median of 46, Kohnen reported. Preoperative manifest refraction was –10 D, but the range was –28 D to +11 D.
“We determined the endothelial cell density (ECD) confidence intervals by inverse variance methods,” he said. “From preop to 84 months, the ECD decreased by 0.6% annually.
“We looked at cataract formation and all other potential problems, including halos, pupil ovalization, corneal edema and decentration,” he said. “New onset of cataract formation was very low, but there was no evidence that this is due to phakic IOL implantation.
“The main ECD loss is revealed early, up until the first postoperative year, at about 100 cells/mm2 (3.5%),” he said. “After the first postoperative year, normalization of ECD decrease is possible.”
Kohnen and colleagues found no prospective, randomized controlled trials, so he said that precise conclusions are not possible.
“We recommend a complete evidence-based evaluation, a prospective, long-term randomized controlled trial and a sufficient number of examined eyes over the entire first postoperative year,” Kohnen said.
Disclosure: Kohnen is a consultant for or has received support from Alcon, Bausch + Lomb, Carl Zeiss Meditec, Hoya, Neoptics, Rayner and Schwind.