Endothelial cell loss with phakic IOL highest in first postop year

CHICAGO – Phakic IOLs are associated with an elevated rate of endothelial cell loss in the first year after implantation, but the cell loss returns to normal in subsequent years, said Helen K. Wu, MD. She warned surgeons, however, that “ongoing monitoring of endothelial cell loss is imperative” in patients with phakic IOLs.

Dr. Wu, speaking here at the Refractive Surgery Subspecialty Day preceding the American Academy of Ophthalmology meeting, spoke about endothelial cell loss after implantation of both anterior and posterior chamber phakic IOLs.

Central endothelial cell density decreases at a rate of about 0.6% annually throughout adulthood, so that by age 40 years people tend to have about 3,000 cells/mm², and by age 70 the count has decreased to about 2,000 cells/mm².

After phacoemulsification, Dr. Wu said, “generally speaking, there is a 10% cell loss.”

Two studies of the Artisan/Verisyse (Ophtec/Advanced Medical Optics) iris-supported phakic IOL found cell loss of 10.9% at 36 months and 17.6% at 24 months postoperative. Eyes with anterior chamber depths of less than 3.2 mm exhibited the greatest cumulative cell loss at 3 years, at 9%, according to U.S. Food and Drug Administration data, she said.

Three models of angle-supported anterior chamber phakic IOL – the Morcher ZSAL-4, the Domilens-Chiron ZB5M and the Bausch & Lomb NuVita – showed endothelial cell loss of 4.2% at 24 months and 12% loss at 2 years, with stabilization between years 1 and 2, she said.

A posterior chamber phakic IOL, the STAAR Surgical Visian ICL, showed endothelial cell loss of between 2% and 6.57% at 2 years, and 12.3% at 4 years, Dr. Wu said. She noted, however, that the number of patients included in the 4-year data was not high enough to achieve statistical significance.

Dr. Wu said that the safety concerns in the labeling of the Aritisan/Verisyse lens indicate that “if endothelial cell loss continues at the rate of 1.8% per year, 39% of paitents are expected to lose 50% of their corneal endothelial cells within 25 years of implantation.”

“The long-term effect on the cornea’s health is unknown,” she said.

Dr. Wu said anterior chamber phakic IOLs tend to be associated with more cell loss than posterior chamber phakic IOLs. She said the ICL’s cell loss “is well below the worry level,” although no long-term data is available. She advised surgeons to continually monitor their patients well beyond the first year after implantation.