Complete phakic IOL safety elusive, study indicates

A sudden and dramatic decrease of endothelial cells may occur years after implantation, surgeon warns.

ByMichela Cimberle

George Baikoff

Long-term follow-up with several models of phakic IOLs shows that none of them is completely safe, as far as endothelial cell loss is concerned.

“The decrease can be sudden and dramatic and may occur several years after implantation,” George Baikoff, MD, said at the meeting of the French Society of Ophthalmology.

Causes are unknown, but there are reasonable suspicions that they might be related to the lens material rather than to the geometry of the implants.

In a retrospective study, Dr. Baikoff included 1,370 phakic IOLs (500 NuVita from Bausch & Lomb, 150 Vivarte from IOLTech, 120 NewLife from IOLTech and 600 Artisan from Ophtec) implanted over 20 years, from 1987 to 2007. In the past 5 years, 86 of these lenses were explanted.

More than half of the removals (51%) were due to endothelial cell loss, he said.

Other causes were cataract (17%), errors in lens power calculation (12%), pigment dispersion (8%) and patient discomfort (12%).

NuVita and Artisan

The angle-supported NuVita had a low explantation rate (5%) at the longest time interval (more than 10 years) from first implantation.

“NuVita was a PMMA lens. We stopped implanting it in the early 1990s, but apart from the well-known problems of pupil ovalization, which were due to oversizing, we had few complications. Our retrospective study confirms that both the material and the design of the lens were, in fact, good,” Dr. Baikoff said.

Endothelial cell loss was the cause of explantation in 2.6% of the cases.

Dr. Baikoff said this was, “definitely less than with the new generation angle-supported lenses.”

The iris-claw Artisan phakic IOLs are known for having a low complication rate. In reality, according to Dr. Baikoff, they also have potential complications and need constant surveillance.

Pigment dispersion, possibly due to a too-high crystalline lens rise, cataract and endothelial cell loss are reported.

“With the Artisan lens, the main cause of endothelial cell loss seems to be the small anterior chamber diameter in myopic patients. Being a one-size-fits-all, this lens can be too large for these eyes,” he said.

In his study, the explantation rate with Artisan IOL was 5%, the same as NuVita. Explants due to endothelial cell loss were 1.8% of the total.

“The characteristic pattern of the Artisan lens, both myopic and hyperopic, is a certain amount of endothelial cell decrease due to surgery, a slight recovery around month 5 and then a progressive decrease,” Dr. Baikoff said.

The mean interval between implantation and removal was just more than 2 years.

Toric Artisan IOLs were not included in the study because there was no case of explantation in the past 5 years.

“This is probably due to the limited indications of these lenses, which entail a more accurate measurement of anterior segment dimensions,” Dr. Baikoff said.

Vivarte and NewLife

The more recently developed angle-supported phakic IOLs, Vivarte and NewLife, underwent an unexpected number of explants in the past 5 years.

“Of 150 Vivarte and 120 NewLife, respectively, 14 (9.33%) and 17 (14.17%) were removed,” Dr. Baikoff said.

Endothelial cell loss was the cause in most cases.

“This complication was mostly unexpected, particularly with the NewLife phakic IOL. All implanted did extremely well in the first 3 years, during which the endothelial cell count remained perfectly stable. Then, a sudden and dramatic decline started, lowering the endothelial cell count from 2,500 to 1,500. The lowest peak was registered at 60 months,” he said.

The causes that trigger this sudden drop are not at all clear. No correlation was found with anterior chamber depth up to 4 years.

“I am more inclined to think that this late complication might be related to the material rather than to the design of the lenses. This would explain why we didn’t have a similar effect with the NuVita IOLs, which had a similar geometry but were made of the old PMMA,” Dr. Baikoff said.

He concluded that none of the phakic IOLs that have so far been developed is absolutely safe.

He recommended caution in performing new implantations and the use of optical coherence tomography to have a well-defined picture of all safety distances within the anterior segment of the eye.

All patients should be made aware that close monitoring, once a year or even once every 6 months, is mandatory with all types of phakic IOLs, Dr. Baikoff said.

For more information:

George Baikoff, MD, can be reached at Clinique Monticelli, 88, Rue du Commandant Rolland, 13008 Marseilles, France; e-mail: g.baik.opht@wanadoo.fr. Dr. Baikoff is a paid consultant for Carl Zeiss Meditec.

Michela Cimberle is an OSN Correspondent based in Treviso, Italy, who covers all aspects of ophthalmology. She focuses geographically on Europe.