August 2019

CATARACT

Presentation spotlight
Long-term survival rates with three different iris-fixated phakic IOLs


by Stefanie Petrou Binder, MD EyeWorld Contributing Writer

One option to improve refractive error while preserving the crystalline lens and retaining the eye’s natural accommodative powers is iris-fixated phakic IOL (pIOL) implantation. Long-term outcomes aid surgeons in their understanding of some of the risks involved with pIOL use. Risk factors influencing long-term survival vary according to the choice of pIOL and the type of eye, and surgeons need to know that some pIOLs may be riskier than others.
A study on the long-term, 10+ year survival of iris-fixated pIOLs was presented at the 36th Congress of the European Society of Cataract and Refractive Surgeons. According to one of the study authors Soraya Jonker, MD, who presented the study outcomes, certain factors were pivotal in determining survival rates of pIOL.
“Using our follow-up data, we could perform survival analyses to estimate the 10- and 15-year survival rates of three types of iris-claw pIOLs,” Dr. Jonker said. “It is estimated that it will take 1 year until 25% of iris-fixated IOLs need to be explanted. We also estimated that 50% of these lenses will be explanted by 15 years after implantation. Risk factors for explantation in general, whether caused by a decrease in the endothelial cell count or due to cataract formation, include high preoperative age, longer axial length, and a smaller anterior chamber depth. Focusing on endothelial cell loss alone, we saw a few other factors determined explantation, including a smaller preoperative anterior chamber depth, a smaller preoperative endothelial cell density, and implantation with either an Artiflex myopic [Ophtec] or an Artisan hyperopic [Ophtec] lens. These were risk factors for shorter survival.”
At Maastricht University Medical Center, specialists implanted 1,037 iris-fixated pIOLs between 1998 and 2016. Yearly follow-up visits were conducted, with visual and refractive parameters, corneal topography measurements, and endothelial cell density and anterior segment OCT assessed.
At baseline, the mean age of the patients was 40 years, with 38% male and 62% female. The patients had a mean spherical equivalent of –9.6 D, preoperative IOP was 15 mm Hg, and mean endothelial cell density was 2,700 cells/mm.
Patients received one of three pIOLs: the Artisan myopia pIOL (n=466) with a mean follow-up time of 7.5 years, the Artisan hyperopia (n=77), followed for a mean 5.8 years, and the Artiflex myopia (n=494), followed for a mean 4.2 years.
“Overall, pIOL explantation in all groups was 12% and seemed to occur more frequently after the 10-year follow-up mark. However, there were differences in outcomes comparing the three implant groups,” Dr. Jonker said.
Explantation in the Artisan myopia group was due to cataract in more than 10% of cases, and endothelial cell loss occurred in 5%. In eyes with the Artisan hyperopia, 8% were explanted due to endothelial cell loss and 3% due to cataract. The highest survival rate was with the Artiflex myopia pIOL where explantation was less than 4%.
“We see different explantation rates in these groups because of the difference in follow-up time,” Dr. Jonker explained.
Looking at all explantations, Dr. Jonker observed a 75% estimated survival of 11 years and a 50% estimated survival of 15 years, using Kaplan-Meier analyses. The risk factors for shorter pIOL survival included high preoperative age, higher preoperative axial length, and smaller preoperative anterior chamber depth, according to Cox regression analyses.
Risk factors for shorter survival due to cataract specifically (7% out of the total 12% of explantations) were the same (higher age, longer eyes, smaller ACD). Those associated with endothelial cell loss (4% out of the total 12% of explantations) included a smaller preoperative anterior chamber depth but also smaller preoperative endothelial cell density and depended on the pIOL type.
“We saw that both the Artisan hyperopic and the Artiflex myopic subgroups had a higher risk of shorter survival compared to the Artisan myopic lens,” she said.

About the doctor

Soraya Jonker, MD

Maastricht University
Medical Center
Maastricht, Netherlands

Financial interests

Jonker
: None

Contact information

Jonker: soraya.jonker@mumc.nl

Long-term survival rates with three different iris-fixated phakic IOLs Long-term survival rates with three different iris-fixated phakic IOLs
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2019-07-29T15:46:33Z
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