Phakic IOLs Maintain Stability, Predictability After 15 Years

Silicone phakic intraocular lenses (pIOLs) sit fairly close to the corneal endothelium, which has the potential to reduce a patient’s endothelial cell density (ECD). But results of a 15-year study published in the Journal of Cataract and Refractive Surgery shows that, when factors such as anterior chamber depth (ACD) are considered beforehand, the implants can provide stability and predictability. 

The prospective clinical study provides data after 15 years of wear with the Artiflex Myopia pIOL (Ophtec B.V.), and 12 years with Artiflex Toric pIOL (Ophtec B.V.). Lenses were implanted from 2003 to 2011 at Centro Hospitalar Universitário do Porto, Portugal. Participants were at least 21 years of age with a stable refraction for more than 2 years. After the first year, patients were examined annually.

The study looked at 217 eyes of 133 patients who received an Artiflex pIOL (30.83% men and 69.17% women, mean age 32.32±5.74 years). The Artiflex Myopia was implanted in 142 eyes of 83 patients (with powers ranging from -3.00 to -14.5 D), and the Artiflex Toric in 75 eyes of 50 patients (with spherical power ranging from -1.00 to -13.50 D, and cylindrical power ranging from -1.00 to -5.00 D). 

Mean preoperative spherical equivalent of -8.36±2.75 improved to -0.11±0.31 for individuals 5 years after surgery (P <.001). At 10 years, the spherical equivalent increased to -0.33±0.62, and at 15 years to -0.80±1.32. Refractive cylinder at baseline was -1.27±1.23, improving to a 5-year mean of -0.10±0.36 (P <.001). Ten-year cylinder increased slightly to -0.25±0.50, and to -0.57±0.79 at 15 years after implantation.

Corrected distance visual acuity (CDVA) was assessed to analyze safety. Seventy-four percent of participants achieved 20/20 or better at 5 years, 68.5% after 10 years, and 60.5% at 15 years. To show efficacy, uncorrected distance visual acuity (UDVA) of 20/20 or better was assessed, and exhibited by 73.0% after 5 years, 57.9% at 10 years, and 50.0% in 15 years.

However, mean ACD of 3.25±0.26 mm at baseline measured lower at each 5-year assessment, with an overall reduction to 2.81±0.24 mm after 15 years. Mean ECD decreased significantly at each 5-year mark (all P <.001), from approximately 2850 cells/mm² before surgery to slightly more than 2110 cells/mm² at 15 years.

Cumulative probability of success was based on American Academy of Ophthalmology (AAO) recommendation of the end point at least 25% endothelial cell loss, and French Health Products and Safety Agency (AFSSAPS) advises explantation at ECD of fewer than 1500 cells/mm². In this study, 7.2% exhibited an ECD reduction of at least 25% in 5 years, 24.3% had this amount of decrease at 10 years, and 35.1% after 15 years. None displayed ECD fewer than 1500 cells/mm² 5 years after receiving a pIOL, but 3.4% reached this benchmark at 10 years, and 10.5% in 15 years.

“The median survival time (i.e. time until 50% reached the AAO endpoint or AFSSAPS explantation criterion) was 15.00 years,” according to the investigation. Investigators conducted univariate analyses and found 3 factors were significantly predictive of endothelial cell loss: pre-surgery age, ACD, and ECD (all P <.001). In fact, the research suggests that preoperative “ACD lower than 3.00 mm should be an exclusion criterion for Artiflex pIOLs implantation.”

A study limitation was that additional, potential risk factors for endothelial cell loss were not scrutinized, such as distance from center and peripheral surfaces of the pIOL to endothelial layer. Strengths involved a fairly large sample, and strong percentages of patients who attended follow-up exams; 199 of 217 individuals completed a 5-year follow-up, 187 of 217 the 10-year visit, and 43 of 45 a 15-year examination.

Reference

Marta A, Leite J, Abreu AC, et al. Long-term results in patients with iris-fixated foldable phakic intraocular lens for myopia and astigmatism. J Cataract Refract Surg. Published online February 11, 2022. doi:10.1097/j.jcrs.0000000000000914