Refractive Changes Still Occur After Foldable Iris-Fixated pIOL Implantation

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Patients implanted with foldable iris-fixated phakic intraocular lenses may experience annual changes in refractive error, visual acuity, and axial length, making the devices a long-term, but not permanent solution.

Visual acuity can significantly decrease in a 5 year span for patients implanted with some foldable iris-fixated phakic intraocular lenses (pIOL), according to research published in the Journal of Cataract & Refractive Surgery. The changes are likely due to myopization caused by lenticular changes and axial length (AL) elongation, researchers say.

Researchers at the University Eye Clinic Maastricht, the Netherlands, conducted a prospective case series to evaluate long-term refractive, visual, and morphometric changes after implantation with a foldable iris-fixated pIOL to correct myopia or astigmatism.

All patients were implanted with an iris-fixated pIOL from January 2004 to June 2016. The team performed measurements annually and reported results on longitudinal visual, refractive, and morphometric outcomes, with up to 5 years of follow up.

A total of 481 eyes of 277 patients (mean age, 39.8±10.9 years; 64% women, 36% men) were included in the study. The mean preoperative corrected distance visual acuity (CDVA) and anterior chamber depth (ACD) were 0.003±0.10 logarithm of the minimum angle of resolution (logMAR) and 3.25±0.34 mm, respectively. The mean follow-up duration was 51±37 months.

At 5 years postoperatively, the researchers found that 91% of eyes were within  ±1.0 D of target. The mean myopization was 0.22 D (P <.001), and the logMAR CDVA increased by a mean 0.015 logMAR (P =.015). CDVA of 20/20 or better was achieved in 88% of eyes. Loss of 2 or more lines of CDVA was observed in 5.5% of eyes. The researchers found that the mean uncorrected distance visual acuity (UDVA) increased by 0.045 logMAR over the 5-year period (P <.001), and UDVA of 20/40 or better was achieved in 96% of eyes. 

In the 5-year period, the team also observed that ACD decreased by 0.04 mm (P <.001), while AL increased by 0.23 mm (P <.001). They found that chronic endothelial cell loss declined by 320 cells/mm2 in the myopic subgroup and 310 cells/mm2 in the toric subgroup (P <.001). 

Explantation of the pIOL was reported in 4.0% of eyes due to cataract (mean survival, 59.0±40.0 months). The researchers found that greater preoperative age (hazard ratio [HR], 1.13; P <.001) and shorter ACD (HR, 6.80; P =.035) were risk factors for shorter survival due to cataract formation.

“The main finding of this study is a slight deterioration of all visual and refractive parameters that can be attributed to age-related increase in crystalline lens thickness and AL elongation,” according to the researchers. “Phakic IOLs should not be considered a permanent solution for refractive errors and regularly be followed up to monitor safety and efficacy.”

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.  


Jonker SMR, Berendschot TTJM, Ronden AE, Saelens IEY, Bauer NJC, Nuijts RMMA. Changes in visual outcomes and ocular morphometrics after foldable myopic and toric intraocular lens implantation: 5-year results. J Cataract Refract Surg. 2022;48(4):393-400. doi:10.1097/j.jcrs.0000000000000772