COMMENTARY

Ten-Year Study Details Post-Intraocular Collamer® Lens Cataract Risk and Benefits

Christopher J. Rapuano, MD

Disclosures

October 05, 2016

Clinical Outcomes and Cataract Formation Rates in Eyes 10 Years After Posterior Phakic Lens Implantation for Myopia

Guber I, Mouvet V, Bergin C, Perritaz S, Othenin-Girard P, Majo F
JAMA Ophthalmol. 2016;134:487-494

Study Summary

Between 1998 and 2004 at one Swiss hospital, 133 eyes (78 patients) underwent placement of a V4 model implantable Collamer® lens (ICL; Staar Surgical, Monrovia, California), a phakic posterior chamber intraocular lens, with the results retrospectively reviewed in 2014. Most of these procedures were performed before the toric version or extended ranges of this particular lens were available, so emmetropia was not always the goal. Seventy-five eyes (56%; 45 patients) were examined at the 10-year follow-up appointment, 15 (11%) had undergone cataract surgery prior to that point, and the remaining 32% of eyes were lost to follow-up.

Sphere and cylinder refractive results, uncorrected and best-corrected visual acuity results, and endothelial cell counts appeared stable over 10 years. Thirteen percent of eyes developed ocular hypertension requiring intraocular pressure (IOP)-lowering treatment. Lens opacity developed in 41% and 55% of eyes at 5 years and 10 years, respectively. Cataract surgery was performed in 5% and 18% of eyes by 5 and 10 years, respectively. The authors found that the less the vault between the crystalline lens and the ICL, the greater the risk for a lens opacity (P=.008) and of undergoing cataract surgery (P=.005).

Viewpoint

While the general category of refractive surgery may not be as popular in the United States or around the world as it was 10-15 years ago, I do not believe that it is because the results are any worse. In fact, I truly believe that the results are better. I primarily perform corneal transplant surgery and feel that I often "give the gift of sight." Having said that, many of my refractive surgery patients are the happiest ones in my entire practice and often tell me that it was a life-changing event.

I have performed many radial keratotomy, astigmatic keratotomy, photorefractive keratectomy (PRK), and laser-assisted in situ keratomileusis (LASIK) surgeries over the years; however, I was always reluctant to implant phakic intraocular lenses. It wasn't that I thought that the short-term refractive results were poor; in fact, for the high myopes who are not good candidates for corneal refractive surgery such as PRK and LASIK, the results were excellent. Instead, I was always most worried about the long-term complications, especially endothelial cell loss, glaucoma, and cataracts.

While this study is the largest and longest that I'm aware of looking at long-term complications of the ICL, it still isn't huge, and about one third of eyes were lost to follow-up at 10 years. Having said that, I was happy to see that there was no loss in mean endothelial cell density over 10 years.

Although there is no control group, 13% of eyes developing ocular hypertension requiring IOP-lowering treatment is certainly troubling, especially in this relatively young population (mean age of 39 years at ICL surgery).

Of considerable concern is the rate of cataract formation and the need for cataract surgery, again especially in this young but also highly myopic population (mean preoperative spherical equivalent, -11.4 diopters). As noted, the researchers found that the less the vault between the crystalline lens and the ICL, the greater the risk for a lens opacity and of undergoing cataract surgery. The authors suggest that in order to maintain an adequate vault height for greater than 10 years to decrease the risk for cataract formation, the immediate vault height after surgery should be greater than 550 µm. This is important information for surgeons to keep in mind.

All surgery carries an inherent risk, but it is universally agreed that the risk for cosmetic surgery must be kept particularly low. Although many people might consider refractive surgery in a patient who is a -11 diopter myope as "cosmetic surgery," most of these patients certainly have functional issues, especially if they cannot wear contact lenses (which carry their own not insignificant risk).

High myopes are functionally blind without optical correction. A patient of mine almost had a panic attack when her home fire alarm went off, and she couldn't immediately locate her glasses to find her way to her young daughter's room (fortunately, it proved a false alarm). Even with glasses, images are substantially minimized and peripheral vision distorted. These are the patients who find refractive surgery a "miracle cure."

This paper gives surgeons some direction on how to minimize the risk for cataract formation. It also provides some additional information for patients, including the fact that they will require continued follow-up examinations to monitor for long-term issues.

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