BLOG: RLE risk vs. benefit discussion critical in this elective procedure
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This entry will continue where last month’s discussion on refractive lens exchange patient selection, limitations and risks left off.
In many ways patient selection for refractive lens exchange (RLE) is similar to the more familiar LASIK work-up, although RLE treats both a wider prescription and age range. Any refractive candidate, whether corneal (LASIK) or intraocular (RLE), needs to have a stable prescription for at least 2 years. Pregnant or nursing patients should not be considered.
But an additional concern when considering RLE is that some patients have extreme prescriptions and axial lengths. This can put someone out of the available prescription range for some of the specialty implants (toric IOL and multifocal IOL). Then, even if the lens is available, these patients still need to meet the same stringent requirements to be a good multifocal IOL candidate, including normal corneal and macular health plus normal corneal topography.
Of course, no matter how good a candidate a patient is on paper, any surgery carries risk. Because RLE is the same surgical technique as cataract extraction (CE) only with a clear crystalline lens, one should expect the same postoperative risks as CE: endophthalmitis, macular edema, posterior capsular opacification and retinal detachment (RD). However, the risk of RD is higher in refractive lens exchange than in cataract surgery, likely because the patient population tends to have high ametropia and is younger. RD has an incidence of 1.5% to 2.2% in RLE (Alió et al.), while it is cited at only 0.7% with routine CE (Kassem et al.). This should not come as a surprise.
Even taking surgery out of the picture, in a normal population RD occurs in one out of 8,500 eyes (Alió et al.). These odds increase to one out of 850 eyes in cases of myopia greater than –10.0 D or axial length greater than 26.0 mm (Alió et al.). Again, this is in nonoperated eyes; we know there is already a higher incidence of predisposing retinal lesions in highly myopic eyes.
Then when it comes to surgery, there is the added risk for iatrogenic factors that increase the incidence of RD postoperatively. Surgical complications such as capsular tear or vitreous loss are known to increase the postoperative risk for RD. However, even in an uncomplicated surgical case, after removing the natural lens and implanting a much thinner IOL we induce a forward movement of the vitreous, which can cause traction on the retina and may lead to an RD. Understanding this mechanism, we can see that presence of a posterior vitreous detachment is protective, lowering the postoperative risk of RD after RLE. In other words, older age is protective for postoperative RD, while younger age, the patient population seeking RLE, incurs higher risk for postoperative RD.
With any refractive surgery, it is important to hit the concept of risks vs. benefits rather hard. These are cosmetic procedures, and the patient needs to make an informed decision about whether they would like to proceed. We all know this, but it is still worth mentioning: Refractive lens exchange is largely not covered by insurance plans and is not an inexpensive procedure, but I learned a long time ago to not assume what a patient is willing to pay when it comes to their vision.
This can feel like one of the most life-changing surgeries we offer, treating the widest prescription and age range of any refractive surgery, and patients can treat their presbyopia with a multifocal IOL, a refractive option that is only available with RLE. Weighing the risks and benefits of each refractive option for the patient in front of them, a savvy referring OD should be comfortable identifying a good refractive lens exchange candidate.
References:
- Alió JL, et al. Eye Vis (Lond). 2014;doi:10.1186/s40662-014-0010-2.
- Kassem R, et al, J Ophthalmol. 2018;doi:10.1155/2018/9206418.
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