Anterior chamber angle-supported phakic intraocular lenses have now become a viable alternative for the correction of moderate and high refractive errors with excellent levels of efficacy, predictability and safety.
Do the pros outweigh the cons?
The main advantage afforded by this procedure is the ease of phakic IOL implantation with conventional instrumentation. The anterior segment surgeon requires no additional training in the majority of cases, even when using the latest IOL designs. It is now clinically proven that the implants do not induce cataract formation or glaucoma and, issues relating to the damaging effects on the corneal endothelium should not apply, so long as appropriate models and rules indicated for each lens are followed.
Each phakic IOL has its own method of correcting moderate to high refractive errors, including astigmatism, each improving or at least preserving the optical quality of the eye. More modern designs, however, may also correct significant aberrations that the eye may harbour naturally, in addition to refractive errors. Together with the potential for exchangeability with the newer lenses, which would certainly prove beneficial as the patient ages, phakic IOLs, in my opinion, have a promising future ahead.
Making way for the new generation
The AcrySof phakic anterior chamber implant, the Duet Kelman lens, the ICARE lens and the Vivarte lens make up the latest generation of anterior chamber phakic IOLs, each demonstrating some form of improved performance and, in some cases, distinct advantages over previous models.
The Kelman Duet implant has recently patented a multi-focal optic that will correct presbyopia simultaneously with far vision correction, either for hyperopia or myopia. The optic is defractive in nature, and is expected to be used in patients to correct moderate to high refractive errors at a presbyopic age. An exchange of the regular myopic or hyperopic optic for this multi-focal optic is an attractive option for patients implanted in the non-presbyopic age range once the presbyopic age is reached. This optic is expected to be manufactured with two different powers for near vision depending on the magnitude of presbyopia.