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Phakic IOLs: Where we are and what the future will bring
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Phakic IOLs are a long-standing refractive surgical procedure that has experienced ups and downs since the early ’50s when the first implantations were performed by Strampelli and Barraquer. Three main pathways have been followed since the beginning of the development of phakic lenses. The longest and most sinuous and problematic has been the one followed by angle-supported phakic IOLs. A second, more straightforward, led to the development of iris-supported lenses, and the third, straightforward as well, is the one of posterior chamber lenses. At the start of and along each of these pathways, there are distinctive personalities that are to be acknowledged in the development of phakic implants.
Today, following many years of progress and difficulties, two types of phakic implants have survived: iris-supported IOLs and posterior chamber IOLs.
Angle-supported lenses have been discontinued due to the consistent mostly negative outcomes, even though there has been long-term success in some models.
Jorge L. Alió
Iris-supported lenses have had a more positive evolution, especially since the introduction of the foldable models, which have reduced the incision size from almost 7 mm to less than 3 mm. Indeed, new biomaterials, such as acrylic instead of silicone, will bring further benefit to this technology.
Posterior chamber lenses, since the initial PRL and ICL implants, have had problems related to implantation in a narrow space. Recently, there has been an attempt to overcome the need for peripheral iridotomy by creating holes, either at the center of or at the periphery of the optics.
These progressive advances have resulted in stable models of iris-supported lenses — the Artisan/Artiflex family (Ophtec) — and posterior chamber models, represented by the ICL models (STAAR Surgical), which are dominant in the market, to a smaller degree the PRL (Carl Zeiss Meditec) emerging again, and new models such as the one from Care Group, the IPCL. These models are going to have a positive evolution in the future and are indeed well-consolidated lenses to be used.
What can we expect in the future? Studies performed by our group have demonstrated that, as expected, the anatomy of the eye is not stable but undergoes significant changes in anterior chamber volume and crystalline lens size. This makes some of the models, which were adequately implanted in the past following the correct indication criteria, borderline today or not well fitted in the eye. This is indeed a long-term problem and a risk that has been underestimated up to now. We need to announce this to our patients as it is likely that after 15 to 20 years, all lenses should be prone to be explanted due to inadequate anatomy and, probably, the onset of complications.
With this in mind, what is the role of phakic IOLs at this moment? If we think that we are offering these lenses to highly disabled refractive patients, what we offer is good science-based technology, with an adequate background of knowledge and clinical testing, and indeed a realistic view of what can be expected in the future. The informed consent should offer patients information about what is happening now, what has happened in the past and what can happen in the future. Positive information has to be included about the good outcomes obtained in terms of refractive correction and visual outcomes. The anatomical hazards and especially the evolutionary condition of the human eye should also be acknowledged, together with the criteria that make patients eligible for this type of implant. Patients should know that regular follow-up is needed to monitor the safety of the implant in the eye, but also because all high myopes and high hyperopes should undergo periodic exams to assess the evolution of their clinical condition. They should know as well that long-term complications may occur, not related to the lens but rather to changes in the eye anatomy.
All things considered, phakic IOLs, if properly selected and indicated, are today a well-established and mature refractive surgical approach for the correction of moderate and high myopia, hyperopia, astigmatism and probably also presbyopia. The designs that have survived the test of time are proven by evidence. Indeed, continuously striving for excellence, to which science and industry together are committed, will lead to the development of new designs, new biomaterials and probably new perspectives in the use of these lenses.
Phakic IOLs are here to stay and will continue to have a role in the future of refractive surgery.
- References:
- Alió JL, Perez-Santonja JJ. Refractive Surgery with Phakic IOLs: Fundamentals and Clinical Practice. 1st ed. New Delhi, India: Jaypee Brothers Medical Publishers; 2004.
- Alió JL, Perez-Santonja JJ. Refractive Surgery with Phakic IOLs: Fundamentals and Clinical Practice. 2nd ed. New Delhi, India: Jaypee Brothers Medical Publishers; 2013.
- Alió JL, et al. Am J Ophthalmol. 2013;doi:10.1016/j.ajo.2013.06.018.
- Javaloy J, et al. J Refract Surg. 2007;doi:10.3928/1081-597X-20070201-07.
- For more information:
- Jorge L. Alió, MD, PhD, is an OSN Europe Edition Board Member. He can be reached at Vissum Corporation, Avenida de Denia, s/n, 03016 Alicante, Spain; email: jlalio@vissum.com.
Disclosure: Alió reports he is a clinical investigator for Care Group and Tekia.