Modular IOL Systems Add to Ophthalmologists' Armamentarium

Sumit (Sam) Garg, MD


January 20, 2022

Intraocular lens (IOL) design has continued to evolve since being introduced in 1949. We have seen an evolution not only in design, but also in material, optics, safety, and efficacy, among other things. Over the years, there has been promise of "new" designs, many based on trying to replicate the natural accommodative mechanism of the eye. Recently the Light Adjustable Lens (RxSight) has gained popularity in the United States. Of interest to me is the various proposed options of IOLs (or scaffolding systems) that allow for modularity.

Despite great advances in biometry — improved diagnostics, improved formulas, improved management of the ocular surface — IOL power errors still can occur. We all recognize that certain eyes (such as post refractive surgery, short/long axial length, abnormal anatomy) have a higher chance of refractive misses. Additionally, a patient's desired refractive target may change with time and/or they may not be happy with their initial refractive outcome of quality of vision (such as dysphotopsia). Modular IOL systems allow for easier exchangeability if needed. Often, an IOL exchange can be very straightforward, but there is always a chance for complication (commonly posterior capsular tear and vitreous loss). Modular IOLs may help us manage many of these issues and allow for safer IOL exchange.

In this installment of Viewpoints, I'll discuss a paper from Ang and colleagues in which they present visual outcomes after optic exchange from a modular IOL (Harmoni Modular IOL [HMIOL]; ClarVista Medical). The HMIOL consists of a base component that resembles a traditional IOL with the exception that the optic component is modular and is assembled once the base is placed in the capsular bag. The study of 114 participants had the HMIOL placed in the nondominant eye and set for a monovision target (-1.50 refractive target), with a contralateral control monofocal IOL set for distance. At 3 months, the cohort was assessed for satisfaction with their monovision. If unsatisfied, the patients were offered an optic exchange for a distance goal. The study did not specifically report safety measures (to be reported separately) but did allude to overall ease of exchange in the patients who elected to do so (65 eyes), with improvement of distance vision and a very high percentage achieving their refractive target. Overall, the patients had good visual outcomes with nearly all patients achieving corrected distance visual acuity of 20/40 or better (12 months after last intervention).

Certainly, this is an initial report of a novel IOL. What is most interesting to me is the possibility of "easier" IOL exchange in patients who would want or need it. The mechanics of how this will work in our clinics is something that will need to be figured out, but the promise of being able to change or "upgrade" an optic for a patient with minimal risk is appealing. The Light Adjustable Lens allows for great accuracy up front, but with the current iteration of the technology, patients cannot change their mind after the IOL is "locked in." Modular lenses, such as the HMIOL, may allow us to exchange the optic of an IOL initially (in the case of a large refractive miss, such as post-refractive eyes), or in the future if the health of an eye changes. Imagine being able to safely change a multifocal optic to a monofocal if a patient develops a visually significant epiretinal membrane or advancing glaucoma. Our current and growing armamentarium of IOLs is allowing us to give patients many options in regard to visual outcomes; however, we still have problem eyes with refractive misses and still have patients who are not happy with visual outcomes. With continued advances in IOL designs, I am hopeful that modular lenses/systems will become a commercially viable option for us in the not-too-distant future.

Sumit (Sam) Garg, MD, is the vice chair of clinical ophthalmology and an associate professor in the Department of Ophthalmology at the Gavin Herbert Eye Institute, University of California, in Irvine. He specializes in corneal and cataract surgery as well as laser refractive surgery.

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