Smart lenses

Smart accommodative lenses using advanced electronics to enable accommodation may be the future of surgical presbyopia correction, Dimitri T Azar MD, MBA, told Cornea Day at the 2016 American Academy of Ophthalmology Annual Meeting in Chicago. In his Castroviejo Lecture of the Cornea Society, Dr Azar, who recently joined Verily, the healthcare subsidiary of Alphabet, and remains Dean of the College of Medicine at University of Illinois at Chicago, reviewed the history of surgical presbyopia correction. Each has its advantages and drawbacks, and many of these may be addressed with smart lenses. CURRENT APPROACHES Smart lenses are just one surgical remedy for presbyopia, Dr Azar noted. Monovision is still an option, and the one currently most often chosen by ophthalmologists for treating their own eyes, he said. It has an 81% success rate in surgically treated myopes, though it significantly reduces binocular contrast sensitivity and task performance. Bifocal or progressive glasses are still needed in many cases, though monovision reduces dependence on them. Extensive patient counselling to explain what it is and what to expect is often required, he said. Laser corneal surgery techniques include Presby-LASIK, which may enhance near vision with multifocal transitional profiles, a peripheral Presby-LASIK zone or a central Presby-LASIK zone. However, it does not work well in many patients and the effect may regress over time, Dr Azar said. Even so, it is viable for some patients. Corneal inlays are another approach, Dr Azar said. These include the AcuFocus KAMRA inlay based on the aperture effect, the hydrogel Raindrop, which changes the central corneal profile. Other inlays involve refractive approaches, such as the FlexiVue 3.0mm lens and others. These lenses’ effects are dependent on placement, and optimal placement may vary. “As corneal surgeons we love this challenge,” noted Dr Azar. Multifocal intraocular lenses (IOLs) also remain viable despite glare and halos, Dr Azar said. Asymmetric optic approaches, where only a portion of the lens provides a near add, such as the Lentis Mplus LS-312 IOL, suggest the possibilities of multifocal lenses have not played out completely. THE FUTURE Dr Azar’s experience with smart lens technology goes back to research he conducted with colleagues at the Massachusetts Eye and Ear Clinic. He holds several patents on accommodating eyeglasses dating from 2008, and believes the same approach can be applied to smaller lenses. “The idea is very simple. You need a controller and an actuator that drives the change in the power of the lens, and a sensor that can feed the information [for accommodation]. All this can be incorporated into a contact lens, a phakic IOL, or a corneal inlay,” Dr Azar said. The accommodative mechanism is also flexible; for example, it may be a movable multi-optic lens, a deforming liquid optic, a variable refractive index lens, or a custom lens based on wavefront and pupil dynamic characteristics, he added. Dr Azar has been collaborating with Verily and Alcon, a subsidiary of Novartis where he is a board member, on an accommodative contact lens. They are building wireless sensors into a variable refractive index lens using advanced sensors and miniaturised low-power electronics driven by data analytics that learn over time. Glucose-sensing and accommodative lenses are in pre-clinical phases, as is an IOL, Dr Azar said. Other smart lenses in development include the Elenza Sapphire AutoFocus IOL, which accommodates by changing refractive index. It initiates near accommodation by sensing pupil constriction and lighting conditions associated with a near vision tasks, but can also avoid accommodation if the changes are related to the environment rather than a near task. Accommodating designs including the PowerVision FluidVision, the NuLens Dynacurve and the FlexOptic IOL also may benefit from smart technology. “My personal experience and opinion is that accommodating contact lenses and IOLs are the future. These are in preclinical evaluation and early research and development,” Dr Azar concluded. Dimitri Azar: dazar@uic.edu

Tags: IOLs