The FDA has approved the first implantable lens that can be adjusted after cataract surgery using ultraviolet light to improve patients’ vision, possibly eliminating the need for eyeglasses or contacts.
The Light Adjustable Lens (RxSight Inc.) is made of a unique material that reacts to ultraviolet (UV) light, which is delivered by RxSight’s Light Delivery Device 17 to 21 days after surgery. Patients receive three or four light treatments over a period of one or two weeks, each lasting about 40 to 150 seconds, depending upon the amount of adjustment needed. The patient must wear special eyeglasses for UV protection from the time of the cataract surgery to the end of the light treatments to protect the new lens from UV light in the environment.
Cataracts are a common eye condition where the natural lens becomes clouded, impairing a patient’s vision. Following cataract surgery, during which the natural lens of the eye that has become cloudy is removed and replaced with an artificial lens (intraocular lens [IOL]), many patients have some minor residual refractive error requiring use of glasses or contact lenses. Refractive error, which is caused when the artificial lens does not focus properly, causes blurred vision.
“Until now, refractive errors that are common following cataract surgery could only be corrected with glasses, contact lenses, or refractive surgery,” said Malvina Eydelman, MD, director of the Division of Ophthalmic, and Ear, Nose, and Throat at the FDA’s Center for Devices and Radiological Health. “This system provides a new option for certain patients that allows the physician to make small adjustments to the implanted lens during several in-office procedures after the initial surgery to improve visual acuity without glasses.”
The device is approved for patients with pre-existing astigmatism of at least 0.75 diopters undergoing cataract surgery.
FDA approval was based on results of a U.S. randomized, pivotal study comparing the Light Adjustable Lens to a commercially available monofocal lens in 600 patients with pre-existing astigmatism at 17 investigational sites. Patients receiving the Light Adjustable Lens, followed by light treatment with the Light Delivery Device, achieved uncorrected visual acuity of 20/20 or better at six months postoperatively at approximately twice the rate of patients receiving a monofocal lens. In addition, 91.8% of Light Adjustable Lens patients achieved a result that was within 0.50 diopters of target manifest refraction spherical equivalent, which is similar to the refractive accuracy seen in recent LASIK studies.
Study safety parameters were based on a comparison to the safety and performance endpoints for intraocular lenses, and results showed that 100% of study eyes had a best corrected visual acuity of 20/40 or better at the six month post-operative visit. The approved device allows correction of up to 2 diopters of post-operative sphere and/or –0.75 to –2 diopters of residual postoperative refractive cylinder.
The device is intended for patients who have astigmatism (in the cornea) before surgery and who do not have macular diseases.
The device should not be used in patients taking systemic medication that may increase sensitivity to UV light, such as tetracycline, doxycycline, psoralens, amiodarone, phenothiazines, chloroquine, hydrochlorothiazide, hypercin, ketoprofen, piroxicam, lomefloxacin, and methoxsalen. Treatment in patients taking such medications may lead to irreversible eye damage. The device is also contraindicated in cases where patients have a history of ocular herpes simplex virus.
Sources: FDA; November 22, 2017; RxSight Inc.; November 22, 2017.