Affecting over two billion people worldwide, presbyopia is extremely common in people over 40. Ageing affects the flexibility and thickness of the natural lens of the eye, so as the lens hardens, when looking at close objects, the eye has difficulty focusing light on the retina. As the eye begins focusing light behind the retina, close-up vision becomes blurry.
Although corneal inlays have been studied for almost five decades, Kamra was the first FDA-approved corneal inlay (April 2015), followed by Raindrop (June 2016). Until this date, these two are the only FDA-approved corneal inlays. Both inlays are implanted in only one eye and are removable.
Corneal inlays have recently become a preferred solution for treating presbyopia not only because of their non-intrusive nature – or because they can be removed if, for any reason, the patient changes their mind – but also due to a few different advantages that make them more desirable than other forms of corrective eye surgery. For instance, the corneal inlay procedure is limited to the cornea, making it much safer than other more intrusive intraocular procedures. Again on the plus side, it can be combined with other refractive procedures, either following or simultaneously, depending on the type of the other procedure. At the same time, imaging and examination of the eye aren’t in any way affected by corneal inlays, and there is no risk in the appearance of defects in the visual field.
Kamra, a ring-shaped implant, increases focus depth through a pinhole effect giving the eye the ability to accommodate at near objects. A study conducted on 180 patients showed significantly increased quality of overall vision with emmetropic and hyperopic patients; however, the increase was not so significant in myopic patients.
A more recent study was conducted on 223 patients who previously underwent LASIK surgery. Within six months after Karma implantation, the patients’ dependence on reading glasses was significantly decreased, and their overall vision significantly increased.
Raindrop, a meniscus-shaped implant, improves near and intermediate visual acuity by creating a multifocal cornea. Unlike Kamra, Raindrop inlay hasn’t been studied on patients who underwent nearsightedness corrective LASIK surgery in the past. Nonetheless, findings from a study of 373 patients suffering from moderate presbyopia showed that two years after the implant, 92% of the patients had significantly improved their near vision.
The potential side effects may include scarring, dry eye or infection, and the surgery is currently not covered by insurance. Although both corneal inlays look promising, a doctor might prefer the specific features of one versus the other. Of course, surgeons that have been professionally trained in corneal implantation are recommended.
Be sure to do your own research before opting for a corneal inlay implant, and consult with a specialist in order to see if other surgical options might be the better choice for your specific needs.