Corneal implants will replace reading glasses for old people
According to statistics, about a billion people suffer from presbyopia (senile hyperopia) in the world. The reason for the development of this condition, characterized by a decrease in visual clarity at close range, is an age-related decrease in the elasticity of the cornea of the eye and a change in its curvature. As a rule, people resort to reading glasses to eliminate this visual defect. However, experts believe that this inconvenient accessory, which has to be removed or put on depending on the type of activity, can be successfully replaced with corneal implants, also known as corneal rings.
Currently, there are three types of such implants under consideration by the US Food and Drug Administration (FDA). One of them, known as the KAMRA implant, is an elastic ring in the shape of a donut, the outer diameter of which is 3.8 mm, and the diameter of the central hole is 1.6 mm. After implantation into the cornea, performed under local anesthesia and taking no more than 10 minutes, the implant functions as a camera diaphragm that corrects the depth of field to ensure good visibility of both near and distant objects. (Here and below are Clearview Institute illustrations.)
Researchers at the University of Wisconsin, working under the leadership of John Vukich, conducted a prospective non-randomized clinical trial of the KAMRA implant involving 507 patients with senile hyperopia who do not suffer from myopia. The age of patients living in the USA, Europe and Asia ranged from 45 to 60 years.
After implantation of the corneal ring, the patients' vision level was monitored for 3 years. For 83% of the operated eyes, the KAMRA implant maintained visual acuity at 20/40 or higher, which corresponds to the standard value considered sufficient for reading newspapers and driving a car without corrective lenses. On average, the operation improved the results obtained by patients when passing the reading test by 2.9 lines. According to the authors, the registered improvements persisted throughout the entire observation period.
The main undesirable side effect of the intervention was the appearance of blurred vision, which disappeared when taking steroid drugs. Moreover, the improvement of the implant shape has reduced the frequency of occurrence of such manifestations. If necessary, the implant can be removed, which makes this approach reversible, unlike other surgical interventions, for example, the LASIK procedure used to correct hyperopia.
Currently, KAMRA corneal rings are already available in a number of regions, including Asia, Europe and South America. In the US market, they, as well as alternative corneal implants Raindrop Near Vision Inlay and Presbia Flexivue Microlens, will appear after receiving FDA approval.
The results of the work were presented at the 118th Annual Congress of the American Academy of Ophthalmology, held on October 17-21 in Chicago.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of the American Academy of Ophthalmology:
Could Reading Glasses Soon Be a Thing of the Past?
21.10.2014