Macular degeneration isn’t always caused due to old age; however, it is one of the major causes for visual impairment in the elderly (people above 50 years of age), and in its worse forms leads to the inability of reading or recognizing faces. This condition usually begins with characteristic yellow deposits in the macula (an oval-shaped, highly pigmented yellow spot near the center of the retina of the human eye). When combined with another visual ailment called Drusen, the risk for permanent damage is even higher.
Up until now, the common treatment for age-related macular degeneration (AMD) is an injection of a drug named Avastin, a humanized monoclonal antibody that recognizes and blocks vascular endothelial growth factor (VEGF); the blocked VEGF is a chemical signal which stimulates the growth of new blood vessels. Though proven effective, the treatment of Avastin interferes in a significant number of cases with the process of blood vessels’ growth. Moreover, it sometimes worsens conditions like coronary artery disease or peripheral artery disease.
Now, NeoVista is developing an alternative treatment to AMD, one that might lead to fewer side effects. The base for this treatment is beta radiation; similarly to the aforementioned anti-VEGF therapy, the new technique affects the abnormal blood vessels of AMD by slowing the development of new vessels and reducing inflammation, resulting in the macula’s return to its normal position. One of the main advantages the NeoVista procedure offers is the small number of treatments: it is only performed once, and patients receive only two doses of an anti-VEGF drug.
The new method is relevant only in the “wet” AMD state, which causes vision loss due to abnormal blood vessel growth in the choriocapillaris, ultimately leading to blood and protein leakage below the macula. It is not applicable for patients that suffer from AMD caused by central geographic atrophy, the “dry” form of advanced AMD. The reason is that this form results from atrophy to the retinal pigment epithelial layer below the retina, and not from abnormal blood vessel growth.
According to NeoVista, the treatment being used in the pivotal study utilizes a typical vitrectomy, which is a surgery to remove some or all of the vitreous humor from the eye. This procedure is combined with radiation delivered using the new system. This radiation is highly focused; the reason is the need to penetrate the target area to a depth of only 3 mm, while covering an area slightly larger than 5 mm in diameter.
Thanks to beta radiation’s attributes – mainly its rapid dissipation – normal tissues are less affected in comparison to other forms of radiation-based treatments. Therefore, application is not only more accurate but more localized. For patients, the meaning is that the risk of radiation-induced toxicity is reduced significantly. Other benefits reported include usage of only local anesthesia, and a short period of time required from the patient: the entire procedure usually takes less than an hour.
TFOT has also covered the development of contact lenses that can automatically dispense drugs to the eye for up to 30 days at a time, and the invention of acoustic maps to aid the blind, made by Researchers at the University of Bristol, England. Another related TFOT story is Professor Yaroslavsky’s theory, which claims that humans have an ability to see through their skin.
For more information about NeoVista’s innovative study, see their website.