Soon, a drop a day might help to keep vision loss at bay. Scientists have said that they may finally have found a treatment that is actually effective for age-related macular degeneration (AMD), which is the number one cause of blindness in the elderly. Best of all, it could be provided in eye drops.
AMD cannot be cured, and there is no truly effective form of treatment either. Ninety percent of people with AMD have ‘dry’ AMD, which is a slowly progressing form of the condition. Wet AMD is different in that it is very rare and progresses very quickly. It is now hoped that the drops will help to provide a real treatment for dry AMD.
Some 2 million people in this country are currently diagnosed with AMD, according to statistics released by the Centers for Disease Control and Prevention. A number of studies have taken part in AMD and possible treatment options, with the most famous one being the AREDS (age-related eye disease study) and AREDS 2, which determined that specific supplementation may help slow down the progression of AMD.
Wet AMD, by contrast, requires injections in the eye twice a month. This stops new blood vessels from forming. In most cases, people are injected with Avastin, which is a bevacizumab cancer drug.
The latest research was completed by Tufts University in Massachusetts, under the guidance of Rajendra Kumar-Singh, associate professor of ophthalmology. The work is classed as a ‘proof of concept’ study and was completed on mice. They found that the PPADS (pyridoxalphosphate-6-azophenyl-2′,4′-disolfunic acid) is able to repair damage to the eye caused by AMD.
It is a known fact that AMD is caused, in part, due to high levels of MAC (membrane attack complex). MAC is a normal part of our immune system, which forms when bacteria invade the system. However, if someone has AMD, MAC targets retina cells as well, leading to loss of vision. PPADS is believed to interfere with MAC, as well as with the growth of new blood vessels. The latter is significant for wet AMD.
The mice were first anesthetized, after which tissue damage was induced, as was blood vessel growth. PPADS was then applied every day. From there, researchers observed the eye damage heal over time. According to Kumar-Singh, human trials have not yet commenced. When they do, however, a refined form of PPADS would be used.
It is the first time that there has been any suggestion of a possible cure or even treatment for AMD that is truly effective and that can be applied topically. This means it doesn’t have to be injected or ingested to be effective. Other scientists have expressed to be very intrigued by the results, particularly because it is based on solid scientific evidence.
The study is now available for peer review, as it has been published in an open sourced journal through a non-profit organization. This adds further credence to the validity of both the study and the results. The authors have encouraged people to look into it and to review the findings. They hope that, eventually, an eye drop can be developed that can be self-administered by patients.
Understanding Dry AMD
Dry AMD is known as ‘atrophic’ AMD, and it is the most common form. It is not known what causes it, nor why it is so slow to progress. No approved treatments exist at present. In people with AMD, the eye starts to form drusden, which are white or yellow deposits, degenerating and destroying the macula. The macula is needed for central vision, which is what is lost over time in people with AMD.
Understanding Wet AMD
Wet AMD is very different. It involves the formation of abnormal blood vessels under the macula. These blood vessels are weak and break and burst, filling the area with blood. This often leads to full macula detachment and, possibly, blindness.
Current Treatment Options
People with dry AMD in intermediate stages are recommended to take AREDS 2 supplementation. This is the only supplement that has been found to show some effectiveness in slowing down progression. However, it only works when AMD is already intermediate. People with wet AMD, by contrast, have to receive injections in the eye to stop the growth of further blood vessels.
The recent study focused specifically on creating eye drops for people with wet AMD. However, it now appears that they could be beneficial for dry AMD as well. Further studies will be required and it is likely to be a number of years before a proper formulation has been designed, tested and is approved for usage. It is also not clear whether these drops will be available over the counter or on prescription, although the latter is more likely.
No effective eye drops currently exist that have shown to have any effectiveness on AMD, wet or dry. Rather, a lot of people with dry AMD also suffer from dry eye syndrome (DES), and there are numerous drops available to address this. Depending on the severity of someone’s DES, they can choose over the counter drops or prescription ones. However, it is important, in all cases, to not self-medicate. Some of the over the counter drops, for instance, have the potential to make DES worse after prolonged use.
Resources and References:
Sight-Saving Eye Drops Could Replace Injections – Eye drops for macular degeneration. (Medical News Today)
Topical Application of PPADS Inhibits Complement Activation and Choroidal Neovascularization in a Model of Age-Related Macular Degeneration – Topical Application of PPADS for age-related maculopathy. (NIH.gov)
Pazopanib for Treatment of Patients with Advanced Renal Cell Carcinoma – Pazopanib for advanced renal cell carcinoma. (Health Economics Research Unit)