A new laser treatment could stop blindness before it starts

Nearly one in three people over the age of 80 have age-related macular degeneration (AMD), a condition that affects the retina and leads to loss of central vision. In the United States, about 20 million adults aged 40 or older are currently living with AMD. The vast majority of them have the “dry” form, which gradually develops and eventually results in difficulty seeing objects directly in front of them. Despite being one of the most common causes of visual impairment among older adults, there is still no effective treatment for dry AMD.

Researchers at Aalto University have identified a promising new method to slow or even stop the early stages of dry AMD. Their approach focuses on enhancing the natural defense systems of retinal cells through the application of controlled heat, according to Professor Ari Koskelainen.

“Cellular functions and protective mechanisms weaken with age, exposing the fundus (the inner surface at the back of the eye) to intense oxidative stress,” explains Koskelainen. “Free oxygen radicals destroy proteins, causing them to misfold and aggregate, and then fatty protein deposits called drusen begin to accumulate, which is the main diagnostic criterion for the dry form of age-related macular degeneration.”

Use heat to stimulate the eye’s repair response

Treatment involves carefully warming the affected tissue by several degrees, a difficult task because it is difficult to measure the temperature behind the retina. Temperatures above 45 degrees Celsius can damage tissue, but Aalto’s team has developed a method that allows the temperature to be monitored in real time while heating the area with near-infrared light. This allows safe and precise control while using heat to activate the eye’s natural healing responses at the cellular level.

When proteins inside the eye misfold, cells can respond in several ways. One mechanism involves heat shock proteins, which are produced in response to stress and can help restore damaged proteins to their original structure. If this process fails, the defective proteins are targeted for degradation into amino acids so they can be recycled.

If protein accumulation does occur, another mechanism called autophagy takes over. This process, discovered by Nobel laureate Yoshinori Ohsumi in 2016, surrounds the accumulation within a lipid membrane similar to a cell membrane. Recognition proteins on the surface of the membrane send a signal to lysosomal enzymes to begin breaking down and removing damaged materials.

“We were able to show that we can activate not only the production of heat shock proteins but also autophagy using heat shock. This process is similar to waste disposal,” says Koskilainen.

Promising results and next steps

The new technology has already yielded positive results in animal studies involving mice and pigs. Human clinical trials are scheduled to begin in Finland in the spring of 2026. The first phase will focus on confirming the safety of laser treatment before moving on to determining how often it should be repeated to get lasting results.

“Treatment should be frequent, because the response can actually start to decline after a few days of treatment,” Koskelainen says.

The results were published in Nature Communications On October 29th. The research team has also launched a separate company, Maculaser, to help bring the treatment to clinical use.

“An optimistic timeline would see the method already being used in hospital eye clinics in less than three years,” Koskelainen adds. “The ultimate goal is for it to be readily available at your local eye doctor.”