A gentle burst of heat at the back of the eye could become a new option for dry age-related macular degeneration, a common condition that can slowly damage central vision in older adults.
Researchers at Aalto University say their experimental treatment uses near-infrared light to warm retinal tissue by a few degrees, with the aim of switching on the eye cells’ own repair and cleanup systems before major damage sets in.
Age-related macular degeneration affects around one third of people over 80, and about 20 million Americans aged 40 and older are living with the condition, according to the university. Most cases are the dry form of AMD.
Professor Ari Koskelainen said aging weakens the cell systems that normally protect the back of the eye.
“Cellular functionality and protective mechanisms weaken with age, which exposes the fundus [the inside surface at the back of the eye] to intense oxidative stress,” he explains. “Free oxygen radicals damage proteins, which causes them to misfold and aggregate, then fatty protein deposits called drusen begin to accumulate, which is the main diagnostic criterion for the dry form of age-related macular degeneration.”
Those deposits, known as drusen, are a key sign of dry AMD. The Aalto team says its method is aimed at the early diagnosis stage, when there may still be a chance to slow or stop the disease process.
The researchers said heating the retina is delicate work because the tissue must be warmed only slightly. If the temperature rises above 45 degrees Celsius, tissue damage can occur.
To address that, the team developed a system that heats tissue with near-infrared light while monitoring temperature in real time, so it stays within a safe range.
The treatment is designed to trigger a mild heat shock response, not to burn tissue. The researchers said that response can increase heat shock proteins, which help damaged proteins fold correctly or break them down into amino acids.
Koskelainen said the heat shocks also activated autophagy, the cell process that breaks down old or damaged material.
“We were able to show that we can activate not only the production of the heat shock proteins, but also autophagy using the heat shocks. This process is like waste disposal,” says Koskelainen.
The method has been tested in mice and pigs, where the researchers said controlled heating activated the intended protective response in retinal tissue.
Human trials are planned to begin in Finland in spring 2026. The first phase will test safety, not whether the treatment improves vision or slows AMD.
Koskelainen said any treatment would likely need to be repeated.
“The treatment needs to be repetitive, since the response can already begin to decline some days after the treatment,” Koskelainen says.
The study was published in Nature Communications on October 29, 2025. Researchers are also working to commercialise the technology through a research-to-business startup called Maculaser.
“An optimistic schedule would see the method already being used in hospital eye clinics in as little as three years’ time,” says Koskelainen. “The eventual goal is that it would be readily available at your local ophthalmologist.”
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