Researchers from Aalto University (Finland) and Karolinska Institutet (Sweden) have developed a precise laser treatment that safely activates the eye’s protective stress responses — without harming tissue.
The method uses focal electroretinography (fERG) to monitor small temperature changes in the retina during laser exposure, ensuring the right amount of heat is applied. This makes it possible to stimulate protective cell pathways while avoiding burns or damage. The laser slightly warms the retinal pigment epithelium (RPE) — a key layer of cells that supports vision. The researchers found that as temperature rises, the fERG signal changes, allowing them to measure heat in real time.
The team first tested low-power exposures to understand how the tissue reacts, then adjusted the laser to reach a target temperature with about 0.6°C precision. They discovered that a temperature of around 44°C (about 5°C above normal body temperature) is ideal: warm enough to trigger protective responses but not high enough to cause injury. At this gentle heat level, RPE cells turned on genes that help protect and repair them — such as heat shock proteins (HSP70, HSP90) and autophagy-related genes that recycle damaged material. Importantly, there was no sign of oxidative stress or cell death at temperatures up to 46.5°C. Damage only began to appear around 48°C.
The treatment also did not increase VEGF, a molecule linked to unwanted blood vessel growth — a key safety point for retinal therapies.
Laser treatments that don’t damage tissue are already used for diseases like diabetic macular edema (DME) and central serous retinopathy (CSR), but doctors have lacked a reliable way to measure and control the dose. This new fERG-guided system acts like a built-in retinal thermometer, giving real-time feedback and allowing patient-specific, site-specific dosing. The result is a reproducible way to activate the retina’s self-protective pathways — potentially transforming laser therapy from destructive to restorative.
Clinical outlook
The optimal temperature for protective effects is around 44°C. The system’s high precision means it could be safely adapted for human use, though improvements in workflow and non-contact monitoring will be needed. Further human studies are required to test long-term effects and benefits for specific diseases like AMD or DME.
The study represents a major step toward precision, non-damaging retinal laser therapy. By finely controlling temperature, clinicians could one day stimulate repair and protection instead of causing injury — ushering in a new era of physiology-based, personalized eye treatment.
The method uses focal electroretinography (fERG) to monitor small temperature changes in the retina during laser exposure, ensuring the right amount of heat is applied. This makes it possible to stimulate protective cell pathways while avoiding burns or damage. The laser slightly warms the retinal pigment epithelium (RPE) — a key layer of cells that supports vision. The researchers found that as temperature rises, the fERG signal changes, allowing them to measure heat in real time.
The team first tested low-power exposures to understand how the tissue reacts, then adjusted the laser to reach a target temperature with about 0.6°C precision. They discovered that a temperature of around 44°C (about 5°C above normal body temperature) is ideal: warm enough to trigger protective responses but not high enough to cause injury. At this gentle heat level, RPE cells turned on genes that help protect and repair them — such as heat shock proteins (HSP70, HSP90) and autophagy-related genes that recycle damaged material. Importantly, there was no sign of oxidative stress or cell death at temperatures up to 46.5°C. Damage only began to appear around 48°C.
The treatment also did not increase VEGF, a molecule linked to unwanted blood vessel growth — a key safety point for retinal therapies.
Laser treatments that don’t damage tissue are already used for diseases like diabetic macular edema (DME) and central serous retinopathy (CSR), but doctors have lacked a reliable way to measure and control the dose. This new fERG-guided system acts like a built-in retinal thermometer, giving real-time feedback and allowing patient-specific, site-specific dosing. The result is a reproducible way to activate the retina’s self-protective pathways — potentially transforming laser therapy from destructive to restorative.
Clinical outlook
The optimal temperature for protective effects is around 44°C. The system’s high precision means it could be safely adapted for human use, though improvements in workflow and non-contact monitoring will be needed. Further human studies are required to test long-term effects and benefits for specific diseases like AMD or DME.
The study represents a major step toward precision, non-damaging retinal laser therapy. By finely controlling temperature, clinicians could one day stimulate repair and protection instead of causing injury — ushering in a new era of physiology-based, personalized eye treatment.
