A groundbreaking new eye test, developed by scientists from University College London (UCL) in collaboration with Western Eye Hospital, London, could predict wet AMD, a leading cause of severe vision loss, three years before symptoms develop.
Researchers hope that their test can be used early on to identify the disease so that vision loss can be prevented effectively.
The findings of the study, funded by Wellcome, are published today (18 December 2020) Expert overview of molecular diagnostics.
Wet age-related macular degeneration (AMD), also known as macular disease, is the most common cause of permanent and severe vision loss in the UK.
Currently, the diagnosis of wet AMD is based on the fact that someone develops symptoms, which leads him to seek advice from a clinician. Initially, someone with a wet AMD would notice distortion in their vision, which would usually disturb their reading. This can very quickly lead to a central vision loss, which can be extremely worrying for elderly patients who are afraid of blindness and loss of independence.
Wet AMD involves abnormal growth of blood vessels leaking fluid into the retina. The introduction of new treatments has led to much improved outcomes for patients for a disease that was considered incurable more than 20 years ago. However, patient outcomes may be even better if treatment is started in the earliest stages of the disease.
The test, called DARC (Detection of apoptotic retinal cells), involves the injection of a fluorescent dye into the bloodstream (via the arm) that attaches to retinal cells, and relieves those who are undergoing stress or in the process of apoptosis, ‘ a form of programmed cell death. The damaged cells look bright white when seen in eye examinations – the more damaged cells are detected, the higher the DARC score.
One challenge in evaluating eye diseases is that specialists often do not agree with the same scans, so the researchers incorporated an AI algorithm into their method.
Using the same technology (test), the researchers found earlier that they can detect the earliest signs of progression of glaucoma. This new study, which is part of the same ongoing clinical trial of DARC, assessed 19 of the study participants who had already shown signs of AMD, but not necessarily in both eyes. The AI was newly trained to detect the formation of leaky and new blood vessels, consistent with the spots picked up by DARC.
The new analysis found that DARC can uniquely elevate endothelial cells (which feed our blood vessels) under tension in the retina. These stressed cells then predict future wet AMD activity with the formation of leaky and new blood vessels seen in patients three years later, using conventional eye scans with Optical Coherence Tomography (OCT).
According to the researchers, their test can be valuable in detecting new lesions in someone affected by AMD, often in the opposite, unaffected eye, and it may be helpful to examine people older than a certain age or with known risk factors.
Principal Researcher Professor Francesca Cordeiro (UCL Institute of Ophthalmology, Imperial College London, and the Western Eye Hospital Imperial College Healthcare NHS Trust) said: ‘Our results are very promising as it shows that DARC can be used as a biomarker for wet AMD in combination with the AI-supported algorithm.
‘Our new test was able to predict new wet AMD lesions up to 36 months before they occur, and that’s great. This means that DARC activity can lead a clinician to treat patients at high risk for new lesions more intensively. wet AMD and also used as a screening tool. ”
The study team hopes to continue their research with a clinical trial with more participants, and hopes to investigate the test in other eye diseases as well.
Sherine Krause, CEO of Fight for Sight for Eye Examinations, said: “Our time to focus report on the social and economic impact of vision loss has highlighted the importance of early detection to prevent vision loss, and it is therefore a to tackle very encouraging development in the root cause of blindness. ”
Reference: December 18, 2020, Expert overview of molecular diagnostics.
DOI: 10.1080 / 14737159.2020.1865806
DARC is commercialized by Novai, a newly formed company of which Professor Cordeiro is chief scientific officer.