Retinal-scan analysis can predict advance of macular degeneration

Using imaging data that is already commonly collected in ophthalmologists’ practices, they could make smarter decisions about when to schedule an individual patient’s next visit in order to optimise the chances of detecting AMD progression before it causes blindness.
However a senior author of the research paper published in the Novber issue of Investigative Ophthalmology & Visual Science, Dr Daniel Rubin, MD, of Stanford University, said that while the model accurately predicted every occurrence of progression to the wet stage within one year, About 40 per cent of the time when the model did predict progression to wet AMD within one year, the prediction was not borne out.
“No test gets it right 100 per cent of the time,” Dr Rubin said. “You can tweak the model to trade off the risk of telling someone they will progress when they actually won’t against the risk of telling th they won’t progress when they actually will.
“With AMD you really don’t want any false negatives, so you tune the model accordingly. The downside is that some patients will wind up being told to come in sooner than, in fact, they probably need to. But that’s nothing compared with the downside of a patient at high risk for progression not coming in soon enough.”
Dr Rubin phasised that the proof-of-principle study needs to be followed up by a larger study, ideally using data gathered from patients seen at other institutions.
Until now, there has been no effective way to tell which individuals with AMD are likely to progress to the wet stage. Current treatments are costly and invasive, making the notion of treating people with early or intermediate stages of AMD a non-starter. Doctors and patients have to hope the next office visit will be early enough to catch wet AMD at its onset, before it takes too great a toll.
In a study the researchers derived a formula that predicts, with high accuracy, whether a patient with mild or intermediate AMD will progress to the wet stage. The formula distinguishes likely from unlikely ‘progressors by analysing patient data that’s routinely collected by ophthalmologists and optometrists when they perform retinal scans with spectral domain optical coherence tomography.”Right now, a patient who goes into the ophthalmologist’s office typically gets an SD-OCT scan anyway,” Dr Rubin said.
“Our technique involves no new procedures in the doctor’s office – patients receive the same care they’ve been getting anyway. We’ve simply added on a computerised image-processing step that analyses not only that scan but any previous ones available from that same patient’s earlier visits.”
From this computerised analysis, the investigators are able to generate a risk score that predicts a patient’s likelihood of progressing to the wet stage within one year, three years or five years. The likelihood of progression within one year is most relevant, because it translates into a concrete recommendation: how soon to schedule the patient’s next office visit.
In the study, the researchers analysed data from 2,146 scans of 330 eyes in 244 patients seen at Stanford Health Care over a five-year period. They found that certain key features in the images, such as the area and height of drusen, the amount of reflectivity at the macular surface, and the degree of change in those features over time, could be weighted to generate a patient’s risk score.
Patients were followed for as long as four years, and predictions of the model were compared with actual instances of progression to wet AMD.