The Importance of Dark Adaptation Functional Testing for AMD
Professor Michael Larsen
Professor Michael Larsen from University of Copenhagen explains why it is important to look at retinal function, and not only structure, when it comes to AMD.
Dark adaptation is the key to detecting subclinical AMD
Function is of great importance. We know a lot about the morphology but we have yet to learn more about the way that it affects the finer aspects of visual function and there’s an underappreciated problem. We know from research that has been done with the MacuLogix instrument that a lot of people have impaired dark adaptation. AMD begins with something diffused and very general and it’s only later that you get to the stages where you have focal lesions so maybe the dark adaptometrist is just the right thing for examining the early face of AMD.
Well, the way we have used it is in research primarily where we looked at the basic aspects of retinal physiology and diabetes and a lot of this was done in people who don’t have retinopathy so it’s because we’re looking at preclinical aspects of dysfunction or metabolic disturbances in the resident, now we can’t measure the metabolism of the retina, except we can get some hints from indirect measurements. We can’t put needles and cannulas into it but we can do electrophysiology and that’s a bit burdensome. We can also do dark adaptometry and for that, the MacuLogix instrument was crucial. And what then happened was that our electrophysiologists hijacked the instrument to be used in day-to-day visual physiology, psychophysics, electrophysiology and then into that package also goes back to dark optometry. For most patients a screening for dark adaptometry is enough and that we can do with the MacuLogix instrument.