"Ocular fixation control as a function of age and exposure duration": Correction to Kosnik et al.

Foveolar drusen decrease fixation stability in pre-symptomatic AMD

“…by looking at the FEM. Moreover, the discovered link between central drusen and fixation stability can explain the discrepancy present in the literature regarding the differences in fixation stability between young and healthy older adults, with some studies reporting an age-related decrease in stability 45–47 and other studies, including ours, reporting no effect of age 48–50 . If the presence of foveal drusen is a common trait among older participants and these drusen do affect fixation stability, as we observe in our experiment, then the putative effect of age on fixation stability in the above studies can in fact be explained by the presence of participants with undetected central drusen in the sample of older adults (since virtually all previous studies used standard retina fundus imaging or SD-OCT).…”

“…Our observation aligns with findings that suggest drusen appearing under the retina is part of normal aging and very prevalent (Ronald Klein 1992, Neil Bresseler 1989[44], [45]), and it would seem that older participants without drusen were actually the outliers but no recent studies with more advanced imaging techniques have been made to confirm those findings. That would also partly explain why some studies reported differences in fixation stability between young and older adults (Cutini 2014, Agathos 2015, Morales 2016[46]–[48]), and some studies do not (Kosnik 1986, Gonzales 2019, Becu 2018[49]–[51]) such as ours. Since having macular drusen is a common trait and that they affect fixation, some results could be distorted if some studies excluded because of signs of drusen and others did not.…”