> "In our report, thinner INL and GCIPL were also associated with a higher risk of developing Parkinson disease. However, it should be noted that the effect siz

> "In our report, thinner INL and GCIPL were also associated with a higher risk of developing Parkinson disease. However, it should be noted that the effect sizes, especially for the INL, are small, so the practical value for an individual as a marker of early Parkinson disease is currently limited." Looking around a bit it seems that individual GCIPL thickness varies quite a bit even in healthy young adults, with the range exceeding the effect detected in the study. Practically this might mean you'd have to have lifelong GCIPL monitoring to detect the early onset of disease (and GCIPL thinning doesn't seem sufficient to diagnose Parkinson's, it occurs in other diseases like Alzheimer's and perhaps even as a natural outcome of aging).