“It is important – imperative – to emphasize that transmissible does not equal contagious. There is absolutely no evidence that people with dementia can spread their disease casually to people around them. Even donated blood appears to be safe, as no association with blood transfusions and Alzheimer’s Disease has ever been detected.”
This isn’t especially surprising. It’s about on par with Alzheimer’s being caused by a microorganism. If we accept that this is true, then it follows that Alzheimer’s, as a symptom, can be transmitted. But unless there is a noteworthy vector of transmission, there’s nothing to worry about.
Speculation about eye care equipment sounds like sensationalism until tested.