Probably all of us have had an eye exam, and those of us who wear corrective lenses are familiar with the narrow it down approach used to identify the proper prescription. That approach relies on you providing feedback to the examiner.
So, the question arose today, out of a conversation about a woman I knew who had a totally immobilising stroke and my partner having recently seen a 9 month old with glasses: how do they arrive at the proper presription when the patient is incapable of responding?
My initial WAG, of a very grey nature, was that they might use some of the technology used in some weapons aiming systems that read the operator’s eye - but I really don’t know how those work. What the heck, 2nd question - how do those optical aiming systems work?