Hi Caiman,
I have 20/20, checked on my own Snellen. Yet every time I go to an OD, they put a "Phoropter", in front of my face, spin the dials, and say, 1 better? 2 better?. Then they want to PRESCRIBE a lens for me - when I have 20/20. When I asked the "tech" what she measured, she stated that I would have to ask the optometrist what my prescription would be. (This is why I "gave up" on the tech, and do this measurement myself.)
https://www.youtube.com/watch?v=CrfuLuibclYI gave up on any trust I might have had for an OD in his office. Is this "right"? Or is this "wrong"? I know they TRY to do a good job - but they always over-prescribe by about -1 diopter. There is no reason for me to "argue" with them on that point. I just do my own measurements - and more accurately in my judgment.
I do not know, and I do not care - what an OD might thing. I just do not want my vision destroyed by an excessive minus lens.
This is why I made the video - so you can check yourself. The legal standard is that I must read the 20/40 line, with both eyes open. That is ONE objective requirement that we all must pass. (That 20/40, is "worst case" for me). By checking with my own test lens - I can see if a -3/4 will give me 20/20. If it does, then I have NO HEALTH PROBLEM. I have "negative status", that I can slowly recover by wearing a plus for near.
If a -3/4 diopter did NOT give me 20/20, then I would know that I have a "medical problem", and would go for a medical exam.
I think that anyone working on "vision improvement" should make these simple measurements himself. This is NOT the "practice of medicine", and you are not "prescribing for yourself". Remove "medical terms" for self-measurement, and you will do better.
If you can, with both eyes open, read better-than 20/40, then you will pass the DMV requirement. That means you can avoid wearing a minus lens - most of the time. I am "practical" here. If I were at 20/40, I would buy a -3/4 minus from Zennioptical for $9, and just keep it in my car.
I would do that, until I can confirm 20/25 on my own Snellen. Then I can stop wearing the minus lens for driving.
But I would be wearing a +1.5 diopter for ALL CLOSE WORK. As my Snellen improved, I would plan to increase that to +2.0 to +2.5 diopters, to keep the 20/25 to 20/20, I eventually objectively confirm.
No, I would not go to an OD for a verification of my own Snellen improvement. I will do that objectively - myself.
I've been working on improving my myopia for the last 1.5 years or so. Before I'd started, my most recent prescription was for -2 right eye, -2.75 left eye. (Back then, I wasn't checking myself with an eye chart, so I don't know what I could clear at that point.)
Fast forward to today. Now, with unaided eyesight, in a well-lit room (bright daylight coming through big windows), I can just barely clear the 20/15 line on an eye chart with the right eye, and can clear the 20/40 line with my left eye (or even 20/30 if I spend some time focusing). However, I just went and had an eye checkup (mostly since I was curious to see what they said about my myopia rehab experiments), and their prescription is: -.75 right eye, -1.75 left eye. These measurements would suggest considerably more myopia than my own eye chart tests would seem to suggest. Indeed, my own tests would suggest that my right eye is not myopic at all. (I no longer wear glasses at all at this point. Nor do I intend to start again.)
How to account for the difference between my own measurement efforts and the optometrist's? The cynic/paranoid side of me wonders if maybe they intentionally over-measure myopia to ensure that everyone goes home with a prescription indicating they need glasses (the optometrist's is physically located within a glasses retail store..). The less paranoid side of me figures it's just a measurement error, but wonders -- my error, or theirs? I'd be curious to hear others' thoughts.