Measurement - The Macguyver test

For measuring my recovery, I designed a little protocol which I named after the famous TV guy that was always making stuff up. I was going to print off a snellen chart, but I figure I'd either end up wasting a lot of time and paper printing new ones each time (since I'd otherwise just end up memorizing the letters on a good day, thus messing up measurement of a bad day), so I wrote a little java app that places a single 12, 18, 27, 40, 60, 91, 136, or 205pt letter on the screen, and I have to press the key for it. I back my chair up against the bed (about 6ft away from my 23.2" monitors), block an eye with a DVD case, and when I'm done (250 letters per eye) the app tells me the percentage success rates for each size. After a few trials, it looks like it gives fairly consistent data.

And here is my pre-op data. Note that I should get about 4% correct for a given font size, since that would be about the guessing success rate

With glasses (aka my best-corrected acuity or BCVA). Left eye, then right.

12pt: 66%, 91%

18pt: 96% 97%

27pt: 94% 100%

40pt: 100% 100%

60pt: 100% 100%

91pt: 100% 100%

136pt: 100% 100%

205pt: 100% 100%

Obviously the hope is to exceed these values post-op, but I'd probably be satisfied with just getting close to them. A 12pt value is really small from 6ft away.

Without glasses (this is what the surgery will really be compared against)

12pt: 0%, 4%

18pt: 5%, 3%

27pt: 5%, 4%

40pt: 10%, 38%

60pt: 68%, 69%

91pt: 91%, 98%

136pt: 100%, 100%

205pt: 96%, 98%

While doing these, I really noticed how non-uniform my uncorrected vision is. Moving my head around so that I'm looking through different spots in my eye would result in letters coming into and out of focus. Sometimes an O would look like an infinity symbol due to something (astigmatism?) for example. I've heard PRK recoveries involve a decent amount of ghosting, but I should keep in mind my uncorrected vision was no picnic pre-op with regards to artifacting either.