stuckindayton Posted July 18, 2022 Share Posted July 18, 2022 3 hours ago, Nate B said: Steve, Thanks for the detailed response. I was under the impression that there were 20 iterations of each color at 5 levels of contrast, each worth 5 points for a total of 100. Is this not the case? Does it basically just test you down to a certain level, then verify it like the audiogram? The reason I ask about the retest is because during my IFC3 they actually let me test three times (standard was 75 back then). During my IFC1 they allowed me to test twice. I thought it may have been SOP for someone who was very borderline. Guess I just got very nice techs both times. The test is based around the idea of five stimuli at five contrast levels, but it doesn't always present every stimulus at every level. It uses a staircase algorithm. If you get two stimuli correct at the first (highest) contrast level, it drops down to the third level. If you get two right on that level, it drops down to the fifth (lowest) contrast level. If you get all five right at that level you get a score of 100. If, at any point, you miss a stimulus, it moves back up one contrast level higher (e.g. if you miss one on the third level it bounces back to the second level) and then if you get two more right it bounces back to one level lower in contrast. So although the test is based on a five by five grid, you rarely see all 25 stimuli. Most people see between 9 (the number of stimuli if you never miss anything) and maybe 15 stimuli if you have a mild color deficiency. Of course, this is just for one color for one eye, so multiply that by six (three cones and two eyes) for the complete test. And as I said previously, if your score is near the pass/fail line the entire test repeats for that color to confirm the result. Wright-Patt will almost never repeat the test because: 1) It's already been repeated as part of the computer logic and 2) What score do you take it you fail once and pass once? Like anything in the standards world, it can be very tough to draw the line when someone is on the fence, but it has to be done. I know it sounds a bit like the WP folks might not care (which is absolutely not the case), but they have to process upwards of 50 folks a week and they have limited resources to do so. Difficult decisions have to be made and they are sometimes not what applicants what to hear. But, they will give you every chance to pass that they can. Steve Link to comment Share on other sites More sharing options...
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