Trying to Convert to 20/?

I honestly don't even know if it's possible to convert this, but I figured it's worth a shot to ask. One of my eyes is 20/20, the other eye is so blurry I can't see shit and the vision goes black after a few seconds until I blink a couple times. My prescription for that eye is sphere +6.75, cyl -1.75, axis 132. Last time I asked my eye doctor, they said the uncorrected vision in that eye was 20/500, but it's gotten so much worse. Anybody have any clue what it could be now, or a rough estimate? Thanks!