Since this thread is still alive I will share what I know. I have compound eye issues. 23 diopter recommended prescription but anything over 19 makes me see double so I live under corrected: 20/100. Pre-emptive buckles done 6 years ago because there is so much tearing of the retina because my eyes have elongated to 38mm (normal is 25mm). There is also Glaucoma present. Drops for that, more aggressive interventions planned. I cannot drive so I ride a bike. Everywhere. Everyday. Rain or shine. My wife is blind so we take a tandem to commute to her worksite because the first bus of the day is still too late to get her in on time. If I enjoyed mountain biking I would do it! My retina doctor would be fine with that. I started playing French Horn at 50 years of age but stopped when the buckles were put in. The doc who did the buckles had no comment on the Brass Playing. The retina specialist was like, Dude, life is too short. Play if you want to play. A major blow to the eye is one thing, the low amplitude, high frequency vibration of road cycling is another, and the bouncing of singletrack still another. Assuming a full suspension downhill type bike, I doubt that what gets through should be a concern for buckled eyes. I really would risk it. Even a retina doc that rides is unlikely to really know the answer to the questions being asked in this thread. Most people with our eyes are legally blind and not doing much riding, if any at all. There is no data set of outcomes for what we want to know. <making Guinea Pig type noises as I run away>