I don't do gravel, MTB, or cyclocross, but I had a retinal tear just before the COVID pandemic began. I noticed a sudden batch of 'floaters' in my right eye, went to my Primary physician, who referred me to an opthamologist down the hall, who immediately referred me to a nearby retinal specialist, who did an in-office laser treatment to seal the tear before it turned into a detachment (which would have required invasive surgery
). It wasn't in the focal point (macular area?) of my eye, so no noticable vision issues. I had not had anything hit my head, nor do I frequent roller coasters (he mentioned those can create tears/detachments, too) but the doctor mentioned it happens frequently as you get older, so if you're +50 and have any sudden appearance or sudden increase in 'floaters' get it checked out ASAP.