I'm happy to educate you ... it may save your eyesight some day.
Several factors can affect one's vulnerability to retina problems. If near sighted or diabetic, you are at risk. And then there's the aging process. As we approach the end of "middle age" the vitreous fluid in the eyeball begins to thicken and shrink. The thicker fluid can stick to the retina and tear a hole in it. Then the fluid gets behind the retina and causes a detachment. For those like me who have thin retinas this can be a hidden time bomb. My second detachment occurred after a morning goose hunt with 3" mag 12 gauge 870 only a few months after the first detachment. I was pushing the envelope and paid the price. First detachment was entirely spontaneous. I didn't recognize the symptoms and by the time I could be flown out for surgery nearly lost the vision for good. Third detachment was only two months after the second. By then the odds of saving that eye were very slim. But it worked. For ten years afterwards I was having periodic laser patch jobs to retina tears in both eyes (extremely painful, unlike cataract laser surgery which is painless). Eventually my eyes "settled" and I was allowed to resume all activities (except bull riding

). I was only 51 years old when I had my first detachment. No, actually I was only fifty and turned 51 by second detachment. I am not diabetic or near sighted.
So, you can understand how the shock of severe recoil could easily exacerbate a retina detachment, especially in a shooter who's at risk. Shooting a heavy recoil rifle from the bench is NOT "proper form". Your body is not allowed to flex enough and too much of the shock is absorbed internally. Shooting prone is the worst form! Best for accuracy but almost all the recoil must be absorbed by the body. Do that with a DGR and risk hurting yourself severely. Imagine trying to get up off the ground with a broken shoulder to fire a followup shot at a wounded charging buffalo. Good luck with that!
My best advice to everyone who shoots thumper guns is know the symptoms of retina problems. If recognized early a tear can be patched before it becomes a detachment. A detachment starting is an emergency situation. Your hunting trip is over and you need to get on a plane to a tertiary hospital immediately. If the detachment makes it to the macula (where optic nerve attaches), the eye is pretty much gone. Go on line and familiarize yourself with symptoms. They can be relatively minor (annoying) until too late.