An English man went partially blind in one eye during a climax following 'vigorous sex', although there's no mention of a partner in the study so he may have just been going to town solo like somebody trying to inflate a bike tire in a hurry.
The doctor concluded that the man performed the "Valsalva maneuver," meaning that he tensed his abdominal muscles and held his breath during sex.
This caused a blood vessel in his eye to pop because of the increased pressure to his chest.
After taking his medical history, the clinician diagnosed him with postcoital valsalva retinopathy.
The case study notes that the man's condition resolved itself over time without any further intervention.
So it corrected itself over time, that's a huge relief. Mostly because I'm very interested in experimenting with this 'Valsalva maneuver.' The study mentioned the increased blood pressure in the head has also caused amnesia in some patients and, God willing, the ability to warp the fabric of space-time by at least one idiot who's about to try it. Wish me luck! *posts Craigslist casual encounter ad for someone willing to make vigorous love to a time traveler*
Thanks to Thaylor H, who is now partially blind in both eyes and can't hear or smell that well either.