A 29-year-old British man rushed to an ER with “an obstruction in the central vision of his left eye...” The cause remained a mystery 'till the man admitted to having “vigorous sexual intercourse” the night before his medical issue appeared.
The cause was clear. The guy did a Valsalva maneuver tensing his abdominal muscles and holding his breath while bumping uglies. The stunt busted a blood vessel in his eye and left him with postcoital valsalva retinopathy.
Seems the Valsalva maneuver wipes out memory too...which is prolly why the guy was doing it in the first place.