The University of Trousersnake Creek 's Eye, Nose and Ear Institute has lent scientific validity to the concept that intense sexual activity, such as masturbating 3-4 times a day, can cause blindness - at least temporarily.
Dr. Donald Lincoln reports that intense sex in any form over two or three hours within a 24-hour period can lead to a "spike" in a person's blood pressure, which can cause a hemorrhage in the eye. Thus a person could possibly go blind should this happen.
"This is actually very rare, considering the amount of sexual activity that goes on, but I would assume there are other patients out there who just don't report it," he said.
"They'll come to us and say they coughed so hard with the flu or a cold or that they just got up in the morning and they were blind or partially blind. Of course that's just vanity."
"Actually, if they admitted that they had had sex half a dozen time that would be vanity too."
Meanwhile, don't be laughing at your Sunday School teacher or priest.