And now, without further ado:
THE IMPOSSIBLE TRUTH BEHIND SNAKE PLISSKEN'S EYE PATCH!
The military career of S.D. "Snake" Plissken is well known. Plissken excelled during his inital training and service, and was selected early on for an assignment to special forces.

After completing his initial training as an operator, Plissken was chosen to participate in a prototype training program. Long before the style known as "mixed martial arts" was developed, the US military took a select few warriors and assigned them to train in different martial arts from around the world. Some soldiers went to Israel to study Krav Maga, some to Thailand, home of Muay Thai, and some went to Botswana to learn Obnu Bilate.
S.D. "Snake" Plisskin went to China to learn the fabled "Five Point Palm Exploding Heart Technique" under legendary Shaolin master Pai Mei.

S.D. "Snake" Plissken was Pai Mei's very first caucasian student, and the collision of Plissken's headstrong nature with Pai Mei's xenophobia did not end well. Plissken was extracted by a SEAL team and flown stateside for medical treatment. He refused to even consider being fitted with a prosthetic eye, and considered the patch to be a sign of honor.
It is unknown whether or not Plissken ever mastered the Five Point Palm Exploding Heart Technique.