If you find yourself in a situation where an eye gouge would be an effective mode of attack, (The SAS five second knockout), don't be afraid to use it. It is an effective way to distract and wound your attacker. Contrary to what you might think, your eyes are actually quite tough, and the most damage you would likely do is scratch the eyeball with your fingernail. This attack will work if executed correctly, and if it doesn't, your opponent will probably flinch and be thrown off balance.

Then again, being close enough to gouge his eyes means that he is also close enough to do some form of damage to your own body. I've studied martial arts for a total of about 4 years, you should too if you expect to use this.