Wednesday night, Jake Shields will meet fellow grappler Demian Maia in the main event of UFC Fight Night 29. Shields, while an excellent ground fighter, is still struggling to live down his embarrassing performance against Georges St. Pierre.

The fight was a fairly predictable one as St. Pierre lit Shields up with his jab while Shields utterly failed to take the champion down or pull guard. The main surprise of the fight—aside from St. Pierre revealing that he had actually forgotten how to throw his right hand with any heat on it—was that Shields was able and worryingly willing to find the mark with several eye gouges.

The eyes are a sensitive subject in combat sports. One need only look to the MMA news of this week to see how concerning eye injuries can be in a fighter's career. Michael Bisping has been facing ongoing issues with his eyes which have left many speculating about his future.

I speak constantly about the benefits of getting to angles against an opponent, and of blind angles such as the one which the front kick to the jaw or the uppercut can come up through. Once you have swollen an opponent's eyes, however, everything comes from a blind angle.

A fighter will aim his jab for the eyes to swell them and blind the opponent. One need only think of Muhammad Ali to remember his back-handed jab, with his hand often open inside his glove, flicking and slapping away at his opponent's features.

In Ali's third bout with Joe Frazier, The Thrilla in Manilla, the two men beat the stuffing out of each other for 14 rounds before Frazier's corner, against Smokin' Joe's will, called the fight off.

Frazier had injured his left eye earlier in his career and had greatly reduced vision for many of his fights, but by the time the Thrilla in Manilla came around, he was almost entirely blind in that eye. The scar tissue in his left eye had developed into a cataract. Ali's continued flicking jabs and combinations across Frazier's face closed up his good eye, and by the mid-point of the bout, Frazier was essentially fighting blind.

The trouble that Frazier gave Ali in their final and greatest bout really drives home the importance of eyesight to a fighter, even an up close infighter like Frazier. If Frazier had even the limited vision which he usually carried into fights, there is good reason to believe that he wouldn't have taken such a beating in Round 14.

Targeting the eyes with legal strikes is not uncommon in MMA or kickboxing, either.

Mirko "Cro Cop" Filipovic made something of a specialty of breaking his opponents' orbital bones.

If you can remember back to BJ Penn versus Joe Stevenson, Penn was able to land a hard elbow straight into the eye of Stevenson on the ground which really turned Joe Daddy's night from a bad start into an agonizing beat down.

Those examples, however, were all legal blows. What we are seeing nowadays is a growing number of MMA fighters who are quite willing to poke an opponent's eye in order to take advantage of the moment or get some breathing space.

Thumbing of the eye in boxing has always been seen as a dirty tactic. It is against the rules because it is primarily career threatening, not to mention being disproportionately effective. In the modern era, gloves are made with the thumb attached to the rest of the glove so that it can't be splayed out and dragged across an opponent's eye.

The dangers of the eye gouge in the clinch are obvious. A fighter's hand can be well hidden from the referee and even the crowd by his back. What is more concerning is the eye gouge as an opponent comes in. This is the kind which we are seeing more and more of in MMA.

A fighter who comes in with a good jab can be countered with a good dipping jab. But that requires good timing. It is an explosive movement and one must measure exactly when to launch the counter and to perform the slip so as not to move too soon or too late.

Gouging an opponent as he comes in takes nowhere near that kind of skill. One can get hit in the face clean and still, with one's hand open, make a good go of raking the thumb or fingers across the attacker's eyeball.

Here is a great example as the late, great Ken Norton has a match turned around on him through an eye gouge. As he snaps Scott Ledeux's head back with a stiff jab, Ledoux is able to run his thumb across Norton's eye and blind the better boxer.

This was the story of Jake Shields versus Georges St. Pierre. St. Pierre was getting in clean and hard with jabs, so Shields gouged him as he came in.

Now it is hard to blame Jake Shields for this. It was a classless move, but it could equally be called a savvy one. Some of the greatest fighters of all time have been incredible technicians, but horrendous sportsmen. Sandy Saddler, one of the greatest featherweight boxers of all time, could beat most men from pillar to post with pure, clean skill, but opted to rough them up with elbows and butts anyway.

To state the obvious, a fighter is in a fight. Not all fighters can simply say "it's only a sport" when they are losing. It is the job of the referee to be vigilant and stop such behavior with breaks of the action whenever a gouge is seen and issue an immediate warning or point deduction.

Josh Koscheck gets a lot of criticism for the fact that his fighting style seems to be based entirely around leaving his hand out, hoping to catch the opponent on his finger as they move in, then cracking them with his formidable right hand when they are smarting from the gouge. Koscheck's pokes are clearly intentional because he will hold his hand closed and open it as the opponent comes in.

But can you blame him? He knows he can get away with it. Against Mike Pierce and Johnny Hendricks, Koscheck went about his usual tactics and, while he was warned against Pierce, nothing ever came of it.

It is not just bad fighters or poor sportsmen doing this, though. Some gouges genuinely seem to stem from open-handed guards and extending the arms in reaction to an opponent coming in.

Just the other week, Jon Jones succeeded in breaking the action in a round which he was losing by allowing Alexander Gustafsson to run onto his extended fingers. Chuck Liddell was mockingly called "The Eyesman" after thumbing Vernon White, Tito Ortiz and Randy Couture within four fights.

Eye gouges will be a constant feature of this sport. Even with a redesign of the gloves to one which encourages the hand to close, it will always be necessary to allow the glove to be opened for gripping and grappling. Boxing has seen a reduction in thumbing of the eyes now that the gloves prevent the thumb from being opened, but such forced closing of the fist can not be achieved in MMA competition.

It is the job of referees to actually penalize eye gouges. However, this can hardly be done fairly without the use of video to review incidents and allow the referee to deem whether a gouge was intentional or not. Of course, with an actual crackdown on eye pokes, video review would also be necessary to stamp out the inevitable faking that would come about if referees were more liberal with point deductions.

I hope, as do most others, that eye gouging will fall out of fashion. But it's been around for centuries and it doesn't seem to have lost any of it's effectiveness.

Pick up Jack's eBooks Advanced Striking and Elementary Striking from his blog, Fights Gone By.

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