Soldiers coming back from the war in Iraq are being treated for many combat-related injuries. But doctors at the VA Hospital in Palo Alto found something they haven't seen before. NBC11's Damian Trujillo investigates why soldiers, with no obvious signs of trauma, are at risk of going blind.

It's hard for Army Specialist Jason Kvasnak to remember every single explosion he survived in Iraq.

"We were in several IED (improvised explosive device) blasts throughout the tour," Kvasnak said.

But Kvasnak remember the one that left him with the injuries no one saw coming.

"It was just massive concussive force and it thrust you forward, or whatever. I just felt really dazed afterwards and ringing in the ears and I couldn't really see straight," Kvasnak said.

Kvasnak hasn't been able to see straight since that blast. He sees double, has sensitivity to light and the headaches he gets from trying to read or watch TV are so bad that he sometimes passes out.

Doctors at the Veterans Affairs Hospital in Palo Alto are seeing more and more troops returning from Iraq with vision problems from exposure to roadside bombs.

"In this war, blast injuries have become the signature injuries. These can cause damage to the eye. They can also cause damage to the visual system and the visual processing centers in the brain," VA research psychologist Gregory Goodrich said.

Many soldiers don't even realize something's wrong with them. They're returning home with only half their visual field, not knowing that they're missing their entire left field of perception.

Without treatment, blast injuries like Kvasnak's can lead to long-term problems, even blindness

"The things that we're finding are damage to the soft tissue in the eye that can lead to glaucoma at any time in their life. There is a life-long risk, and bear in mind that these people are very young. In general, the median age so far is 28 years old some are as young as 19 when they are injured so that is a long lifetime," VA ophthalmologist Glenn Cockerham said.

The traumatic injury leads to a lifetime of treatment that starts with intense rehabilitation.

A driving simulator like the one at the VA in Palo Alto is an important tool in getting injured soldiers back on the road to recovery.

Soldiers are required to wear protective eye gear but since the vision loss is a result of a closed head injury, goggles and glasses aren't enough to protect the eyes from IED blasts.

Doctors encourage all Iraq veterans to have their eyes checked since many of the symptoms could take years to show up and by then, it could be too late.