MONDAY, Nov. 12 (HealthDay News) -- Undiagnosed, chronic vision problems are common in U.S. veterans with traumatic brain injury or post-traumatic stress disorder (PTSD), two new studies show.

One study looked at 31 veterans of the Iraq and Afghanistan wars with mild blast-related traumatic brain injury and found that 67 percent had chronic vision disorders. Even though none had suffered direct eye wounds, they still had vision problems more than a year after the incident that caused their traumatic brain injury.

The most common vision problems reported by the veterans were sensitivity to light and difficulty with convergence, which is the ability to focus both eyes simultaneously to read or to see nearby objects.

Another issue reported by veterans was reduced accommodation, the ability to focus when moving their gaze between far and near objects. Other complaints included double vision and floaters, which are tiny spots, specks and other objects that seem to move across the visual field.

For many of the veterans, it took five years or more to regain normal vision. That's much longer than the recovery time seen in patients with sports-related concussions or non-blast-related traumatic brain injury, according to the study, scheduled for presentation Sunday at the annual meeting of the American Academy of Ophthalmology in Chicago.

"Physicians who care for veterans with [traumatic brain injury] need to know that many of them have vision problems," study leader Dr. M. Teresa Magone, a staff ophthalmologist with the Veterans Affairs Medical Center in Washington, D.C., said in an academy news release. "It is critical that these patients receive vision assessment and when appropriate, be referred to ophthalmologists to make sure they get the eye care they need, for as long as they need it."

A second study scheduled for presentation Sunday at the ophthalmology meeting found that veterans with PTSD or depression are much more likely to develop dry eye syndrome than veterans without these mental health disorders.

The researchers reviewed more than 2 million veterans' medical records and found that about 20 percent of those with PTSD or depression have dry eye syndrome, a condition that disrupts the tear glands' normal ability to keep the eyes moist.

Dry eye syndrome can cause eyes to feel scratchy or irritated, to become overly watery, or secrete stringy mucus. The effects of the condition can range from mild to severe. Treatment options included warm compresses, artificial tears and surgical insertion of plugs to retain tears.

The average age of veterans with dry eye is younger than dry eye patients in the general population. It's not known if the veterans' dry eye was caused by PTSD or depression, by the medications used to treat these mental health conditions, or a combination of factors, the researchers said.

"Many vets won't mention that their eyes always feel gritty or seem to water for no reason, unless they're asked," study leader Dr. Anat Galor, an assistant professor of clinical ophthalmology with the Bascom Palmer Eye Institute at the University of Miami, said in the news release.

"Since dry eye can escalate and permanently damage vision if untreated, it's crucial that health professionals who care for veterans with psychiatric diagnoses ask them about specific dry eye symptoms and refer them to an ophthalmologist if needed," Galor said.

Data and conclusions presented at medical meetings are typically considered preliminary until published in a peer-reviewed medical journal.

More information

The U.S. Centers for Disease Control and Prevention has more about vision problems.