Developing a cataract of the eye is usually thought of as something to worry about as one ages, when an opacity, or cloudiness, of the lens develops over time. But a cataract can also happen suddenly, as a result of direct force trauma on the battlefield, or exposure to gasses, chemicals, or new weaponry in war zones.
"In case of traumatic cataract, it can be from direct and indirect trauma to the eye," explained Dr. Mariia Viswanathan, an ophthalmologist and the chief of Education, Training, Research, and Surveillance at the Clinical Care and Integration branch of the Defense Health Agency's Vision Center of Excellence (VCE). "It's damaging the protein, and so the loss of transparency. It can be force trauma, it can be chemical trauma, it can be ionization. Different types of weapons can cause traumatic cataract. It's a very complex process."
Traumatic cataracts in service members can occur immediately after an eye injury, months, or even years later. They can also be the result of non-battlefield situations, the VCE says.
They can be produced by severe head trauma via road traffic accidents, recreational and sports activities, firearms or explosive injuries, or the absence of ocular protective devices. Regardless of how it occurs, the effects cannot be undone when it comes to traumatic cataracts, said Viswanathan.
"The opaque lens is like a boiled egg," Viswanathan said. "You have the part that is transparent. If you boil it, it becomes white - you cannot do anything to make it transparent again. It's the same with the (ocular) lens. We have particular proteins in the lens that keep a particular structure. If there is any influence on the lens, the structure is damaged, and that's when they become disorganized and the lens is opaque, as a boiled egg."
Usually, traumatic cataract in one eye does not mean it will affect both eyes, she said, unless the blast injury that causes it affects the entire body, or a particular physical system. In addition, total blindness is not necessarily the outcome of a traumatic cataract. There is often a way to surgically address some of the ocular damage to at least improve the vision, without restoring it entirely.
Throughout the 20th century, the incidence of eye injuries among war fighters increased with each major armed conflict, the VCE says. As recently as 2008, 13% of combat casualties requiring evacuation were reported to have sustained ocular injuries.
Viswanathan said that cases of traumatic cataracts have leveled off in recent times, depending on the conflicts U.S. service members have been involved in because advances in eye protection have been accompanied by advances in armaments deployed by the enemy.
"From my perspective...protection for the eyes became better 15 to 20 years ago," she said. But incidents of eye damage remained high because weapons became increasingly sophisticated.
"They're more powerful," Viswanathan said. "It can be laser. If it does not involve active physical force, there are laser and microwave weapons. It's not really well researched because these are new weapons, and there is not enough data yet to support some kind of decisions on how (their) effects last, but it has been seen that they are doing damage to the lens."
Non-traumatic cataract
Along with aging, cataracts can develop due to other risk factors, such as smoking, exposure to excessive ultraviolet rays (mostly sunlight), the presence of pre-existing ocular diseases, previous eye surgeries, or systemic diseases such as diabetes or autoimmune disorders. Non-traumatic cataracts most commonly affect people over 40.
Likewise, conditions that cause age-related cataracts, such as diabetes, could influence both eyes, Viswanathan said. But even simple inflammation might cause it in just one eye.
"There's a big difference between people who age and get cataracts versus traumatic cataracts due to an ocular injury," said Helen White, the VCE's branch chief of Functional Requirement Management & Governance. "Cataract surgery for the general population due to maturing of the eyes is done at a high success rate. It's about a 10-minute procedure for each eye and a short recovery time before you go home. Within 90 days many people see better and there is a boost in their vision, with the best corrected vision at 20/40. You may still need to wear glasses to read, but may not need glasses for distance."
White is referring to the replacement of the cloudy, cataract-affected lens with an artificial intraocular lens (IOL), a procedure she has undergone herself.
"I don't need glasses or contacts for distance anymore," White said. "Following surgery, I wear one contact lens for reading - that's it."
The bottom line? Non-traumatic cataracts are often avoidable by the use of eye protection and a healthy lifestyle.