Traumatic Glaucoma and the Risk of Permanent Vision Loss
Glaucoma involves an increase in intraocular pressure that exerts force on the optic nerve, which may result in permanent damage. A number of different mechanisms can lead to glaucoma. Aging is a primary risk factor for developing primary open-angle glaucoma, the most common form of the disease worldwide. However, it is important to understand the disease can affect younger people, too, especially as the result of a mechanical injury.
Traumatic Glaucoma Following an Injury
Ocular trauma is common, and the majority of injuries result in only minor not requiring prolonged medical attention. However, it is important for clinicians and patients alike to recognize that some forms of ocular trauma can manifest as secondary glaucoma, a condition also called traumatic glaucoma. The condition is clinically defined as a rise in intraocular pressure above 21 millimeters of mercury after a traumatic event. While the trauma could involve blunt injury that leads to bruising and swelling, penetrating events can also lead to traumatic glaucoma. The development of the condition is not always acute, and the chronic form could lead to significant morbidity since it may not necessarily present with any symptoms.
An elevation in intraocular pressure following trauma can arise from several different issues. One is hyphema, which refers to the pooling of blood inside the eye’s anterior chamber. The blood can collect within the trabecular meshwork, which makes it impossible for fluid to drain from the eye. The buildup of fluid then leads to glaucoma. Furthermore, the inflammation resulting from injury can also contribute to a blocked trabecular meshwork, especially when the lens or the iris begins to swell. Another concern is the potential for the development of peripheral anterior synechiae — adhesions that form between the outside of the iris and other structures of the anterior chamber. Such adhesions block the normal outflow of aqueous humor and can also result in the buildup of fluid in the eye.
Warning Signs of Serious Ocular Injury
While trauma to the eye should almost always be evaluated by a qualified care provider, there are some signs and symptoms that make the injury more concerning. For example, individuals may be able to see hyphema, the collection of blood in the lower part of the iris, or notice significant swelling of the globe itself. People experiencing aching pain within the eye or who notice either blurred vision or increased sensitivity to light should be concerned about the possibility of serious pathological processes. When these signs and symptoms occur, it is important to immediately consult an ophthalmologist.
Pain often subsides when the inflammation resolves. However, intraocular pressure can remain elevated and cause damage to the optic nerve. In other words, a person may think the injury has resolved and go through a period of asymptomatic glaucoma that eventually progresses to vision loss. Once a reduced visual field is notices, irreversible damage is already done. Thus, it is very important for people to visit an ophthalmologist following an eye trauma. Clinicians generally check both the intraocular pressure and the angle structures to ensure glaucoma is not present.
Diagnosis and Treatment of Traumatic Glaucoma
To diagnose traumatic glaucoma, an ophthalmologist typically uses a slit lamp microscope and a gonioscope to observe the angle structures of the eye and ensure they are open enough for adequate fluid outflow. Sometimes, a clinician uses biomicroscopy or optical coherence tomography to obtain an image of the eye. In addition, an ophthalmologist uses a specialized device to examine the inside of the eye and specifically focus on the appearance, size and thickness of the optic nerve. Compression results in predictable patterns of change in the optic nerve. If it is suspected a patient has already experienced some vision loss, formal visual field testing may also be completed. Since vision loss begins in the periphery, a patient is not always initially aware it is occurring.
Fortunately, treatment options exist when a patient is diagnosed with traumatic glaucoma, and the therapies can preserve sight. Depending on the etiology of the increased intraocular pressure, a clinician may recommend pharmacologic agents, such as beta blockers, prostaglandin analogues or surgical therapies. Usually, surgery is only an option when pharmacologic therapies have proven insufficient. In an acute setting, steroids could play a role in reducing inflammation to help open the natural pathways out of the eye. Obtaining treatment early on in the trauma process can help prevent further damage.
