Yes, it is possible for glaucoma to affect only one eye. Glaucoma is a group of eye conditions that damage the optic nerve, a bundle of nerve fibers sending images from the eye to the brain, often due to abnormally high pressure inside the eye. While glaucoma commonly develops in both eyes, its presentation can be asymmetric, meaning one eye might be affected more severely or exclusively, a condition known as unilateral glaucoma.
Understanding Glaucoma in a Single Eye
Glaucoma develops when there is damage to the optic nerve, typically linked to elevated intraocular pressure (IOP). While primary open-angle glaucoma often affects both eyes, it can progress unevenly between them. One eye might exhibit more advanced optic nerve damage or higher eye pressure compared to the other. This asymmetry can sometimes lead to a diagnosis of glaucoma in one eye while the other remains unaffected.
Secondary glaucomas are conditions where optic nerve damage and elevated eye pressure result from another eye condition or systemic disease. These forms of glaucoma are more frequently unilateral because the initiating cause affects only one eye. For instance, an injury or inflammation might impact only one eye’s fluid drainage system, leading to pressure buildup and optic nerve damage in that eye.
Specific Causes and Risk Factors for Unilateral Glaucoma
Several conditions can lead to unilateral glaucoma, primarily through secondary mechanisms. Trauma to a single eye is a common cause, as an injury can directly damage the eye’s drainage angle, leading to increased intraocular pressure. Such injuries include blunt force trauma or penetrating wounds that disrupt the eye’s fluid outflow structures.
Ocular inflammation, specifically uveitis, can also induce unilateral glaucoma. Uveitis, inflammation of the eye’s middle layer, can clog drainage pathways when affecting one eye, causing pressure to rise. Certain eye surgeries or procedures, such as cataract or retinal procedures, can lead to elevated pressure in the operated eye.
Steroid-induced glaucoma is another cause of unilateral presentation, particularly when steroid eye drops are administered to one eye for inflammation or allergies. Prolonged use of these drops can increase intraocular pressure in the treated eye. Conditions like pigment dispersion or pseudoexfoliation syndrome, while potentially bilateral, often manifest asymmetrically, with one eye developing glaucoma earlier or more severely due to uneven pigment release or protein deposits affecting drainage.
Diagnosis and Management of Unilateral Glaucoma
Diagnosing unilateral glaucoma involves a comprehensive eye examination, even if symptoms are only present in one eye. This examination includes measuring intraocular pressure using tonometry, a thorough inspection of the optic nerve for signs of damage, and visual field testing to detect any loss of peripheral vision. Imaging techniques, such as optical coherence tomography (OCT), are also used to provide detailed scans of the optic nerve head and surrounding nerve fiber layer, helping to identify subtle changes.
Management of unilateral glaucoma primarily focuses on lowering eye pressure to prevent further optic nerve damage and preserve vision. Treatment modalities often begin with prescribed eye drops, which work by either reducing fluid production or improving fluid drainage from the eye. If eye drops are insufficient, laser procedures, such as selective laser trabeculoplasty (SLT), may be considered to enhance the eye’s natural drainage.
In cases where medication and laser treatments are ineffective, surgical options, such as trabeculectomy or the implantation of drainage devices, may be necessary to create a new outflow pathway for fluid. Even when glaucoma is diagnosed in only one eye, the “unaffected” eye is closely monitored. This is because some underlying causes might eventually affect both eyes, or the initially unaffected eye could still be at risk of developing glaucoma later.