What are the differential diagnoses for visual field defects?

Visual field defects are not an independent disease, but rather a sign of various ocular or neurological disorders. Differential diagnosis should focus on conditions such as glaucoma, retinal diseases, optic nerve disorders, brain lesions, and migraine, with accurate distinction based on symptom characteristics and diagnostic test results. The specific analysis is as follows:

1. Glaucoma: As a common cause of blindness, glaucoma leads to visual field loss due to elevated intraocular pressure damaging the optic nerve. In early stages, it typically presents as peripheral vision narrowing—similar to viewing the world through a keyhole—which gradually encroaches on central vision as the disease progresses. Patients often experience eye discomfort, eye pain, or headaches. Diagnosis can be confirmed through intraocular pressure measurement and assessment of the retinal nerve fiber layer.

2. Retinal Diseases: Conditions such as retinal detachment and retinitis pigmentosa damage photoreceptor cells in the retina, resulting in corresponding visual field defects. Retinal detachment usually causes sudden shadowing or curtain-like obstruction in the visual field, often accompanied by flashes of light and rapid vision loss. Retinitis pigmentosa manifests as progressive constriction of the peripheral visual field, with poor night vision being a hallmark feature. Fundus examination reveals characteristic pathological changes.

3. Optic Nerve Disorders: Diseases including optic neuritis and optic atrophy disrupt the transmission of visual signals, leading to visual field defects. Optic neuritis has an acute onset, commonly associated with sudden vision loss and pain during eye movement, with visual field testing often revealing central scotomas. Optic atrophy typically follows a chronic course, presenting with concentric (progressive inward) narrowing of the visual field; pallor of the optic disc is a key clinical sign.

4. Brain Lesions: Tumors or cerebral infarctions that compress the visual pathways can cause visual field defects whose patterns correlate with the lesion's location. For example, pituitary adenomas often lead to bitemporal hemianopia, where patients lose vision in the outer (temporal) fields of both eyes, making it difficult to see objects to either side. Visual field defects caused by cerebral infarction typically appear suddenly and are frequently accompanied by other neurological symptoms such as limb weakness or speech difficulties.

5. Migraine: Some migraine sufferers experience transient visual field disturbances prior to an attack, often manifesting as flashing lights, zigzag lines, or blind spots (scintillating scotoma). These symptoms usually last 20–30 minutes and resolve as the headache begins. Such visual disturbances are temporary, and their episodic nature, along with a history of migraines, helps differentiate them from structural or organic diseases.

Individuals experiencing visual field defects should seek prompt medical evaluation to determine the underlying cause through visual field testing, fundus examination, and imaging studies. Routine health check-ups, avoiding excessive eye strain, and managing baseline health indicators such as blood pressure and blood glucose levels are essential for reducing the risk of ocular and neurological disorders.