What are the signs and symptoms of glaucoma?

Signs and Symptoms of Glaucoma

Glaucoma is typically asymptomatic in its early stages, with most patients unaware they have the condition until significant optic nerve damage and visual field loss have occurred. 1

Structural Signs of Glaucoma

Optic Nerve Head Changes

• Progressive narrowing of the neuroretinal rim with increased cupping of the optic disc
• Diffuse or focal narrowing/notching of the optic disc rim, especially at inferior or superior poles
• Violation of the ISNT rule (normal rim width should be: Inferior > Superior > Nasal > Temporal)
• Vertical elongation of the optic cup
• Optic disc hemorrhages involving the disc rim, parapapillary retinal nerve fiber layer (RNFL), or lamina cribrosa
• Optic disc neural rim asymmetry between eyes consistent with neural tissue loss
• Beta-zone parapapillary atrophy
• Nasalization of central optic nerve head vessels 1, 2

Retinal Nerve Fiber Layer Changes

• Diffuse or localized thinning of the parapapillary RNFL, especially at inferior or superior poles
• RNFL defects visible on imaging or clinical examination 1

Functional Signs and Symptoms

Visual Field Defects

• Nasal step (peripheral field defect in the nasal area)
• Arcuate field defect (curved visual field loss following nerve fiber bundle pattern)
• Paracentral depression (clusters of test sites near central vision)
• Visual field loss across horizontal midline in one hemifield exceeding loss in opposite hemifield (in early/moderate cases)
• Loss within 5 degrees of fixation in severe cases 1

Symptoms (Usually Late in Disease)

• Gradual, progressive peripheral vision loss (typically unnoticed until advanced)
• Difficulty with night vision
• Loss of contrast sensitivity
• Difficulty adapting to dark environments
• Central vision usually preserved until late stages 3, 4

Intraocular Pressure (IOP)

• Often elevated (>21 mmHg), but nearly 40% of patients with primary open-angle glaucoma may have normal IOP measurements (normal-tension glaucoma)
• IOP alone is not diagnostic of glaucoma 1

Severity Classification

Glaucoma severity can be categorized as:

1. Mild: Definite optic disc/RNFL abnormalities with normal visual field testing
2. Moderate: Definite optic disc/RNFL abnormalities with visual field abnormalities in one hemifield not within 5 degrees of fixation
3. Severe: Definite optic disc/RNFL abnormalities with visual field abnormalities in both hemifields and/or loss within 5 degrees of fixation in at least one hemifield
4. Indeterminate: Definite optic disc/RNFL abnormalities with inability to perform or unreliable visual field testing 1

Important Considerations

Acute Angle-Closure Glaucoma (Different from POAG)

Unlike primary open-angle glaucoma, acute angle-closure glaucoma presents with dramatic symptoms:

• Sudden severe eye pain
• Headache
• Nausea/vomiting
• Blurred vision
• Halos around lights
• Red eye
• Fixed, mid-dilated pupil
• Very high IOP 5

Risk Factors

• Older age (especially >40 for African Americans, >65 for whites)
• African or Hispanic/Latino ethnicity
• Family history of glaucoma
• Elevated IOP
• Low ocular perfusion pressure
• Type 2 diabetes mellitus
• Myopia
• Thin central cornea 1, 3, 6

Clinical Implications

• Primary open-angle glaucoma affects approximately 76 million people worldwide
• It is the second leading cause of blindness globally
• Nearly half of those affected are unaware of their condition
• Early detection is critical as vision loss is irreversible but disease progression can be slowed with treatment 1, 3, 7

Remember that glaucoma is often called the "silent thief of sight" because most patients with primary open-angle glaucoma remain asymptomatic until significant, irreversible damage has occurred, highlighting the importance of regular comprehensive eye examinations for early detection.