Can Glaucoma affect only one eye?

Can Glaucoma Affect Only One Eye?

Glaucoma is a group of eye conditions characterized by damage to the optic nerve, often linked to elevated intraocular pressure (IOP). It’s a leading cause of irreversible vision loss worldwide. Many people wonder: can glaucoma affect only one eye? The short answer is yes, at least initially—but the situation can be more complex over time.

Understanding Glaucoma

• Primary open‐angle glaucoma (POAG)
  • Most common form (Weinreb & Khaw, 2004)
  • Develops slowly, often without early symptoms
  • Both eyes are at risk, but one eye may show damage first
• Primary angle‐closure glaucoma (PACG)
  • Less common but can be sudden and severe (Foster & Johnson, 2001)
  • Occurs when the iris blocks drainage of aqueous fluid
  • Often presents in one eye first, but the fellow eye is at risk
• Secondary glaucomas
  • Result from injury, inflammation, steroids, or other eye diseases
  • Can be strictly unilateral if the underlying cause is limited to one eye

Can Glaucoma Really Be in Just One Eye?

1. Initial Asymmetry
   • In POAG, both eyes usually develop elevated pressure, but one eye often has higher IOP or more advanced optic nerve damage early on.
   • Imaging and visual field tests can reveal nerve changes in one eye before the other.
2. True Unilateral Cases
   • Secondary glaucomas (e.g., due to trauma, uveitis, or steroid use) can remain confined to the injured or inflamed eye.
   • Angle‐closure attacks may strike one eye suddenly; without treatment, the second eye can follow suit.
3. Progression Over Time
   • Even if glaucoma seems limited to one eye at diagnosis, close monitoring is essential.
   • Contralateral (second eye) involvement can occur months to years later, especially in POAG.

Signs and Symptoms of One-Eye Glaucoma

Many patients with early glaucoma notice no symptoms. When they do occur, they can include:

• Peripheral vision loss (often described as “tunnel vision”)
• Blurring of vision in one eye
• Halos around lights (more common in angle‐closure)
• Eye pain, headache, nausea/vomiting (acute angle‐closure)

Because glaucoma can be painless and asymptomatic, it’s sometimes called the “silent thief of sight.” If you experience any changes—especially in one eye—don’t ignore them.

Diagnosing Unilateral Glaucoma

A thorough eye exam is crucial:

1. Tonometry – measures IOP in each eye.
2. Gonioscopy – checks the drainage angle structure.
3. Optic nerve imaging (OCT, fundus photography) – assesses nerve fiber layer thickness.
4. Visual field testing – maps peripheral vision defects.

If only one eye shows abnormalities, your ophthalmologist will monitor the other eye closely and may recommend preventive treatment.

Why Early Detection Matters

• Slow Progression: Early-stage glaucoma often has no symptoms.
• Irreversible Damage: Once nerve fibers are lost, vision cannot be restored.
• Better Outcomes: Treatment started early preserves vision longer and may prevent the second eye from developing glaucoma.

Consider doing a free, online symptom check for any eye discomfort or vision changes—even if they seem minor.

Treatment Options for One-Eye Glaucoma

Treatment aims to lower IOP and protect the optic nerve:

• Eye Drops
  • Prostaglandin analogs, beta-blockers, carbonic anhydrase inhibitors
  • Usually first-line for POAG
• Laser Therapy
  • Selective laser trabeculoplasty (SLT) for open-angle glaucoma
  • Peripheral iridotomy for angle-closure glaucoma
• Surgery
  • Trabeculectomy or minimally invasive glaucoma surgery (MIGS) when drops/laser are insufficient
• Management of Underlying Causes
  • For secondary glaucoma, address inflammation, steroid use, tumors, or trauma

Your doctor will tailor the approach based on the type of glaucoma, pressure levels, age, and overall eye health.

Living with Unilateral Glaucoma

• Regular Monitoring
  • Follow-up visits every 3–6 months, or as recommended
  • Visual field tests and optic nerve imaging at intervals
• Medication Adherence
  • Take eye drops exactly as prescribed—skipping doses can accelerate nerve damage
• Healthy Lifestyle
  • Exercise moderately, eat a balanced diet, avoid smoking
  • Manage coexisting conditions (e.g., hypertension, diabetes)
• Awareness of Symptoms
  • Report new eye pain, vision changes, or headaches immediately

When to Speak to a Doctor

If you notice any of the following—even in just one eye—contact an eye care professional promptly:

• Sudden vision loss or blurriness
• Halos around lights
• Severe eye pain or headache, especially with nausea/vomiting
• Any new field-of-vision changes

Early evaluation can make a significant difference in outcomes.

Key Takeaways

• Glaucoma often affects both eyes, but one eye can show damage first or—less commonly—be the only eye involved initially.
• Primary open-angle glaucoma is typically bilateral but asymmetric; angle-closure and secondary glaucomas can be truly unilateral.
• Early detection and treatment are essential to preserve vision.
• Regular check-ups, consistent medication use, and prompt attention to symptoms protect both eyes.
• Consider a free, online symptom check for peace of mind if you experience any worrying signs.

Speak to a doctor about any serious or life-threatening concerns. Your ophthalmologist can confirm a diagnosis and recommend the best treatment plan to safeguard your vision.