Symptoms
High IOP itself doesn't usually cause noticeable symptoms in the early stages. This is why regular eye exams are vital. Symptoms tend to appear later, typically associated with glaucoma, which is often the result of prolonged elevated IOP:
Gradual loss of peripheral vision
Tunnel vision in advanced stages
Eye pain (less common, often associated with acute angle-closure glaucoma)
Headaches (rare, associated with very high IOP)
Blurred vision
Halos around lights
Causes
IOP is determined by the balance between the production and drainage of aqueous humor, the fluid inside the eye. Imbalances can lead to increased IOP:
Excessive Aqueous Humor Production: The eye produces too much fluid.
Inadequate Aqueous Humor Drainage: The drainage angle (where fluid exits the eye) is blocked or narrowed.
Open-angle glaucoma: The drainage angle is open but the trabecular meshwork (the drainage system) is not functioning properly.
Angle-closure glaucoma: The angle between the iris and cornea is narrowed or closed, blocking drainage.
Secondary Causes:
Certain medications (e.g., corticosteroids)
Eye injuries
Eye inflammation (uveitis)
Other eye conditions (e.g., pigment dispersion syndrome, pseudoexfoliation syndrome)
Medicine Used
Medications aim to lower IOP by either decreasing fluid production or increasing fluid drainage:
Prostaglandin analogs: (e.g., Latanoprost, Travoprost, Bimatoprost) - Increase fluid outflow.
Beta-blockers: (e.g., Timolol, Betaxolol) - Decrease fluid production.
Alpha-adrenergic agonists: (e.g., Brimonidine, Apraclonidine) - Decrease fluid production and increase outflow.
Carbonic anhydrase inhibitors: (e.g., Dorzolamide, Brinzolamide, Acetazolamide) - Decrease fluid production.
Rho kinase inhibitors (e.g., Netarsudil) - Increase fluid outflow.
Combination medications: Containing two or more of the above.
Precautions
Regular Eye Exams: Especially important if you have a family history of glaucoma, are over 40, or have other risk factors.
Adherence to Medication: If prescribed IOP-lowering medications, take them exactly as directed.
Avoid Steroids (if possible): Prolonged use of corticosteroid medications (especially eye drops) can increase IOP. Discuss alternatives with your doctor if possible.
Healthy Lifestyle: Maintain a healthy diet, exercise regularly, and avoid smoking. These can contribute to overall eye health.
Protect Your Eyes: Wear eye protection during activities that could cause eye injury.
How long does an outbreak last?
IOP itself is not an outbreak, but a pressure inside of the eye. The duration of elevated IOP depends on the underlying cause and the effectiveness of treatment. Without treatment, elevated IOP can be chronic and lead to progressive vision loss over years. Acute angle-closure glaucoma can cause rapid pressure increases.
How is it diagnosed?
IOP is measured during a comprehensive eye exam using:
Tonometry: Several types of tonometers are used to measure IOP. Common methods include:
Goldmann Applanation Tonometry: Considered the gold standard, this involves numbing the eye and using a tonometer mounted on a slit lamp.
Non-contact Tonometry (Air-puff): Uses a puff of air to flatten the cornea.
iCare Tonometer: A portable tonometer that gently touches the cornea.
Other Diagnostic Tests: In addition to IOP measurement, other tests are performed to assess glaucoma risk and optic nerve damage:
Gonioscopy: Examines the drainage angle.
Visual Field Testing: Measures peripheral vision.
Optical Coherence Tomography (OCT): Scans the optic nerve and retinal nerve fiber layer for damage.
Timeline of Symptoms
Early Stages: Typically asymptomatic. Gradual elevation of IOP without noticeable changes in vision.
Progressive Stages: Gradual loss of peripheral vision may begin. This is often unnoticed until it becomes significant.
Advanced Stages: Tunnel vision develops. Difficulty with activities requiring peripheral vision (e.g., driving).
Acute Angle-Closure Glaucoma: Sudden, severe eye pain, redness, blurred vision, halos, nausea, and vomiting. Requires immediate medical attention.
Important Considerations
Early Detection is Key: Glaucoma is often asymptomatic in its early stages. Early detection and treatment can significantly slow or prevent vision loss.
Regular Follow-up: If diagnosed with elevated IOP or glaucoma, regular follow-up appointments with an ophthalmologist are essential to monitor IOP and adjust treatment as needed.
Lowering IOP Doesn't Guarantee No Vision Loss: While lowering IOP is the primary goal of treatment, some individuals may still experience progression of optic nerve damage despite achieving target IOP levels.
Treatment is Lifelong: Glaucoma treatment is usually lifelong.
Discuss Risks and Benefits: Talk to your doctor about the potential risks and benefits of each treatment option.