01/22/2026
Eye pressure, or intraocular pressure (IOP), is the fluid pressure inside the eye, normally 10–21 mmHg, maintained by aqueous humor production and drainage; high IOP (above 21 mmHg) can damage the optic nerve, potentially leading to glaucoma, while low pressure (hypotony) can also be problematic. It's measured with tonometry, often the air-puff test, and factors like age, caffeine, tight neckties, or steroid use can affect it, requiring regular checks for overall eye health.
What it is?
*A measure of fluid pressure within the eye, essential for its shape and function.
*Maintained by a balance between fluid (aqueous humor) production and drainage.
Normal vs. Abnormal Pressure
*Normal: 10–21 mmHg (millimeters of mercury).
*High (Ocular Hypertension): Above 21 mmHg, a risk factor for glaucoma.
*Low (Hypotony): Below 6 mmHg, also potentially harmful.
How it's Measured (Tonometry)
*A puff of air flattens the cornea; the machine measures the force needed, indicating pressure.
Causes of High Eye Pressure (Ocular Hypertension)
*Imbalance: Too much fluid produced or poor drainage through the trabecular meshwork.
Risk Factors
*Age (over 40)
*Family history
*Diabetes
*High blood pressure
*Certain medications (steroids)
*Eye injury
*Severe nearsightedness.
What Affects Eye Pressure?
*Increases: Caffeine, heavy lifting, tight neckties, certain yoga poses, some medications (ketamine).
*Decreases: Alcohol, cannabis.
Why It Matters?
*Sustained high pressure can damage the optic nerve, leading to vision loss, often starting with peripheral vision loss.
*Glaucoma can occur with normal eye pressure (normal-tension glaucoma).
When to See a Doctor?
*If you experience blurred vision, eye pain, halos around lights, headaches, or vision loss.
*Regular eye exams are crucial, as symptoms may not appear until significant damage occurs.