What is normal eye pressure, and does it rule out glaucoma?
Eye pressure in many adults is approximately 10–21 mmHg, but the number alone is insufficient. Glaucoma can occur within that range, while some people with raised pressure have no optic nerve damage.
Details
Why one number is not enough
Glaucoma damages the optic nerve. The amount of pressure that the nerve can tolerate varies between people. A reading within the usual range therefore does not exclude disease, and a higher reading does not establish the diagnosis. The measurement must be interpreted alongside the examination, family history and earlier results.
What else may be checked?
An ophthalmologist may examine the optic nerve through dilated pupils, test the visual field and request nerve imaging or additional measurements. Monitoring and treatment depend on the likelihood or presence of damage, rather than prescribing drops for every high reading.
When to seek urgent help
Sudden severe eye pain with redness, blurred vision or nausea needs immediate assessment. Common open-angle glaucoma, however, may initially cause no noticeable symptoms. Do not wait for pain before attending a recommended eye examination.
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