Raised pressure damages the optic nerve from the outside in, so central vision stays sharp while the periphery quietly goes. Nothing hurts, and nothing warns you.
20/200
How we find it
1
Pressure
Contact tonometry, which is more accurate than the air puff. A normal reading does not rule glaucoma out, which is why it is one test of three.
Every exam
2
Optic nerve OCT
Measures the nerve fibre layer in microns. Thinning shows up here roughly five years before it shows in a visual field.
From age 40
3
Visual field
What you can see without moving your eye. This is where the loss becomes measurable, and where we track whether treatment is holding.
Annual
Risk is not evenly spread.
Family history
4 to 9x risk
Age over 60
Screen annually
African or Caribbean heritage
Screen from 40
High myopia
Higher risk
Long term steroid use
Higher risk
Previous eye injury
Higher risk
If any of these apply, an annual exam is not optional. Damage already done cannot be recovered; treatment only protects what is left, which is why finding it early is the entire strategy.
20/20
What happens if we find it
1
Repeat and confirm
One high reading is not a diagnosis. We repeat at a different time of day before anything else happens.
2
Referral
To the hospital eye service with our images and fields attached, so they start from our data rather than repeating it.
3
Treatment
Usually a nightly drop, sometimes laser. Both aim at the same thing: lowering pressure enough to stop further loss.
4
Shared monitoring
We keep the fields and OCT between hospital visits, which usually means fewer trips across town for you.