Glaucoma is a group of eye diseases in which the optic nerve, which connects your eye to your brain, is damaged by the pressure of the fluid inside the eye.
This may be because the pressure is higher than normal, or because the nerve is more susceptible to damage from pressure. This may affect one or both of your eyes. There are two main types of glaucoma - chronic glaucoma (more common), which happens slowly and acute glaucoma which happens quickly.
Primary Open Angle Claucoma (POAG) is the most common form of chronic glaucoma.
Who is at risk of chronic glaucoma?
Anyone can develop chronic glaucoma, but the risk increased if you:
- are aged over 40
- are very short-sighted
- are of African/ Caribbean origin
- are closely related to someone with chronic glaucoma
- have raised eye pressure (Ocular Hypertension - OHT)
- are diabetic
- have high blood pressure
If you are over 40 and have a parent, child or sibling with glaucoma - you are eligible for free NHS eye tests, it is recommended with a family history of glaucoma to have annual eye examinations.
It is so important to have regular eye tests, as there are no symptoms in the early stages of chronic glaucoma. Glaucoma causes irreversible nerve damage, therefore it is imperative that it is caught early. In most cases it can be controlled with eye drops or surgical options.
How do we check for glaucoma?
Traditionally there are three main tests we do for glaucoma.
- Visual assessment of the optic nerve by the optometrist using an opthalmoscope or volk lens. Retinal photographs can also be taken to compare changes in the appearance of the optic nerve over a number of years.
- Eye pressure measurement - the 'puff of air test'! The tonometer blows air into the eye multiple times to get an average eye pressure reading. In addition to this test, at Chakshu London opticians we will carry out pachymetry, a test that measures the thickness of your cornea. The pressure reading can be affected by the corneal thickness - thick corneas will give an artificially high reading and thin corneas will give an artificially low reading. This improves the accuracy of the eye pressure measurements.
- The visual field test. Glaucoma initially starts to affect the peripheral vision, which is why glaucoma patients don't always notice any symptoms in the early stages. If left untreated, glaucoma causes tunnel vision and eventual blindness.
We have invested in the latest technology and can offer an OCT scan in addition to the above tests, which is typically done in hospital clinics.
The OCT scan will take a 3D scan of the nerves at the back of the eye and compare your data to the norm for your age and ethnicity. This helps us to notice signs of nerve damage even earlier than the tests mentioned above. You can upgrade your eye test to include the OCT scan, it gives further assurance that the eyes are healthy and if any anomalies are noted, then they can managed more efficiently.