Eye Health
In conjunction with World Glaucoma Week 2014, Ipoh Echo talks to Consultant Eye Surgeon Dr S.S. Gill about this “silent thief of sight.” – PART 3
In this 3rd part, Dr Gill talks about the checks done on a patient who is suspected of having glaucoma the “silent thief of vision” – a blinding condition that does not have any symptoms.
1. TONOMETRY
This is the measurement of the eye pressure (intraocular pressure or IOP). If a person has higher than normal eye pressure, it would mean that the person would have a higher risk for glaucoma. A Goldmann tonometer is used for this. Sometimes a non-contact air-puff tonometer is used but this is less accurate than the Goldmann tonometer which is the gold standard in eye pressure check. If this test is positive, further tests are mandatory.
2. GONIOSCOPY or examination of the eye drainage area
A device called a gonioscope is used to examine the angle where the aqueous (eye fluid) drains in order to diagnose the type of glaucoma. This is important so that the correct treatment can be given.
3. OPTIC NERVE CHECK
An instrument called an ophthalmoscope or Fundus Imaging Camera is used to examine the optic nerve to look for glaucoma changes. The picture on the left shows a normal optic nerve (optic disc). The picture on the right shows the damage that occurs to the optic nerve or optic disc due to glaucoma (indicated by the arrows).
4. VISUAL FIELD TESTING (PERIMETRY)
A visual field test (perimetry) checks for any “missing areas” of vision that a patient will not notice. The test takes about 15-20 minutes to do. You will be shown a sequence of lights that appear in the periphery of a dome and you will be asked to click on a button when you see the light appearing. This picks up any “tunnel vision” found in glaucoma patients.
5. OPTICAL COHERENCE TOMOGRAPHY (O.C.T.) SCAN
This is a new and accurate way of helping to evaluate glaucoma. In glaucoma, the nerve fibre layer (RNFL) gets thinned-out resulting in loss of vision peripherally (tunnel-vision). The OCT Scan is able to measure the nerve fibre layer thickness to assist in accurately confirming glaucoma. Also, when several scans are done over time, (serial OCT Scans), it can detect whether the glaucoma is worsening or not. While it can be so helpful, the downside is that the test may not be available in every eye facility.
FREE GLAUCOMA SCREENING:
In conjunction with World Glaucoma Week, Gill Eye Centre is offering free glaucoma screening for a limited time. BY APPOINTMENT ONLY
