As a patient of ours you are already aware of the importance of eye examinations. Apart from sight correction, regular examinations allow our optometrists to inspect your eyes for numerous conditions that affect general health as well as those that can affect your vision. A basic assessment of your visual fields is often carried out during a standard eye test. If there is a history of glaucoma then it will always be undertaken. It provides the optometrist with an indication of the sensitivity of your vision over a 30° field of view.
Advanced Visual Field Analysis
Why is it recommended?
There are a number of good reasons for a full investigation of the visual fields but the single most important reason (and the reason we carry out a basic screening as part of many normal eye tests) is in the detection of glaucoma. Glaucoma is the leading cause of preventative blindness in the United Kingdom and is found to some extent in 1 in 50 people over the age of 40. It can affect children and younger adults, though this is less common. It
is due to a build-up of fluid within the eye leading to pressure on the optic nerve. The symptoms are not obvious to the individual until the disease is well established. Vision that is lost to glaucoma can never be recovered, though early detection and treatment can prevent future damage. Because of the hereditary links, those who have glaucoma, or have close relatives with the condition, are encouraged to have regular eye tests incorporating basic screening annually, and to undergo this more detailed assessment at least every couple of years, or as recommended by your optometrist. Apart from glaucoma, there are other conditions that can be diagnosed; diseases of the macula (central area of vision) and other neurological conditions can also be assessed using this new perimeter. Since our new equipment will plot and store detailed information about your own eyes, we are able to detect any variations much sooner. As with many medical conditions, it is the comparison of results taken over a period of time that allows detection of problems at an earlier stage.
What is involved?
Since the equipment is capable of assessing or testing for various conditions, and because the test will automatically adapt to your own needs, the length of time taken for this procedure can vary greatly. An in-depth glaucoma assessment, or neurological analysis may take 15 minutes or more. In most cases the advanced analysis would have been advised because the basic screening showed an area that needed further investigation. This may only take 8 minutes or
so depending on the outcome of the test. Whichever test routine is being undertaken, the process is similar and involves looking into a bowl-shaped disc. Small lights of varying intensity and position are briefly illuminated and you will need to respond by pressing a button. You will be shown how to respond before the test starts, and unlike older equipment there is no ‘closed-in’ feeling that some people find claustrophobic.
How much does it cost, and how often should it be carried out?
Unfortunately this type of in-depth field analysis goes well beyond the basic requirements and is not funded by the National Health Service (unless the hospital has specifically arranged for us to carry out analysis on their behalf). We charge a fee of £18 for this additional procedure. Your optometrist is the best judge of how often this should be carried out but as a guideline those over 35 should consider an initial assessment, if only to check for glaucoma, followed perhaps every few years. You would probably be advised to increase the frequency where glaucoma is present, or whenever the basic screening during an eye test presents any symptoms.