Below is a list of the impairments that we currently check & offer advice for at our St Albans opticians:
Diabetic retinopathy is caused by a growth of blood vessels through the retina when diabetes is uncontrolled and often needs laser treatment to close the blood vessels. This is very similar in principle to spot welding a car.
Diabetics often don’t know they have a problem,but the symptoms of always being thirsty and tired are classic signs. Variable vision when an uncontrolled diabetic episode occurs is common.
Strokes or CVA (Cerebral Vascular Accident) occur when a blood vessel is blocked and stops blood to a particular part of the brain. The Visual Cortex occupies approx a 1⁄3rd of the back of the brain and when a Stroke occurs, part of the vision can be lost. Being aware of this when helping a stroke victim eat or walk is very important as they often cannot see half of their food or half of the lounge. Early symptoms of a stroke such as loss of speech, numbness down one side of the body and a facial palsy (a drooping of one side of the face) should be acted upon quickly. Often aspirin is administered to thin the blood however this should only be done by a Doctor as rarely aspirin can cause a blood vessel to burst.
Glaucoma is a condition where typically the eye pressure gets too high, this causes the blood vessels within the eye to close progressively from the periphery towards the centre of the vision. The retina dies as it cannot get the oxygen and nutrients from the blood vessels it needs. The picture shows the tunnel vision effect of advanced Glaucoma. Flashes of light are noticed by the patient which indicate a retinal detachment or split. Glaucoma is normally treated with drops such as Xalatan which dilate the drainage canal within the eye. Sometimes a laser is used to cut a small hole in the iris and a final option is an operation on the drainage duct to open it up. The symptoms of glaucoma are not obvious and a regular eye examination using the “Puff of Air” or other device is needed to establish the eye’s pressure. Visual fields and the size of the optic nerve ratio are two key factors considered. Visual field assessment is often impossible on elderly or confused patients because they need to interact with the test, so an experienced Optometrist viewing the patient’s retina in a dark room is still the best way to decide if there is a problem. There are many hand-held devices available to measure eye pressure, I have found that the “Puff of Air” device is the safest as many patients move their heads during the process of measuring eye pressure and any device that is in contact with the eye can cause an injury both to the patient and the Optician. I have therefore decided that the lowest risk of injury is provided by the “Puff of Air” device. Some anti-psychotic medication and steroids can cause Glaucoma, hence the need for a full listing of the client’s medicine. Some ethnic groups such as African-Caribbeans are up to six times more likely to suffer from Glaucoma. If a patient has a blood relative who has Glaucoma then the risk of them having it is high and hence the need to ask the question. Glaucoma, despite the knowledge of the disease is still a complex eye disorder and people can even have normal eye pressure with this condition. Symptoms of this can be a sudden flood of floaters, a grey curtain appearing, and flashes of light or rarely excruciating pain sufficient to make the patient vomit. Often there are no symptoms other than just a gradual closing in of the vision from the edges.
CataractsCataracts is an Indian word meaning “white water”, most people over 65 have some form of lens opacity and gradually these opacities build up to the point where an implant is needed to correct it. Generally the operation takes 45 minutes under local anaesthetic. The patient is admitted in the morning and goes home in the afternoon. Often the world will look a nicotine colour and diffuse. UV400 filtered lenses and photo-chromatic lenses help to prevent cataracts as UV light is a common cause of this eye condition.
Typically the patient will need to wait 4-6 weeks before having their spectacles changed. Sometimes the lens implant clouds up, this does not need another operation as a YAG laser can scrub the lens clean and again is a simple and quick procedure. Hand-held auto refractors have been assessed by myself as it would appear to be a simple and easy way of finding the prescription of a patient, however due to the high incidence of cataracts and the lack of ability of many patients to concentrate on the fixation target, it has proved to me to be an unreliable method and therefore not used. I have found that a skilled Optometrist provides the best and most reliable results with very few errors.
Some anti-psychotic medication such as chlorpromazine interact with sunlight and can cause cataracts. You may have seen patients whose skin takes on a purple tinge when in sunlight when on this or similar medication. This why a full background history of the client’s medication is necessary.
FloatersFloaters often look like tadpoles moving across your vision. They are the remains of a blood vessel that forms within the eye to make the lens and just before you are born, dissolves but some of the small cells are left and stay in the jelly at the back of the eye. These floaters are common to most people and are not a problem. However a sudden shower of floaters can be a Vitreous Detachment (the jelly) and or a Retinal Detachment which is accompanied by flashes of light. This is very serious and should not be ignored.
Macular DegenerationMacular Degeneration accounts for 40% of all people registered blind, 95% are of the Dry type and 5% are of the Wet type. Lutein is a chemical found in dark green vegetables and your body absorbs it to line the inside of your eye to form the black pigment layer you see as the dark pupil. Insufficient Lutein can cause this layer to break down and cause Macular Degeneration which results in central vision loss. A food supplement is available to combat this when detected early enough, hence an annual eye examination is recommended for everyone over 70.
Ultra-Violet and Blue light can cause cataracts and accelerate the Black Pigment layers break-down, a UV400 filter or lenses that change colour with the light help prevent this. Often a yellow tinted lens will help increase contrast for patients with advanced Macular Degeneration. Patients with Macular Degeneration will not look directly at you as all they can see is a black blob, typically they will look at you sideways, using their peripheral vision, unfortunately this is 10 times less clear than their central vision.