15 November 2011
Conditions that can affect the eyes
There are many different conditions that can affect your eyes in lots of different ways. You only get one pair of eyes, so make sure you know
how to keep them healthy.
Below are some of the most common conditions that can affect your eyes.
Age related cataracts are a normal age related change. As we get older the lens inside our eye gradually changes and becomes less transparent
(clear). A lens that has turned misty, or cloudy, is said to have a cataract.
Over time a cataract can get worse, gradually making vision
mistier. A straight forward operation can usually remove the misty lens and replace it with an artificial lens to enable you to see more clearly
What are the symptoms of age related cataract?
Cataracts usually develop slowly and although symptoms vary there are some symptoms that most people experience:
When a cataract
starts to develop, you may feel that your sight isn't quite right. For example, if you wear glasses you may feel that your lenses are dirty, even
when they're clean.
Gradually, you may find your sight becomes cloudier and colours appear less bright or more washed out. Edges of stairs or
steps become more difficult to see and you may feel you need a lot more light to read smaller print.
Another common symptom of a
cataract is a problem with bright lights. Lights can seem to glare, or you may find that car headlights dazzle you more than they used to.
may also notice a slight change in your colour vision - things may appear more yellow than before. This often happens if one eye develops a
cataract first and colours look different when you compare one eye with the other.
If you notice any of these changes, you should have your eyes tested, as the Optometrist will be able to tell whether you have developed a cataract or not. The Optometrist will then discuss the
degree to which the cataract is affecting your vision and, if you agree, refer you via your GP to the local eye clinic.
If the cataract is at an
early stage and not affecting the quality of your vision you may find that you won’t be directly referred to your doctor but the Optometrist will
ask to see you more regularly to assess its development.
Age-related macular degeneration (AMD) is an eye condition that affects the tiny part of the retina at the back
of your eye, called the macula.
AMD causes problems with your central vision, but does not lead to total loss of sight and is
not painful. AMD affects your vision you use when you're looking directly at something, for example when you're reading, looking at photos or
watching television. AMD may make this central vision distorted or blurry and, over a period of time, it may even cause a blank patch in the
centre of your vision.
There are two types of macular degeneration; wet, and dry.
Dry macular degeneration is by far
the more common and the less serious type. Dry AMD is caused by gradual age related wear and tear to the macular.
Wet AMD is far
less common, but can be more serious as it can lead to sudden and dramatic loss of central vision.
What causes AMD?
At present, the exact cause for AMD is not known. However, the following things are thought to increase your chances of developing
• Age: AMD develops as people grow older and is most often seen in people over the age of 65, although it
can develop in people who are in their forties and fifties.
• Gender: more women develop AMD than men. This is
attributed to the fact that women tend to live longer than men.
• Genes: some genes have been identified which seem to be linked to the development of AMD in some people. This has been
discovered by looking at families with more than one member who has AMD, but not all cases of AMD are thought to be inherited.
Smoking: smoking greatly increases your risk of developing AMD. Studies also show that by stopping smoking, you can reduce your
risk of developing AMD.
• Sunlight: some studies suggest that exposure to high levels of UV throughout your
life may increase your risk of developing AMD. Wearing sunglasses to protect your eyes from the UV
light in sunlight is a good idea for everyone throughout their life.
• What you eat: a number of studies have
looked at diet as a risk factor for someone developing AMD. At the moment there isn't agreement on how much of a risk factor diet is. There is
some evidence that vitamins A, C and E and zinc may help to slow the progression of AMD in people who already have the condition.
Symptoms vary from person to person, but usually the first problems people notice are with their ability to see detail. You may have problems
reading small print, even if you wear your usual reading glasses, or you may find
that there is a slight smudge in your sight or that your vision has a small blurred area in the centre.
Straight lines may look distorted or wavy
or as if there's a little bump in them. You may also find you become sensitive to bright light or that you see shapes and lights that aren't
actually there. Sometimes people may only notice these changes in one eye.
Your Optometrist will be able to measure any changes
in your vision and examine the back of your eye. If they detect any changes to your macula or any cause for concern they will arrange an
appointment with the Ophthalmologist (hospital eye consultant) for further tests.
Glaucoma is not one disorder but a range of conditions characterised by a change in the appearance of the optic
nerve (due to damage of the nerve fibres) and characteristic visual field defects. Glaucoma may be associated with an increase in the pressure
inside the eye. This damage to the optic nerve fibres can lead to loss a permanent loss of peripheral vision if left untreated.
How does glaucoma develop?
There is a constant flow of fluid (the aqueous humour) through the eye. The flow into and out of the eye is carefully monitored in order to ensure that the eye
maintains its round shape and does not become too hard or too soft.
It is secreted into the eye
from an area behind the iris (the coloured part of the eye) and flows around through the pupil and drains out of the eye through several
microscopic channels. Glaucoma usually develops when this flow of fluid becomes obstructed and causing a build-up of pressure within the
Types of glaucoma
There are various forms of glaucoma – the most common is primary open angle glaucoma.
Primary open angle glaucoma usually affects
both eyes, but not necessarily at the same time or rate. With this form of glaucoma the build up in pressure is very slow. Therefore visual loss
is gradual and painless.
Without regular eye checks the problem may not be detected until there is evidence of severe visual impairment.
The far edges of vision are affected first and therefore this may not be noticed by the sufferer. If left untreated then the loss of
vision will continue until eventually encroaching on the central vision. This is why it is important to have regular sight tests, as this form of
glaucoma can go unnoticed by the sufferer but can be detected during a routine sight test.
Because primary open angle glaucoma is not
usually recognised until it is advanced, people are screened for the condition as part of the optician's routine examination. Our
Optometrists will check the pressure inside the eye, observe the nerve at the back of the eye and test the field of vision to check for signs of
glaucoma. However, as primary open angle glaucoma is rare in people under the age of 40, glaucoma screenings are usually only carried out after
Although diabetes is a general health condition it can cause complications which affect our eyes and vision.
How does diabetes affect your sight?
Diabetes can affect the eye in a number of ways but the most common ocular complication of diabetes is a diabetic retinopathy. This is when
the diabetes caused changes in the retina at the back of the eye. A healthy retina is essential for good vision. These changes are painless and
may be asymptomatic so it is very important that people with diabetes have regular retinal screening. This means any changes to the retina can be
detected and treated as soon as possible because they cause damage to the vision. People with diabetes are entitled to an NHS funded sight test.
If a person with diabetes has unstable blood sugar, it can cause their glasses prescription to fluctuate so it is important that when you
attend a sight test, and in general, that you have good control of your blood sugar levels.