EYE DISEASE
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| This page is meant to provide a brief insight into some of the more common eye diseases encountered in routine optometry practice.
It is not meant to be comprehensive, there are many excellent sites devoted to these conditions, (see links page).
However I hope that you will find the information here of interest. |
CATARACTS |
| A cataract is clouding of the lens in the eye. This is a common occurence as we get older, in fact
a majority of people over 60 have a degree of cataract formation. The clouding can take place in various parts of the
lens, which will also have a different effect on vision. For example clouding in the middle of the lens can be associated
with an increase in myopia (short-sightedness), clouding at the back of the lens can severely reduce vision for what
appears to be a minimal cataract. |
| Cataracts are associated with many causes. The main cause is simply increasing age, although there
is an increased risk in certain medical problems eg diabeties, and also when some medications are taken for a long time eg steroids.
There is also an increased risk of cataract development after an eye injury, particlarly if the eye is penetrated. |
| Although there can be many causes, there is realy only one treatment and that is surgery. Normally the cataract
is allowed to develop until it is significantly affected the persons sight before surgery is suggested. With modern techniques
the results of surgery are very good, restoring sight mostly to what it was before the cataract developed. Often not needing
optical correction for distance vision. Although because the lens is required to focus for near and that is removed during the operation,
An optical correction for near will be required. |
GLAUCOMA |
| The term Glaucoma actually refers to a number of closely related conditions that medically are referred to as "the Glaucomas".
It is beyond the scope of this page to cover all the conditions involved, so we will mainly cover the type of glaucoma most commonly seen in
Optometric practice i.e. Primary Open angle Glaucoma (POAG). Primary because it isn't associated with any other eye condition and open angle as opposed
to closed angle which is a very sudden onset and often painful condition |
| POAG is a slowly progressive condition from which we are all at risk, although there are some factors that increase the risk namely:
Increasing age (it is very rare below 40), if there is a direct family history of glaucoma, certain medical conditions increase the risk e.g. diabeties. Asians and
Afro-caribbeans also have an increased risk of developing glaucoma. |
| The onset of POAG can be very insideous, often taking many years to develop to a point where the patient becomes aware of vision problems. It is painless
and slowly restricts the peripheral vision. As it occurs so slowly it is amazing how much peripheral vision can be lost before you become aware that there is a problem.
Clinically, we see a change in the appearance of the optic nerve at the back of the eye, which will also be associated with a change in the visual field. The
pressure in the eye may also be raised, but that is not always the case. |
| We are now one of the few Optometry practises in the UK to also be able to assess the thickness of the nerve fibre layer at the back of your eye using the new GDx VCC
scanning laser ophthalmoscope. This can provide even more information
as to your risk of developing Glaucoma. Click Here for more information on the GDX VCC.
If you are suspected of having POAG you will be referred via your GP to see an eye specialist (Ophthalmologist) for further investigation. If POAG is confirmed,
treatment is mostly with eye drops to reduce the pressure in the eyes. |
| POAG is most successfully managed if it is caught early, especially as any damage that has occured is irreversable, therefore regular eye
examinations are advised for everyone, especially if you have an increased risk. |
MACULA DEGENERATION |
| Or AGE RELATED MACULA DEGENERATION (ARMD) is again a variety of conditions all under the same heading. This is a frustrating condition where the
macula region (the area at the back of the eye with which we see most clearly) degrades. This results in reduced vision, sometimes to the point where the sufferer just sees a black hole in the middle of the
vision. It is frustrating to the patient as it can severely affect their ability to undertake everyday tasks such as reading, TV, driving etc. and frustrating to the eye care proffessionals
as it is a condition about which very little can be done. |
| There are 2 main types. Firstly a form characterised by a slow and progressive reduction in middle vision. The back of the eye will sometimes appear as below. This form
is by far the most common and the vision loss is often less in this type. Although there is actual no cure, there are suggestions that vitamin and dietary suppliments
can help to reduce progression of early changes. Lutein, zinc and vitamines A, C and E have been found to be the most beneficial. There are now a number of vitamine supplements available, formulated
specifically to prevent macula degeneration. Examples are I-Caps and Vision Ace. |
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| The other form is much more sudden in onset, the patient often becoming aware of a sudden distortion in the middle vision.
This is due to new blood vessels growing under the macula and then leaking. Clinically we may see haemorrhaging and leaking fluid at the
back of the eye. It is sometimes possible to treat this type of ARMD with a laser, however not everyone is suitable and treatment has to
be undertaken soon after the onset of the problem. Unfortunately the treatment is not always successful. |
| On the bright side, this condition will not cause blindness as it can only affect the middle vision, all patient retain peripheral vision
which allows them to get around. There is also alot of research being undertaken into the causes and treatments for this all too common problem. So in the future the
outlook for patients with this problem may not be so bleak. |
DIABETIC EYE DISEASE |
| People who suffer from diabeties are at risk of developing problems with their eyes. In the early days just before and for some time after diagnosis,
or if their control is poor, patients may suffer from alterations in the optics of their eyes. This presents as blurred vision, correctable by different spectacles.
This however is transient and vision normally returns to a stable level once good control is achieved. It is therefore not a significant problem. |
| The more serious changes are caused by the small blood vessels at the back of the eye becoming leaky. This has a number of different effects,
if the leakage is near the macula then it can obstruct the vision (diabetic maculopathy). If this occurs in the periphery, then ultimatly new blood vessels grow, these are
structuraly poor, leak more along with developing scar tissue, and can lead to retinal detachments and complete loss of vision. |
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| The picture above shows a degree of peripheral haemorrhaging and leaking vessels around the macula. |
| Luckily only a small percentage of diabetics will develop such sight threatening disease. It is known that the risks of this occuring
increase the longer someone has been diabetic and how well they have controlled it. In general, younger patients with insulin dependant diabeties (known as type 1)
tend to be at risk of the peripheral disease. Older patients with Type 2 (even if they are insulin requiring) are at greater risk of the maculopathy changes. |
| The good news is that the risk of developing sight threatening disease is drastically reduced if the early changes are detected and if developing
beyond a certain level are treated, usually with a laser to stop progression. This is why all diabetics should have at least an annual eye examination, including
their pupils dillated to give a good view to the back of the eyes. |
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Last modified: March 2003
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