Astigmatism

For normal undistorted vision, the cornea should be smooth and equally curved in all directions. When astigmatism is present, the cornea is warped and curves more in one direction than the other. In other words, the cornea is shaped more like the side of a rugby ball than a football where, in one direction, the surface is steeper (more curved) than the other.

Normally, light enters the eye and is focused precisely on the retina. With astigmatism, the warped cornea causes the light rays to bend improperly depending on where they strike the cornea. They are not refracted (bent) equally in all directions and so one focal point on the retina is not attained. Some light rays are not focused on the retina but are focused in front of or behind the retina. The result of multiple focal points is distorted vision. Objects appear somewhat indistinct and slanted. Vision with astigmatism can be compared to what one sees when looking through a glass bottle or seeing yourself in the Hall of Mirrors at the funfair, with images appearing too tall, too thin, too wide, or blurred.

Astigmatism is most often caused by a defect in the curvature of the cornea but may also occur from an unequal bending of light by the lens inside the eye. Astigmatism can occur in conjunction with short-sightedness (myopia) or long-sightedness (hyperopia) and usually remains unchanged through life despite natural changes in the amount of myopia or hyperopia.

Astigmatism can also result from corneal scars or surgery. Eye surgery may cause the cornea to scar and warp, changing the path of light as it enters the eye. Some patients experience surgically induced astigmatism after eye surgery. Tightly tied sutures can cause a slight wrinkling of the cornea. The patient will experience distorted vision or astigmatism until healing or loosening of the sutures relieves the problem.

Astigmatism is diagnosed during a routine eye examination. A visual acuity test is performed to determine the unaided ability of the eye to focus light correctly. A process called refraction is used to measure the refractive error of the eye (myopia or hyperopia) and includes specific test to detect, measure and correct astigmatism. The final result determines the prescription for corrective lenses that correct myopia, hyperopia and astigmatism as necessary

A small amount of astigmatism is common and usually does not need correction. However, in cases where the problem is more severe, glasses and contact lenses are used to correct vision. To correct astigmatism, glasses or contact lenses are ground to neutralise the defective curvature of the cornea. Hard or gas permeable contact lenses generally improve astigmatism better than soft contact lenses. But in many cases soft contact lenses can be helpful.

For a complete examination and professional advice regarding you vision correction needs, contact us to make an appointment.

Chalazion

A chalazion is an enlargement of a long, thin oil gland in the eyelid that results from an obstruction of the gland opening at the edge of the eyelid.

At first, a chalazion looks and feels like a stye, with swollen eyelid, pain, and irritation. However, after a few days the symptoms disappear, leaving a round, painless swelling in the eyelid that grows slowly for the first week. A red or gray area may develop underneath the eyelid.

Most chalazions disappear without treatment after a few months but always be sure to have any growths examined by a professional. Contact us to make an appointment.

Colour Vision Deficiency

What is colour vision deficiency?
Colour vision deficiency almost never means 'seeing in black and white'. The nerve cells which receive and process light at the back of the eye - the retina - are of two main types: the 'rods', which operate at night and the 'cones', which allow us to see fine detail and colours by day. Three different chemicals can be found within the cone nerve cells, so that each cone responds best to red, green or blue light in a similar manner to colour television. The fault of defective colour vision lies in one set of chemicals, usually those controlling principally either red or green colours.

It is not generally realised that defective colour vision can range from near- normal appreciation of hues, where the chemical within the "red" or "green" cones is only slightly altered, to a medium degree of confusion where the chemical is altered considerably. For the first group, pale colours will give most common difficulties in identification, and deep colours will be confused if the lighting is poor, or the person is tired or under pressure to make a quick decision of colour name.

Only a third of those with colour vision problems have the more severe form where one sort of chemical is completely lacking and very strong colours are frequently confused, though still within a limited range of up to ten main colours. Complete colour deficiency, where all colours are seen as varying shades of black and white is extremely rare.

Why are more men than women colour deficient?
Like many other medical conditions, defective colour vision may be inherited and carried through the mother (whose vision will be apparently normal) to the son. Frequently, brothers within the same family are affected, but this is not always the case as there is only a 50/50 chance the sons of "carriers" will have altered colour vision.

A female can only inherit defective colour vision if her father has the problem and her mother is a carrier or herself colour deficient. The pattern of inheritance is simple, so future generations of colour blind individuals can be easily predicted.

Will Inherited colour deficiency change with age?
No. The inherited alterations to colour vision involve both eyes and remain stable through life.

Can one develop colour deficiency?
Yes, but not in the inherited form. A whole range of prescribed drugs, systemic conditions such as diabetes, multiple sclerosis and cardiovascular diseases (including high blood pressure), some liver diseases and many eye diseases, can affect the cones or the nerve pathways from them to the brain. In these cases, colour vision may be temporarily or permanently altered, often in one eye at a time. Difficulty in colour discrimination may be noticed along with other visual problems, such as overall blurring of near or distance vision, or gaps in the field of vision. Women and men are equally at risk from this type of colour vision deficiency.

Drugs prescribed for arthritis, malaria, depression and heart disease can, on occasion, significantly impair colour vision. Even long-term use of aspirin can change colour perception. Tobacco and alcohol taken in excess can have similar effects. Many industrial chemicals can permanently alter appreciation of colours. Glaucoma, cataract and most eye problems affecting the retina or nerve pathways to the brain can give gradually worsening problems with many different colours, including blues and greens.

Since colour vision changes can be an early sign of disease or a side effect of prescribed medication, if you are aware that your appreciation of colours is changing, it is important to discuss it with your optometrist.

Can colour vision deficiency be a handicap?
Colour is relevant to many aspects of everyday life and some jobs and careers do involve some degree of colour identification. Colour coding is important in industry and for signal lights, so it is understandable that British Rail and the London Underground check for defective colour vision at a pre-employment medical. Many large companies involved with printing inks, textiles, paints and electronic components screen prospective employees and may refuse entry for certain jobs if colour perception is inadequate. Despite the introduction of instruments for colour matching, the human eye is still the most sensitive instrument of all. Restrictions in some branches of the Services, Police Force and Civil Service are often strongly enforced.

Although some people with abnormal colour vision are not denied a driving licence, there have been a few cases of death caused by people with faulty colour perception driving through a red traffic light. In some countries, law prohibits colour defective people from driving commercial vehicles.

Colour also has a special place in the child's world, being used as an aid to learning. Studies have failed to show any educational handicap resulting from faulty colour vision, but parents, GPs and teachers may not necessarily be well-informed on this subject. It is always sensible to inform teachers if a child is known to have difficulty in identifying colours.

Can anything be done to correct colour deficiency?
Although nothing can replace a faulty mechanism in the retina of the eye - which is essentially a part of the brain - many colour defective people do learn ways of compensating for their difficulty with experience and help from relatives and colleagues. It is important that good lighting is always available.

Many people find help, albeit limited, identifying certain colours that they would otherwise misname, with the aid of a small red or red-mauve filter of transparent plastics or glass held in front of the eye. Often red cellophane can help. This is best tried at home with a selection of transparent coloured materials, but it is not usual to prescribe tinted spectacles for this purpose, since only one eye must use the filter. A red tinted contact lens (branded the 'Chromagen' lens can be worn in one eye to help colour recognition, but the results cannot be guaranteed. There is no way of restoring the lost sensation or appreciation of colour.
How can I have my colour vision tested?
Straightforward clinical tests have been devised to screen for defective colour vision, most taking only a matter of minutes. These involve reading coloured numbers from a book or arranging coloured papers in order, or naming coloured lights. Campbell Eyecare can administer such a test as part of an eye examination if your optometrist believes it to be necessary or if you request it or . Some school medical examinations may include colour vision tests. But for the individual, the best advice is that if there is the slightest reason for doubt contact us to book a comprehensive eye examination that includes a test for colour vision.

Conjunctivitis

Conjunctivitis is inflammation of the conjunctiva, the thin, transparent layer that lines the inner eyelid and covers the white part of the eye.

The three main types of conjunctivitis are infectious, allergic and chemical. The infectious type, commonly called "pink eye" in the USA is caused by a contagious virus or bacteria. Your body's allergies to pollen, cosmetics, animals or fabrics often bring on allergic conjunctivitis. Irritants like air pollution, noxious fumes and chlorine in swimming pools may produce the chemical form of the condition.

Common symptoms of conjunctivitis are red watery eyes, inflamed inner eyelids, blurred vision, a scratchy feeling in the eyes and, sometimes, a pus-like or watery discharge. Conjunctivitis can sometimes develop into something that can harm vision so you should see your optometrist promptly for diagnosis and treatment.

A good way to treat allergic or chemical conjunctivitis is to avoid the cause. If that does not work after examination and diagnosis, your optometrist may prescribe certain eye drops which relieve discomfort and aid resolution. Infectious conjunctivitis, caused by bacteria, can be treated with antibiotic eye drops. Other forms, caused by viruses, cannot be treated with antibiotics. They must be fought off by your body's immune system.

To control the spread of infectious conjunctivitis, you should keep your hands away from your eyes, thoroughly wash your hands before applying eye medications and do not share towels, washcloths, cosmetics or eye drops with others.

As with any problem with your eyes, no matter how seemingly minor, it must be investigated by an expert. If you have any problems with your eyes, don't wait or self medicate, contact us for an appointment where your optometrist will thoroughly investigate and manage the problem. If you are a contact lens wearer, remove your contact lenses immediately and keep them out until you have been seen by your optometrist.

Corneal Dystrophy

What is Corneal Dystrophy?
The globe of the eye is made of five layers and the cornea is the transparent front portion. It is also the most sensitive structure in the body because of the high number of nerve endings per square millimetre, even more so than the tips of your fingers.

The cornea owes its transparency to the presence of a regular lattice structure of collagen fibres. Anything which affects this regularity results in loss of the transparency which is essential for good corneal function and health.

Corneal dystrophies are a group of rare disorders which usually affect both eyes. They may be present at birth, but more frequently develop during adolescence and progress gradually throughout life. Some forms are mild, others severe.

What are the causes of Corneal Dystrophies?
This group of disorders tends to run in families and the causes of most corneal dystrophies will lie in individual genetic make-up.

What are the effects of a Corneal Dystrophy?
Although age of onset, symptoms and progression differ in the various dystrophies, most cases of corneal dystrophy fall into three types, classified by their inheritance pattern and appearance. These are Granular Dystrophies, Macular Dystrophy and Lattice-like Dystrophies.

0. Granular Dystrophy usually starts at around 5 years of age. This can be seen as small white dots in the centre of the cornea or may take the form of lines radiating from the centre. These signs can increase in size and number and by 50 years of age, opacities are visible to the naked eye.

0. Macular Dystrophy (not to be confused with macular degeneration which affects the retina at the back of the eye) usually starts in the first decade of life and appears as a thin superficial corneal veil with isolated opacities when seen with a slit lamp. It is the least common type of dystrophy. Acute, short lived, attacks may be experienced and there is increasing haziness of the central part of the cornea and increasing isolated opacities.

0. Lattice Dystrophy can develop in infancy but more usually during the second decade of life. This is seen as a cobweb of fine lines which develop into a lattice-like pattern. By 40 years of age onwards, the centre of the cornea can become irregular with ill-defined opacity. Although in some people the pattern of progress is less severe, acute attacks are experienced which can contribute to relatively early onset of sight loss.

Among the many other types, Map/Dot/Fingerprint Dystrophy, Fuch’s Dystrophy, Meesman Dystrophy and RET-Buckler Dystrophy are most encountered.

What are the genetics behind dystrophies?
Dominant, single gene diseases result from one of a pair of matched autosomal genes having a disease and the other being normal. With each pregnancy there is a 1 in 2 chance of the disease appearing in the offspring. Recessive single gene disease requires both parents to carry the condition and this results in a 1 in 4 inheritance risk in each pregnancy. Only siblings within a single generation are affected, unless members of that generation create offspring with another carrier of the specific gene.

It is valuable to seek genetic advice on all conditions, which have an hereditary cause in order to identify how this may affect individual family members.

What is the prognosis?
Although there are many more forms of corneal dystrophy, likely outcome varies with the type of dystrophy:

0. Granular dystrophies are usually mild and may be unnoticed by those with the condition. In some cases sight is not affected even in later years.

0. Macular Dystrophy is a severe dystrophy which may cause considerable damage by 30 years of age.

0. Lattice Dystrophies can be either mild or severe and from middle-age these may cause acute attacks, capable of causing serious sight loss.

Is there any treatment?
In some conditions corneal grafting offers a good prospect of visual improvement, but there is nothing that can be done to stop a dystrophy that has been diagnosed. If you or someone in your family has been diagnosed with a corneal dystrophy, contact us to make an appointment to discuss your condition.

At Campbell Eyecare, even a routine examination involves a thorough examination of all parts of the eye including a high magnification examination of the cornea and all its layers to detect even the earliest signs of corneal dystrophy.

Diabetes and your vision

What is diabetes?
Diabetes mellitus or `sugar diabetes' affects about one person in fifty in the UK. This means that the body cannot cope normally with sugar and other carbohydrates in the diet. Research indicates there may be up to half a million people who are undiagnosed.

Diabetes can start in childhood, but it often begins later in life. It can cause complications, which affect different parts of the body. There are two types of diabetes mellitus - one is controlled by insulin injections and the other by diet or tablets, but they both affect the eyes in the same way.

If you have diabetes this does not necessarily mean that your sight will be affected, but there is a higher risk. If your diabetes is well controlled then you are less likely to have problems, or they may be less serious. However if there are complications which affect the eyes then this can result in loss of sight.

Why are regular eye tests are important?
Most sight loss from diabetic retinopathy can be prevented. But it is vital that it is diagnosed early. You may not realise that there is anything wrong with your eyesight, and so regular eye checks are extremely important.

How can diabetes affect the eye?
Your eye has a lens and an aperture (opening) at the front, which adjust to bring objects into focus on the retina at the back of the eye. The retina is made up of a delicate tissue that is sensitive to light, rather like the film in a camera.

At the centre of the retina is the macula, which is a small area about the size of a pinhead. This is the most highly specialised part of the retina and it is vital because it enables you to see fine detail and read small print. The other parts of the retina give you side vision (peripheral vision). Filling the cavity of the eye in front of the retina is a clear jelly-like substance called the vitreous humour.

Diabetes can affect the eye in a number of ways. These usually involve the fine network of blood vessels in the retina - hence the term diabetic retinopathy.

Temporary blurring
Your vision may become blurred for a few days or weeks while your diabetes is first being controlled. This is due to the swelling of the lens of the eye and will soon clear without treatment soon after the diabetes is controlled.

Cataract
This can occur in two forms:

• Young people with diabetes very occasionally develop a special type of cataract. Although their vision gets worse, it can be restored by surgery;

• Older people with diabetes can be especially prone to developing cataracts. Cataracts can be successfully removed by surgery and usually it is possible to insert a lens implant. However this is unsuitable for some people and your optometrist will tell you if this is the case.

Diabetic retinopathy
The most serious diabetic eye condition involves the retina and is called diabetic retinopathy.

Background diabetic retinopathy
This condition is very common in people who have had diabetes for a long time. Your optometrist may be able to see abnormalities in your eyes, but there is no threat to your sight.

There are two types of diabetic retinopathy, which can damage your sight. Both involve the fine network of blood vessels in the retina. They are described below.

Maculopathy
This happens when the blood vessels in the retina start to leak.

• If the macula is affected, you will find that your central vision gradually gets worse. You may find it difficult to recognise people's faces in the distance or to see detail such as small print. The amount of central vision that is lost varies from person to person. However the vision which allows you to get around at home and outside (navigation vision) will be preserved.

• It is very rare for someone with maculopathy to lose all his or her sight.

Proliferative diabetic retinopathy
Sometimes diabetes can cause the blood vessels in the retina to become blocked. If this happens then new blood vessels form in the eye. This is nature's way of trying to repair the damage so that the retina has a new blood supply.

Unfortunately these new blood vessels are weak. They are also in the wrong place - growing on the surface of the retina and into the vitreous jelly. Consequently these blood vessels can bleed very easily and cause scar tissue to form in the eye. The scarring pulls and distorts the retina. When the retina is pulled out of position this is called retinal detachment.

• This condition is rarer than background retinopathy and is more often found in people who have been insulin dependent for many years.

• The new blood vessels will rarely affect your vision, but their consequences, such as bleeding or retinal detachment can cause your vision to get worse suddenly.

• Your eyesight may become blurred and patchy as the bleeding obscures part of your vision.

• Without treatment, total loss of vision can happen in proliferative retinopathy.

With treatment most sight-threatening diabetic problems can be prevented if caught early enough.

The importance of early treatment
Although your vision may be good, changes can be taking place to your retina that need treatment and because most sight loss in diabetes is preventable:

• Early diagnosis is vital

• Have an eye examination every year

• Do not wait until your vision has deteriorated to have an eye test.

Your optometrist can examine for diabetic retinopathy. Campbell Eyecare uses digital retinal photographs to detect abnormalities. If a problem is found you will be referred to an ophthalmologist at a hospital eye clinic.

Remember, however, that if your vision is getting worse, this does not necessarily mean you have diabetic retinopathy. It may simply be a problem that can be corrected by glasses.

What is the treatment?
Most sight-threatening diabetic problems can be prevented by laser treatment if it is given early enough. It is important to realise however that laser treatment aims to save the sight you have - not to make it better. The laser, a beam of high intensity light, can be focused with extreme precision. So the blood vessels that are leaking fluid into the retina can be sealed.

If new blood vessels are growing, more extensive laser treatment has to be carried out. In eight out of ten cases laser treatment causes the new blood vessels to disappear.

How is laser treatment carried out?
All treatment is carried out in an outpatient clinic and you will not have to stay in hospital. Eye drops are used to enlarge the pupils so that the doctor can look into your eye. The eye is then numbed with drops and a small contact lens is put onto your eye to stop it blinking. The eyes need to be moved in certain directions but this can easily be done with the contact lens in place.

Is it painful?
The treatment for sealing blood vessels doesn't usually cause any discomfort. However the treatment to remove new blood vessels can be a bit uncomfortable so you may be given a pain-relieving tablet at the same time as the eyedrops. If the treatment does become painful, then it is possible to have an injection around the eye to numb the pain. Don't be afraid to ask for this injection, especially if you have found a previous session of laser treatment distressing.

Does laser treatment have any side effects?
The treatment for sealing blood vessels has few side effects, although you may lose a little central vision or notice the laser burns as small blank spots.

The laser treatment to remove new blood vessels is more complicated and there may be more side effects. It is quite common to lose some vision to the sides (peripheral vision), and this may mean that you will not be able to drive in future. Night and colour vision may also be reduced. Occasionally your central vision may not be as good as before so that print isn't as easy to see. This is usually temporary but sometimes this doesn't improve. No treatment is possible without some side effects. But the risks of laser treatment are far less than the risks of not having treatment.

What if my eye becomes painful after treatment or if my vision gets worse?
The laser is very bright and causes a temporary reduction of sight, which may last an hour or two after the treatment. Most people have a headache after the more lengthy treatment and you can take a headache tablet for this. However if the pain is severe, or if your eyesight gets worse, you should contact your consultant straightaway.

If your eye condition becomes more severe, causing retinal detachment and scar tissue, it may be possible to perform vitreous surgery. This is highly specialised and you should discuss the various options with a consultant ophthalmologist.
Research is continuing into diabetes-related eye conditions, and their treatment is constantly improving.

Contact us to book an appointment for professional monitoring of your condition.

Double Vision

What is Double Vision?
If you see two of whatever you are looking at simultaneously, you may have a condition known as double vision, referred to medically as diplopia. Double and blurred vision are often thought to be the same, but they are not. In blurred vision, a single image appears unclear and fuzzy. In double vision, two images are seen at the same time, creating understandable confusion for anyone who has it.

What causes double vision?
There are 2 of possible causes.

0. Refractive - Light from an object is split into two images by a defect in the eye's optical system. Cataracts might, for example, cause such a defect.

0. Failure of both eyes to point at the object being viewed, a condition referred to as "strabismus" or "squint". In normal vision, both eyes look at the same object. The images seen by the two eyes are fused into a single picture by the brain. If the eyes do not point at the same object, the image seen by each eye is different and cannot be fused. The result is double vision possibly caused because of a defect in the muscles which control the movement of the eyes or in the control of these muscles through the nerves and brain.

What are its implications?
Double vision can be extremely discomforting. The brain acts to alleviate the discomfort by suppressing, or blanking out, one of the images. In young children, if this suppression persists over a continued length of time, it can lead to an impairment of the development of the visual system. The suppressed eye may get to the point where it is unable to see well, no matter how good the spectacle or contact lens correction, a condition called amblyopia or “lazy eye”. Since it is a result of a defect in the interpretative mechanisms of the eye and brain, it is more difficult to treat than a refractive condition (one having to do with the eye's ability to bend light).

How is it treated?
Treatment of double vision may consist of eye exercises, surgical straightening of the eye or a combination of the two. Therapy is aimed at re-aligning the squinting eye where possible without surgery and re-stimulating the part of the visual pathway to the brain, which is not working correctly.

Double vision can occasionally develop in a person who has never had the problem before due to trauma to the head or a problem with the nerve supply to the muscles around the eye. This type of 'sudden onset diplopia' can be a sign of a serious problems with the visual system so if you are experiencing double vision you should contact us immediately to have a thorough, professional investigation of the visual system.

What is dry eye?

Tears serve to lubricate the eye and they are produced around the clock, but when insufficient moisture is produced stinging, burning, scratchiness and other symptoms are experienced and may be referred to as Dry Eye, Keratitis Sicca, Keratoconjunctivitis Sicca (KCS) or Xerophthalmia.

When we blink, tears form a film that spreads over the eye, making the surface smooth and optically clear and enabling good vision. There are three layers in the thin film of tears: an oily layer, a watery layer and a layer of mucus, each with specific function. The outermost, oily layer is produced by small glands at the edge of the eyelid (meibomian glands) and the main purpose of this layer is to smooth the tear surface, aid lubrication and reduce evaporation.

The middle, watery layer, is produced by small glands scattered through the conjunctiva, (the delicate membrane lining the inside of the eyelid) and by the large lacrimal (tear) gland. This layer cleanses the eye and washes away foreign particles or irritants. The innermost layer consists of mucus that allows the water layer to spread evenly over the surface of the eye. Without mucus, tears would not adhere to the eye.

What causes it?
Dry eye is caused when the tear gland produces insufficient tears. This can happen as part of the normal ageing process, and is more common among women so although the condition is not common it tends to occur with increasing age when it is not always noticed because the effect of dry eye tends to balance another age-related change; poor tear drainage. The result of this is a balance between not making as much lacrimal fluid (tears) and not being able to drain away the lacrimal fluid efficiently.

The main causes of an insufficient film of tears are deterioration of lacrimal tissue, dysfunction of the Meibomian gland destabilising the film of tears or a blockage in the excretory ducts of the lacrimal gland. People with Sjogren's syndrome are at risk of dry eye as part of a more systemic problem involving salivary glands and other sites of mucous membrane. Salivary gland involvement produces a dry mouth as well. This syndrome and dry eyes generally, may be found in people with rheumatoid arthritis.

What are the effects of the condition?
In the early stages there is an increase in mucus strands and as the tear film breaks down, the mucin layer becomes contaminated. Where this contaminated matter cannot be dispersed it tends to move with blinking. Mucin is a substance that dries very quickly and rehydrates very slowly.

People with dry eye rarely have a sensation that the eye is dry but instead experience irritation, burning, a sensation of having a foreign body in the eye, mucus discharge and possible temporary blurring of vision.

Blinking may cause pain to people with severe forms of keratitis.

What is the treatment?
There is a series of tests designed to identify the cause and type of dry eye and these include Rose Bengal staining where a dye is used to identify problems and the Phenol Red test, which involves measuring the amount of wetting of a special coloured thread which is placed under the lower eyelid for 15 seconds.
The aim of treatment will be to relieve discomfort and prevent corneal damage.

In some situations relief may be found by blinking consciously when doing close or continuous work. It is also helpful to close the eyes for a spell from time to time.

Eye drops may be prescribed or purchased over the counter and since there is a variety, it may be helpful to try others if your present product does not suit you.

Some drops contain preservative that means they are safe to use for a month after opening, but although these drops are cheap and suitable for most sufferers, some people do not tolerate the preservative and may need to get prescription from the hospital pharmacy for a preservative free medication.

Lubricant ointments are also helpful, particularly at night. These are also available without preservative.

Some women benefit from hormone replacement therapy (HRT), especially those whose dry eye problems began around or after the menopause.

Antihistamines or certain types of travel sickness pills, inhibit tear secretion and symptoms can vary from day to day and be affected by general health.

In severe cases permanent or semi-permanent or short acting occlusion of the drainage channels of the eye (puncta) can help to keep the eye lubricated and provide relief from symptoms.

Surgical procedures may be indicated if punctum plugs are helping to relieve symptoms and patients require a more permanent solution. It involves closing the tear drainage holes in the eyelids permanently. It is a minor operation that is suitable for some patients.

How can I avoid Dry Eye?
Avoiding the following situations will minimise your risk of Dry Eye.

• Reduce the dry atmosphere caused by central heating by using a humidifier;

• Avoid car heaters, particularly at face level;

• Sit away from direct heat such as gas or electric fire s;

• Use eyedrops just before activities which cause additional pain or discomfort such as television, reading, sewing and writing;

• Remember to blink regularly, particularly when doing close or concentrated work. Blink properly with full lid closure, not "half" blinking;

• Avoid smoky atmospheres.

What is the prognosis?
Prognosis varies considerably and may depend in part upon individual lifestyle choices and overall health as well as the severity and cause of the condition. There is no definite cure, but people can usually be made more comfortable.

Contact us at the practice if you are experiencing any symptoms of dry eye for a thorough examination and expert advice and treatment.

Dyslexia and vision

What is Dyslexia?
People with specific learning difficulties have problems with certain areas of academic performance, yet do well in other subjects and are generally intelligent. The most common type of specific learning difficulty is specific reading difficulty; and this is often called dyslexia.

Dyslexic children are usually poor at spelling and may seem intelligent in conversation but have trouble with written language. Leonardo da Vinci and Einstein are both thought to have been dyslexic.

Dyslexia can only be diagnosed with certainty by a psychologist who, in addition to other tests, will calculate a person's expected reading age from their IQ and age. The difference between this and the actual reading age as measured with a reading test, gives a measure of the reading difficulty. The term dyslexia is usually reserved for a severe degree of reading difficulty.

The psychologist would also ensure that the poor reading was not secondary to another problem, such as inadequate schooling or low intelligence. Psychological assessments can be arranged through your school or privately through a local Dyslexia Institute

Visual Factors in Dyslexia
Most experts agree that problems with sight are not usually a main cause of dyslexia. Certain visual problems however do occur more often in dyslexia and these may, in some cases contribute to the reading difficulty.

These visual problems would not normally be detected in a school eye test. The most common visual anomalies in dyslexia are a reduced ability to focus close to and poor or unstable co-ordination of the two eyes binocular instability). Several simple tests can detect binocular instability.

These visual problems can cause eyestrain, visual stress, or visual distortions. This may slow reading and discourage children from prolonged reading.

Not all dyslexic people have these visual problems, but some have visual anomalies without realising it. People with a mild specific learning difficulty, perhaps not bad enough to be called dyslexia, can also have these visual problems. The visual problems may be treated with simple eye exercises or corrective glasses may be prescribed.

Coloured Overlays and Specific Tinted Lenses

At Campbell Eyecare, we can assess the possible benefits of coloured plastic overlays to aid reading. Professor Arnold Wilkins, a child psychologist, has developed The Wilkins Rate of Reading Test which utilises different colours of overlays placed on top of a page of print or on the computer screen. This allows us to measure the patient’s ability to read normal black print on a white background compared to the preferred overlay. If there appears to be an improvement, the patient is given an overlay to use at home and in the classroom, plus instructions to change the computer settings to produce the same colour as a background on the computer screen for word processing.

The parent(s) and teacher are requested to monitor the use of the overlay, without prompting, by the patient. If there is an improvement in reading and reduction in symptoms over a period of a month or so, the patient is assessed for specific tinted lenses using the Intuitive Colorimeter. This allows us to measure the exact colour and density of tint to suit the individual, which are then manufactured by Cerium Visual Technology Ltd. The final tint normally does not match the colour of the overlay.

This service is not currently funded under the NHS, although almost 10% of the population are known to have a reading difficulty of some sort.

Entropion

Entropion is a condition that commonly affects the lower eyelid, causing it to turn inwards, resulting in the eyelashes rubbing on the front of the eye. This causes discomfort, redness and sometimes a sticky eye. If left untreated, it can lead to corneal ulcers.

Entropion is the medical term used to describe rolling inward of the lower eyelid and eyelashes towards the eye. The skin of the eyelid and the eyelashes rub against the cornea (the front part of the eye) and conjunctiva (the mucous membrane that protects the eye). This rubbing can lead to excessive tearing, crusting of the eyelid, mucous discharge, a feeling that something is in the eye, irritation of the cornea, and impaired vision.

Most cases of entropion are due to relaxation of the tissues of the eyelid because of ageing. Some cases result from scarring of the inner surface of the eyelid caused by chemical and thermal burns, inflammatory diseases such as ocular pemphigoid, or allergic reactions. Rarely entropion can be present at birth if the eyelids do not form properly.

Entropion should be repaired surgically before the rubbing damages the cornea by causing infection and scarring. Prior to surgery, taping the lower lid down and using lubricating drops and ointment can protect the eye. In some cases, sutures (stitches) can be placed through the lower eyelid until more definitive surgery can be performed.

The surgery to repair entropion is usually performed under local anaesthesia as an outpatient. In most cases, the doctor will tighten the eyelid and its attachments. Following the surgery a patch is worn overnight used in conjunction with antibiotic ointment for about a week. After the eyelids have healed, the eye should feel comfortable and no longer have the risk of corneal scarring, infection, and loss of vision.

Episcleritis

Episcleritis is an inflammation of the episclera, a membrane covering the sclera of the eye.

The sclera is composed of collagenous fibres to form a white, hollow ball. It is the 'skeleton' of the eyeball and is covered by the episclera, a thin layer of tissue containing many blood vessels that nourish the sclera. On the front of the eye, the episclera is covered by the conjunctiva. Inflammation of the episclera is usually mild and usually does not progress to the more serious, scleritis. The cause is unknown, but certain diseases such as rheumatoid arthritis, Sjogren's syndrome, syphilis, herpes zoster, and tuberculosis have been associated with episcleritis. It is a common condition.

Although usually self limiting, episcleritis can progress into a more serious condition so it is important to have any red or sore eyes examined by a professional. Contact us to make an appointment.

Eyelids and the tear film

The eyelids play a key role in protecting the eyes. They help spread moisture (tears) over the surface of the eyes when they close (for example, while blinking); thus, they help prevent the eyes from becoming dry. The eyelids also provide a mechanical barrier against injury, closing reflexively when an object comes too close to the eye. The reflex is triggered by the sight of an approaching object, the touch of an object on the surface of the eye, or the eyelashes being exposed to wind or small particles such as dust or sand.

Tears are a salty fluid that continuously bathes the surface of the eye to keep it moist. This fluid also contains antibodies that help protect the eye from infection. Tears are produced by the lacrimal (tear) glands, located near the outer corner of the eye. The fluid flows over the eye and exits through two small openings in the eyelids (lacrimal ducts); these openings lead to the nasolacrimal duct, a channel that empties into the nose.

If the lacrimal glands don't produce enough tears, the eyes can become painfully dry and can be damaged. A rare cause of inadequate tear production is Sjögren's syndrome. The eyes can also become dry when evaporation causes an excessive loss of tears, for example, if the eyelids don't close properly.