The following sections contain information on various eye conditions, their symptoms and effects on your sight and what can be done to help.
- Macular Degeneration
- Diabetic Retinopathy
- Dry Eyes
- Retinitis Pigmentosa
- Charles Bonnet Syndrome
A cataract is a clouding of the normally clear lens of the eye. It may vary in its severity from a small amount of clouding to dense areas of haziness. A cataract is usually an age-related condition, which disturbs the passage of light and prevents the eye from focussing correctly. The lens is situated behind the iris (the coloured part of the eye). Its purpose is to bend light rays so that they provide a clear image to the retina at the back of the eye.
A cataract is caused by metabolic changes within the lens. These changes are very common with age. Cataracts may also occasionally be caused by injury, radiation, medication or other eye diseases.
How do cataracts affect sight?
The person with a cataract may have blurred vision, suffer from glare and find bright lights uncomfortable. Colours may not appear to be as bright and objects look dull.
The progression of cataracts varies between each individual and often between each eye in the same person. In some cases, the person affected can see well in the house but find vision is reduced by glare or at night.
Many people have mild cataract without noticing any great affect on their vision. In more severe cases when the day to day vision is causing problems and vision can’t be improved with a change of glasses treatment is usually required.
In some cases a change of glasses may be of benefit. In others, cataract surgery may be the best form of treatment. This procedure is usually performed under local anaesthetic on a day surgery or in-patient basis. Special lighting and magnifiers are also useful.
Macular Degeneration (MD) is damage or breakdown of the macula. The macula is the part of the retina which allows us to see clearly and appreciate colour. It is the small spot (approximately 3mm) near the middle of the retina, which is responsible for the central part of what we see. The retina is at the back of the eye. It is made up of cells which are sensitive to light.
How does it affect sight?
In the early stages of MD, central vision is blurred and seeing at a distance or close work is difficult. The eye may still have good side vision, but blank spots appear in the centre. This makes reading, sewing or seeing faces difficult.
Other symptoms include: dimming of colour vision, difficulty in judging heights and distances, and some difficulty with tasks such as pouring tea. Sometimes only one eye loses vision, while the other eye may see well for years.
MD does not lead to total blindness. People with MD mostly retain good side vision. This means they can cope well with most daily tasks. The latest magnification devices can be very useful.
Who is susceptible?
Apart from some rarer forms, MD is not hereditary. The condition occurs most commonly in older people.
Diagnosis and treatment
An ophthalmologist can detect MD in its early stages. Robsons Newcastle have a sophisticated Retinal Imaging camera which takes high resolution images of the retina and can identify Macular Degeneration as part of the process. Please see Retinal Imaging for details.Special magnifying glasses, daily living aids such as needle threaders, large print books, proper lighting or a combination of these can help the person with MD to be independent and lead a normal life.
Laser treatment can be useful if the condition is detected early.
Recent research has shown some evidence that good diet can help limit progression of macular disease. In particular fruit and vegetables, containing high levels of antioxidants and pigments such as lutein, are important parts of the diet. Vitamin supplements are also available which are especially designed to supply these vital ingredients.
In some cases of wet macular degeneration, where the vision is lost suddenly, laser treatment can limit the damage. If you do notice a sudden lose of vision it is always vital to see an optometrist as soon as possible.
Glaucoma is the leading cause of preventable blindness in the UK, responsible for 13% of those on the blind register. It is estimated that about half a million people suffer from glaucoma in the UK alone; about half of these have the chronic form of the disease and in this group half remain undetected. If it is diagnosed early blindness is often preventable.
The eye is normally filled with ‘intra ocular’ fluid which constantly drains away and is then replaced. In the case of glaucoma, intra ocular fluid is not drained away properly, or it may be produced in large amounts. If this causes too much pressure in the eye, the optic nerve is damaged, blind areas in the field of vision develop. Glaucoma tends to happen slowly, often with no noticeable changes until after the damage is done.
How does it affect sight?
In acute glaucoma the pressure rises very quickly and symptoms include pain, blurred vision and haloes around lights. In the more common chronic glaucomas side vision is affected first. This can happen very gradually and may not be noticed until quite advanced damage has occurred. This is why it is important to have routine eye examinations even if you don’t think any changes have occurred.
Diagnosis and treatment
The good news is that most glaucoma cases can be treated. A painless examination is made to measure the pressure within the eye. The optometrist also views the back of the eye to examine the optic nerve for any damage and may carry out a detailed check of your side vision. Although damage cannot be reversed, treatment can prevent it from becoming worse. The longer high pressure remains in the eye, the more likely damage will occur.
Treatment aims to reduce the pressure by helping fluid to drain out of the eye, or by reducing the amount produced.
Eye drops are most often used to treat glaucoma, although sometimes laser and surgery are necessary. Glaucoma is a life-long condition which requires continual management to prevent loss of vision.
Who is susceptible?
Most cases of glaucoma occur in the older age group. If there is a family history of glaucoma, there is a higher risk of developing the condition. People over the age of 40 and those with a family history should have a regular glaucoma test.
This is caused by diabetes, although having diabetes does not necessarily lead to sight loss. Retinopathy affects the retina. The retina is at the back of the eye and is made up of cells which are sensitive to light.
Early diabetic retinopathy is sometimes the first indication of diabetes. If your optometrist sees changes to the retinal blood vessels during your eye examination, they may advise further checks with your doctor.
A network of blood vessels feeds the retina. Diabetes can cause blood vessels to break and this can interfere with vision. Blood clots and scars may form on the retina, blocking the light rays from nerve cells and interfering with their nutrition.
Complete loss of vision can occur when scar tissue develops at the back of the eye. This sometimes pulls and detaches the retina.
Prevention and treatment
Preventing diabetic retinopathy or its advancement is helped by correct management of diabetes and regular eye check-ups with an ophthalmologist. Laser light beams directed to the affected part of the retina may be used to seal leaking blood vessels.
Who is susceptible?
Diabetics with high blood pressure, pregnancy, nephritis or prolonged poor diabetic management are considered to have a higher risk of developing this condition
What is it?
The eye ball is protected by a layer of tears which have antibacterial properties and keep the eyes moisterised and comfortable. In addition the tear layer provides a smooth surface for the refraction of the light as it enters the eye.
Dry eye occurs when some of the tear components aren’t produced in sufficient quantity. This can cause grittiness and irritation and also some blurring of vision – particularly is associated with computer use. Paradoxically the eye may respond by producing extra tears – but these are often of reduced quality so the eye still feels uncomfortable.
Prevention and Treatment
Avoiding dehydration and dry working environments is helpful. If you work in modern air conditioned/ central heated offices remember to drink plenty of water during the day. At home simply humidifiers on radiators can improve the atmosphere.
Usually tear supplements are beneficial – theses range from eye drops throught gels to overnight ointments. Your optometrist can advise you on which is most suitable depending on your circumstances and symptoms.
Alcon have recently introduced their new Systane eye drops. These drops are quite fluid as they enter the eye but then adjusts the viscosity to balance with the patient’s natural tear layer. We are getting very encouraging reports from people who have previously found eye drops uncomfortable to use.
It is also thought that certain vitamins, minerals and other dietary supplements can significantly improve tear quality and quantity. Many papers have been published both in the USA and Britain on this subject and in over 50% of patients the use of supplements can give noticeable improvements.
The principle elements of the treatment are Evening Primrose oil (Gamma Linolenic Acid), Zinc & Vitamen A. Evening Primrose Oil is changed in the body to a beneficial hormone which helps regulate the menstrual cycle, skin condition and blood pressure. It affects mucous tissues and can assist in asthma attacks. The eyelids are made up of mucous tissue and Evening Primrose can improve secretions from the lids hence Contact Lens wearers have regularly reported, that when taking it their lenses are more comfortable.
Vitamin A has always been recognised as being good for the eyes and is believed to control the quality of tears making for better comfort and vision.
Zinc stimulates the tear glands to produce more tears which means eye surfaces dry up less. As a direct result vision may be improved and more vital oxygen, the nutrient of the cornea, gets to the eyes.
Who is susceptible
Dry eyes are more common in the elderly, however with modern dry environments it can affect people of any age. Particularly contact lens wearers and people working on computers. Some general conditions such as arthritis make the condition more prominent
Retinitis Pigmentosa (RP) is a degenerative, inherited eye condition which affects the retina, resulting in progressive vision loss. Several layers of cells form the retina. These include rod and cone cells. Their function is to receive and turn light into electrical impulses which pass along the optic nerve to the brain, enabling sight to occur.
How does it affect sight?
In some cases people experience tunnel vision. This is because the rod cells at the outer edge of the retina have begun to die. Tunnel vision can be compared to looking through a pipe or tube. Sometimes vision loss is central, leaving side vision intact. Other major symptoms include poor night vision and difficulty with glare.
Who is susceptible?
Those with RP are born with a genetic condition which results in sight loss later in life. Although it is hereditary, there are types which will skip several generations, so it may be difficult to trace in the family. Recessive RP may appear ‘out of the blue’ with no family history.
After diagnosis of RP
The rate of rod and cone failure is different in most people, so it is difficult to tell how the condition will progress. For some people vision loss can take place slowly during many years. Sometimes the loss is quick, following years of no apparent deterioration. It is possible to cope with the limitations and frustrations caused by RP. World wide research aimed at finding a cure for RP is making good progress.
What is Charles Bonnet Syndrome?
Charles Bonnet syndrome (or CBS for short) is a term used to describe the situation when people with sight problems start to see things which they know aren’t real. These can take all kinds of forms from simple patterns of straight lines to detailed pictures of people or buildings.
Although the condition was described in 1760 it is still largely unknown by doctors and nurses. This is partly because of a lack of knowledge about the syndrome and partly because people experiencing it don’t talk about their problems out of fear of being thought of as mental health difficulties.
Who is affected by Charles Bonnet Syndrome?
Charles Bonnet syndrome affects people with sight difficulties and usually only people who have lost their sight later in life. But it can affect people of any age, usually appearing after a period of worsening sight. The visual hallucinations often stop within a year to eighteen months.
What causes Charles Bonnet Syndrome?
When people lose their sight their brains are not receiving as many pictures as they used to. Sometimes, new fantasy pictures or old pictures stored in the brain are released and experienced as though they were seen.
These experiences seem to happen when there is not much going on, for example when people are sitting alone, somewhere quiet, which is familiar to them, or when they are in lying in bed at night.
It is fairly normal for people who start to see things to worry about there being something wrong with their minds. People often keep quiet about their hallucinations. It is important to realise that failing eyesight, not any other mental difficulties, normally causes CBS.
In CBS people quickly learn that the hallucinations although interesting are not real.
If you think you are having Charles Bonnet Syndrome hallucinations then tell your GP about them.
What kind of things do people see?
Firstly, there are the hallucinations of patterns and lines, which can become quite complicated like brickwork, mosaic or tiles.
Secondly, there are more complicated pictures of people or places. These pictures appear out of the blue and can carry on for a few minutes or sometimes several hours. Generally the pictures are pleasant although the effects can be scary.
Is there a cure for Charles Bonnet Syndrome?
Unfortunately at the moment there is no known cure or treatment for CBS. However, just knowing that it is poor vision and not mental illness that causes these problems often helps people come to terms with them. Generally these experiences will disappear after about a year or eighteen months but of course this will not happen for everyone with the condition.
One lady we saw recently was seeing a carpet of pink flowers where she knew there were none. Once we explained CBS to her she was extremely relieved. Her response was “well, at least pink flowers aren’t a bad thing to see”.