Diabetic retinopathy is a complication of diabetes that affects the retina. It is one of the commonest causes of blindness in people between the ages of 30-65, and 12% of people who are each year registered blind and partially sighted have diabetic eye disease. At any one time up to 10% of people with diabetes will have retinopathy requiring medical follow up or treatment. Diabetic Retinopathy can be caused by fluctuations in blood sugar and results in changes to the focusing of the eye's crystalline lens and temporary visual blurring, particularly if diabetic control is poor. Diabetes can also cause cataracts in young people or accelerate the development of cataract in older people. Retinopathy is usually classified according to its severity and may differ in both eyes. Tight control of diabetes can reduce the risk of retinopathy by 60% in type I (insulin dependent) and 40% in type II (non-insulin dependent) and will also reduce the risk of other diabetic complications.
Although the majority of people who have had diabetes for long enough will have some degree of retinopathy, regular eye checks will enable early diagnosis and treatment. When people first develop diabetic retinopathy they have very few or no symptoms and if diagnosed at this early stage it is treatable. Consequently, it is important for diabetics to have regular eye tests. People with insulin dependent diabetes must have their eyes examined at diagnosis, again after they have had diabetes for 4 years and then regularly. People with non-insulin dependent diabetes should have an eye examination at diagnosis and yearly thereafter by their diabetic specialist, general physician, ophthalmologist or optician.
Diabetic retinopathy is usually treated with laser treatment and in some cases surgery.
Diabetic retinopathy is initially treated with lasers, a procedure known as photocoagulation. This treatment is designed to maintain vision, not improve it, and is highly effective in most patients. Blindness is prevented in at least one eye of 80-90% of cases.
The laser is a low-energy, highly concentrated light that is beamed through the special lens into the eye. The light passes freely through the transparent structures of the eye and continues on through the transparent layers of the retina. The light is stopped by the pigment layer of the retina, where it is converted into heat. The heat coagulates the retinal layers. This helps to preserve vision by preventing future bleeding and new blood vessel formation. Shrinkage of swollen retina is helped in some cases and prevents further deterioration of vision.
Immediately after treatment you will be completely dazzled by light and Later vision may still be temporarily blurred. Changes may occur in colour vision, night vision and in the field of vision. On very rare occasions vision can be made worse. It is rare for the effect on colour vision to be a problem.
After the laser treatment progress of the disease is controlled, but may require future laser treatment. Regular eye checks are essential.
In some patients where there has been recurrent bleeding and the vitreous is clouded with blood or a retinal detachment is present, a vitrectomy operation may be necessary. In this surgical procedure, the blood and scar tissue is removed from the centre of the eye and replaced with a clear artificial solution. Following vitrectomy, patients can often see well enough to move around on their own.
However, the improvement in vision can be limited and sight may take weeks or even months to improve. In some cases of severe diabetic retinopathy a successful procedure means stabilizing the vision to prevent it getting worse, not creating an improvement.
The macula is the most central part of the retina and is where light is focused when looking at an object. It is where detailed vision takes place and is responsible for sight in the centre of the field of vision. The rest of the retina (peripheral) is responsible for side and night vision. Macular degeneration affects the macula and impairs central vision.
It accounts for almost 50% of all visual impairment in the developed world. It usually affects people over 50 years of age and is known as Age-related Macular Degeneration (ARMD or AMD). There are other forms of macular disease affecting younger people, often termed 'macular dystrophy', that may run in families - this type of macular degeneration is rare. Macular degeneration can also be caused by eye injury, infection or inflammation. Diabetes can cause macular disease (known as diabetic retinopathy).
If detected early enough laser treatment can be effective in arresting AMD in a minority of patients. For the majority of patients it remains untreatable. Initially only one eye may be affected and symptoms in the early stages may not be noticed since one good eye can mask the sight problem of the other eye.
The central part of your vision is 'reduced'. You may see the outline of a face but not the features Straight lines may appear wavy or misshapen. Judging distances and heights becomes difficult. You may find it difficult to match similar shades of the same colour You may constantly need better lighting In general you will have little problem walking from one place to another although crossing busy roads may be more difficult. However, you are likely to have difficulty reading, watching television and other activities where detailed vision is required.
AMD alone does not result in total blindness. Only the central (reading) vision is affected and the surrounding vision remains normal. Useful side vision that allows you to see to get around is retained in both forms of AMD.
If your optometrist or general physician suspects that you have age-related macular degeneration (AMD), you will be referred to an ophthalmic clinic for diagnosis.
When you attend for an outpatient appointment, you will be examined by one of our ophthalmologists to confirm the diagnosis andthe type of AMD present. There are 2 types - 'dry type' and 'wet type'. Dry AMD develops gradually, over a number of years, causing fading in the central areas of vision, while wet AMD progresses more rapidly. You will have a sight test and then a full eye examination. You should always avoid driving on the day of your appointment as your pupils will need to be dilated on each appointment.
There is as yet no available treatment for dry type AMD. For wet type, laser treatment may occasionally halt the progress of the disease if diagnosed very early.
Before the laser is applied local anesthetic drops are put on the eye to numb it and drops instilled to dilate the pupil. This allows a contact lens held by the doctor to be placed against the eye. The contact lens helps keep the lids open while allowing the doctor to view the back of the eye in greater detail.
The laser (photocoagulation) focuses a high energy light beam in small bursts onto the damaged retina. The purpose of the laser is to seal the leaking blood vessels. Treatment takes only a few minutes. Sometimes a dull thud sensation or occasionally a sharp pain is felt. Any discomfort experienced that day can be relieved by rest and a mild painkiller. If pain persist after 24 hours you must report to an eye casualty department.
Immediately after the treatment you will be completely dazzled by light and vision may be temporarily blurred. There will be a small blind patch at the site of the laser treatment but this will not interfere with your vision unless it is very close to the middle. Changes may occur in colour vision, night vision and in the field of vision. On very rare occasions vision can be made worse. It is rare for an effect on colour vision to be a problem.
The retina is the light sensitive tissue layer at the back of the eye. The cones and rods of the retina send electrical messages of what is seen along the optic nerve to the brain where they are interpreted into the images we see.
When a retinal detachment develops a separation occurs between the retina and the eye wall at the back of the eye. The part that is detached (peeled off) will not work properly and the picture the brain receives becomes patchy or may be lost completely. An operation is necessary to replace the detached retina in the correct position.
People often describe seeing "something black" or "a curtain", "cobweb" or "flashing lights". In older people, these do not necessarily indicate a serious problem, but the sudden appearance of floaters and flashes requires a full eye examination to exclude the presence of retinal holes or tears.
Nearly all retinal detachments develop because of a hole or tear in the retina. This usually occurs when the retina becomes 'thin', which can occur in short sighted people, or if the vitreous (the jelly-like substance that fills the eye) separates from the retina. Other eye or health problems such as diabetes and injuries, a blow to the eye or cataract operations, can occasionally lead to a retinal detachment.
If you have a suspected retinal detachment you must go to an emergency department as soon as possible. You will need a sight test and full eye examination. Your vision will be blurred temporarily due to eye drops and prevent you from reading and driving. You must avoid driving whenever you have your retinas examined.
If you are diagnosed with a retinal detachment, you will be advised to have surgery as soon as possible to reattach the retina.
Depending on the causes and condition of the retinal detachment there are a range of treatment options:A retinal hole or tear
To seal the retina around the tear and prevent the retina peeling off you may be asked to have:
Laser - the retinal hole can be heat sealed by directing a laser beam through the pupil of the eye. The scar produced seals the hole.
OR Cryotherapy - a freezing treatment applied by a pen shaped probe to the outside of the eye. This freezes through to the retinal hole and, as with laser treatment, promotes scar tissue as a seal.
These procedures can be a little uncomfortable but not painful and are usually performed under a local anaesthetic. They are only effective for retinal holes or tears. A detached retina
In addition to the above treatments this may require more complicated operations and procedures, such as the encircling band or sponge or vitrectomy. These procedures require a general anaesthetic and a 2-3 day stay in hospital.
Floaters are shapes people can see drifting across their vision. Their exact form is variable - they often appear as small dots or irregularly shaped strands. I f severe Floaters cloud the vision or cause loss of vision. They occur when the vitreous (the jelly-like substance that fills the eye) ages and strands of a protein called collagen become visible within it. These strands swirl gently when the eye moves, giving rise to the perception of Floaters. In some people, usually over the age of 40, the vitreous can separate from the retina. When this happens it tugs on the retina, causing the eye to see flashes of bright white light. A sudden increase (shower) of floaters is usually seen at the same time. This is called posterior vitreous detachment and may lead to retinal detachment..
Generally people should not be concerned about seeing one or two floaters in their vision, particularly if they have been there for some time. A sudden increase in the number of floaters, particularly if also seen with white flashing lights, is a symptom of posterior vitreous detachment. If you see this you should see an eye doctor urgently to ensure you are not suffering from a retinal detachment.
It is technically possible to remove floaters by performing an operation to remove the vitreous - a vitrectomy. This operation carries significant risks to sight due to possible complications, including retinal detachment and cataract. Most eye surgeons are reluctant to recommend this surgery unless there is a threat to sight.