Age related macular degeneration
Age-related macular degeneration (AMD) involves damage to the macula and affects central vision
How AMD affects vision?
The macula is a small, but extremely important area located at the centre of the retina, the light-sensing tissue that lines the back of the eye. It is responsible for seeing fine details clearly. If you have AMD, you lose the ability to see fine details, both close-up and at a distance. This affects only your central vision. Your side, or peripheral, vision usually remains normal. For example, when people with AMD look at a clock, they can see the clock’s outline but cannot tell what time it is; similarly, they gradually lose the ability to recognise people’s faces
Types of AMD?
There are two types of AMD. Most people (about 75%) have a form called “early” or “dry” AMD, which develops when there is a build-up of waste material under the macula and thinning of the retina at the macula. Most people with this condition have near normal vision or milder sight loss. A minority of patients with early (dry) AMD can progress to the vision-threatening forms of AMD called late AMD. The commonest form of late AMD is “exudative” or “wet” AMD. Wet AMD occurs when abnormal blood vessels grow underneath the retina. These unhealthy vessels leak blood and fluid, which can prevent the retina from working properly. Eventually the bleeding and scarring can lead to severe permanent loss of central vision, but the eye is not usually at risk of losing all vision (going 'blind') as the ability to see in the periphery remains. There is a rarer form of late AMD called geographic atrophy, where vision is lost through severe thinning or even loss of the macula tissue without any leaking blood vessels.
Treatments for AMD?
We provide intravitreal injections (injections into the eye) for wet AMD using a medicine called Ranibizumab (also known as Lucentis, the brand name). Ranibizumab is one of a group of anti-VEGF medicines which, when injected into the eye on a regular basis, can stop the abnormal blood vessels growing, leaking and bleeding under the retina. Most people with wet AMD need to have these injections several times a year, so we now provide the service at our main hospital. Laser treatment is also available for AMD, but is not effective for most cases. There is currently no treatment for dry AMD.
Diabetic retinopathy is a complication of diabetes, and causes damage to the blood vessels in the retina. Causes of diabetic retinopathy Many diabetics – particularly those with poor diabetic control which results in too-high blood sugar levels over long periods of time – have damaged blood vessels in the retina, the tissue lining the back of the eye that detects light and allows us to see. This condition, called diabetic retinopathy, affects up to eight out of 10 patients who have had diabetes for 10 years or more.
Types of diabetic retinopathy
Many people with mild diabetic retinopathy have good vision, but there are two types of sight-threatening diabetic retinopathy: diabetic macular oedema (DMO) and proliferative diabetic retinopathy (PDR). In DMO, fluid leaks out of the tiny damaged blood vessels in the back of the eye, and accumulates in the macula, the central part of the retina which is responsible for seeing fine details and central vision. This leads to swelling of the tissue and blurred vision. Eventually, patients with diabetic macular oedema can develop poor central vision and be unable to read or drive, but the vision to the side usually remains normal. Proliferative diabetic retinopathy is when the retinal blood vessels close resulting in the retina being starved of blood. This causes abnormal and very fragile blood vessels to grow on the surface of the retina which can lead to permanent loss of vision from bleeding into the eye, retinal scarring and retinal detachment.
Treatment for diabetic retinopathy
Regular eye checks are essential for all diabetics, so signs of diabetic retinopathy can be detected as early as possible. If you diabetic and experience blurred vision, you should visit an eye specialist immediately. If you develop DMO, you might require laser photocoagulation, which involves placing tiny laser burns in the area of leakage in the retina which slow the leakage of fluid and reduce the fluid in the eye. This may not significantly improve vision for some patients – although it can stop your vision from getting worse. Other treatments are available and have been shown to benefit patients with DMO, including injections of anti-VEGF drugs such as bevacizumab and ranibizumab. Ask your specialist if these treatments are suitable for you or available to you.
Diabetic macular oedema
Diabetic eye disease is a leading cause of blindness. It is caused by changes to the tiny blood vessels of the retina (the light sensitive layer at the back of the eye). In diabetic macular oedema, blood vessels leak fluid into the retina.
How does diabetic macular oedema cause vision loss?
Vision loss occurs when the fluid reaches the macula (the centre of the retina that provides sharp vision) and builds up, causing swelling. At first, you may not notice changes to your vision. Over time, diabetic macular oedema can cause your central vision to become blurred. A healthy macula is essential for good vision.
Who is at risk of diabetic macular oedema?
All people with type 1 and type 2 diabetes are at risk of diabetic macular oedema. You are at greater risk if you: Have had diabetes for a long time–about one in three people living with diabetes for 20 years or more will develop diabetic macular oedema Have poorly controlled blood sugars Have high blood pressure Have high cholesterol levels Smoking Are pregnant Large studies have shown that people who have well-controlled blood sugar, blood pressure and cholesterol levels, and do not smoke are less likely to develop diabetic macular oedema.
How to reduce the risks of diabetic macula oedema
To reduce the risk of diabetic macular oedema, it is important not to smoke and to ensure that your blood sugar, blood pressure, and cholesterol levels are well controlled. This can be achieved by regular visits to your diabetes nurse, general practitioner or hospital doctor.
How is diabetic macular oedema detected?
Diabetic macula oedema may be detected during your annual eye screening visits, which are offered to all patients with diabetes. Digital photographs of your retina may show signs of early diabetic macular oedema. You may not notice any changes in your vision at this stage. If diabetic macular oedema is detected, you will be referred to the medical retina clinic for further assessment, it is important to resume attending your annual local diabetes eye screening appointments.
Keratoconus is a non-inflammatory eye condition in which the normally round dome-shaped clear window of the eye (cornea) progressively thins causing a cone-like bulge to develop.
What is keratoconus?
Keratoconus is an eye condition in which the normally round dome-shaped clear window of the eye (cornea) progressively thins causing a cone-shaped bulge to develop. Exactly why this happens is unknown, but genetic factors play a role and it is more common in people with allergic diseases such as asthma, in Down's syndrome and in some disorders of connective tissue such as Marfan's disease. It affects up to one in 1,000 people and is more common in people of Asian heritage. It is usually diagnosed in teenagers and young people.
How does kerataconus affect vision?
The change in shape and thinning of the cornea and, in later stages, scarring causing loss of transparency of the cornea impairs the ability of the eye to focus properly, causing poor vision.
Treatments for keratoconus
In the early stages, spectacles or soft contact lenses may be used to correct vision. As the cornea becomes thinner and steeper, rigid gas permeable (RGP) contact lenses are often required to correct vision more adequately. In very advanced cases, where contact lenses fail to improve vision, a corneal transplant may be needed. Changes caused by keratoconus can take many years to develop. For this reason we monitor those with the condition and invite them back for repeat assessments for up to five years from an initial visit. When a person with keratoconus attends a clinic at Moorfields , the following tests might be performed; 1. Vision (reading chart) 2. Refraction (spectacle test) 3. Corneal scan (Pentacam) Any necessary contact lens checks will also be undertaken. The results are compared with those from your previous visits. If the results are getting steadily worse, we will discuss with you whether you need to undergo corneal cross-linking (CXL). CXL is a new treatment that can stop keratoconus getting worse. It is effective in more than nine out of 10 patients, with a single 30-minute day-case procedure, but it is only suitable where the corneal shape is continuing to deteriorate. Beyond a certain stage, if the cornea is too thin, it could be unsafe to perform the procedure. Usually in people in their late 30s, the cornea naturally stiffens and CXL is generally not required. Below this age, the cornea is more flexible and disease progression (and worsening vision) are more likely to occur.
Retinal detachment occurs when the thin lining at the back of your eye begins to pull away from the blood vessels that supply it.
What is a retinal detachment?
The retina is a thin layer of nerve cells that lines the inside of the eye. It is sensitive to light (like the film in a camera) and you need it to be able to see properly. Retinas detach because they have one or more holes in them, which allows fluid to pass underneath them. This fluid causes the retina to become separated from the supporting and nourishing tissues underneath it. Small blood vessels might also be bleeding into the vitreous (the jelly-like substance in the centre of the eye), which might cause further clouding of the vision. Without treatment, a retinal detachment usually leads to blindness in the affected eye.
Causes of retinal detachment
Most retinal detachments occur as a natural ageing process in the eye. It is unlikely that it would be caused by anything that you have done. Anyone can develop a retinal detachment at any time, but certain people are at higher risk than others. These include people who are short sighted, those who have had cataract surgery in the past, and those who have recently suffered a severe direct blow to the eye. Some types of retinal detachments can run in families, but these are rare.
Treatment for retinal detachment
The treatment involves surgery. During the operation, your eye doctor will seal the retinal holes and reattach your retina. Your operation will be supervised by an experienced eye surgeon, who will either perform the surgery themselves or oversee a more junior surgeon who might undertake part or all of the operation.
Glaucoma is the name given to a group of eye conditions in which the optic nerve is damaged where it leaves the eye.
What is glaucoma?
Glaucoma is the name given to a group of eye conditions in which the optic nerve is damaged where it leaves the eye. Although any vision which has been lost to glaucoma cannot be recovered, with early diagnosis, careful monitoring and regular use of the treatments, further damage to vision can be prevented and most patients retain useful sight for life. While there are usually no warning signs, regular eye tests will help detect the onset of the disease Glaucoma is one of the world's leading causes of blindness.
How glaucoma affects vision
Glaucoma involves loss of vision due to damage of the optic nerve. The optic nerve carries sight images to the brain and any damage to the nerve results in damage to sight. For the eye to work properly a certain level of pressure is needed for the eye to keep its shape but if the eye pressure gets too high, it squeezes the optic nerve and kills some of the nerve fibres, which leads to sight loss. The first areas to be affected are the off-centre parts of the vision. If the glaucoma is left untreated, the damage can progress to tunnel vision and eventual loss of central vision, although blindness is rare. Usually, but not always, the damage occurs because pressure within the eye increases and presses on the nerve, which damages it.
Types of glaucoma
There are four main types of glaucoma: primary open angle glaucoma, primary angle closure glaucoma, secondary glaucoma, developmental glaucoma (congenital glaucoma). Primary open angle glaucoma - This is the most common type of glaucoma and develops very slowly Angle closure glaucoma - This is rare and can occur slowly (chronic) or may develop rapidly (acute) with a sudden, painful build-up of pressure in the eye Secondary glaucoma -This occurs as a result of an eye injury or another eye condition, such as uveitis (inflammation of the middle layer of the eye) Developmental glaucoma (congenital glaucoma) -This is rare but can be serious. It is usually present at birth or develops shortly after birth. It is caused by an abnormality of the eye. You are also at increased risk of developing open-angle glaucoma if you are of black-African or black-Caribbean origin. The other types of glaucoma, such as acute angle-closure glaucoma, are much less common. However, people of Asian origin are more at risk of getting this type of glaucoma compared with those from other ethnic groups.
cataract is clouding or opacity of the lens inside the eye. It causes gradual blurring of vision and often glare.
How cataract affects vision
Inside your eye, behind the iris and pupil is a lens. In a normal eye, this lens is clear. It helps focus light rays on to the back of the eye (the retina), which sends messages to the brain allowing us to see. When cataract develops, the lens becomes cloudy and prevents the light rays from passing on to the retina. The picture that the retina receives becomes dull and fuzzy. Cataract usually forms slowly and most people experience a gradual blurring of vision.
Causes of cataract
Most forms of cataract develop in adult life. The normal process of ageing causes the lens to harden and become cloudy. This is called age-related cataract and it is the most common type. It can occur at any time after the age of 40. Although most cataracts are age related, there are other types, including congenital (present at birth), drug induced (steroids), and traumatic (injury to the eye). Cataract is also more common in people who have certain diseases such as diabetes.
Treatments for cataract
Surgery is the only available treatment for cataract and is very effective, straight-forward and quick for the vast majority of patients. We advise patients to have surgery when their cataract progresses to the point that it is interfering with daily activities or lifestyle – but it is usually safe to delay surgery if you do not feel that you have a problem with your vision or do not wish to have surgery.
Myopia (short sight)
Myopia is when people cannot see clearly in the distance without glasses or contact lenses
Myopic (short-sighted) people cannot see clearly in the distance without glasses or contact lenses. This is because of a focusing problem. Usually, light comes in through the lens and focuses on the retina at the back of the eye. In myopia, the light is focused too far forward in the eye, in front of the retina, which causes things to look blurred in the distance. People typically become short-sighted in their teenage years or twenties.
Causes of myopia
Several factors probably combine to cause myopia. There is a tendency for myopia to run in families. Myopia usually appears around puberty, but can appear at any age from early childhood. In most cases, myopia stabilises in once the body is fully grown, usually in the mid-twenties or earlier. A widely held misconception is that myopia corrects itself with age. Although patients with low-level myopia can read without glasses throughout life, their distance vision remains poor.
Treatments for myopia
It is generally possible to correct myopia with prescription glasses or contact lenses, using concave (curved inwards) lenses, which move the focus of the light backwards onto the retina, allowing you to see clearly. Glasses and contact lenses are available from high-street optician outlets. If you choose contact lenses, daily disposables are the safest type for most patients with myopia. Overnight wear should be avoided, as this increases the risk of infection. Safe surgical procedures such as LASIK or Phakic IOLs implantation are also available
Hypermetropia is when people cannot see clearly close up without glasses or contact lenses.
Hypermetropia is a common problem with the eye’s focusing that can affect your vision at all distances, but especially close-up. This is because of a focusing problem. Usually, light comes in through the lens and focuses on the retina at the back of the eye. In hypermetropia, the light is focused too far back in the eye, behind the retina, which causes things to look blurred close-up. Many very young children have mild hypermetropia that gets better by itself as they grow older. The percentage of people with hypermetropia increases with age.
Treatments for hypermetropia
Long sight can be easily corrected with glasses or contact lenses, using convex (curved outwards) lenses, which move the focus of the light forward onto the retina, allowing you to see clearly. Laser eye surgery is also an option.
Astigmatism is a common and treatable eye condition which causes irregular focus.
Astigmatism is a common and treatable eye condition. The front surface of a normal eye is round like a football, but people with astigmatism have eyes shaped more like an oval rugby ball. This changes the path of light so that the image formed at the back of the eye is not sharply focused. People with astigmatism will usually also be short or long sighted. People can be born with astigmatism or it can develop later in life. Many people have a little astigmatism and their sight is unaffected. If the astigmatism is more severe, you might notice: • Blurring and distortion of near or far-away objects • Headaches when trying to focus • Tired eyes
Causes of astigmatism
The exact cause is usually unknown although genetics can play a part. Sometimes astigmatism can develop after an eye injury, surgery or because of an eye disease. Astigmatism is not caused by reading in bad light, using a computer or watching too much television.
Treatment for astigmatism
Astigmatism can usually be treated with prescription glasses or contact lenses. Safe surgical procedures such as LASIK or Toric ICL implantation are also available