There is a wide range of diseases and conditions that can affect our eyes, causing visual impairment and often blindness. In this section we highlight some of the more common diseases.
There are a group of diseases that lead to macular degeneration, characterised by the gradual breakdown of the macula (the central portion of the retina). The macula is responsible for central detailed vision, essential for reading, driving and recognising faces. Central vision loss occurs when photoreceptor cells in the macula degenerate. Macular degeneration is the most common cause of vision loss in individuals over the age of fifty, and is the leading cause of irreversible blindness in the developed world.
Age-related Macular Degeneration
Age-related macular degeneration (AMD) is a retinal degenerative disease that causes a progressive loss of central vision. It is the leading cause of blindness in the UK and is diagnosed as either wet or dry. People with AMD may first notice a blurring of central vision, especially during tasks such as reading. Also, straight lines may appear distorted or warped. As the disease progresses, blind spots may form within the central visual field. In most cases, if one eye has AMD, the other eye will develop the disease.
AMD is the common cause of blindness that the London Project is focusing on curing. You can read more about AMD in the Our Vision section, where we go into more detail about all forms of the disease.
Stargardt's Disease is the most common form of inherited juvenile macular degeneration. The disease not only causes the loss of central vision but also affects colour vision. With onset from about the age of 6, the effects vary from minor to complete loss of central vision.
For more information about Stargardt’s Disease visit the MD Support website.
A cataract is a clouding of the lens. The lens is contained in a sealed bag or capsule and as old cells die they become trapped within the capsule. Over time, the cells accumulate causing the lens to cloud, making images look blurred or fuzzy. For most people, cataracts are a natural result of the ageing process, and are most common in people over the age of 60.
For more information about cataracts visit the All About Vision website.
Diabetic retinopathy is the leading cause of blindness in people of working age in the UK and is the result of the effects of diabetes on the eyes. It damages the blood vessels in the eye and can eventually lead to blindness. Diabetic patients require routine eye examinations so related eye problems can be detected and treated as early as possible.
Researchers have found that diabetic patients who are able to maintain appropriate blood sugar levels have fewer eye problems than those with poor control. Diet and exercise play important roles in the overall health of those with diabetes.
Glaucoma is the second leading cause of vision loss in the world, and affects around 1 in 50 people over 40 in the UK. It is the name given to a group of eye diseases in which the flow of fluid out of the eye is obstructed, causing pressure within the eye to increase. This damages the optic nerve, and if untreated, will eventually lead to irreversible blindness. The damage often occurs before people realise, so early diagnosis and effective treatment are vital.
There are several types of glaucoma; chronic, acute, secondary and developmental glaucoma. Chronic glaucoma is caused by a gradual increase in the pressure within the eye, whereas acute glaucoma is the result of a sudden increase in internal pressure of the eye. There are two other main types of glaucoma. When a rise in eye pressure is caused by another eye condition this is called secondary glaucoma. There is also a rare but potentially serious condition in babies called developmental or congenital glaucoma
For more information about all forms of Glaucoma visit the International Glaucoma Association website.
Juvenile Retinoschisis is an inherited disease diagnosed in childhood that causes progressive loss of central and peripheral vision due to degeneration of the retina. Juvenile retinoschisis, also known as X-linked retinoschisis, occurs almost exclusively in males. Although the condition begins at birth, symptoms do not typically become apparent until after the age of 10. About half of all patients diagnosed with juvenile retinoschisis first notice a decline in vision. Other early symptoms of the disease include an inability of both eyes to focus on an object, and roving, involuntary eye movements.
For more information about Juvenile Retinoschisis visit the Foundation Fighting Blindness website.
A macular hole affects the very central portion of the retina. It can happen for a variety of reasons such as eye injuries and certain diseases, however, the most common cause is related to the normal ageing process. The vitreous gel inside the eye is firmly attached to the macula. With age, the vitreous gel becomes thinner and separates from the retina. Sometimes this creates traction on the macula, causing a hole to form.
For more information about macular holes visit the Eye Care Trust website.
Optic Nerve Disease
If the optic nerve is diseased or severely damaged, vision loss or blindness can occur. Optic nerve disease can result as a consequence of a variety of other conditions including glaucoma, inflammatory conditions and hereditary conditions such as Leber's Hereditary Optic Neuropathy.
Optic nerve disease is usually incurable. This means that, in the majority of patients, if vision is lost and not recovered in a very short time, it is unlikely to ever be restored. Therefore effective clinical management relies upon accurate assessments of the optic nerve function.
For more information about Optic Nerve Disease visit the International Foundation for Optic Nerve Disease website.
Retinal detachments often occur in eyes with retinas that are weakened by a hole or tear. This allows fluid to seep underneath, weakening the attachment so that the retina becomes detached, causing the sensory and pigment layers to separate. When the retina becomes detached it cannot correctly compose a picture and so vision becomes blurred and dimmed. As it can cause devastating damage to the vision if left untreated, retinal detachment is considered an ocular emergency that requires immediate medical attention and surgery. It is a problem that occurs most frequently in the middle-aged and elderly.
For more information about retinal detachment visit the Retina Source website.
Retinitis Pigmentosa (RP) is the name given to a group of hereditary eye disorders. These disorders affect the retina, which is the light-sensitive tissue lining the back of the eye. In RP, sight loss is gradual but progressive. It is unusual for people with RP to become totally blind as most retain some useful vision well into old age. Around 1 in 3,500 people in the developed world have the inherited condition, which arises from one of a number of faulty genes. As yet there is no cure or way to halt the progress of RP. At present the best prospect for future therapy lies in the identification of faulty genes.
For more information about Retinitis Pigmentosa visit the British Retinitis Pigmentosa Society website.
Uveal melanoma is the most common type of cancer originating in the eye. Approximately 500 new cases of uveal melanoma are diagnosed in the UK each year and the risk of being diagnosed with the disease increases with age. It is fatal in every second patient, due to the spreading of the disease to other parts of the body, most commonly the liver.
Symptoms include blurred vision, flashing lights, shadows and cataracts. However, for many there are no obvious symptoms and diagnosis is often made by an optician during routine sight tests.
For more information about uveal melanoma visit the Cancer Backup website.