Wales Council of the Blind

Glossary Browser

Albinism eye condition

Albinism is a comparatively rare genetically inherited group of conditions which results in a reduction or complete lack of pigment (colour) in the skin, hair and eyes of people with the condition. This can result in pale skin which burns easily in the sun, virtually white hair, very severe short-sight and photophobia (a severe sensitivity to light).

Alstrom syndrome eye condition

Alstrom Syndrome is an ultra rare recessively inherited genetic disorder, which means that both parents will carry the gene although probably be unaffected themselves. ASUK know of around 80 families in the UK who are affected, this figure could be higher due to delayed diagnosis and the rarity of the condition, many may still be undiagnosed. The condition is characterised by retinal degeration, hearing loss, obesity & insulin resistance.

Aniridia eye condition

Aniridia is a rare congenital eye condition causing incomplete formation of the iris. This can cause loss of vision, usually affecting both eyes.

Anophthalmia eye condition

Anophthalmia is a medical term that is used to describe the absence of the globe and ocular (eye) tissue from the orbit.

Bardet-Biedel Syndrome (BBS) eye condition

BBS is a multi-system disorder that has a significant impact on the quality of life and may be life-limiting. Features include rod-cone dystrophy, a progressive eye disorder that leads to blindness, characterised by tunnel vision and night blindness; obesity; renal abnormalities; developmental delay; speech and language difficulties; extra fingers and/or toes and learning difficulties.

Behcet's Syndrome eye condition

A chronic condition caused by disturbances in the body's immune system and around 70% of patients will experience inflamation of the eye.

Best's disease eye condition

Best disease is a genetic condition you are born with, although it does not usually start to affect your vision until later in life.

Birdshot uveitis eye condition

A form of uveitis where oval spots can be seen on the retina.

Blepharitis (eyelid problems) eye condition

An inflamation of the eyelids which can make the eyes feel irritated or itchy, but rarely causes serious eye damage.

Cataract eye condition

A cataract is a clouding of the lens inside your eye which causes your sight to become cloudy and misty. Cataracts are treated by surgery, during which the cloudy lens is removed and replaced by an artificial lens.

Central retinal vein occlusion (CRVO) eye condition

Central retinal vein occlusion (CRVO) is an eye condition that affects the retina — the light-sensitive layer of tissue in the back of your eye. It happens when a blood clot blocks the main vein where blood flows out of the retina. It usually only affects 1 eye.

Cerebrovascular disease eye condition

Cerebrovascular diseases are conditions caused by problems that affect the blood supply to the brain. One of the most common types is stroke, which can cause loss of vision in one eye or on one side of the field of vision

Charles Bonnet syndrome eye condition

A condition where people who have lost their sight experience hallucinations.

Chorioretinitis (choroid retinitis) eye condition

A form of uveitis where the inflamation affects the back of the eye.

Choroidal degeneration eye condition

Mentioned on CVI, but no reliable definition found.

Coat's Disease eye condition

Coats disease, also known as exudative retinitis, is a very rare eye condition that affects the smaller blood vessels (capillaries) found in the retina.

Coloboma eye condition

Coloboma means that part of one or more structures inside an unborn baby’s eye does not fully develop during pregnancy.

Colour blindness eye condition

Effects can vary: there are extremely rare cases where people are unable to see any colour at all, but most can see as clearly as other people but are unable to fully see red, green or blue.

Congenital cataracts eye condition

Cataracts which are present at birth (rather than as part of the ageing process).

Corneal dystrophies eye condition

Corneal dystrophies are a rare group of genetic conditions which cause changes to the cornea without any inflammation, infection, or other eye disease.

Corneal transplantation eye condition

A treatment rather than condition??

Deafblindness eye condition

A person is deafblind if they have a combined sight and hearing impairment that causes difficulties with communication, access to information and mobility.

Degenerative Vitreous Syndrome (DVS) eye condition

The spontaneous occurrence in the ageing vitreous of opacities (floaters) that substantially interfere with activities of daily living. See source for more information on the vitreous and floaters.

Diabetes/diabetic retinopathy eye condition

Diabetes can affect the eye in several ways, the most common being problems with blood vessels in the eye.

Diabetic macular oedema eye condition

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, macular-oedema">diabetic macular oedema can cause your central vision to become blurred. A healthy macula is essential for good vision.

Dry eye eye condition

Caused by a problem with the tears which leaves eyes feeling dry, scratchy and uncomfortable.

Flashes/floaters eye condition

Flashes of light/small dark spots or strands which move. Generally harmless, but can be sign of retinal detachment

Fuch's dystrophy eye condition

Fuchs’ endothelial corneal dystrophy (FECD) is an eye condition that affects your cornea, the clear front "window" of your eye.

Giant cell or temporal arteritis eye condition

A condition affecting the arteries which can cause serious sight loss if untreated.

Glaucoma eye condition

Glaucoma is the name of a group of eye diseases that damage the optic nerve. The optic nerve transfers visual information from the eye to the brain and if it’s damaged, it can result in sight loss and even blindness. There are three main types of glaucoma: primary, secondary, and developmental (glaucoma in babies and children).

Hemianopia eye condition

Hemianopsia, or hemianopia, is a loss of vision or blindness (anopsia) in half the visual field, usually on one side of the vertical midline. The most common causes of this damage are stroke, brain tumour, and trauma.

Keratitis eye condition

Keratitis is a condition in which the eye's cornea, the clear dome on the front surface of the eye, becomes inflamed.

Keratoconus eye condition

Keratoconus (KC) is a disorder of the eye that results in progressive thinning of the cornea. This may result in blurry vision, double vision, nearsightedness, irregular astigmatism, and light sensitivity leading to poor quality-of-life.

Light sensitivity (photophobia) eye condition

Light sensitivity also known as photophobia, often affects people who have an underlying eye condition.

Macular Degeneration eye condition

Loss of central vision due to damage to the macular. Most common in older people (AMD) but can occur in younger people.

Macular hole eye condition

A macular hole is a small defect in the retinal layer that develops at the centre of the macula. If the macula is damaged it is difficult to drive, watch TV, read or recognise faces.

Marfan syndrome eye condition

Marfan syndrome is an inherited disorder of the body’s connective tissue that leads to medical problems affecting the heart, eyes and skeleton, requiring treatment to prevent life-threatening complications.

Microphthalmia eye condition

Microphthalmia literally means small eye. Children may be born with one or both eyes, small and underdeveloped. Some children may be blind, but others may have some residual sight or light perception.

Monocular vision eye condition

Blinding or removal of one eye due to accident, injury or disease.

Myopia eye condition

Myopia, also known as “being short sighted”, causes your vision to be blurry in the distance but clearer when looking at things up close.

Norrie Disease eye condition

Norrie disease is a rare X-linked genetic condition which causes boys to be born blind or with severe sight impairment. Secondary symptoms can include progressive hearing loss, cognitive impairment, autism and delayed development.

Nystagmus eye condition

Nystagmus is a complex eye condition, characterised by involuntary eye movements, from side to side, up and down or round and round. This affects the ability to focus, see the world in three dimensions and recognise faces. There are two main types of nystagmus, one which appears in the first weeks or months of life and is called Congenital or Infantile Nystagmus and another which develops later in life which is called Acquired Nystagmus. There are many possible causes of both kinds of nystagmus.

Ocular pemphigoid eye condition

Mucous Membrane Pemphigoid (MMP) is a rare autoimmune disease (a group of diseases caused by the reaction of the person’s immune system producing antibodies - known as autoantibodies - which damage normally healthy body substances). When the eyes are affected it is called Ocular MMP (OMMP).

Optic neuropathy eye condition

Optic neuropathy is damage to the optic nerve from any cause. The optic nerve is a bundle of millions of fibers in the retina that sends visual signals to the brain.

Posterior vitreous detachment eye condition

Posterior vitreous detachment (PVD) is a condition where your vitreous gel comes away from the retina at the back of your eye.

Pseudoxanthoma Elasticum (PXE) eye condition

Condition affecting the macular in one or both eyes, causing problems with central vision.

Punctate inner choroidopathy eye condition

Punctate inner choroidopathy (PIC) is a rare condition caused by inflammation at the back of the eye. It is more common in women, and in short-sighted people.

Retinal detachment eye condition

Retinal detachment is an eye problem that happens when your retina (a light-sensitive layer of tissue in the back of your eye) is pulled away from its normal position at the back of your eye.

Retinitis pigmentosa eye condition

Retinitis pigmentosa is the term used for a group of closely related inherited eye conditions that affect the retina, the specialised light-sensitive tissue at the back of the eye. A person’s sight loss usually happens gradually, over many years – and sometimes eventually leads to registered blindness. Retinitis pigmentosa is the most common inherited eye condition, affecting around one in 4,000 people in the UK.

Retinoblastoma eye condition

Retinoblastoma (Rb) is a type of eye cancer that affects young children, mainly under the age of six. It develops in the cells of the retina, the light sensitive lining of the eye. Around 40-50 cases are diagnosed in the UK every year – approximately one child a week. Retinoblastoma can either affect one or both eyes.

Retinopathy of prematurity eye condition

Retinopathy of prematurity is a condition that can affect babies who are born early, before the blood vessels that supply the light-sensitive layer of the eye (the retina) have finished growing.

Sorsby's fundus dystrophy eye condition

Sorsby's fundus dystrophy causes similar symptoms to age-related macular degeneration (AMD), although it generally affects people at a younger age.

Stargardt's disease eye condition

Causes some of the cells on the macula to stop working leading to problems with central vision, detailed vision and sometimes with colour perception.

Stickler syndrome eye condition

Stickler Syndrome is a genetic condition affecting connective tissue (essentially collagen), with variable symptoms. There are now known to be at least 11 distinct sub-groups of Stickler Syndrome, but the effect in each are typically in four main areas, including the eyes.

Strabismus (squint) eye condition

Strabismus, often referred to as a squint and sometimes as a "turn" in the eye is an eye condition where the eyes do not look in the same direction as each other.

Stroke-related eye conditions eye condition

Strokes occur when a part of your brain is starved of oxygen and nutrients. A stroke can result in visual field loss, blurry vision, double vision and moving images.

Thyroid eye disease eye condition

Thyroid eye disease (TED) is an eye condition that usually occurs when you have a problem with your thyroid gland. It causes the eye muscles, eyelids, tear glands and soft tissues in and around your eye socket to become inflamed.

Usher syndrome eye condition

Form of deafblindness where people are born deaf or hard of hearing and start to lose their sight (with retinitis pigmentosa) in the school years.

Uveitis eye condition

An inflamation of the middle layer of the eye (the uvea)

Visual cortex disorder eye condition

Mentioned on CVI, but no reliable definition found.

Wolfram syndrome eye condition

Wolfram Syndrome is a rare genetic disorder which is also known as DIDMOAD syndrome after its 4 most common features (Diabetes Insipidus, Diabetes Mellitus, Optic Atrophy and Deafness). Everyone with Wolfram Syndrome will have optic atrophy at some stage, which means that the optic nerve wastes away and causes colour blindness and gradual loss of vision. Wolfram Syndrome is very rare and affects around 1 in 770,000 of the total UK population.