Below are definitions of common terms.

Anterior chamber

This is the front section of the eye in the space between the cornea and the iris. It is filled with fluid called aqueous humor.

Anterior uveitis

Anterior uveitis means inflammation in the front section of the eye, consisting of the cornea, anterior chamber, iris and lens. The iris is the most common source of inflammation and when the iris is inflamed, white blood cells are shed into the anterior chamber. It is these cells that are observed on slit lamp examination and how many cells there are forms the basis for rating the degree of inflammation.

Antinuclear Antibodies (ANA)

If you test positive for ANA it can indicate the presence of specific antibodies which cause inflammation inside the person’s own body.  In turn this can suggest the presence of an autoimmune disease.

Aqueous humour

Is a watery fluid produced by the ciliary body, it is constantly regenerated.


A healthy immune system produces substances called antibodies that help fight and destroy viruses, bacteria and other foreign bodies that invade the body. In autoimmune disorders, the immune system produces antibodies against the body’s own healthy cells and tissues.

Therefore, autoimmune diseases cause the immune system to destroy and attack the person’s own body tissue, such as parts of the eye.  Autoimmune diseases, which affect the eye, will require immune suppression therapy. Such diseases include uveitis and jia among many others.

Band keratopathy

Calcium deposits in the cornea.  Occurs more commonly in children with juvenile arthritis and chronic uveitis.

Bilateral uveitis

Uveitis in both eyes.

Cataract and uveitis

The lens inside the eye is mostly comprised of water and protein.  If the protein clumps together it causes the lens to become cloudy – a cataract.  Cataract develops in patients with uveitis because of the uveitis itself and also because of the prolonged use of steroid medications.

Cells and the grading of cells

Leukocytes (white blood cells) can be seen during a slit lamp examination.  The cells are a byproduct of inflammation caused by the uveitis.  If the uveitis is anterior, cells can be seen and counted in the fluid in the front chamber of the eye (aqueous humor).  Once dilated, the presence of cells can also be observed in the middle chamber of the eye (the vitreous).

How many cells there are forms the basis of how severe the inflammation is at a particular given time.  The inflammation, and in turn the uveitis, is graded from 1-4, the least severe being 1 (the aqueous calls numbering 6-15) and the most severe inflammation being 4+ (when cells numbers are greater than 60).

Chronic uveitis

Inflammation, which lasts more than 3 months and is there all the time to one degree or another, is considered to be chronic.  Inflammation, which goes for a while but then returns, is known as recurrent.

Choroid and choroiditis

Inflammation of the choroid.  The choroid is in the middle layer of the eye between the retina and the sclera.  It is made up of blood vessels that nourish the back of the eye.  The choroid also absorbs excess light.  Inflammation of the choroid is called choroiditis.

Ciliary body

The ciliary body sits behind the iris and is responsible for making aqueous humor, the fluid in the eye that nourishes the lens and the cornea.

Corticosteroids (steroids)

Corticosteroids are prescribed to lessen inflammation of the body including the eyes. They lessen swelling, redness, itching, and allergic reactions.  However the long-term use of steroids to treat uveitis has side effects. These include the formation of cataract and, in some individuals, a rise in intraocular pressure, which can lead to glaucoma.

Detached retina

A retinal detachment happens when the retina is pulled away from the back of the eye. A detached retina is a very serious problem that causes blindness unless it is treated.  Most people notice floaters and flashes before the retina detaches, and if a person experiences either they should be examined promptly by an ophthalmologist.


Where the pupil is temporarily enlarged with special eye drops called mydriatics, which allow a specialist a better view of the inside of the eye.


When blood vessels in the iris leak protein into the anterior chamber flare is said to be present.  Like cells, it is measured on a scale from 1-4.  If permanent change to the blood vessels occurs, the flare is considered chronic, and can be present regardless of whether or not a uveitis ‘flare up’ is occurring.  Flare in the vitreous can also be observed and rated.


These are ‘seen’ as repeated tiny bright lights or flashes of lightning and can be associated with a retinal tear.  An ophthalmologist should examine anyone experiencing these symptoms as soon as possible.


Floaters appear as specks, strands, or “cobwebs” in front of the eyes.  Floaters can have a variety of causes some not at all serious.  New floaters can indicate a flare up of uveitis, and so it is wise to inform your ophthalmologist as soon as possible.


The back of the eyeball.


In most cases glaucoma is caused by too high pressure in the eye, which reduces blood flow to the optic nerve.  It can cause damage to the optic nerve resulting in permanent loss of vision.  Normal pressure is considered to be between 12-21 mm hg, but a person can have glaucoma even if the pressure is in range.  Patients with uveitis are at an increased risk of developing glaucoma because of the uveitis itself, and because of the use of steroids.

Idiopathic uveitis

If the cause of the uveitis cannot be discovered, in that autoimmune disorders, infections, disease and injuries to the eye have been ruled out, the uveitis is said to be idiopathic.  Because some systemic illnesses can present with symptoms to the eyes first, it can be worthwhile retesting periodically.

Immunosuppressive chemotherapy

Immunosuppressive therapy is also sometimes referred to as “chemotherapy” because some of the drugs used today were developed originally to fight cancer. The dose of these drugs, when used to treat uveitis, is much smaller than the dose used to treat cancer.

Autoimmune related uveitis is caused by the immune system itself, so the use of these drugs is designed to calm an overly aggressive immune system, allowing the body to eventually re-regulate itself. It is used with the hope that after a length of time the drug can be tapered and then stopped without recurrence of the autoimmune attack. Sometimes resumption of the attack does occur, in which case the patient must be re-treated.

Intermediate uveitis

Intermediate uveitis is inflammation predominantly located in the front (anterior) part of the vitreous.

Intraocular pressure (IOP)

Normal pressure is usually between 12-21 mm hg. Factors that can affect iop include inflammation and steroids.


The iris is the part of the eye that gives it its colour. It is located behind the cornea and in front of the lens, and its root is connected to the ciliary body.  It is responsible for adjusting the size of the pupil.


Inflammation, which is located in the iris, is called iritis.  However it is usually termed anterior uveitis because there is, more often than not, additional inflammation of the ciliary body.

JRA/JIA uveitis

An estimated 20% of children with juvenile rheumatoid arthritis (also known as jra or most recently jia) will develop uveitis. Children with jra should be screened routinely for uveitis upon diagnosis of jra, particularly because many of the children do not experience any symptoms until vision fails.  If the uveitis is detected and appropriately treated early, the majority should have a very good prognosis.

Keratic precipitates (KP)

When white blood cells settle (precipitate) or clump together on the back of the cornea this is called KP.


Keratitis is inflammation of the cornea.


The lens is a transparent ‘dome’, and its purpose is to focus an image on the retina.


The macula is responsible for detailed central vision and is located approximately in the centre of the retina.

Macular oedema

Swelling of the macular causes vision to reduce.  Macular oedema is a complication of uveitis and can cause permanent loss of vision if left untreated.


Mydriatics, or ‘dilating drops’, are used to temporarily enlarge (dilate) the pupil.  Once dilated a specialist is able to get a better view of the inside of the eye.  Mydriatics can also be used to prevent the lens from sticking to the iris causing synechiae.

Optic nerve

The optic nerve carries the visual signal from the retina to the brain.  If damaged, vision is reduced or lost permanently.

Optic neuritis

Optic neuritis is inflammation of the optic nerve.


When inflammation is located in the anterior, intermediate and posterior parts of the eye, it is classified as panuveitis.

Pediatric uveitis

5-10% of uveitis sufferers are aged 16 and under.

Uveitis is a particularly serious and potentially sight-threatening disease for this small section of patients who often present with serious complications associated with chronic uveitis on diagnosis.

Some of the reasons being that many children experience no symptoms until their vision starts to fail, or that children are unable to articulate any symptoms due to age or lack of vocabulary.

Posterior chamber

The posterior chamber is filled with aqueous fluid and is located towards the rear of the eye between the back of the iris and the front of the vitreous.

Posterior uveitis

When inflammation is located predominately at the back of the eye affecting the choroid, vitreous and or retina it is classified as posterior uveitis.


The pupil is the adjustable opening in the centre of the iris that allows light to enter the eye.


The retina is a thin layer of nerve tissue which lines the back of the eye. The retina sends images via the optic nerve to the brain.

Secondary Glaucoma

When other diseases or drugs cause glaucoma, the condition is referred to as secondary glaucoma.

Synechiae (sin-eeky-eye)

Synechiae can be compared to scar tissue, which forms after a severe flare up of anterior uveitis.  It causes the iris to stick to the cornea (anterior synechiae) or to the lens (posterior synechiae).  It can cause the pupil to become ‘fixed’ and raise intraocular pressure resulting in certain types of glaucoma.  If the synechiae have recently formed, dilating drops can be used to try and break the adhesion.


The uvea is the middle of three layers making up the wall of the eye.  It is comprised of the iris, ciliary body, and choroid.


Uveitis means inflammation of the uvea, inside the eye, which is made up of three parts: the iris, the ciliary body and the choroid. Uveitis can affect one or more of the three parts of the eye; and depending upon where the inflammation occurs, the uveitis is categorized into:

  • Anterior uveitis: affecting the front chamber of the eye (the most common form).
  • Intermediate uveitis: affecting the middle section of the uvea.
  • Posterior uveitis: affecting the rear of the uvea.
  • Panuveitis: affecting all three parts of the uvea.

Uveitis can be a serious ocular condition. It can be acute, recurrent or chronic and can affect anyone of any age. It is a treatable condition, but if left untreated or undertreated it can result in blindness, illustrated by the fact that uveitis is the third leading cause of preventable blindness worldwide. For this reason, patients are urged to receive treatment from an ocular immunologist or uveitis specialist who has advanced training in inflammatory eye disease.

In the uk there are an estimated 9,000 uveitis sufferers, 10% of whom are children. There are many causes of uveitis, from autoimmune diseases to infections, but for 35% to 50% of people no cause is found and the uveitis is said to be idiopathic.

Vitreous (vit-ree-us) humour

The vitreous is a clear gel that fills the space between the lens and the retina – the vitreous cavity.  The vitreous is in contact with the retina and helps to keep it in place.  Aqueous fluid at the front of the eye is constantly renewed, but the vitreous is not.  Therefore, if inflammation of the pars plana, or choroid, or optic verve or retina occurs, and cells enter the vitreous humour, (known as vitritis), the patient can see specks or floaters, which can only be removed by surgery known as a vitrectomy.