In both of these inherited conditions, there is a tendency for the iris and the margin of the cornea to form slightly abnormally.
As a result, the place where the intraocular fluid drains back into the blood stream is less open and the pressure in the eye may rise causing a form of glaucoma. If that happens, treatment follows a similar line as for other types of primary open angle glaucoma.
In general, medical treatment is given by drops etc., but should the pressure in the eye remain at a level which causes deterioration in the field of vision, then surgery is likely to be considered.
Heterochromic cyclitis is a rare type of inflammation of the coloured tissue in the eye (iris and ciliary body) which in itself is mild but can be associated with occasional sudden rises in the eye pressure, i.e. secondary glaucoma.
Treatment aims to:-
Reduce the inflammation.
Bring down the pressure.
The inflammation is usually treated with steroids and pupil-dilating drops and the pressure is reduced by the use of glaucoma medications, most commonly beta blocking drops such as Betagan, Betoptic, Timoptol or Teoptic. Sometimes a different type of drop may be used on its own or in conjunction with the beta blocker.
In general, the condition has occasional recurrences but settles down eventually. Impairment of vision associated with cataract changes may occur in the affected eye. The cataract can, of course, be treated surgically should the need arise.
The condition may lead to the coloured part of the eye (the iris) being different in the two eyes due to depigmentation (heterochromic), hence the name of the condition.
The association between a port-wine stain on the face and scalp and raised eye pressure - the Sturge-Weber syndrome is an uncommon one and usually occurs at an early age, although it has occasionally been found to develop insidiously in young adults, or even in later life.
Mild cases can sometimes be controlled by medical treatment (usually eye drops) but in most cases surgery is necessary to improve the drainage of fluid from the eye.
The degree of glaucoma varies considerably from person to person and in these cases only the eye specialist who has examined the patient can judge what treatment is necessary for that individual.
The clear fluid in the eye, which is secreted from the ciliary body, passes through the pupil and drains away into the bloodstrean through a sponge-like meshwork which lies just in front of the iris.
When the iris is inflammed, protein and cells escape into the clear fluid, making the vision misty. The cells may be deposited as white dots (referred to as KP) on the inner surface of the clear cornea.
The number of cells is a measure of severity and sometimes there may be so many that they settle to form a sludge at the bottom of the fluid in front of the iris, this is called a hypopyon.
These cells and the protein may block the drainage of fluid through the aforementioned meshwork, causing the pressure in the eye to rise and form a secondary glaucoma.
The ciliary body is usually involved as well as the iris. The ciliary body contains a muscle which focuses the lens attached to it and inflammation of the focusing muscle and tissues may make it painful to change focus.
Adhesions may form between the iris and the lens which is just behind it. If the choroid is involved, there may be generally misty vision and floating black specks, lines and blobs in the field of vision, called floaters.
In most cases, uveitis is treated with mydriatics such as cyclopentolate, atropine (to dilate and rest the iris) and corticosteroids (steroids) such as Predsol or Betnesol (to reduce the inflammation).
The steroids may be given by mouth or, if the inflammation is severe, by injection under the conjunctiva, the membrane covering the white of the eye. If eye pressure rises, pressure lowering eye drop may be necessary and occasionally acetazolamide tablets (Diamox) may be given by mouth for a time. The treatment may have to be continued over a fairly long period although many cases settle down quite quickly.