Inflammation of the iris and associated structures - Iritis and Anterior Uveitis
Iritis and Anterior Uveitis: Iritis or anterior uveitis is an inflamatory condition at the front of an eye. The iris is the colored circle at the front of the eye, however there is a further section of the same tissue just behind it called the cilliary body. Both the iris and the cilliary body are part of the uveal body which lines the inside of the eye. The only part of the uveal body that is visible to the naked eye is the iris. Inflamation of any part of the uveal body is called uveitis. If the front part is inflamed then it is called anterior uveitis. Anterior uveitis is the most common form of uveitis. 60% of uveitis is anterior, 15% is intermediate, 20% is posterior, and 5% involves all of the uveal body.
How is iritis diagnosed?
The above image taken using a slit lamp shows an eye with iritis / anterior uveitis with KP – keratic precipitates. The KP shows as white dots on the center of the image. These dots are as a result of deposits of cells and protein on the back inside of the cornea = posterior cornea. The cornea is the front window of an eye. With uveitis inflamatory cells are being produced which float inside the eye. Protein is also being produced which is somewhat sticky and makes the cells bunch up. These collections of cells and protein stick to the posterior cornea and show as keratic precipitates. The same occurs at the area where the fluid drains out of the eye. This is called the trabecular meshwork. When the trabacular meshwork starts to become blocked the eye pressure increases. An increase in eye pressure is likely to lead to glaucoma.
The more cells and the more flare there is in the front of the eye the more severe the anterior uveitis (Iritis) is.
p.s. Iritis is the correct spelling, not Iritus 😉
Iritis and Anterior Uveitis
The above image shows cells in the anterior chamber at the front of an eye, just behind the cornea. The severity of the uveitis can be assessed by counting the cells using the slit lamp microscope. A grading system is used by an Optometrist and an Ophthalmologist for this. Symptoms resulting from iritis are covered by the local MECS scheme. MECS is an enhanced Optometric service in Essex, provided by Primary eycare Ltd.
The above image shows a cross section of the space between the cornea and the iris, there are cells and there is flare, typical of iritis / anterior uveitis. The cells are visible to the left of the image, just behind the cornea and the flare is visible all the way from the back of the cornea to the front of the lens. Flare shows as a grey band in the above image. This image is taken with the use of a slit lamp microscope, beam splitter and camera system.
Patients may also develop keratic precipitates = KP, which are deposits of cells at the inner surface of the cornea. these keratic precipitates typically distribute themselves in a triangular fashion, with the base of the prism at the bottom of the cornea.
Signs and Symptoms of Iritis:
Patients with iritis / anterior uveitis will notice the following symptoms in the rist instance: a gritty slightly red eye.
With time the eye will become painful, light sensitive and the vision will become blurry both for distance and for reading. Floaters will appear and eventually there will be significant vision loss if not treated. Secondary complications can also occur, the most common one is glaucoma as the the drainage of fluid out of the eye becomes compromised.
However, iritis can be treated very well in most cases. It is crucial to see an Optometrist as soon as possible if you notice any of the above signs. You will then be referred to an eye clinic for treatment urgently. For the correct diagnosis of anterior uveitis the use of a slit lamp in a dark room is crucial, a modern well equiped optometric practice will have access to a slit lamp. If you have iritis in the past you will know the early signs, don’t hesitate to call asap and see us for advice.
Background information for Anterior Uveitis:
About 10% of patients with artheritis / spondylitis have secondary uveitis.
Corneal infections and ocular herpes – shingles can also cause secondary uveitis.
40:100.000 patients have uveitis, so it is quite rare, but sight threatening if present.
Mean onset of age is around 40 years.
15 – 30 % of infectious choroiditis patients have secondary uveitis.