Uvea is the part of the eye, which is a pigmented layer that lies between the inner retina and outer middle vascular structure of the eye. It consists of the iris, the ciliary body and the choroid. Uvea contains the most blood vessels of the eye. Chronic iridocyclitis and uveitis are conditions wherein there is an inflammation of the iris or uvea of the eye respectively. It is a medical emergency and needs an immediate medical attention.
What is Chronic Iridocyclitis or Uveitis?
Inflammation of the uvea is called Uveitis. The parts next to uvea include iris, retina, optic nerve, vitreous humour and sclera can also be affected. Chronic iridocyclitis is the subtype of uveitis where the iris and the ciliary body inflame due to certain reasons.
Classification of Chronic Iridocyclitis or Uveitis
- Classification of Uveitis Based on Anatomic Location: Depending on the anatomic location of uveitis, it is categorised as follows:
- Anterior Uveitis: It is the term used for the inflammation of anterior chamber and iris. When it involves inflammation of the anterior chamber and iris, it is called as Iritis.
- While when in addition to iritis, it involves inflammation of ciliary body it is called Iridocyclitis. It is the most common type that occurs in 90% of the cases of uveitis and is the most painful.
- Intermediate Uveitis: It is the term for inflammation of the cells of the vitreous humour, which is the middle part of the eye.
- Posterior Uveitis: It is the term for inflammation of the retina and choroid, and even the optic nerve, which make up the posterior part of the eye. It is the least common type of all uveitis.
- Pan Uveitis: It the term for inflammation of all the layers of the eye. It is the most serious form of uveitis. It is one of the most common causes of the Behcet's disease, which causes serious damage to the retina.
Intermediate, posterior and pan uveitis most affect the vision and are recurrent forms.
- Classification of Uveitis Based on Severity of the Condition: Depending on it severity it is of three different types:
- Acute: It has a fast or a sudden onset and lasts for less than three months.
- Chronic: It has a slow onset and lasts for more than three months
- Recurrent: Even after treatment, uveitis comes back or relapses. Recurrence is very common.
Signs and Symptoms of Chronic Iridocyclitis or Uveitis
The symptoms of chronic iridocyclitis or uveitis vary depending on the location of it. The symptoms based on the location are as follows:
- Symptoms of Anterior Chronic Iridocyclitis or Uveitis: Generally anterior chronic iridocyclitis or uveitis affects only one eye. It involves symptoms such as:
- Symptoms of Intermediate Chronic Iridocyclitis or Uveitis: Both the eyes are usually affected and the symptoms are –
- Painless blurred vision
- Floaters observed
- Symptoms of Posterior Chronic Iridocyclitis or Uveitis: One eye is affected and symptoms take longer to develop. The symptoms of this type of chronic iridocyclitis or uveitis are –
- Painless blurred vision
- Floaters observed
- In some cases severe loss of vision.
Epidemiology of Chronic Iridocyclitis or Uveitis
Chronic iridocyclitis or uveitis occurs in age group 20-59 years and is less common in children. It can affect any age group and does not have predilection to gender. Uveitis affects 1 in 4500 people. In western countries anterior iridocyclitis or uveitis accounts for 50% and 90% of cases while in Asian countries it ranges between 20-50% cases. In developed countries, uveitis causes visual impairment in approximately 1 in 10 people. It is most dangerous in the colder months of the year.
Prognosis of Chronic Iridocyclitis or Uveitis
In case of anterior chronic iridocyclitis or uveitis, prompt treatment is needed once detected. The earlier the diagnosis, the better is the prognosis and quickly it gets treated. However, chronic iridocyclitis or uveitis recurs when the underlying cause is an autoimmune disease. Intermediate and posterior chronic iridocyclitis or uveitis lasts for a longer time and these are recurrent in nature. They have to be under long term care of an eye-specialist with regular eye check-ups. When uveitis is caused by an infection, it gets cleared by treatment and does not recur. The type of uveitis along with severity, duration and their response to the treatment all impact the prognosis of chronic iridocyclitis or uveitis.
Causes and Risk Factors of Chronic Iridocyclitis or Uveitis
Both external and internal factors can cause iridocyclitis or uveitis. The following are the causes:
- Autoimmune Diseases: Chronic Iridocyclitis or uveitis can be caused by Behect's diseases, rheumatoid arthritis, Reiter's syndrome, ankylosing spondylitis.
- Inflammatory diseases such as psoriasis, inflammatory ulcerative colitis
- Infections caused by Toxoplasma, HIV, Syphilis, Herpes virus, Cytomegalovirus, gonorrhoea and tuberculosis.
- Iatrogenic Causes of Chronic Iridocyclitis or Uveitis: It is caused due to side effects from medical treatment or due to blow or wound in the eye.
- Cancers such as leukemia, lymphoma, and ocular melanoma.
- While in some cases chronic iridocyclitis or uveitis can be idiopathic, that is there is no known cause for its occurence.
Pathophysiology of Chronic Iridocyclitis or Uveitis
The presence of autoimmune and infectious diseases predisposes people to have iridocyclitis or uveitis. Additionally, genetic, traumatic or infectious mechanisms promote uveitis. However, the cause of chronic iridocyclitis or uveitis is often unknown. In case of trauma, the combination of microbial contamination and accumulation of necrotic products at the site of injury triggers inflammatory reaction.
While in case of the infections, an immune reaction directed at foreign molecules may injure the uveal tract vessels.
Complications of Chronic Iridocyclitis or Uveitis
If iridocyclitis or uveitis is not treated well, then it can lead to blurring of vision and eventually there is loss of vision. Complications include:
- Formation of bands of tissue (synechiae) due to inflammation in between the iris and the lens.
- Macular oedema
- Retinal detachment.
Diagnosis of Chronic Iridocyclitis or Uveitis
The doctor or eye specialist checks for the symptoms, records the medical history and performs testing of the vision to know the difference between both the eyes since in all types of uveitis, the vision will worsen.
The examinations of the eye include:
- An eye chart to measure if the patient's vision has decreased.
- A funduscopic examination is done to check if the pupil is widened (dilated) by passing a light through the eye to check the back and inside part of the eye.
- Ocular pressure is checked by means of an instrument such as tonometer or tonopen to measure pressure inside the eye.
- A slit lamp (a special microscope) noninvasively inspects all parts of the eye to check for the signs of inflammation.
- The corneal epithelium is inspected for abrasions, edema, and ulcers.
- The aqueous humour is checked properly. Normally it is optically clear. In case of the uveitis, it becomes opaque due to the accumulation of the protein content which causes flare during examination.
- If there is any underlying problem then further investigations are required such as tests of Optical Coherence tomography (OCT) which takes special pictures of the eye.
- Blood tests are done to check if any infections or any autoimmune disease is present.
- Radiology X-ray may be used to check coexisting arthritis and chest X-ray may be helpful in detection of sarcoidosis.
Treatment of Chronic Iridocyclitis or Uveitis
The treatment depends on the type of chronic iridocyclitis or uveitis the person is suffering. Any treatment aims to relieve pain and discomfort in the eyes and treat the underlying cause and reduce inflammation. It also prevents further tissue damage and restores the lost vision. The treatment may involve directly treating the eye or it may involve taking the drugs orally.
- Steriod Eye Drops to Treat Chronic Iridocyclitis or Uveitis: To reduce inflammation, intake of steroid drugs is necessary. The examples include prednisolone and dexamethasone. Steroids are given as:
- Topical Steroids: Topical steroids include eye drops and ointments containing steroids.
- Periocular Steroids: These are given as injections and are administered locally around the eye.
- Oral steroids: These are used in extreme cases of iridocyclitis or uveitis in which eye drops or injections have failed to give relief.
However, steroids are never to be given in case of the underlying eye infection.
- Treatment to Relieve Pain and Discomfort due to Chronic Iridocyclitis or Uveitis:
- Cycloplegic eye drops are given to relieve pain.
- For patients who eyes are light sensitive or show symptoms of photophobia they are advised to wear dark glasses.
- In case of eye pain, taking of painkiller such as paracetamol is suggested.
- Immunosuppressive Medicines for Treating Chronic Iridoctyclitis or Uveitis: These drugs help to control side effects of steroids and control iridocyclitis or uveitis.
- Biological Agents to Treat Chronic Iridocyclitis or Uveitis: TNF Alpha blockers such as Etanercept and Infliximab are used especially for treating iridocyclitis or uveitis occurring due to Behcet's disease.
- Treating Underlying Cause or Condition that Caused Chronic Iridocyclitis or Uveitis: In case, chronic iridocyclitis or uveitis happens due to any autoimmune disease or an infection that must be treated to cure uveitis.
- Surgery to Cure Chronic Iridocyclitis or Uveitis: Surgery is used only in case of persistent uveitis.
Anterior chronic iridocyclitis or uveitis is generally treated with steroid containing eye drops and with eye drops that dilate the pupil. In case of intermediate, posterior and pan chronic iridocyclitis or uveitis, the treatments often include injections around the eye, medications given by mouth or in some cases timed release capsules are surgically implanted inside the eye. In some instances immunosuppressive agents may be given. For any of the above treatment the doctors must ensure that the person is not suffering from an eye infection as the treatment would completely vary.
Prevention of Chronic Iridocyclitis or Uveitis
- Prevention of infectious diseases
- Timely treatment for the underlying disease
- Avoiding eye injuries
- Increasing immunity
- Immediately contacting an eye specialist after noticing the first sign of inflammation.
Any diseases related to the eye must be identified and treated immediately. The failure to do so can result in permanent loss of vision. In case of chronic iridocyclitis or uveitis too, it cannot be self-treated, and needs to be treated by an eye specialist. Timely treatment promotes good prognosis and prevents complications in future.