Intermediate Uveitis - A Descriptive Review

Introduction

Vision plays an essential role in carrying out daily activities. Eyes contain delicate structures that help in processing colors and surroundings. As it contains delicate structures, it can easily be harmed, and care has to be taken. Intermediate uveitis is a condition that causes inflammation in the uvea. Symptoms can range from the blurring of the vision to loss of vision. It can cause various complications also that need to be managed. Treatment approaches should be chosen wisely to achieve the proper result.

What Is Uvea?

Uvea is the middle layer of the eyeball which is pigmented. It consists of three parts, namely,

iris (colored portion of the eye), ciliary body (part of the eye helping in focusing the lens), and choroid (part of the eye connecting the retina to the sclera).

What Is Uveitis?

Uveitis is the inflammation present inside the eye. Inflammation or redness occurs when there is a reaction between the immune system and the infection occurs. In some cases, the immune system attacks the healthy part of the eye. It causes pain, vision loss, and redness. Uveitis damages the uvea of the eye and other adjacent structures. It can be present for a short term or prevail for a longer duration.

Depending on the location of uveitis, it can be categorized into the following:

• Anterior uveitis.

• Intermediate uveitis.

• Posterior uveitis.

• Panuveitis.

Anterior uveitis affects the front portion of the eye at the iris. It is usually a less serious and common type.

Posterior uveitis affects the choroid and retina at the back of the eye.

Panuveitis affect all the structures of the uvea.

What Is Intermediate Uveitis?

Intermediate uveitis (IU) affects the vitreous part, peripheral retina, and the ciliary body of the eye. It also has various names, such as peripheral uveitis, chronic posterior cyclitis, and peripheral uveoretinitis.

What Are the Causes of Intermediate Uveitis?

The cause cannot always be identified. The following are a few known causes of intermediate uveitis.

• Autoimmune Diseases - Sarcoidosis, multiple sclerosis, and inflammatory bowel disease are some autoimmune diseases that can cause IU.

• Infections - Include mycobacterium tuberculosis, Lyme disease, leprosy, syphilis, and Whipple disease.

• Cancers - Lymphomas (cancer of the lymphatic system) can also cause Intermediate uveitis.

Are Children Affected by Intermediate Uveitis?

Idiopathic IU is seen to be occurring in most cases of the pediatric group. The cause of intermediate uveitis is unknown. Bilateral intermediate uveitis is seen to be affecting a larger group of cases.

What Are the Symptoms of Intermediate Uveitis?

• Blurry vision or floaters in mild cases.

• Eye pain.

• Sensitivity to light.

• Red eyes.

• Keratic precipitates are present.

• Posterior synechiae may or may not be present.

• Vitritis.

• Vitreous snowballs (inflammatory aggregates are also present).

In severe cases, they present with vision loss as the floaters get aggregated in the vitreous along with snow banking.

What Is the Diagnosis for Intermediate Uveitis?

Diagnosis of the IU is based mainly on clinical examination and clinical findings.

Proper medical history of the condition's onset and recurrence of the disease should be noted.

Laboratory tests and imaging procedures need not be mandatory for diagnosis.

• Complete Blood Count - A blood test can detect the presence of any infection.

• Chest X-ray is taken to look for abnormal findings and rule out tuberculosis.

• Computed Tomography - A CT scan is done to rule out pulmonary sarcoidosis.

• Fluorescein Angiography - It is a diagnostic procedure that detects the presence of vasculitis.

• Ultrasound Biomicroscopy (UBM) - UBM demonstrates the presence of exudates and cell aggregates.

• Ultrasonography (USG) - USG is a diagnostic tool that helps to rule out intraocular tumors.

• Vitrectomy - This process is a therapeutic and diagnostic procedure done when the presence of tumors is suspected.

What Are the Complications of Intermediate Uveitis?

IU shows its complications due to its presence over long periods. When left untreated, it leads to vision loss.

• Glaucoma - Damage of optic nerve leading to defective or loss of vision.

• Cataracts - Formation of a cloudy portion in the lens leads to cataracts resulting in blurred vision.

• Macular Edema - Leakage of blood vessels leads to macular edema formation.

• Maculopathy - A disease related to the retinal part of the eye.

• Retinal Vasculitis - Vasculitis is the inflammation of the vessels. Blood vessels present in the eye lead to retinal vasculitis.

What Is the Treatment for Intermediate Uveitis?

The treatment approach is directed towards eliminating the cause in the first place. Malignancies need to be ruled out.

1) Drug Therapy

• Corticosteroids - Periocular corticosteroids are the first choice. Long-acting Methylprednisolone or Triamcinolone acetonide is given. Complications followed by injections are to be monitored and managed accordingly. Oral corticosteroids come into a role when local corticosteroids fail to act.

2) Immunomodulatory Therapy

It is a therapy aimed at diseases that affect the immune system.

Methotrexate, Cyclosporin, and Tacrolimus can be used in treating IU.

Anti-proliferative drugs or Anti metabolites: Folate analog, Methotrexate is administered either subcutaneously or orally. Azathioprine is administered daily orally, which alters the purine metabolism.

3) Inhibitors of T Cell Signaling:

Cyclosporin, Tacrolimus, Biologic response modifiers, and Daclizumab are the drugs that inhibit T-cell signaling.

4) Surgical Therapy:

• Laser Photocoagulation and Cryotherapy: When drug therapy does not work, recurrent inflammation is seen despite the use of drug therapy. Cryotherapy is performed by

• Vitrectomy: This surgical procedure opts in patients with chronic inflammation. Vitrectomy improves the visual outcome and reduces inflammation.

• Cataract: Cataracts occur as a complication of corticosteroid therapy or chronic inflammation. Cataract surgery and intraocular lens implantation were done to control the inflammation.

The treatment procedure can be concluded in five steps, as listed under.

Step 1 - Steroids are administered with a local injection every four weeks.

Step 2 - When local therapy is ineffective, oral corticosteroids are administered.

Step 3 - When corticosteroids fail, systemic immunomodulatory therapy is indicated.

Step 4 - Indirect laser photocoagulation or cryotherapy is indicated when immunomodulatory therapy is contraindicated.

Step 5 - Upon failure of all the treatment approaches to achieve the best result, posterior hyaloidal separation is performed along with immunomodulatory therapy.

Conclusion

Intermediate uveitis is a condition that leads to defective vision. Minor symptoms, when noticed, should be brought to the physician's notice. Symptoms can worsen, leading to further complications that make the treatment hectic and vast. Treatment approaches are chosen wisely and further proceeded.