Introduction  

Retinitis is a degenerative retinal disorder that can lead to permanent vision impairment.

Retinitis pigmentosa (RP) is the most common form of this eye disease. RP is a family of rare, genetic eye conditions that bring about the deterioration and breakdown of cells in the retina. It is a chronic eye condition which causes gradual degeneration of the retina resulting in visual impairment.

The patient may inherit RP from either or both parents. Retinitis pigmentosa affects 1 in 4000 people worldwide. When the eye disorder sets in and how fast it progresses varies from patient to patient. Often, RP starts in childhood, and a majority of the patients with the condition lose much of their vision by early adulthood. By the age of 40, many of the patients are legally blind.

Sub-Types

  • Retinitis pigmentosa (RP) 
  • CMV retinitis 
  • Infectious retinitis
     

Causes and Risk Factors

Retinitis pigmentosa involves both eyes and is an inherited disorder. Once one eye is affected, the other eye also develops the disorder within some years.

Infectious retinitis is due to infection by bacteria, fungi, parasites or viruses such as herpes zoster virus (HZV) and herpes simplex virus (HSV).

The herpes virus,  cytomegalovirus (CMV), causes CMV retinitis. It is in the same viral group as the viruses that cause infectious retinitis. CMV causes no known harm to most people.  However, it can be reactivated in people with weak immune systems causing retinitis.

Some of the factors that increase the risk of infectious retinitis include:  

  • People with a family history of retinitis pigmentosa 
  • A compromised immune system
  • Exposure to endemic areas
  • Active maternal infection during pregnancy or childbirth.
     

Signs & Symptoms

Often, the signs of retinitis pigmentosa start in childhood or early teen years. The symptoms differ from person to person. The common retinitis pigmentosa symptoms may include:

  • Loss  of central vision, which also affects color vision
  • Glare
  • A gradual loss of side vision
  • Trouble reading print 
  • Difficulty figuring out detailed images
  • Loss of night vision 

The symptoms of CMV retinitis and infectious retinitis may include:

  • Loss of side vision 
  • Loss of central vision (which affects reading ability and color vision) 
  • Clouds or specks (floaters) 
  • Blurred vision 
  • Sensitivity to light
  • Red and painful eyes

The symptoms may progress slowly or appear all over a sudden. The disorders could also be asymptomatic (showing no symptoms).

Diagnosis

The eye care professional takes a full health history of the patient and performs an eye exam. To make a diagnosis, he/she may do the following tests:

  • Electroretinography 
  • Color vision test
  • Visual field testing
  • Refraction test, for the patients who needs glasses
  • Eye ultrasound
  • OCT
  • Genetic test

For a specific diagnosis, a laboratory analysis of the patient’s blood and fluid samples may be necessary.

Treatment 

Treatment is aimed at addressing the underlying cause of the disorder.

Medical Treatment

Treatment for retinitis pigmentosa depends on the symptoms and the general health and age of the patient. It also depends on the severity of the disease. The eye doctor may prescribe eye drops in some cases. They may also recommend supplements including lutein, vitamin A and omega-3 fatty acid DHA.

For CMV retinitis, doctors treat the retinitis and strive to strengthen the patient’s immune system. Antiviral medication may be prescribed. 

At times, oral or intravenous medications are necessary for the treatment of infectious retinitis. The doctor may also use injections to administer local therapy into the eye. 

Surgical Treatment

In advanced cases of retinitis pigmentosa, surgery may be necessary to replace the retina. 

Laser therapy or surgery may be indicated for some cases of CMV retinitis and infectious retinitis.

Prognosis/Long-term outlook

Retinitis pigmentosa is a progressive eye disorder which means it gets worse with time. The patient may lose eyesight slowly or quickly.

Herpetic viral infections are more severe and may cause retinal detachment.

People with RP should try vision rehabilitation therapy. It can help them to use the vision they have more effectively.

Prevention/Follow Up

Using UV sunglasses can protect the retina and may help to delay the start of retinitis pigmentosa symptoms.

A healthy diet and regular exercise can boost the immune system and help prevent 
CMV retinitis