What are the other Names for this Condition? (Also known as/Synonyms)

• CMV Retinitis
• Retinitis due to Cytomegalovirus Infection

What is Cytomegalovirus Retinitis? (Definition/Background Information)

• Retinitis is an eye condition that results in the inflammation of the retina from various causes. When the condition develops due to infection by cytomegalovirus (CMV), a universally found pathogen belonging to the herpes virus family, it is known as Cytomegalovirus Retinitis or CMV Retinitis
• The retina is a layer of tissue situated at the back of the eye that helps in sensing light. When the blood supply to the retina is blocked, it will not be able to receive enough blood and oxygen leading to a loss of vision
• Cytomegalovirus Retinitis is a progressive and potentially vision-threatening inflammatory eye disease, especially in individuals who are immunocompromised. The condition is mostly associated with individuals who have active HIV infections or AIDS
• The signs and symptoms of Cytomegalovirus Retinitis may include slow loss of peripheral and central vision, eye flashes and floaters, and sensitivity to light. A healthcare provider may use physical exams, eye exams, blood and body fluid culture, and imaging scans to diagnose CMV Retinitis
• In a majority with healthy immune system, cytomegalovirus infection is self-resolving and may not require any treatment. In those with severe symptoms (mostly immunocompromised patients), the treatment measures for Cytomegalovirus Retinitis may include antiviral medication for CMV infection and therapy for retinitis with oral/systemic medication and corticosteroids, as necessary. In some, regular medical checkup and prophylactic treatment may be recommended to prevent recurrences
• The prognosis of Cytomegalovirus Retinitis is dependent upon various factors, but is good in many cases with appropriate treatment. However, in those with poor immune system, the prognosis may be unpredictable, since the condition can be progressive and recurrent. Without treatment, it can severely damage the retina and optic nerve resulting in permanent vision impairment. Incidentally, CMV Retinitis is the most common cause of blindness in individuals with AIDS

Who gets Cytomegalovirus Retinitis? (Age and Sex Distribution)

• Cytomegalovirus Retinitis can affect individuals of any age; however, almost all cases are reported from individuals who have poor immune function (immunocompromised status)
• Both males and females are affected and no gender predilection is noted
• Individuals of different racial and ethnic backgrounds may be affected and no particular preference is noted; although, a vast majority of the cases are reported from the developing nations and only a few from the developed nations

What are the Risk Factors for Cytomegalovirus Retinitis? (Predisposing Factors)

The risk factors for Cytomegalovirus Retinitis may include a variety of conditions such as:

• All individuals with a weak immunity and exposed to the CMV virus have a very high risk. Such individuals include:
  • HIV infected and AIDS patients; almost 85% of CMV Retinitis cases are reported among this subset of individuals
  • Patients who have undergone any organ or bone marrow transplantation (on immunosuppressant drugs)
  • Patients undergoing  immunosuppressive therapy for a variety of reasons, resulting in reduced blood lymphocyte count
  • Individuals with cancer or those undergoing chemotherapy for cancer
• Those undergoing repeated blood transfusions for conditions, such as myelodysplastic syndrome, or chronic kidney failure requiring kidney dialysis for prolonged periods
• Individuals on chronic steroid therapy (either low or high dosage), for a diverse set of health issues
• Infected pregnant women have a high risk of transmitting the causative pathogen to their offspring during pregnancy or at the time of childbirth
• Healthcare workers administering to such patients or newborn babies are at a high risk; since, CMV spreads through close physical contact
• Chronic alcohol dependence
• Severe malnourishment, such as protein deficiency, or Kwashiorkor

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one's chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Cytomegalovirus Retinitis? (Etiology)

Cytomegalovirus Retinitis occurs from exposure of the body to the microorganism cytomegalovirus (CMV); when the virus travels to the eye, it causes an inflammation of the retina resulting in retinitis.

• It is reported that the most common cause of retinitis is cytomegalovirus infection. The condition is always only noted in individuals with a compromised or poor immune system.
• The CMV viruses are latently present in most humans (in about 60-80% of the human population). However, the virus remains inactive, since healthy humans have a strong and robust immune system
• In those, who have a highly susceptible or compromised immune system, the cytomegalovirus gets reactivated and can affect many body areas, such as the eyes, gastrointestinal tract, nervous system, etc.

An involvement of the retina is usually preceded by a condition known as uveitis, which occurs from damage to a part of the eye structure called uvea (pigmented layer of the eye consisting of the iris, ciliary body, and choroid).

What are the Signs and Symptoms of Cytomegalovirus Retinitis?

The signs and symptoms of Cytomegalovirus Retinitis may vary between the individuals and can either occur suddenly or over a period of time. The signs and symptoms may include:

• Progressive loss of vision: Usually, a loss of peripheral vision is noted; although occasionally, it can also result in loss of central vision
• Nyctalopia or night vision loss; unable to see in dim light
• Blurred vision
• Eye floaters: The individuals experience illusions that some small objects such as spots, hairs, or strings are moving in the eye; the floaters are often slow onset, developing over a period of days
• Flashes in the eye: Sudden appearance of ‘flashing’ bright lights causing vision distortion (photopsia)
• Light-sensitivity (photophobia)
• Impaired color vision
• Eye pain, in some cases
• The condition usually affects one eye (unilateral), but both the eyes (bilateral) may be involved by the infection
• Signs and symptoms associated with uveitis may be noted

According to some studies, the condition can be asymptomatic in over 50% of the individuals and present no noticeable symptoms, especially during the initial stages.

How is Cytomegalovirus Retinitis Diagnosed?

A healthcare professional may diagnose Cytomegalovirus Retinitis using the following tests and procedures:

• Physical examination and analysis of previous medical history
• Eye examination by an eye specialist (ophthalmologists or retinal experts)
• Blood tests that include the following:
  • To check for the presence of antibodies in blood
  • Blood culture for infections
  • Complete blood count (CBC) with differential
  • Erythrocyte sedimentation rate (ESR)
  • CMV DNA serum PCR test (a special blood test)
  • CMV antibody test, to understand how the body reacts to the CMV virus
• Antibody titer in aqueous humor and vitreous humor fluid samples
• Test of body fluids for cytomegalovirus
• Fundoscopic (ophthalmoscopic) examination by an eye specialist, who examines the back part of the eye (or the fundus)
• Visual acuity test using a special and standardized test chart (Snellen chart)
• Slit-lamp examination: Examination of the eye structure using a special instrument called a slit-lamp. In this procedure, the pupils are dilated and the internal eye structure is examined
• Tonometry: Measurement of intraocular pressure or eye fluid pressure, especially to detect conditions such as glaucoma
• Fundus fluorescein angiography (FFA): In this technique, the eye blood vessels are examined using a fluorescein dye
• Fundus autofluorescence (FAF): It is a non-invasive diagnostic technique to examine the fundus of the eye without using a fluorescent dye by a specialized fundus camera 
• Indocyanine green (ICG) angiography: It is used to examine the blood vessels of the choroid using a dye, called indocyanine green, particularly to study the choroid
• B-scan ultrasonography: Special ultrasound scan of the eye through a non-invasive diagnostic tool, to assess health of eye structures
• Electroretinogram (ERG): It is a technique to measure electrical activities in the retinal cells
• Optical coherence tomography (OCT) of eye: It is an ocular imaging technique to visualize the eye structure
• Tests to determine the underlying condition causing Retinitis

There are 3 classical forms of Cytomegalovirus Retinitis described:

• Pizza or cottage cheese with ketchup retinopathy: Here, there are confluent areas of retinal necrosis with hemorrhages seen mostly in the posterior pole of the eye. Such areas of necrosis expand causing full thickness retinal necrosis, reactive glyosis, and pigment epithelial atrophy
• Indolent type: Here, there is granular peripheral retinal lesion with minimal to no hemorrhages
• Frosted branch angiitis: In this type, the retinal blood vessels are involved along-with uveitis, retinal edema, and loss of vision

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Cytomegalovirus Retinitis?

The complications of Cytomegalovirus Retinitis may include:

• Complications that develop from uveitis
• Glaucoma: A condition that can cause blindness due to higher intraocular pressure
• Cataracts: When the lens of the eye becomes clouded and cause vision loss
• Retinal detachment: An eye condition wherein the retina gets separated from the eye structures that holds the retinal layers together; over 35% of the individuals with CMV Retinitis reported retinal detachment, when about 25% of the retina was involved
• Over time and due to a lack of proper treatment, the condition can affect other surrounding eye structures such as the lens, optic nerve, and vitreous fluid
• Retinal neovascularization: It can result in loss of partial vision
• Retinal vasculitis: Inflammation of the retinal arterioles (small blood vessels)
• Vision loss: Retinitis can lead to permanent damage to the eye structure and cause blindness, if it is left untreated
• Recurrent Retinitis: The condition may recur if the underlying infectious cause is not identified and treated adequately

How is Cytomegalovirus Retinitis Treated?

Early diagnosis and treatment of Cytomegalovirus Retinitis is extremely crucial in preventing complications that may result in irreversible damage to the eye. In general, the management would involve arresting progression of the condition and addressing the underlying causative condition and associated symptoms, with the goal of preserving vision.

A treatment of cytomegalovirus infection may include:

• Individuals with immunodeficiency viruses have shown improvement with antiretroviral therapy drugs that are normally prescribed for AIDS and HIV infections
• Intravenously or orally administered antiviral medications are effective in treating patients with weak immunity systems, caused by conditions other than HIV infection or AIDS
• Medication with nutritional supplementation are normally adequate to aid in recovery for newborn babies and individuals with weak immune systems
• Healthy individuals, adults, and children may not require any treatment, if no symptoms are present
• If healthy individuals are mildly affected, medical help should be sought and certain basic self-care steps to recovery followed, such as having plenty of fluids and adequate rest

The treatment measures for retinitis may involve:

• Use of eye drops and oral antiviral medications (including pain medications)
• Oral corticosteroids to control inflammation; steroids may also be administered intravenously depending on the underlying cause. It should be started 24 to 48 hours after the initiation of anti-viral medications
• Dark glasses may be prescribed for light-sensitivity
• In case of chronic retinitis that fails to get better with medication, surgical procedures, such as vitrectomy or laser surgery, to treat the condition may be considered
• Visual rehabilitation
• Current research include advances in the use of stem cells and gene therapy to treat retinitis
• Long-term follow-up may be necessary to prevent recurrent infections, in some cases

How can Cytomegalovirus Retinitis be Prevented?

CMV infection can be prevented by averting immunodeficiency infections, providing adequate treatment and medical care after an organ transplant (especially lung or bone marrow), or when a body immunity system is weakened by other illnesses. Antiviral medications are effective against CMV infections in the immunocompromised.

The risks for Cytomegalovirus Retinitis may be lowered through the following measures:

• Practicing safe sex
• Washing hands with a hand sanitizer suitably at regular intervals, especially for individuals in the high-risk group
• Avoiding the use of commonly shared items, such as items used in the preparation of food and drink, towels and bedspreads, etc.
• Use of proper disposal techniques while handling tissues, diapers, other contaminated items; washing hands thoroughly after disposing them
• Avoiding actions, such as kissing or hugging, in a manner that puts you in direct contact with a child’s eyes, lips, and nose. Pregnant ladies have to be careful during pregnancy to minimize their risk for infections
• Screening organ donors for the presence of CMV
• Educate the immunocompromised patients and create an awareness of possible conditions, to enable them be better prepared and seek timely medical treatment
• Maintaining long-term follow-up to watch out for any recurrences

What is the Prognosis of Cytomegalovirus Retinitis? (Outcomes/Resolutions)

• The prognosis of Cytomegalovirus Retinitis depends on the following set of factors:
  • Overall health status of the individual, whether immunocompetent or immunocompromised
  • Severity of signs and symptoms and development of any complication(s)
  • Initiation of early diagnosis and treatment
• The condition is self-limiting in individuals with healthy immunities; it resolves within a few weeks and no treatment may be necessary
• Also, individuals who do not have severe signs and symptoms, lack complications, and generally respond well to treatment have a better prognosis
• In individuals with poor immune function, especially with AIDS or on immunosuppressive drugs, the visual prognosis may be guarded to poor

Additional and Relevant Useful Information for Cytomegalovirus Retinitis:

Please visit our Eye & Vision Health Center for more physician-approved health information:

http://www.dovemed.com/health-topics/vision-center/