Measles Infection of the Eye: Conjunctivitis, Corneal Ulcers, Blindness

Understanding Measles Infection of the Eye

Measles is a highly contagious viral infection that can have severe effects on the eyes. Measles can cause several types of eye infections and damage that in some cases can lead to permanent vision loss. Understanding how the measles virus affects the eyes and the symptoms to look for can help get prompt treatment.

Conjunctivitis

One of the most common eye manifestations of measles infection is conjunctivitis, or pinkeye. Up to 60% of people with measles develop viral conjunctivitis, which causes:

• Redness in the whites of the eyes
• Itchy, irritated eyes
• Burning sensation in the eyes
• Excessive tear production
• Yellow, mucus-like discharge

Measles conjunctivitis usually occurs in the early stages of the illness along with fever, cough, runny nose and the characteristic head-to-toe rash. The conjunctivitis normally resolves on its own without treatment as the measles runs its course.

Corneal Ulceration and Scarring

Another potential complication of measles virus infection is corneal ulceration, erosion and scarring. The measles virus can directly infect the outer layer of the cornea, causing:

• Painful corneal ulceration
• Corneal erosion and loss of the outer epithelial layer
• Corneal haze and opacification
• Corneal vascularization and scarring
• Secondary bacterial infection

This corneal damage leads to significantly impaired vision. Measles-induced corneal ulcers and scarring occurs more frequently in malnourished children and those with vitamin A deficiency.

Optic Neuritis

The optic nerve, which transmits visual information from the eye to the brain, can also fall victim to direct invasion of the measles virus. Measles optic neuritis causes:

• Pain with eye movement
• Loss of color vision
• Diminished visual acuity
• Visual field defects
• Impaired pupil responses
• Complete blindness if bilateral

If not treated promptly, measles optic neuritis can result in permanent optic nerve damage and vision loss.

Retinitis and Chorioretinitis

Two other serious eye conditions associated with measles are retinitis, inflammation of the retina, and chorioretinitis, inflammation of the choroid layer behind the retina. Symptoms include:

• Blurry vision
• Floating spots in vision
• Sensitivity to light
• Eye pain
• Reduced visual acuity

Retinitis and chorioretinitis can create permanent blind spots and vision impairment. Timely treatment is key to try to limit damage and preserve vision.

Causes and Risk Factors for Measles Eye Infections

Measles is caused by a single-stranded RNA virus in the paramyxovirus family. The virus spreads through respiratory droplets and directly infects the epithelial surfaces of the upper respiratory tract, eyes, and GI tract. But how does it actually cause eye problems?

Direct Viral Infection

The measles virus can directly invade and destroy epithelial cells of the conjunctiva, cornea, retina, choroid, and optic nerve. Cell breakdown causes inflammation, ulceration, and impaired function.

Suppressed Immune System

Measles virus proliferates by suppressing the host's immune responses. This suppression leaves eyes vulnerable to unchecked viral replication, secondary infections, and disabling damage.

Post-Infection Autoimmunity

Some eye complications like optic neuritis may be caused by an autoimmune reaction triggered by measles. The body mistakenly attacks the optic nerves weeks after measles infection has cleared.

Nutritional Deficiencies

Malnutrition and vitamin A deficiency in particular increase the risks of severe eye problems like corneal ulceration and blindness. Vitamin A helps maintain the epithelial surfaces the virus targets.

Delayed Treatment

The longer the eyes are infected with the replicating measles virus, the greater the viral destruction, inflammation, and loss of vision. Prompt treatment is vital.

Diagnosing Measles Infection of the Eyes

Doctors use a combination of approaches to diagnose eye involvement in measles:

Patient History

Information about characteristic measles symptoms 1-2 weeks earlier like fever, cough, rash, and conjunctivitis help identify the cause.

Visual Acuity Assessment

Eye charts measure sharpness of vision to detect functional impairment signaling problems like keratitis, retinitis, or optic neuritis.

Eye Exam

Slit lamp exam reveals signs of conjunctivitis, corneal ulcers, inflammation, and scarring. Ophthalmoscopy shows retinal/choroidal involvement.

Fluorescein Staining

Yellow fluorescein dye applied to the eyes highlights scratches, ulcers, and areas of epithelial erosion on the cornea.

Measles Serology

Blood tests measuring measles virus-specific IgM antibodies confirm recent infection.

Eye Swab PCR

Polymerase chain reaction (PCR) of secretions from the eye can detect traces of the measles virus's genetic material.

Treating Measles Infection of the Eyes

Treatment aims to curb the replicating measles virus, manage eye inflammation/damage, and prevent permanent vision impairment. Options may include:

Vitamin A Supplements

High-dose vitamin A helps strengthen epithelial surfaces in eyes vulnerable to measles damage. The WHO recommends vitamin A for all measles patients.

Antiviral Medication

Oral antivirals like acyclovir may be given to fight the measles virus directly, especially in severe eye infections.

Corticosteroid Eye Drops

Steroid eye drops reduce inflammation and irritation from conjunctivitis, keratitis, uveitis, and optic neuritis.

Antibiotic Eye Drops

Topical antibiotics prevent or treat secondary bacterial infection of the eyes, which can worsen damage.

Dark Glasses

Wearing dark glasses helps protect eyes sensitive to light due to retinitis and other photophobia-inducing infections.

Surgery

In advanced cases, corneal transplant or glaucoma surgery may be needed to try to preserve vision disabled by measles eye complications.

Preventing Measles Infection of the Eyes

The most effective form of prevention is vaccination. The MMR (measles-mumps-rubella) vaccine prevents over 95% of measles infections and their disabling effects on eyesight. Other preventive strategies include:

• Timely MMR vaccination of children
• Ensuring MMR immunity before travel
• Isolation of infected patients
• Containing outbreaks through contact tracing
• Vitamin A supplementation in deficient regions
• Supportive nutrition and hydration
• Following up suspected measles with prompt eye exams
• Seeking medical treatment rapidly if eye symptoms manifest

Global vaccination efforts continue to be the best hope for eliminating measles and the threat of permanent vision loss from associated eye complications.

Prognosis for Measles Eye Infections

The prognosis depends greatly on the severity of eye involvement and how quickly treatment is initiated. Some key points about the prognosis include:

• Conjunctivitis usually resolves fully without permanent damage
• Mild corneal scarring may heal with minimal vision loss
• Severe corneal scarring can impair vision permanently
• Optic neuritis often improves with steroid treatment
• Retinitis and chorioretinitis can cause permanent blind spots
• Vision loss is more likely if treatment is delayed
• Measles blindness is largely preventable with vaccination

Ongoing research aims to develop more effective antiviral medications to limit vision damage from measles eye infections when they do occur.

The Importance of Measles Vaccination for Eye Health

Given the potential for permanent vision impairment, vaccination to prevent measles infection is extremely important for eye health. Reasons to prioritize measles immunization include:

Measles Spreads Rapidly

Measles is among the most contagious viruses worldwide, spreading through airborne droplets with ease. Outbreaks can quickly get out of control.

Eye Damage Has Serious Consequences

Permanent blindness, corneal scars, chronic light sensitivity, and lifelong vision deficits profoundly reduce quality of life.

Eye Problems Peak in Young Children

Corneal scarring and blindness due to measles predominantly affects children under 5 years old.

Global Measles Deaths Are High

Despite progress, measles still caused over 140,000 deaths globally in 2018 - most preventable by vaccination.

MMR Vaccine Is Safe and Effective

Over 50 years of monitoring proves the MMR vaccine's excellent safety record and ability to prevent disease and blindness.

Coverage Gaps Allow Outbreaks

Suboptimal vaccine coverage permits periodic measles outbreaks, threatening unvaccinated eyes.

It Takes High Population Immunity

At least 95% of people need MMR immunity to protect vulnerable individuals and stop transmission.

The Outlook for Measles Eye Infections

In regions with high vaccination rates like the Americas, measles eye infections are now rare. However, gaps in coverage lead to outbreaks across Europe, Africa, and Asia where corneal/retinal measles complications persist. Continued vaccination efforts are needed for a future free from measles blindness.

Ongoing research also aims to:

• Develop new oral and topical antivirals to minimize eye damage
• Test vitamin A and omega-3 fatty acid supplements for protection
• Perfect corneal transplant and stem cell techniques to repair scars
• Engineer methods to regrow damaged optic nerves
• Better understand and prevent post-infection autoimmune eye disease

While progress has been made, measles eye infections will remain a threat until this highly contagious virus is globally controlled through vaccination, so that one day no child suffers permanent blindness from measles again.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.