In a recent article published in the New England Journal of Medicine (NEJM) on May 7, 2015, the Ebola virus was detected in the eye of a 43-year-old physician 9 weeks after he was cleared of the virus in his blood stream. After several symptoms presented in his left eye, including blurred vision with halos, sensitivity to light, eye pressure, and even change in eye color from blue to green, doctors determined that the Ebola survivor was suffering from a condition known as uveitis, or inflammation within the eye. Upon further evaluation, the patient’s ocular fluid unexpectedly tested positive for the Ebola virus. Fortunately, his vision was saved, responding well to a combination of ophthalmic drops. Interestingly, while the virus remained undetected in the patient’s blood after 9 weeks, the virus persisted in “immune privileged” sites such as his testes as well as the left eye.
Immune privileged sites like the eyes, testes, and brain are unique in that they are generally protected from bodily infections, as they possess a barrier to prevent migration of infectious agents such as viruses, bacteria, or fungi. Specifically, immune privileged sites like the eye do not have the normal immune response to infection as other parts of the body. What may be an evolutionary trait in safeguarding vision, the eye’s innately low inflammatory response to infection prevents damage to the intricate and essential structures of the eye at the time of infection. How is it then that viruses like Ebola and other infectious agents manifest in the eye if it is “immune privileged?”
“In the uveitis community we were all surprised to learn that inflammation within the eyes of Ebola patients is from persistence of the virus in the eye. Prior to the recent publication in NEJM we were under the impression that such inflammation is likely from an immune mediated process and not from persistence of the virus,” said Dr. Narsing Rao, Professor of Ophthalmology and Director of Uveitis Service and Ophthalmic Pathology Laboratory at USC Roski Eye Institute Keck School of Medicine.
Cause of Infections of the Eye
- Immune compromised individuals such as those with HIV, cancers of the blood, on immunosuppressed medications, or even individuals who have weakened immunity due to sickness, are more susceptible to eye infections as their ocular immune systems become insufficient. “Although your eyes have a natural defense mechanism in place to prevent infection, when our immunity is compromised you are still vulnerable to attack from any number of infections which can include viruses, bacteria or even fungi,” said Dr. Rao.
- Those who wear contact lenses are at risk of infections of the ocular surface, due to low oxygen levels to the cornea (outermost part of the eye) or if the lenses have not been appropriately cleaned allowing build-up of infective agents.
- Infection through physical transfer of certain viruses, bacteria, parasites or fungi may occur simply by touching other exposed and infected areas, then touching your eyes. Although we currently do not know whether the Ebola virus was transmitted through physical contact or migration across the blood-ocular barrier, the treating doctors were at least able to accurately determine the underlying cause.
Infections occur in all parts of the eye (see table below)
Infections of the eye can occur in one or both eyes and in individuals of all ages. Typically, those who have ocular infections may describe redness, irritation, discharge, swelling around the eyelid and eye, pain and possible loss in vision.
|Type of Ocular Infection||Area of Inflammation|
|Conjunctivitis||Surface of the eye|
|Keratitis||Cornea, the transparent outermost part of the eye|
|Uveitis||Uvea, the inner layer of the eye|
|Vitritis||“Jelly-like” ocular fluid in the eye|
|Neuroretinitis||Optic nerve and retina|
Common Infections of the Eye
Viral infections like adenoviral conjunctivitis, commonly known as “pink eye” is one of the most common eye infections worldwide. The Herpes family of viruses can affect the eye in a number of ways. Activation of the herpes simplex virus may result in serious infections of the cornea, often leading to persistent scarring. Reactivation of the herpes zoster (chickenpox) virus, can produce a characteristic pattern of infection in and around the eye.
- Other viruses include: Cytomegalovirus, hepatitis B, mumps, measles, influenza,
Bacterial infections of the eye such as Chlamydia and gonorrhea also cause eye infections. Most notably women with such STIs may transfer these to their newborns.
- Other bacteria include: Staphylococcus, Streptococcus, Cat scratch disease, syphilis, tuberculosis, leprosy, lyme
Fungal infections can affect any part of the eye. Ocular histoplasmosis syndrome (OHS), a fungal infection of the lungs, is caused by inhaling spores. The fungus can migrate to the retina, causing subsequent visual impairment.
- Other fungal infections include: Candida, the fungus that causes thrush and yeast infections, aspergillus, cryptococcus , and mucormycosis
Tips to preventing Eye infections
- Wash your hands thoroughly before touching your eyes or face
- Thoroughly clean your contact lenses, store in clean containers, and use fresh solutions without sharing
- Do not share your makeup, face towels, or any eye drops
- Wear protective eyewear outdoors or in a workplace where there may be hazards
- Seek medical attention immediately if you notice symptoms of a suspected eye infection
- Always use protection to prevent STI
Here at the USC Roski Eye Institute, Department of Ophthalmology, we have a spectrum of doctors with expertise in the diagnosis and treatment of a wide variety of eye infections.
Next, read about our patient stories.