Eye Infections: Symptoms, Causes and Types

Eye infections occur when harmful microorganisms such as bacteria, fungi, and viruses invade any part of the eyeball or the surrounding area.

This includes the eye’s clear front surface ( cornea ) and the thin, moist membrane that lines the outer eye and the inner eyelids (conjunctiva).

Symptoms of red-eye infection

  • Ocular pain
  • Crying eyes.
  • Dry eyes .
  • Sensitivity to light.
  • Swollen eyes.
  • Itch.
  • Blurry vision.

Every time you suspect an eye infection, you should always visit your ophthalmologist for an eye exam. Trying to self-diagnose your condition can delay effective treatment and potentially damage your eyesight.

How an infected eye looks

An endophthalmitis is a severe form of eye infection and inflammation. If you wear contact lenses, you should only use your glasses until you have visited your eye doctor to receive a diagnosis and treatment.

There are many different types of eye infections, and your ophthalmologist needs to determine the particular kind of eye infection you have to be able to prescribe the proper treatment.

Your doctor may take a sample from the affected area of ​​your eye for a culture to evaluate the exact type of infection you have, if any. This can help determine the most effective treatment, such as an antibiotic that selectively targets the type of bacteria that causes the disease.

Causes and types of eye infections

Examples of viral, fungal, and bacterial eye infections include:


Pink eye or conjunctivitis

Conjunctivitis, also called “pink eye” is a common and highly contagious eye infection that is often transmitted to children in daycare centers, classrooms, and similar settings.

Teachers and daycare workers are also at greater risk of having eye problems when working in enclosed spaces with young children.

The common types of infectious conjunctivitis often have viral or bacterial origins.

Babies can also acquire conjunctival eye infections (gonococcal and chlamydial conjunctivitis) when a mother has a sexually transmitted disease—other viral eye infections (viral keratitis).

In addition to the common pink eye, other viral eye infections include ocular herpes, which occurs with exposure to the Herpes simplex virus.

Fungal keratitis

This type of eye infection made worldwide news in 2006 when a contact lens solution that was now being withdrawn from the market was linked to an outbreak among contact lens wearers.

Fungal eye infection was associated with fungi, commonly found in organic matter.

This and other fungi can invade the eye in different ways, such as through a penetrating wound caused by the branch of a tree.

Acanthamoeba keratosis

Contact lens wearers have a higher risk of encountering parasites that can invade the eye and cause a severe and eye-threatening infection called Acanthamoeba keratitis.

Contact lens wearers should observe specific safety tips, such as avoiding swimming with contacts placed. If you wear contact lenses while swimming or relaxing in a hot tub, remove and disinfect your lenses immediately afterward.

There is an increased risk of fungal and bacterial eye infections among contact lens wearers, and proper care of contact lenses should be followed.

FDA guidelines recommend that manufacturers include a discard date (not just an expiration date) on cleaning and disinfecting contact lenses to minimize the risk of eye infection.


Although uncommon in the United States, an eye infection known as trachoma, related to Chlamydia trachomatis, is so widespread in certain underdeveloped regions that it is one of the leading causes of blindness.

Flies can spread the infection in unhealthy environments, and reinfection is a common problem. Trachoma usually infects the inner eyelid, which begins to heal.

The scarring causes a “twist” of the eyelid, and the lashes begin to graze and destroy the corneal tissue, with resultant permanent blindness.

Good hygiene and the availability of treatments such as oral antibiotics are essential to control trachoma.


When an eye infection penetrates the inside of the eye, as with bacterial endophthalmitis, blindness can occur without immediate treatment, often with potent antibiotics.

This infection can occur with a penetrating eye injury or a rare eye surgery complication such as cataract surgery.

Each time the eyeball is penetrated and injured significantly, there is a 4 to 8 percent risk of endophthalmitis.