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Eye Infection Symptoms

Eye Infection Symptoms

Eye infections affect everyone at some point of time. Some of these infections resolve on their own, while some may require medical intervention. This article outlines the symptoms of some common infections of the eye.
Rajib Singha
Last Updated: Apr 17, 2018
Breast milk may be a natural home remedy for pink eye, especially in babies. Although, this treatment is not backed up by clinical research, there is a fair amount of anecdotal evidence that vouches for its efficacy.

Eye infections are caused by bacteria, viruses or fungi. They can infect one or both eyes. In most cases, an infection that begins in one eye, usually spreads to the other eye. Eye infections may occur in people of all ages. However, children and young adults are affected more often. The symptoms of an eye infection, in most cases, may mimic those that indicate eye problems caused by irritants or allergens.

Common Eye Infections and their Symptoms


Conjunctivitis, known to most people as pink eye, is most commonly caused by a viral or bacterial infection of the conjunctiva, which swells up and reddens, and hence the name. Conjunctivitis may also be caused by allergens, chemicals, or dry eyes. A viral or bacterial conjunctivitis may trigger the following symptoms:
  • Itchiness
  • Swollen eyelids
  • Excessive tearing
  • Reddening of the white of one or both eyes
  • Feeling of a grain of sand being stuck under the eyelids
  • A stinging pain in the eyes when they are exposed to wind
  • Watery discharge (usually indicates a viral infection)
  • Thicker, yellow-green discharge (usually indicates a bacterial infection)
Causal Pathogen -
  • Adenovirus, Herpes virus
  • Staphylococcus, Haemophilus influenzae type b (Hib), Bartonella henselae, Neisseria gonorrhoeae (bacteria)


Sty, also known as hordeolum, is a bacterial infection that mostly affects the lower or the upper eyelid. Mostly, the outside portion of an eyelid has the sty. However, in some cases, the same can also form on the inner part of an eyelid. The main symptom of this eye infection is a red pimple-like bump that forms on the lower or the upper eyelid. Other symptoms  include:
  • Painful swelling of the part where the sty has formed
  • Watery eyes
  • Red eyes
  • A yellow spot, filled with pus along the edge of an eyelid
Causal Pathogen - Staphylococcus bacteria.


A relatively severe eye infection than the two mentioned above, trachoma is caused by bacteria. According to an estimate made by the World Health Organization (WHO), this infection is responsible for causing blindness in nearly 8 million people across the world. One important factor that contributes to the severity of this infection, is perhaps, its early symptoms  which are too mild to raise any concern. Trachoma usually begins with:
  • Irritation in the eyes and eyelids; it is usually mild
  • Eye discharge; pus or mucus
Without treatment, the infection starts causing more severe symptoms, which include:
  • Photophobia; increased sensitivity to light
  • Pain in the eyes
  • Ingrown eyelashes; eyelashes start turning back so that they scratch the cornea. This causes intense itching in the eyes
  • Scarring of the cornea; with time, the ingrown eyelashes start scarring the cornea, causing cloudy vision
  • Complete blindness, if the scarring is left untreated
Causal Pathogen - Chlamydia trachomatis (similar to the bacteria that cause chlamydia).


The iris and the pupil are covered by a transparent tissue called the cornea. Some factors may cause inflammation in this tissue, causing a condition called keratitis. It may be caused by infectious or non-infectious agents. Infectious keratitis may be caused by bacteria (bacterial keratitis), viruses (viral keratitis), fungi (fungal keratitis) or parasites (parasitic keratitis). Keratitis causes the following symptoms:
  • Red or bloodshot eyes
  • Watery eyes
  • Eye pain; mild to severe
  • Blurred vision
  • Sensitivity to light
  • Increased tearing, discharge from the eyes
  • White to gray areas on the cornea
  • Itching
Keratitis is also known as corneal ulcer.

Causal Pathogen -
  • Herpes simplex, Herpes zoster (viruses)
  • Fusarium, Aspergillus, Candida (species of fungi)
  • Streptococcus, Pseudomonas, Enterobacteriaceae, Staphylococcus (bacteria)
  • Acanthamoeba (parasite)

As we can infer from the above information, most of the eye infections have similar symptoms. So, self-diagnosing a particular infection may be difficult. While pink eye and sty are usually mild and self-resolving, keratitis and especially, trachoma are more severe infections. So, if you suspect that your symptoms are persisting, severe or getting worse, see your doctor. When it comes to eyes, never take any chances. Take care!

Disclaimer: The information provided in this article is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.