Definition & Overview

An eye allergy is a common condition that affects millions of people worldwide. Similar to respiratory and skin allergies, an eye allergy occurs when the body’s immune system detects germs, bacteria or allergens and fights back resulting in an allergic reaction. While the most common type of eye allergy won’t result in impaired vision, some types are more aggressive and could damage the sensitive parts of the eye if not treated promptly.

Most allergic eye problems are a result of a condition called allergic conjunctivitis, which results in the following symptoms: itching, red eyes, a burning sensation, and swollen eyelids. This condition can be relieved by simple treatment methods and does not result in impaired vision, mainly because the components of the eye that are used to receive light and transfer the signals to the brain aren’t affected. The parts of the eye that are most affected are the eyelids, eye membrane, and the white portion of the eye called the sclera.

There are two types of allergic conjunctivitis: seasonal and perennial. Seasonal allergic conjunctivitis (SAC), like the name suggests, only occurs in certain seasons as substances in the environment, such as pollens, act as the main trigger.

Perennial allergic conjunctivitis (PAC) also has triggers, but unlike SAC that only occurs during certain seasons, perennial allergic conjunctivitis can manifest itself the entire year. The triggers of PAC are mostly found indoors, such as dust mites and mold, but the condition can also be triggered by outdoor factors as well in some areas. The symptoms of PAC are considered to be milder than those of SAC.

Both SAC and PAC usually do not cause any major damage. However, severe eye allergies, such as vernal keratoconjunctivitis and atopic keratoconjunctivitis will result in impaired vision if not treated promptly.

Vernal keratoconjunctivitis is a more serious eye allergy that mostly affects young men. The condition can occur any time of the year and has symptoms similar to allergic conjunctivitis, but with several more including tearing of the mucus and sensitivity to light (photophobia).

Meanwhile, atopic keratoconjunctivitis affects mostly older men who have or previously diagnosed with allergic dermatitis. In addition to the symptoms similar to allergic conjunctivitis, patients with atopic keratoconjunctivitis may also experience a significant production of mucus that can result in the eyelids sticking together. The condition can result in the scarring of the cornea and may result in impaired vision.

Cause of Condition

Allergens and foreign substances are the most common causes of allergic eye problems. The environment is filled with airborne allergens, such as pollens from flowers, trees, grass, and weed. Although normally harmless, the body’s immune system considers allergens as threats and initiates an action to destroy them.

Allergens can also be found in the comfort of our own homes. These include dust mites, pet dander, and a variety of foreign substances can trigger an allergic reaction in some people. However, not everybody will have an allergic reaction to certain foreign substance. Some individuals will be able to manage pollens and foreign substances without experiencing an allergy.

Key Symptoms

The primary symptoms of an eye allergy are redness in the eyes, a burning sensation, watery eyes, and swollen eyelids. However, in severe conditions, the symptoms can also include sensitivity to light and impaired vision. An eye allergy may coincide with a nasal allergy, in which case, the symptoms would also include a runny nose, sneezing, a sore throat, headaches, or itchiness.

Who to See & Types of Treatment Available

Minor eye allergies will usually go away without medical treatment as long as the particular allergen is avoided. In most cases, antihistamine eye drops and over-the-counter pain medications are usually enough to treat the symptoms.

Patients with a severe form of an eye allergy, such as vernal keratoconjunctivitis or atopic keratoconjunctivitis, should consult an ophthalmologist. These types of allergies usually affect the cornea and unless they are treated by an ophthalmologist with access to the right equipment, the condition can worsen and result in vision problems.

In any type of eye allergy, the first step to treatment is always to avoid the particular allergen. Unfortunately, this is easier said than done due to the number of allergens. Patients will undergo several tests to identify the specific allergen. Once the allergen has been identified, the doctor can prescribe allergy shots that will slowly increase the patient’s resistance to that particular allergen.


  • Bhatt U, Lagnado R, Dua HS. Follicular Conjunctivitis. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology. 2013 ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013: vol 4, chap 7.

  • Snyder RW, Slade DS. Antibiotic Therapy for Ocular Infection. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology. 2013 ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013: vol 4, chap 26.

  • Yanoff M, Cameron D. Diseases of the visual system. In: Goldman L, Ausiello D, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 431.

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