Context: Allergy symptoms that affect the eyes are common in adults and children worldwide, and are often associated with nasal allergy symptoms, prompting the term 'rhinoconjunctivitis' to describe the condition. However, this condition has not always been recognized, and earlier literature reported allergic conjunctivitis only within a subset of nasal allergy patients.
Evidence acquisition: To assess the current state of ocular allergy epidemiology, pathophysiology, and currently available treatment options, we performed a MEDLINE search for articles regarding ocular allergy, rhinoconjunctivitis, vernal keratoconjunctivitis (VKC), atopic keratoconjunctivitis (AKC), and giant papillary conjunctivitis (GPC).
Evidence synthesis: The more severe forms of ocular allergy are not only distressing, but can also threaten a patient's vision. Each type of ocular allergy is associated with ocular redness, itching, and tearing; however, AKC and VKC can threaten the cornea, and research has revealed that involvement of different immune cell populations (mast cells, eosinophils, and lymphocytes) may cause these more severe symptoms. A variety of treatment options exist to control ocular allergy symptoms. Nonpharmacologic options include allergen avoidance and lubrication with saline, and if these fail to be sufficiently effective, symptom relief may be provided by medicinal agents that are either applied topically to the eye or taken orally. Recent evidence suggests that nasal allergy treatments applied topically to the nose may also positively affect ocular allergy symptoms, which raises the interesting possibility that a parasympathetic nasal-ocular neural reflex pathway may be involved in the stimulation of allergic responses in the eye.
Conclusions: Ocular allergy is underdiagnosed and has a significant impact on the life of the patient. It is vital to reach a better understanding of ocular allergic mechanisms and inflammation, which may lead to improved treatment.