Allergic Conjunctivitis

Allergic conjunctivitis is a common, under-appreciated, and largely benign condition. Allergic conjunctivitis prevalence has increased over the past decade, making it one of clinical practice's most frequently encountered conditions. Allergic conjunctivitis results from various factors, including genetics, inflammation, air pollution, atopy, pollen exposure, and contact with pets. Allergic conjunctivitis can convert to keratoconjunctivitis and may result in a visual decline. While rarely posing a threat to vision, it can significantly impair patients' quality of life. Simple allergic conjunctivitis can be classified into 3 subtypes: acute, seasonal, and perennial. Additionally, allergic conjunctivitis encompasses a broad range of conditions, including seasonal allergic conjunctivitis (SAC), perennial allergic conjunctivitis (PAC), vernal keratoconjunctivitis (VKC), and atopic keratoconjunctivitis (AKC). While VKC and AKC exhibit distinct clinical and pathophysiological features from SAC and PAC, specific markers remain consistent. Giant papillary conjunctivitis (GPC) is another condition that arises from contact lens use or ocular prostheses-related microtrauma. Treatment and certain aspects of pathophysiology show considerable overlap between atopic conjunctivitis (VKC, AKC) and giant papillary conjunctivitis. Therefore, these conditions are all classified as ocular allergies. Initial treatment strategies may be similar, although outcomes and complication rates vary.