for more severe forms of allergic conjunctivitis such as vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC). VKC and AKC Both vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC) are chronic allergic diseases wherein eosinophils, conjunctival fibroblasts, epithelial cells, mast cells, and TH2 lymphocytes aggravate the biochemistry and histology of the conjunctiva. VKC is a disease of childhood and is prevalent in males living in warm climates. AKC is frequently observed in males between the ages of 30 and 50. VKC and AKC can be treated by medications used to combat allergic conjunctivitis or the use of steroids. Maxwell-Lyons sign, shield ulcer, cobblestones papillae, gelatinous thickening at the limbus, and Horner-Trantas dots are specific features of vernal type. Giant papillary conjunctivitis Giant papillary conjunctivitis is not a true ocular allergic reaction and is caused by repeated mechanical irritation of the conjunctiva. Repeated contact with the conjunctival surface caused by the use of contact lenses is associated with GPC. PKC Phlyctenular keratoconjunctivitis (PKC) results from a delayed hypersensitivity/inflammatory reaction to antigens expressed by various pathogens. Common agents include Staph. aureus, Mycobacterium tuberculosis, Chlamydia and Candida. Management A detailed history allows doctors to determine whether the presenting symptoms are due to an allergen or another source. Diagnostic tests such as conjunctival scrapings to look for eosinophils are helpful in determining the cause of the allergic response. Antihistamines, mast cell stabilizers or dual activity drugs are safe and usually effective. Corticosteroids are reserved for more severe cases of inflammation, and their use should be monitored by an optometrist due to possible side-effects. When an allergen is identified, the person should avoid the allergen as much as possible. Non-pharmacological methods If the allergen is encountered and the symptoms are mild, a cold compress or artificial tears can be used to provide relief. Mast cell stabilizers Mast cell stabilizers can help people with allergic conjunctivitis. They tend to have delayed results, but they have fewer side-effects than the other treatments and last much longer than those of antihistamines. Some people are given an antihistamine at the same time so that there is some relief of symptoms before the mast cell stabilizers becomes effective. Doctors commonly prescribe lodoxamide and nedocromil as mast cell stabilizers, which come as eye drops. A mast cell stabilizer is a class of non-steroid controller medicine that reduces the release of inflammation-causing chemicals from mast cells. They block a calcium channel essential for mast