Cromolyn may be effective in the management of several allergic eye diseases. All of these disorders appear to involve mast cells and eosinophils. These conditions include seasonal allergic conjunctivitis, vernal keratoconjunctivitis, atopic keratoconjunctivitis, and giant papillary conjunctivitis. Nedocromil is more efficacious than cromolyn in the treatment of vernal keratoconjunctivitis and is effective in patients whose chronic symptoms of allergic conjunctivitis are not controlled fully by cromolyn. Ocular preparations of nedocromil, however, are not commercially available in the United States. Current evidence supports preferential use of topical antihistamines (e.g., azelastine, levocabastine, or olopatadine) or mast cell stabilizers (e.g., lodoxamide) for allergic eye conditions.
Ocular cromolyn therapy is virtually as effective as oral antihistamines for seasonal allergic conjunctivitis. It reduces itching, stinging, and photosensitivity. Therapeutic response in seasonal allergic conjunctivitis may be related to allergen-specific IgE antibody levels.
As with other allergic diseases, the drug should be started when the patient is relatively free of symptoms. It is administered at a dose of one to two drops four times daily. Ocular cromolyn is not effective acutely. However, it can also be used prophylactically before specific allergen exposure.
Vernal keratoconjunctivitis is recurrent, bilateral, interstitial inflammation of the conjunctivae that occurs more frequently in warm, dry climates. Most affected patients develop symptoms before puberty and symptoms usually resolve by 25 yr of age. Symptoms of severe itching, tearing, burning, mucoid discharge, and photophobia may occur perennially but are characteristically worse during spring and summer months. Abnormalities may include giant papillae on upper tarsal conjunctivae, corneal plaques, scarring, and decreased visual acuity.
Several studies indicate that ocular cromolyn is effective for vernal keratoconjunctivitis. Beneficial effects seem to occur within 1 wk of initiating therapy and are manifested by decreased pruritus and mucus secretion. The dosage is one to two drops four times daily. Nedocromil is significantly more effective than cromolyn in treating vernal keratoconjunctivitis and is more effective in controlling keratitis, reducing the need for additional topical corticosteroid treatment.
Atopic keratoconjunctivitis is the ocular counterpart to atopic dermatitis. However, only a small percentage of patients with atopic dermatitis develop atopic keratoconjunctivitis. Associated symptoms include severe itching, burning, mucoid discharge, and photosensitivity. Cataracts and keratoconus may develop. Double-blind placebo-controlled crossover studies have shown beneficial effects of cromolyn on discharge, photophobia, papillary hypertrophy, and both limbal and corneal changes. In addition, dosage reductions for topical corticosteroids have been reported.
Evidence suggests that giant papillary conjunctivitis is triggered by an inflammatory response to any foreign substance, such as a contact lens or ocular prosthesis, which irritates the upper tarsal conjunctivae. Because pathological changes are similar to those seen in allergic eye disorders, cromolyn has been employed. A reduction in symptoms and an increased tolerance to contact lens wear has been demonstrated in many patients. The dose is the same as for other ocular disorders. Affected patients should discontinue contact lens wear while the condition persists and should consider switching to disposable contact lenses once it resolves.
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