PATHOGENESIS
Vernal keratoconjunctivitis (VKC) is a seasonally recurring, bilateral inflammation of the cornea and conjunctiva that occurs predominantly in young males, who frequently, but not invariably, have a personal or family history of atopy. The disease may persist year-round in tropical climates. The immunopathogenesis seems to involve both types I and IV hypersensitivity reactions. The conjunctival inflammatory infiltrate in VKC consists of eosinophils, lymphocytes, plasma cells, and monocytes.
Abu El-Asrar AM, Al-Mansouri S, Tabbara KF, Missotten L, Geboes K. Immunopathogenesis of conjunctival remodeling in vernal keratoconjunctivitis. Eye (Lond). 2006;20(1):71–79.
CLINICAL PRESENTATION
Symptoms consist of itching, blepharospasm, photophobia, blurred vision, and copious mucoid discharge. Clinically, 2 forms of VKC may be seen: palpebral and limbal.
The inflammation in palpebral VKC is located predominantly on the palpebral conjunctiva, where a diffuse papillary hypertrophy develops, usually more prominently in the upper region. Bulbar conjunctival hyperemia and chemosis may also occur. In more severe cases, giant papillae resembling cobblestones may develop on the upper tarsus (Fig 11-3).
Limbal VKC may develop alone or in association with palpebral VKC. It occurs predominantly in patients of African or Asian descent and is more prevalent in hot climates. The limbus has a thickened, gelatinous appearance, with scattered opalescent mounds and vascular injection. Horner-Trantas dots, whitish macroaggregates of degenerated eosinophils and epithelial cells, may be seen in the hypertrophied limbus of patients with limbal VKC (Fig 11-4).
Several types of corneal changes associated with upper-tarsal lesions may also develop in VKC. Punctate epithelial erosions in the superior and central cornea are frequently noted. Pannus occurs most commonly in the superior cornea, but occasionally 360° corneal vascularization may develop. Oval or shield-shaped noninfectious epithelial ulcers (the so-called shield ulcer) with underlying stromal opacification may develop in the superior or central cornea (Fig 11-5). An association between VKC and keratoconus has been reported. Stem cell deficiency may also occur in severe cases.
MANAGEMENT
Therapy should be based on the severity of the patient’s symptoms and the ocular surface disease. Mild cases may be successfully managed with topical anti-histamines. Climatotherapy, such as the use of home air-conditioning or relocation to a cooler environment, can be helpful. Patients with mild to moderate disease may respond to topical mast-cell stabilizers. In patients with seasonal exacerbations, these drops are typically started at least 2 weeks before symptoms usually begin. In patients with year-round disease, long-term maintenance dosing can be used. Severe cases may require the use of topical corticosteroids. Because of the likely development of corticosteroid-related complications from long-term administration, however, these drugs should be reserved for exacerbations that result in moderate to severe discomfort and/or decreased vision. During these exacerbations, intermittent (pulse) therapy is very effective. Topical corticosteroids can be used relatively frequently (eg, every 2 hours) for 5–7 days and then rapidly tapered. Because of the propensity of particles of suspended corticosteroid (eg, prednisolone acetate) to lodge between papillae, the use of less potent but soluble corticosteroids such as dexamethasone phosphate is generally preferred. Low-dose steroids can be useful in some cases for maintenance treatment of VKC. Whenever steroids are prescribed, the potential dangers of long-term topical corticosteroid use are critical to review to emphasize the importance of close follow-up and monitoring for adverse effects.
Cooperative patients can be offered an alternative to topical delivery that avoids the problem of continuing self-medication: supratarsal injection of corticosteroid. The supratarsal subconjunctival space is located superior to the upper border of the superior tarsus and is most easily reached by everting the upper eyelid. After the upper eyelid is everted and the supratarsal conjunctiva has been anesthetized, supratarsal injection of 0.5–1.0 mL of either a relatively short-acting corticosteroid such as dexamethasone phosphate (4 mg/mL) or a longer-acting corticosteroid such as triamcinolone acetonide (40 mg/mL) can be performed. Monitoring of intraocular pressure is mandatory, as corticosteroid spikes are possible. The importance of close follow-up with an eye care provider is essential to monitor for cataract formation or permanent vision loss.
Steroid-sparing agents have been shown to be effective. Topical cyclosporine 0.5%–2.0% applied 2–4 times daily, topical tacrolimus ointment 0.03%–0.10% applied twice daily, or tacrolimus suspension 0.10% can also be used to treat refractory cases of VKC. Reported adverse effects of cyclosporine include punctate epithelial keratopathy and ocular surface irritation. Systemic anti-inflammatory therapy should be reserved for very severe cases.
Harada N, Inada N, Ishimori A, Shoji J, Sawa M. Follow-up study on patients with vernal keratoconjunctivitis undergoing topical 0.1% tacrolimus treatment. Nippon Ganka Gakkai Zasshi. 2014;118(4):378–384.
Hazarika AK, Singh PK. Efficacy of topical application of 0.03% tacrolimus eye ointment in the management of allergic conjunctivitis. J Nat Sci Biol Med. 2015;6(Suppl 1):S10–S12.
Labcharoenwongs P, Jirapongsananuruk O, Visitsunthorn N, Kosrirukvongs P, Saengin P, Vichyanond P. A double-masked comparison of 0.1% tacrolimus ointment and 2% cyclosporine eye drops in the treatment of vernal keratoconjunctivitis in children. Asian Pac J Allergy Immunol. 2012;30(3):177–184.
Pucci N, Caputo R, di Grande L, et al. Tacrolimus vs. cyclosporine eyedrops in severe cyclosporine-resistant vernal keratoconjunctivitis: A randomized, comparative, double-blind, crossover study. Pediatr Allergy Immunol. 2015;26(3):256–261.
Sangwan VS, Jain V, Vemuganti GK, Murthy SI. Vernal keratoconjunctivitis with limbal stem cell deficiency. Cornea. 2011;30(5):491–496.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.