Season – More common in summer. Hence, the name Spring catarrh is a misnomer. Recently it is being labelled as Warm weather conjunctivitis. Climate – More prevalent in the tropics. VKC cases are mostly seen in hot months of summer, therefore, more suitable term for this condition is "summer catarrh" Ref. Pathology
Conjunctival epithelium undergoes hyperplasia and sends downward projection into sub-epithelial tissue. Adenoid layer shows marked cellular infiltration by eosinophils, lymphocytes, plasma cells and histiocytes. Fibrous layer show proliferation which later undergoes hyaline changes. Conjunctival vessels also show proliferation, increased permeability and vasodilation. Diagnosis
Classification
Based on severity, authors have classified VKC into clinical grades:Grade 0 - Absence of symptoms
Grade 1 MILD - Symptoms but no corneal involvement
Grade 2 MODERATE - Symptoms with photophobia but no corneal involvement
Grade 3 SEVERE - Symptoms, photophobia, mild to moderate SPKs OR with Diffuse SPK or corneal ulcer

Treatment
Local therapy- Topical steroids are effective. Commonly used solutions are of fluorometholone, medrysone, betamethasone or dexamethasone. Mast cell stabilizers such as sodium cromoglycate (2%) drops 4–5 times a day are quite effective in controlling VKC, especially atopic ones. Azelastine eyedrops are also effective. Topical antihistamines can be used. Acetyl cysteine (0.5%) used topically has mucolytic properties and is useful in the treatment of early plaque formation. Topical Cyclosporine is reserved for unresponsive cases. Systemic therapy- Oral antihistamines and oral steroids for severe cases. Treatment of large papillae- Cryo application, surgical excision or supratarsal application of long-acting steroids.
General measures include use of dark goggles to prevent photophobia, cold compresses and ice pack for soothing effects, change of place from hot to cold areas. Desensitization has also been tried without much rewarding results. Treatment of vernal keratopathy- Punctuate epithelial keratitis require no extra treatment except that instillation of steroids should be increased. Large vernal plaque requires surgical excision. Ulcerative vernal keratitis require surgical treatment in the form of debridement, superficial keratectomy, excimer laser therapeutic keratectomy, as well as amniotic membrane transplantation to enhance re-epithelialisation. Recently treatment with tacrolimus ointment (0.1%) used topically twice daily is showing encouraging results. See also
Conjunctivitis
Allergic conjunctivitis

References
Further reading
Khurana, A. K. (2014). Comprehensive ophthalmology. Anshan. ISBN 978-1-84829-072-3. == External links ==