Classification of Subtypes of Vernal Keratoconjunctivitis by Cluster Analysis Based on Clinical Features

Background: Vernal keratoconjunctivitis (VKC) is a refractory ocular allergic disorder that mainly affects boys. A few studies have attempted to develop a classification of subtypes of VKC. In this study, we investigated a computational approach called cluster analysis to separate VKC cases into groups based on clinically relevant characteristics.Methods: In total, 41 consecutive patients clinically diagnosed with VKC at the Department of Ophthalmology of Fukuoka University Hospital were included. Patients were treated with immunosuppressive eye drops without simultaneous corticosteroid eye drops, except for the occurrence of exacerbations. Collated variables were age at onset, clinical score of ocular lesions at baseline, clinical score of ocular lesions at final visit, clinical score of atopic dermatitis (AD) at baseline, frequency of exacerbations of VKC, serum total IgE level and peripheral blood eosinophil count.Results: VKC patients were grouped into three clusters by cluster analysis, and cluster 1, 2, and 3 comprised 25, 9 and 7 cases, respectively. There were differences in the incidence of complications of AD and age at onset among the clusters; therefore, we named the three clusters for better understanding as traditional VKC (cluster 1), early-onset atopic keratoconjunctivitis (AKC)/VKC (cluster 2) and puberty-onset AKC (cluster 3).Conclusion: We found in this study that VKC in childhood has three phenotypes which were previously unknown. Our findings may help to establish precision medicine by focusing on the phenotype of each case to develop individualized medicine to prevent exacerbations.