Incidence of keratoconus in subjects with vernal keratoconjunctivitis: A videokeratographic study

Purpose: To detect the incidence of keratoconus by videokeratography in pat ients with vernal keratoconjunctivitis (VKC) and to evaluate the clinical c haracteristics of VKC associated with keratoconus, Design: A prospective, cross-sectional (prevalence) study. Participants: Eighty-two consecutive subjects with the diagnosis of VKC, Methods: Both eyes of VKC subjects were investigated by videokeratography i n comparison with slit-lamp biomicroscopy and keratometry, To detect kerato conus, corneal topography maps were examined with modified Robinowitz-McDon nell test. Main Outcome Measures: In this test, maps with central corneal power greate r than 47.2 diopters and/or the inferosuperior asymmetry value greater than 1.4 were considered to have a keratoconus pattern. The findings of VKC wer e also recorded. Results: The distribution of clinical forms of VKC were as follows: 46.34% mixed, 43.90% palpebral, and 9.76% limbal types. Twenty-six (31.7%) of 82 s ubjects had complications with kerotopathy such as pseudogerontoxon, puncta te keratitis, and shield ulcer. Forty-four eyes (26.8%) were detected as ke ratoconus by quantitative evaluation of videokeratography maps, 14 eyes (8. 5%) by biomicroscopy, and 30 eyes (18.3%) by keratometry, The increased inc idence of keratoconus was associated with male gender, long-standing diseas e, mixed and palpebral forms, and advanced corneal lesions. Conclusions: The higher incidence of keratoconus in our study compared with the previous reports may result from early detection of mild keratoconus b y interpretation of color-coded videokeratographic maps with a sensitive qu antitative method. (C) 2001 by the American Academy of Ophthalmology.