Evaluation of the corneal topographic characteristics of keratoconus with orbscan II in patients with and without atopy

Purpose: To analyze the differences in corneal topography in keratoconus patients with and without atopy. Methods: In the Beyoglu Eye Research and Training Hospital Refractive Surgery Department, corneal examination with the Orbscan H device (Bausch & Lomb) was done to all patients between May and June 2004 who were diagnosed as keratoconus with corneal topography findings and who did not have any surgical procedure. The atopy grading was done according to the criteria of the UK Atopy Study Group (1994). Patients were divided into 2 groups according to the presence of atopy. The Orbscan findings of the 2 groups were compared. Results: Among 70 keratoconus patients, 33 patients had partial or full atopy. Sixty-six eyes of the 33 patients were classified as the atopic group, whereas 74 eyes of the remaining 37 patients were classified as the control group. The mean age of the patients was 27.7 +/- 9.5 years in the atopic group and 26.9 +/- 9.5 years in the control group. The central corneal thickness was 428.5 +/- 37.1 mu m in the atopic group and 491.8 +/- 56.3 mu m in the control group. There was a statistically significant difference between the mean central and thinnest corneal pachymetric readings, the distance of thinnest point to corneal center, anterior and posterior elevation values, distances of the anterior and posterior elevation to the central cornea, and irregularity indexes in the 2 groups (P < 0.05). Conclusions: This study shows that corneal topographic and pachymetric characteristics of keratoconus may be different in atopic eyes from those in nonatopic eyes. Atopic keratoconus patients could possibly be evaluated as a separate entity in keratoconus disease.