Epidemiological and scanning‐slit topography variables in keratoconus

Purpose To identify and to correlate epidemiological and scanning‐slit topographical variables of keratoconus in a homogeneous caucasian population from Valladolid, Spain. Methods Retrospective, cohort study of a group of keratoconic patients followed at the Ocular Surface Unit in the Hospital Clínico Universitario de Valladolid. Clinical records were reviewed to get information about: age, gender, central corneal thickness (CCT), thinnest corneal thickness (TCT), anterior best fit sphere (aBFS), posterior best fit sphere (pBFS), steepest simulated K (SSK), flattest simulated K (FSK), mean k at 3 and 5 mm (M3, M5), irregularity index at 3 and 5mm (II3, II5) and topographical pattern in the keratometric map. Correlation analysis were made among the variables mentioned above. Results Two hundred and two patients were included, 116 men and 86 women. There were differences in CCT (p<0,001), TCT (p<0,001), aBFS (p<0,001), pBFS (p<0,001), SSK (p<0,001), FSK (p<0,001), M3 (p<0,001) and M5 (p<0,001) between men and women. There was no correlation between age and the other studied variables (p>0,05). The most prevalent topographic pattern was asymmetric bow tie with skewed radial axes (ABT SRAX) (34,1%), followed by inferior steepening (32,7%). The central nipple pattern presented the more advanced values in all the studied variables. Conclusion Keratoconus is more frequent in males, however, women revealed more advanced values in scanning‐slit topography variables. Sex could be a prognostic factor in the evolution of keratoconic patients from Valladolid.