Official ESCRS | European Society of Cataract & Refractive Surgeons


Deviation of cone apex from pupil center (chord μ) in eyes with keratoconus depending on cone location based on Kmax

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Session Details

Session Title: Presented Poster Session: Corneal Cross-Linking

Venue: Poster Village: Pod 3

First Author: : K.Kisza UK

Co Author(s): :    M. Kubrak-Kisza   M. Nanavaty                    

Abstract Details


To compare the deviation of cone apex from pupil center (chord μ) in keratoconus patients depending on cone location in the view of potential cross-linking and surface ablation treatment for progressing keratoconus.


Sussex Eye Hospital, Brighton and Sussex University Hospital NHS Trust, UK


This is an retrospective observational study. Keratoconus was classified as central (central 3mm optical zone), paracentral/peripheral (> 3mm optical zone) based on X and Y coordinates of Kmax. The chord μ parameter, which is a distance from corneal apex to pupil center displayed in polar coordinates, was obtained from Pentacam XL's topometric/keratoconus staging display from central 8mm zone.


There were 20 eyes (10 patients) in this study. 10 eyes with central cones and 10 eyes with paracentral/peripheral cones. For central cones the mean chord μ value was 0.49±0.21mm (0.2-0.85), for paracentral/peripheral 0.57±0.17mm (0.33-0.9). There was no statistically significant difference between keratoconus groups (p=0.16).


There are no significant differences in position of corneal apex in relation to pupil center in keratoconus eyes with different cone locations based on Kmax. Potential surface ablation procedures for treatment of keratoconus are not likely to be affected by different cone locations.

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