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Bulgarian Review of Ophthalmology

Topometric indices in patients with corneal ectasia and healthy controls

Angel Atanasov, Marin Atanasov, Marieta Konareva-Kostyaneva


Purpose: To determine the diagnostic value of the topometric indices and their role in diagnosing corneal ectasia.

Patients and methods: Using corneal topography OCULUS Keratograph 5M  we examined  80 eyes of 43 patients with corneal ectasia and 86 eye of 43 patients with no signs of corneal disease. We evaluated the topographic maps and the following indices generated by the device: Rv(Vertical radius), Rh (horizontal radius), Кmax, ISV (Index of Surface Variance),  IVA- (Index of Vertical Asymmetry), KI - (Keratoconus Index), CKI- (Center Keratoconus Index ), RMin (Minimal radius),

IHA-(Index of Height Asymmetry), IHD- (Index of Height Decentration), ABR( Aberration). The statistical analyzis was performed by SPSS version 15 and the following test: (Mann–Whitney U test) и ROC (Receiver Operating Characteristic Analysis).

Results: Statistically significant difference was found for all of the examined parameters p<0.001 using 95% confidence interval. The ROC analysis determined area under the curve in the range from 0,992 for ABR and IHA to 0,927 for CKI.

Conclusion: The topometric indices have excellent capabilties in differentiating ectatic from normal corneas.


keratoconus, marginal pelucid degeneration, ectasia

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About The Authors

Angel Atanasov
Medical University of Plovdiv

Marin Atanasov
Medical University of Plovdiv

Marieta Konareva-Kostyaneva
Medical University of Plovdiv