International Journal of Keratoconus and Ectatic Corneal Diseases

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VOLUME 1 , ISSUE 3 ( September-December, 2012 ) > List of Articles


Correlation of Topometric and Tomographic Indices with Visual Acuity in Patients with Keratoconus

Isaac C Ramos, Bernardo T Lopes, Fernando Faria-Correia, Bruno de Freitas Valbon, Michael Wellington Belin, Renato Ambrósio

Citation Information : Ramos IC, Lopes BT, Faria-Correia F, Valbon BD, Belin MW, Ambrósio R. Correlation of Topometric and Tomographic Indices with Visual Acuity in Patients with Keratoconus. Int J Kerat Ect Cor Dis 2012; 1 (3):167-172.

DOI: 10.5005/jp-journals-10025-1032

Published Online: 01-08-2015

Copyright Statement:  Copyright © 2012; The Author(s).



To evaluate the correlations of Pentacam keratometric, topometric (derived from front surface curvature) and tomographic (derived from 3D corneal shape analysis) indices with best corrected visual acuity in patients with keratoconus.

Materials and methods

One eye randomly selected of 123 patients with bilateral keratoconus was retrospectively enrolled. All patients underwent a comprehensive ophthalmic examination including subjective refraction, distance best-spectacle corrected visual acuity (DCVA) measurement, and rotating Scheimpflug corneal tomography (Pentacam HR; Oculus, Wetzlar, Germany) at the same office visit. The correlations between the logarithm of the minimum angle of resolution (LogMAR) of DCVA and keratometric indices, topometric indices and tomographic indices were tested with nonparametric Spearman correlation coefficients (?).


The mean LogMAR DCVA was 0.32 (~20/42) ±0.27 [range: −0.10 (20/15) to 1.30 (20/400)]. There were strong correlations between DCVA and many keratometric, topometric and tomographic indices. A strong positive correlation was found between DCVA and BAD-Df (ρ = 0.648, p < 0.001), BAD-Db (ρ = 0.633, p < 0.001), K2 (ρ = 0.643, p < 0.001), Kmax (ρ = 0.608, p < 0.001), TKC (ρ = 0.558, p < 0.001), BAD-D (ρ = 0.577, p < 0.001), ISV (ρ = 0.573, p < 0.001), CKI (ρ = 0.530, p < 0.001), KI (ρ = 0.531, p < 0.001). A strong negative correlation was seen between DCVA and Asph Q front 30° (ρ = −0.521, p < 0.001).


There are significant correlations between visual acuity and Pentacam parameters. Such parameters may be considered for improving staging of the disease, as well as for monitoring progression or treatment as outcome measures. There is a potential for combining parameters to enhance the correlations.

How to cite this article

Lopes BT, Ramos IC, Faria-Correia F, Luz A, de Freitas Valbon B, Belin MW, Ambrósio R Jr. Correlation of Topometric and Tomographic Indices with Visual Acuity in Patients with Keratoconus. Int J Kerat Ect Cor Dis 2012;1(3):167-172.

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