Purchase this article with an account.
M. Suzuki, T. Tanabe, S. Amano, T. Oshika; Changes in Corneal Irregular Astigmatism and Visual Acuity in Eyes With Keratoconus . Invest. Ophthalmol. Vis. Sci. 2005;46(13):4952.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose:To quantitatively investigate time course of changes in corneal irregular astigmatism and best spectacle–corrected visual acuity (BSCVA) in eyes with keratoconus. Methods:Subjects were 85 eyes of 64 patients with keratoconus who had undergone videokeratography (TMS, Tomey) examinations at least twice with an interval of 1 year or longer between each examination. Their age ranged between 14 and 65 (28.9 ± 8.5, mean ± SD) years old. By means of Fourier series harmonic analysis, topography data were decomposed into spherical component, regular astigmatism, asymmetry, and higher order irregularity. The yearly change rate of each Fourier component and logarithmic minimum angle of resolution (logMAR) of BSCVA was calculated by use of the least square method. Results:In eyes that showed apparent progression of keratoconus on color–coded maps, the yearly change rate of logMAR BSCVA was significantly positive (P=0.0023), but not in the eyes without apparent progression (P=0.1572). In eyes with progression on maps, the yearly change rate of logMAR BSCVA was significantly correlated with change rate of higher order irregularity per year (r=0.775, P= 0.0002), but not with spherical component (P=0.183), regular astigmatism (P=0.382), and asymmetry (P=0.727). In eyes without apparent progression, the yearly change rate of logMAR BSCVA was not correlated with the change rate of any Fourier components. Conclusions:The current quantitative study indicated that progression of keratoconus is associated with deterioration of BSCVA, which is significantly correlated with increases in corneal higher order irregularity as calculated by Fourier analysis of videokeratography data.
This PDF is available to Subscribers Only