Fourier analysis of corneal irregular astigmatism due to the anterior corneal surface in dry eye

Session Details

Session Title: Cornea
Session Date/Time: Friday 09/02/2018 | 08:30-10:00
Paper Time: 08:48
Venue: Annex A

First Author: S.Koh JAPAN
Co Author(s): N. Maeda  Y. Takai  M. Ogawa  S. Asonuma  K. Maruyama  K. Nishida  

Abstract Details

Purpose:

To evaluate corneal irregular astigmatism due to the anterior corneal surface using Fourier harmonic analysis with a Placido ring-based corneal topographer (Placido-based topographer) and 3-dimensional anterior segment optical coherence tomography (OCT) in dry eyes.

Setting:

Osaka University Hospital, Osaka, Japan

Methods:

Forty-four eyes of 44 subjects with dry eye and 20 eyes of 20 normal control subjects were enrolled. Corneal topographic data were obtained using a Placido-based topographer and OCT. Dioptric data from the central 3-mm zone of the anterior corneal surface were decomposed using Fourier harmonic analysis. Spherical, regular astigmatism, and irregular astigmatism (asymmetry and higher-order irregularity) refractive error components of the cornea from the two imaging modalities were compared.

Results:

Forty-four eyes of 44 subjects with dry eye and 20 eyes of 20 normal control subjects were enrolled. Corneal topographic data were obtained using a Placido-based topographer and OCT. Dioptric data from the central 3-mm zone of the anterior corneal surface were decomposed using Fourier harmonic analysis. Spherical, regular astigmatism, and irregular astigmatism (asymmetry and higher-order irregularity) refractive error components of the cornea from the two imaging modalities were compared.

Conclusions:

The amount of corneal irregular astigmatism, quantified using Fourier harmonic analysis, was significantly higher in dry eyes than in normal eyes. Measurements obtained with OCT and the Placido-based topographer differed in subjects with dry eye. Therefore, caution should be practiced when trying to use these measurements interchangeably.

Financial Disclosure:

None