Posters

Novel color-LED reflection topography: distribution and repeatability of corneal astigmatism measurements (magnitude and axis)

Poster Details

First Author: G.Asimellis GREECE

Co Author(s):    A. Kanellopoulos              

Abstract Details

Purpose:

To evaluate distribution and repeatability of anterior-surface corneal astigmatism measurements (axis and magnitude) employing a novel corneal topographer.

Setting:

LaserVision.gr Clinical and Research Eye Institute

Methods:

Anterior-surface corneal astigmatism was investigated in a total of 195 eyes via a novel multicolored-spot reflection topographer (Cassini, i-Optics, the Hague, The Netherlands). Two patient groups were studied, a younger-age group-A, and an older-age group-B. Three consecutive acquisitions were obtained from each eye. Repeatability of measurement was assessed via Bland-Altman plot analysis and is reported as coefficient of repeatability.

Results:

Group-A (average age 34.3 years) had on average with-the-rule astigmatism, while the older-age group-B (average age 72.3 years) had on average against-the-rule astigmatism. Average astigmatism magnitude measurement repeatability in group-A was 0.45 D, and in group-B 0.39 D. Average astigmatism axis measurement repeatability in group-A was 5.42°, and in group-B 5.47°. The axis measurement repeatability improved with increasing magnitude of astigmatism: in the subgroups with astigmatism between 3.00 to 6.00 D, axis repeatability was 1.44° (group-A) and 1.25° (group-B), while in the subgroups with astigmatism larger than 6.00 D, repeatability was 1.14° and 0.62°, respectively.

Conclusions:

This novel corneal topography device appears to offer high precision in reporting corneal astigmatism. This study reaffirms the established trend of corneal astigmatism shift from an average ‘with-the-rule’ to ‘against-the-rule’ with aging. FINANCIAL DISCLOUSRE: One or more of the authors travel has been funded, fully or partially, by a company producing, developing or supplying the product or procedure presented