Related Experiment Video
Updated: Oct 9, 2025
Comparison of Agreement and Accuracy using Binocular Wavefront Optometer with Autorefractor and Phoropter
Published on: September 16, 2025
The use of autorefractors using the image-size principle in determining on-axis and off-axis refraction. Part 2:
David A Atchison1, Marwan Suheimat1, Stanislovas Zacharovas1
1Centre for Vision and Eye Research, Queensland University of Technology, Kelvin Grove, Queensland, Australia.
Purpose:
To determine, through simulations, the likely validity of Grand-Seiko autorefractors with annular targets in peripheral refraction.
Methods:
Using a physical model eye, the distance inside the eye to which the Grand Seiko AutoRef/Keratometer WAM-5500 beam was converging and the effective size of its outer diameter at the cornea were determined. Grand-Seiko refraction was calculated from Rx = (θ + α)/h1 , where θ is the angle of the ingoing radiation beam, h1 is the height of the beam at the anterior cornea and α is the angle of the beam emerging from the eye following reflection at the retina. Two eye models were used: a Navarro schematic eye and a Navarro schematic eye with a contact lens having a highly positive aspheric front surface.
Results:
The instrument beam was determined to be converging towards the eye to a distance of 24.4 mm behind the corneal vertex, with a 2.46 mm effective size outer diameter of the beam at the anterior cornea. The Grand-Seiko refractions provided accurate estimates of peripheral refraction for the model eyes. The results were closer to Zernike refractions than to Zernike paraxial refraction. Spherical aberration influenced refraction by up to 0.5 D, and peripheral coma had limited influence.
Conclusion:
Grand-Seiko autorefractors in current use, and having a circular annulus with an ingoing effective outer diameter at the front of the eye of about 2.4 mm, are likely to give valid peripheral refractions.
