The use of autorefractors using the image-size principle in determining on-axis and off-axis refraction. Part 2: Theoretical study of peripheral refraction with the Grand Seiko AutoRef/Keratometer WAM-5500.

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 R  = (θ + α)/h , where θ is the angle of the ingoing radiation beam, h 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.

The use of autorefractors using the image-size principle in determining on-axis and off-axis refraction. Part 1: Analysis of optical principles of autorefractors.

Purpose: To study the optical principles and properties of autorefractors that use the image-size principle in which the size of the reimaged retinal image determines refraction.

Methods: The retinal illumination and reimaging of the retinal image were described, as were variations in the basic system. Imaging was determined for systems in which the light source is either diverging or converging as it passes into the eye.

Digital holographic microscope for human eye retinal structures recording in vivo.

We introduce the digital holographic microscope for recording in vivo human eye retinal structures. Current eye imaging technologies cannot provide images with resolutions better than 1 µm within depths of a few hundred micrometers. This can be improved with digital holography, in which a hologram of the eye captured with digital camera contains information about structures over the full depth of the eye.

Comparison of diffraction patterns exposed by pulsed and CW lasers on positive-tone photoresist.

Two different grating formation geometries for recording onto the positive-tone photoresist with pulsed laser and continuous-wave sources are analyzed and compared. Diffraction efficiency measurements and atomic force microscopy (AFM) examination have been performed in order to investigate the optical and topographical properties of the recorded structures. Gratings patterned by a continuous-wave laser and by a pulsed laser working in the single pulse and multipulse regimes showed different surface roughness and optical properties.