Ultrasonic system for accurate distance measurement in the air.

This paper presents a system that accurately measures the distance travelled by ultrasound waves through the air. The simple design of the system and its obtained accuracy provide a tool for non-contact distance measurements required in the laser's optical system that investigates the surface of the eyeball.

An interferometric method for the dynamic evaluation of the tear film.

Purpose: This study describes a non-invasive method for the in vivo assessment of precorneal tear film stability.

Methods: A lateral shearing interferometer (LSI) is used for the measurement. The interference fringes obtained from the tear film layer are analysed using the fast Fourier transform (FFT) technique.

Interferometric measurements of dynamic changes of tear film.

Tear film stability plays an important role in the quality of vision. We present an interferometric method for assessing the stability of precorneal tear film in real time. A lateral shearing technique is applied as a noninvasive and sensitive method for investigating tear film stability and the smoothness of the tear film surface by quantitative evaluation of the interference fringe pattern.

Linear birefringence measurements of the in vitro human cornea.

This paper presents results of an in vitro investigation of the optical anisotropy of the human cornea. Computer controlled imaging polarimetry and the Jones formalism were used to investigate the distribution of the birefringence and the azimuth angle across the surface of 12 corneas taken from the corneal bank. Each map of the birefringence and the azimuth angle has no rotational symmetry and is different for each cornea.