PURPOSE The mouse eye has potential to become an important model for studies on the genetic control of eye growth and myopia. However, no data are published on the development of its optical properties. We developed a paraxial schematic model of the growing eye for the most common laboratory mouse strain, the C57BL/6 mouse, for the age range between 22 and 100 days. METHODS Refractive develop...

A nonlinear optical double-doped single-crystal LiNbO3:Gd:Mg (Gd concentration is 0.003, Mg—0.65 wt % in the crystal) has been researched by several methods: laser conoscopy, photoinduced light scattering (PILS), spectroscopy, and Raman scattering. The crystal shown to have no photorefraction effect a high uniformity. Fine features of structure studied via spectra. Spectra registered first seco...

The majority of individuals with Down syndrome (DS) do not exhibit accurate accommodation, with the aetiology of this deficit unknown. This study examines the mechanism underlying hypoaccommodation in DS by simultaneously investigating the 'near triad' - accommodation, vergence and pupillary response. An objective photorefraction system measured accommodation, pupil size and gaze position (verg...

Background: Clinical determination of convergence accommodation to convergence (CA/C) ratios may be useful for analysis of accommodation and vergence disorders, but there are no standard clinical methods of measurement of CA/C ratios. This study compared two potential clinical CA/C measurement methods to a laboratory procedure. Methods: CA/C ratios were measured for 19 young adult subjects usin...

PURPOSE The goal of this study was to compare objectively the sensitivity of the accommodation system in human infants and adults under binocular and monocular viewing conditions. METHODS Full-term infants from 2 to 4 months of age and pre-presbyopic adults were presented with a high-contrast cartoon stimulus moving sinusoidally in diopters around a mean position of 2 D (50 cm). Three stimulu...

PURPOSE To develop a low-cost automated video system to effectively screen children aged 6 months to 6 years for amblyogenic factors. METHODS In 1994 one of the authors (G.C.) described video vision development assessment, a digitizable analog video-based system combining Brückner pupil red reflex imaging and eccentric photorefraction to screen young children for amblyogenic factors. The imag...

Photorefractive methods have become popular in the measurement of refractive and accommodative states of infants and children owing to their photographic nature and rapid speed of measurement. As in the case of any method that measures the refractive state of the human eye, monochromatic aberrations will reduce the accuracy of the measurement. Monochromatic aberrations cannot be as easily predi...

We examined the spherical equivalent refractions of 237 subjects who had been seen four or more times in a longitudinal study of refractive development in normal children. We employed both photorefraction and autorefraction using a Canon R1 autorefractor. We performed an analysis of variance (F-test for Lack of Fit) to determine the significance of a linear regression in fitting these refractio...