The rotary bending fatigue properties of medical-grade Nitinol wires were investigated under conditions of 0.5-10% strain amplitudes to a maximum of 10(7) cycles. The results from this study provide insight into the behavior of Nitinol under fully reversed (εmin/εmax=-1) fatigue conditions for three compositions, two surface conditions and three test temperatures. For pseudoelastic conditions t...

introduction international commission on radiological protection (icrp) has provided a comprehensive discussion on threshold dose for radiation-induced cataract in icrp publication 116. accordingly, various parts of the eye lens have different radio-sensitivities. recently, some studies have been performed to develop a realistic eye model with the aim of providing accurate estimation of fluence...

PURPOSE Less accommodation was found when human subjects read in blue (peak at about 440 nm) than when they read in red light (above 600 nm; [Kroger & Binder, British Journal of Ophthalmology 84 (2000) 890]). On the other hand, emmetropization in chickens did not appear to compensate for the chromatic defocus (385 nm versus 665 nm; [Rohrer, Schaeffel & Zrenner, Journal of Physiology 449 (1992) ...

Aim. The aim of this study was to investigate the association between anthropometry, amplitude of accommodation assessed by minus-lens to blur (AAPUB) and push-up to blur (AAMLB), and spherical equivalent refraction (SEQ). Method. A total of two hundred and one subjects aged between 17 and 70 years with mean age of 34.2 ± 13.3 years, consisting of 93 males and 108 females were recruited for thi...

BACKGROUND To validate the association between accommodation and visual asthenopia by measuring objective accommodative amplitude with the Optical Quality Analysis System (OQAS®, Visiometrics, Terrassa, Spain), and to investigate associations among accommodation, ocular surface instability, and visual asthenopia while viewing 3D displays. METHODS Fifteen normal adults without any ocular disea...

A special case was set up in which accommodation and vergence were totally deprived of their stimuli, in order to determine whether their responses remained coordinated or whether they became dissociated. A dynamic, infrared optometer and infrared, eye-movement sensors were used simultaneously to monitor accommodation and vergence respectively in the dark. Responses were recorded continuously o...

When viewing natural scenes saccadic eye movements are used to position retinal images of interest on the fovea, while vergence eye movements act to minimise retinal disparity and maintain a single binocular view of the target. Despite these disruptions to the retinal image, we perceive a stable visual world due to suppression of the magnocellular visual pathway which processes low spatial freq...

BACKGROUND According to the Helmholtz theory of accommodation the loss of accommodation amplitude is caused by the growing sclerosis of the crystalline lens, whereas the ciliary muscle and the lens capsule are mainly uneffected by age. A permanent treatment method for presbyopia which offers a dynamic accommodation ability is a recent field of study. The concept followed in this paper uses femt...

PURPOSE Evidence exists for an additional inhibitory accommodative control system mediated by the sympathetic branch of the autonomic nervous system (ANS). This work aims to show the relative prevalence of sympathetic inhibition in young emmetropic and myopic adults, and to evaluate the effect of sympathetic facility on accommodative and oculomotor function. METHODS Profiling of ciliary muscl...