Asthenopia, or visual fatigue, is a frequent complaint from observers of stereoscopic three-dimensional displays. It has been proposed that asthenopia is a consequence of anomalous oculomotor responses generated by conflict between accommodative and convergence stimuli. The hypothesis was examined by measuring accommodation and convergence continuously with a Shin-Nippon SRW5000 infrared autore...

Purpose. To evaluate the movement of the anterior and posterior lens poles during naturally stimulated accommodation in children using anterior segment optical coherence tomography (OCT). Methods. This is a prospective, observational, noncomparative case series including 18 eyes of nine children. Analysis of the anterior segment in the accommodated and unaccommodated state (with cycloplegia) wa...

We consider here passive mechanical wrists, capable of imparting a desired dumping matrix to a grasped workpiece. Previous work 112. 131 has shown how to select a dumping matrix such that an assembly operatwn can be modc force-guided Thc passive mechanical wrist is to be progmnvnable it can adopt a widc range of damping matrices by virtue of a number of t u d e dampers which inrcrconneet the jo...

PURPOSE Accommodation is a dioptric change in power of the crystalline lens resulting from ciliary muscle contraction that leads to an increase in lens surface curvatures and thickness and changes in the position of lens surfaces. Previous studies have used A-scan ultrasound to measure changes in the position of lens surfaces with voluntary accommodation, but have not simultaneously measured th...

PURPOSE To identify variables associated with myopia progression and to identify any interaction between accommodative function, myopia progression, age, and treatment effect in the Cambridge Anti-Myopia Study. METHODS Contact lenses were used to improve static accommodation by altering ocular spherical aberration, and vision training was performed to improve dynamic accommodation. One hundre...

28 Purpose This study investigated whether vergence and accommodation development in pre29 term infants is pre-programmed or is driven by experience. 30 Methods 32 healthy infants, born at mean 34 weeks gestation (range 31.2-36 weeks) were 31 compared with 45 healthy full-term infants (mean 40.0 weeks) over a 6 month period, starting at 32 4-6 weeks post-natally. Simultaneous accommodation and ...

PURPOSE To determine the relative importance of lens geometry and mechanical properties for the mechanics of accommodation and the role of these elements in the causes and potential correction of presbyopia. SETTING Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey, USA. DESIGN Experimental study. METHODS Finite element methods and ray-tracing...

PURPOSE This study investigated whether vergence and accommodation development in preterm infants is preprogrammed or is driven by experience. METHODS Thirty-two healthy infants, born at mean 34 weeks gestation (range, 31.2-36 weeks), were compared with 45 healthy full-term infants (mean 40.0 weeks) over a 6-month period, starting at 4 to 6 weeks postnatally. Simultaneous accommodation and co...

Accommodation stimulus-response function (ASRF) and its relationship to retinal image quality were investigated using a modified wavefront sensor. Ten subjects were presented with six vergence stimuli between 0.17 D and 5 D. For each vergence distance, ocular wavefronts and subjective visual acuity were measured. Wavefronts were analysed for a fixed 3-mm pupil diameter and for natural pupil siz...

The barostat is considered the gold standard for evaluation of proximal gastric motility especially for the accommodation response to a meal. The procedure is invasive because it involves the introduction of an intragastric catheter and bag and is not always well tolerated. Moreover, the barostat bag itself may influence motility. Nowadays magnetic resonance imaging (MRI) is able to measure sev...