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Athlete Monitoring
Published in Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan, Strength and Conditioning in Sports, 2023
Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan
A lens is a device that facilitates and influences perception, comprehension, or evaluation. The sport scientist’s lens, which governs their personal overarching SS perspective, is a critical aspect that makes the sport scientist valuable to the sport team and coaches alike. As a law school trains a lawyer to view the world through a particular lens, a sport scientist should be prepared (i) from an appropriate sport and exercise science curriculum, (ii) by relevant mentors, and (iii) through performing meaningful practical work (14). The combination of these three factors in training helps shape the sport scientist’s lens. This training should be viewed as a journey in which the scientist learns over time to formalize their lens with experience conceptualize how to best go about problem-solving in their setting, but also help bridge the gap between theory and application.
Basic Principles of Laser
Published in Anita Prasad, Laser Techniques in Ophthalmology, 2022
Lenses are classified into anterior and posterior segment lenses. Anterior segment lenses are used to visualize lens capsule, IOL, and ocular angle.Posterior segment lenses are used to visualize vitreous and retina. They are further classified as: Concave CL (negative lens) – creates an upright, virtual fundal imageConvex lens (positive lens) – creates an inverted, real fundal imageMirror lens
Comparative Anatomy and Physiology of the Mammalian Eye
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
The lens is a biconvex transparent structure and is the second refracting unit of the eye. It lies posterior to the iris and is suspended from the ciliary body by the zonular fibers (Figure 21). It also has a posterior attachment to the anterior vitreous face where it lies in a depression of the vitreous, the patellar fossa. It is a unique tissue in that it is avascular, transparent, lacks nerve supply, and has the highest concentration of protein and glutathione in the body.3 Embryologically, the lens originates from the surface ectoderm which is induced to form the lens placode and invaginate by the advancing optic vesicle and cup.167
Proteomic characterization of the human lens and Cataractogenesis
Published in Expert Review of Proteomics, 2021
The ocular lens is a transparent tissue suspended behind the cornea and is responsible for transmission and focusing of light to the retina. Gradual opacification of the lens occurs with age and most frequently originates in the central nucleus of the lens, classified as an age-related nuclear cataract (ARNC) (Figure 1) [1]. When light passes through the cataractous lens, it is scattered and the degraded signal limits visual acuity and perception. Cataracts were first documented in ancient Egypt as the ‘white disease of the eye’, and the earliest known descriptions of the lens come from the Roman medical textbook De Medicina written AD 30 [2]. Despite a long history of lens research, cataract causes 51% of global blindness and affects >65% of people over the age of 80 [3,4]. As life expectancies increase, so too will the prevalence of ARNC. In 2010, twenty-four million Americans displayed cataract according to a LOCS II grading scale, but this number is expected to grow to more than fifty million by 2050 [4]. Cataract surgery costs more than 3.5 USD Billion per year in the US and delay of cataract may subsequently save Billions of dollars annually [5]. To date, no drug treatment has been developed for human cataract and surgical remediation is most often employed when access is available [6]. To reduce anticipated strain on the global medical system, it is desirable to characterize aging and pathology-specific molecular changes in the lens for development of pharmaceutical delay or prevention of ARNC.
The Normal Accommodative Convergence/Accommodation (AC/A) Ratio
Published in Journal of Binocular Vision and Ocular Motility, 2018
An alternative source of the difference may be due to a difference in a participant’s ability to exert or relax accommodation through different strength lenses (convex and concave), Figure 2 illustrates that for DG, those participants who could view the target clearly through −2.00DS (n = 30) or −3.00DS (n = 3) had a significantly lower median AC/A ratio (p < 0.05) than those who could only view clearly through −1.00DS (n = 17). This may indicate that of this visually normal cohort, there may be a sub-set that do not actually display ‘normal’ accommodative behaviour, although the same effect was not found in SG which may contradict that hypothesis. Alternatively the difference may be that the weaker concave lens is not instigating sufficient accommodative power to produce the same level of calculated AC/A ratio that a stronger lens does. A drawback of the stimulus ratio measurement is that an assumption is made as to how much accommodation is being exerted at a given time. The only ‘control’ we have in this instance is to ensure that participants are instructed to continually keep the target clear throughout the assessment which was the approach that was taken here. Therefore, with respect to these results, accommodation was controlled to the same level that can be expected clinically.
Optical and pharmacological strategies of myopia control
Published in Clinical and Experimental Optometry, 2018
There are two categories of optical lens designs: concentric ring or bifocal lens design and progressive power or peripheral add lens design. Both designs impact the central and peripheral retinal images (Figure 2). The concentric ring lens design incorporates alternating distance correction and treatment (plus power) zones to provide two focal planes or simultaneous distance correction and retinal myopic defocus. The rationale behind this design is to provide good visual acuity while myopic defocus is simultaneously induced onto the retina during both distance and near viewing.2011 On the other hand, the progressive power lens design incorporates a gradual change in curvature to provide a central zone of distance correction with a progressive change to include a relative plus add in the periphery. This design aims to provide clear central vision while inducing peripheral myopic defocus during both distance and near viewing. Further details of various investigational lens designs reported in the literature are summarised in Table 1.