Ocular accommodation and cognitive demand: An additional indicator besides pupil size and cardiovascular measures?

<p>Abstract</p> <p>Background</p> <p>The aim of the present study was to assess accommodation as a possible indicator of changes in the autonomic balance caused by altered cognitive demand. Accounting for accommodative responses from a human factors perspective may be motivated by the interest of designing virtual image displays or by establishing an autonomic indicator that allows for remote measurement at the human eye. Heart period, pulse transit time, and the pupillary response were considered as reference for possible closed-loop accommodative effects. Cognitive demand was varied by presenting monocularly numbers at a viewing distance of 5 D (20 cm) which had to be read, added or multiplied; further, letters were presented in a "n-back" task.</p> <p>Results</p> <p>Cardiovascular parameters and pupil size indicated a change in autonomic balance, while error rates and reaction time confirmed the increased cognitive demand during task processing. An observed decrease in accommodation could not be attributed to the cognitive demand itself for two reasons: (1) the cognitive demand induced a shift in gaze direction which, for methodological reasons, accounted for a substantial part of the observed accommodative changes. (2) Remaining effects disappeared when the correctness of task processing was taken into account.</p> <p>Conclusion</p> <p>Although the expectation of accommodation as possible autonomic indicator of cognitive demand was not confirmed, the present results are informative for the field of applied psychophysiology noting that it seems not to be worthwhile to include closed-loop accommodation in future studies. From a human factors perspective, expected changes of accommodation due to cognitive demand are of minor importance for design specifications – of, for example, complex visual displays.</p

Optical Interventions for Myopia Control

Myopia is a common eye problem that is becoming more prevalent worldwide, particularly in East Asia. The cost of long-term care for myopia-related eye diseases significantly impacts the respective economies and places a great burden on the public health services. There is no doubt that myopia is a major East Asian public health concern and a significant concern globally, and effective control of myopia would help to alleviate the costs that are related to this problem. Currently, there are many types of optical interventions involving the use of spectacle lenses or contact lenses to slow down myopia progression in children. However, none of these myopia control methods have been proven to stop the development or progression of myopia completely and each method has their own limitations. Orthokeratology, soft bifocal contact lenses, prismatic bifocals, and myopic defocus incorporated spectacle lenses have all been shown to have clinically meaningful reductions in myopia progression ranging from 45% to 60%. Although pharmaceutical agents such as atropine have relatively better myopia control effects than optical methods, the associated side effects and uncertainty in the safety of long-term atropine use may hinder its widespread clinical application. Optical interventions are non-invasive and have become more popular compared to pharmaceutical treatments. This chapter provides an overview of the optical interventions for slowing myopia progression and their effectiveness in myopia control. Other myopia control methods will also be discussed briefly

Environmental effects of ozone depletion, UV radiation and interactions with climate change : UNEP Environmental Effects Assessment Panel, update 2017

Peer reviewe