scholarly journals A Review of Depth of Focus in Measurement of the Amplitude of Accommodation

Vision ◽  
2018 ◽  
Vol 2 (3) ◽  
pp. 37 ◽  
Author(s):  
David Burns ◽  
Peter Allen ◽  
David Edgar ◽  
Bruce Evans
Keyword(s):  
Human Vision ◽  
Depth Of Focus ◽  
Potential Confounding Variable ◽  
Subjective Judgement ◽  
Method Of Measurement ◽  
Method Factors ◽  
Routine Assessment ◽  
Source Of Error ◽  
Push Up

The aim of this review is to investigate the role of depth of focus (DoF) as a potential confounding variable in the measurement of the amplitude of accommodation (AoA). The role of DoF in human vision is briefly summarised, and it is noted that the prevalent method of measuring AoA is the push-up method. Factors influencing the effect of DoF on the push-up and other methods of measuring AoA are reviewed in detail. DoF is shown to add substantial measurement error in the routine assessment of accommodation when the AoA is measured by methods involving subjective judgement of an object’s clarity. Reliable compensation for this source of error is not realistically possible because of the complexity of the aetiology of DoF, and its inter-individual and intra-individual variation. The method of measurement also influences the extent of the error. It is concluded that methods of measurement of AoA that exclude DoF should be preferred.

Glioma patient-reported outcomes: patients and clinicians

2021 ◽  
pp. bmjspcare-2020-002699
Author(s):  
Marthe Peeters ◽  
Germaine Ottenheijm ◽  
Paul Bienfait ◽  
Daniëlle Eekers ◽  
Anja Gijtenbeek ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Patient Reported Outcomes ◽  
Successful Implementation ◽  
Nurse Specialist ◽  
Patient Reported ◽  
Semistructured Interviews ◽  
Routine Assessment

IntroductionRoutine assessment of patient-reported outcomes (PROs) in oncology has shown to improve the quality of the delivered care and to prolong survival. However, for successful implementation of routine assessment of PROs, more knowledge on their usability in clinical practice is needed.ObjectiveThis study aimed to cross-sectionally assess the perspective of patients and clinicians on the practicality of routinely measuring PROs in clinical practice for glioma patients.MethodsSemistructured interviews were conducted evaluating the role of healthcare professionals (HCP) in discussing results of PRO measures (PROMs), and the preferred topics, methods and frequency of PRO assessment. Glioma patients, their proxies and HCPs involved in the treatment of glioma patients from eight centres in the Netherlands were included.ResultsTwenty-four patients, 16 proxies and 35 HCPs were interviewed. The majority of patients, proxies and HCPs (92%, 81% and 80%, respectively) were willing to discuss PRO results during consultations. Although HCPs prefer that results are discussed with the nurse specialist, only one-third of patients/proxies agreed. Functioning of daily life was considered important in all three groups. Most participants indicated that discussion of PROM results should take place during standard follow-up visits, and completed at home about 1 week in advance. On group level, there was no preference for administration of questionnaires on paper or digitally. Lastly, all centres had staff available to send questionnaires on paper.ConclusionThis study shows that routine assessment of PROs is desired by patients, proxies and HCP’s in neuro-oncological care in Dutch hospitals.

The quadrupole moment of the carbon dioxide molecule

1963 ◽  
Vol 273 (1353) ◽  
pp. 275-289 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Atom ◽  
Quadrupole Moment ◽  
Polarizability Tensor ◽  
Sulphur Hexafluoride ◽  
Inhomogeneous Electric Field ◽  
Carbon Dioxide Molecule ◽  
Method Of Measurement ◽  
The Difference

A direct measurement of the magnitude and sign of the quadrupole moment of the carbon dioxide molecule has been made by determining the birefringence induced in gaseous C0 2 by an inhomogeneous electric field. The method of measurement and the experimental details are described. The observable is the product of the molecular quadrupole moment 0 and the difference between parallel and perpendicular components of the optical polarizability tensor. F o r CO 2 , this quantity was found to have the value — (9.1±0.5)x 10 -50 e.s.u. can be determined by other methods, but unfortunately the present uncertainty in this quantity is greater than that of the product. The most satisfactory value of a a 8 -a 1 is taken to be 2.2 x 10 -24 cm 3 , giving for the molecular quadrupole moment of CO 2 — 4.1 x 10 -26 e.s.u., the sign indicating that the oxygen atoms are negative with respect to the carbon atom. The role of the ‘ quadrupole polarizability ’ of the molecule in complicating the interpretation of the experimental results is discussed, and experiments on argon and sulphur hexafluoride used to provide an estimate of its effect in the case of CO 2 .

scholarly journals Role of Microscope in Endodontics

2020 ◽  
Vol 11 (4) ◽  
pp. 8012-8015
Author(s):  
Manoj Chandak ◽  
Manju Waradhpande ◽  
Kajol Relan ◽  
Pooja Chandak ◽  
Rakhi Chandak ◽  
...  
Keyword(s):  
Root Apex ◽  
Human Vision ◽  
Caries Detection ◽  
Visually Guided ◽  
Image Size ◽  
Flap Surgery ◽  
Clinical Procedures ◽  
Retrograde Filling ◽  
The Right

Microscope is used in medical field to run over the limitations of human vision. Over the years many magnification devices are invented to achieve the goal. Quote given by Prof Syngcuk Kim that states “You can only treat what you can see”.   If the right tools are available many things can be visualized. They are endoscopes, intraoral camera, magnifying glass, surgical loupes, surgical microscope. Surgical loupes and Dental Operating Microscope are most convenient and practical to use in endodontics. By increasing the image size, fine details can be visualized. Hence to increase the image size, magnification is necessary. The invention of microscopes in modern endodontics helps in visually guided and sensory aided endodontic procedure. Magnification helps visualise finer details of the area to be treated. Dental microscope is used for diagnostic and clinical procedures (non-surgical ) as well as endodontic surgical procedures. The microscope as a diagnostic tool may be used in caries detection, fracture line and craze evaluation, crown margins or restorations that are deficient, in caries elimination, access preparation,  calcifications removal. It is also helpful in orifice detection and treating internal resorptions. All procedure are performed under various magnification grades. They are flap surgery, cutting of bone, root apex identification, apicoectomy, removal of inflamed tissue, observe resected end of root, root end preparation, retrograde filling, and suturing, surgical correction of unsuccessful RCT. Also, Cervical resorption and External resorption and perforation repairs can be done using Microscope. The invention of microscopes in modern endodontics helps in visually guided and sensory aided endodontic procedure. Furthermore the role of microscopes in endodontics is reviewed.

scholarly journals The Effect of Color and Positional Noise on Reading Performance in Human Vision

2021 ◽  
Vol 9 (B) ◽  
pp. 130-135
Author(s):  
Abdullah Alsalhi ◽  
Nadia Northway ◽  
Glyn Walsh ◽  
Abd Elaziz Mohamed Elmadina
Keyword(s):  
Word Recognition ◽  
Letter Position ◽  
Reading Performance ◽  
Human Vision ◽  
English Speakers ◽  
Horizontal Line ◽  
Vertical Displacements ◽  
Distant Visual Acuity ◽  
Mean Differences

BACKGROUND: Reading can be described as a complex cognitive process of decrypting signs to create meaning. Eventually, it is a way of language achievement, communication, and sharing information and ideas. Changing lighting and color are known to improve visual comfort and the perceptual difficulties that affect reading for those with poor vision. AIM: This study aims to investigate the effect of changing the wavelengths and different levels of positional noise on reading performance for participants with best-corrected distant visual acuity (BCVA) of 6/6 or better. METHODOLOGY: Twenty English speakers with BCVA 6/6 or better were asked to read words presented in a printed format. The stimuli were black print words in a horizontal arrangement on matte white card. They were degraded using positional noise produced by random vertical displacements of the letter position below or above the horizontal line on three levels. RESULTS: Introducing positional noise affected word recognition differently with different wavelengths. The role of short wavelength in enhancing orthographic reading and word recognition is clear – they reduce the effects of positional noise. The error rate and duration time have different effects with different wavelengths, even when positional noise is introduced. CONCLUSION: The reading rate is not affected by changing the wavelength of the light. However, the mean differences in wpm were affected by changing the wavelengths. Also, introducing positional noise affects word recognition differently with different wavelengths.

scholarly journals Apparent anomalies in nuclear feulgen-DNA contents. Role of systematic microdensitometric errors.

1976 ◽  
Vol 71 (1) ◽  
pp. 68-88 ◽  
Author(s):  
K S Bedi ◽  
D J Goldstein
Keyword(s):  
Cell Types ◽  
Residual Distribution ◽  
Peak Wavelength ◽  
Measuring Range ◽  
Potential Source ◽  
Dna Contents ◽  
Different Cell Types ◽  
Source Of Error ◽  
Distribution Error

The Feulgen-DNA contents of human leukocytes, sperm, and oral squames were investigated by scanning and integrating microdensitometry, both with and without correction for residual distribution error and glare. Maximally stained sperm had absorbances which at lambdamax exceeded the measuring range of the Vickers M86 microdensitometer; this potential source of error could be avoided either by using shorter hydrolysis times or by measuring at an off-peak wavelength. Small but statistically significant apparent differences between leukocyte types were found in uncorrected but not fully corrected measurements, and some apparent differences disappeared when only one of the residual instrumental errors was eliminated. In uncorrected measurements, the apparent Feulgen-DNA content of maximally stained polymorphs measured at lambdamax was significantly lower than that of squames, while in all experimental series uncorrected measurements showed apparent diploid:haploid ratios significantly greater than two. In fully corrected measurements no significant differences were found between leukocytes and squames, and in four independent estimations the lowest diploid:haploid ratio found was 1.99 +/- 0.05, and the highest 2.03 +/- 0.05. Discrepancies found in uncorrected measurements could be correlated with morphology of the nuclei concerned. Glare particularly affected measurements of relatively compact nuclei such as those of sperm, polymorphs and lymphocytes, while residual distribution error was especially marked with nuclei having a high perimeter:area ratio (e.g. sperm and polymorphs). Uncorrected instrumental errors, especially residual distribution error and glare, probably account for at least some of the previously reported apparent differences between the Feulgen-DNA contents of different cell types. On the basis of our experimental evidence, and a consideration of the published work of others, it appears that within the rather narrow limits of random experimental error there seems little or no reason to postulate either genuine differences in the amounts of DNA present in the cells studied, or nonstoichiometry of a correctly performed Feulgen reaction.

Alternative views of security in Latin America: Towards a global contribution to human security

2015 ◽  
Vol 5 (1) ◽  
pp. 26-53 ◽  
Author(s):  
Oscar A. Gómez
Keyword(s):  
Latin America ◽  
Human Security ◽  
Human Vision ◽  
Communication Interface ◽  
Main Hypothesis ◽  
Institutional Review ◽  
Slow Development ◽  
America Latina

This article analyzes the peripheral role of Latin America in global discussions about human security. The main hypothesis is that proposals for opening security theories and practices to a “human vision” failed to merge with the evolution of security concepts and institutions in the region over the last twenty years. Hence, there is no constructive communication interface between citizen and human security activities that inform security practices in the medium and long term. This article describes two approaches: (a) the slow development of human security concepts that may be somehow useful to the region due to (b) the positioning of citizen security as an alternative security paradigm in Latin America. Following a conceptual and institutional review of these approaches, the article concludes with some proposals to establish a dynamic and effective bridge between these two visions. Spanish El presente artículo analiza el papel periférico de Latinoamérica en las discusiones mundiales sobre el concepto/enfoque de seguridad humana. La hipótesis de trabajo es que las propuestas para abrir la teoría y práctica de seguridad en la región a la visión humana no han logrado acoplarse a la evolución en las concepciones e instituciones de seguridad durante los últimos veinte años; por tanto, no existe una interface constructiva de comunicación entre lo ciudadano y lo humano que informe el quehacer en seguridad en el mediano y largo plazo. El estudio describe dos hilos conductores: (a) el lento desarrollo de versiones elaboradas del concepto de seguridad humana que resulten útiles a las sociedades de la región, en parte producto de (b) el posicionamiento de la seguridad ciudadana como el paradigma alternativo de seguridad en América Latina. Después de hacer una revisión de estos hilos en lo conceptual e institucional, el artículo cierra con algunas propuestas para establecer un puente más dinámico y efectivo entre las dos visiones. French Cet article analyse le rôle périphérique de l'Amérique latine dans le débat mondial sur le concept / approche de la sécurité humaine. L'hypothèse de travail est que les propositions visant à ouvrir la théorie et la pratique de la sécurité dans la région à la vision humaine ont échoué à engager l'évolution des concepts et des institutions de sécurité au cours des ces vingt dernières années; par conséquent, il n'existe pas d'interface de communication constructive entre le citoyen et l'activité humaine à informer sur les initiatives de sécurité dans le moyen et long terme. L'étude décrit deux fils conducteurs: (1) la lenteur du développement des versions du concept de sécurité humaine élaborées qui sont utiles aux entreprises dans la région, en partie le produit de (2) la conception de la sécurité « citoyenne » comme un paradigme alternatif de la sécurité en Amérique latine. Après un examen de ces discussions sur le conceptuel et l'institutionnel, l'article se termine par quelques propositions destinées à établir un pont plus dynamique et efficient entre les deux points de vue.

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