Simple Magnification Research Articles

Tools of dermatology: A historical perspective

Dermatology is one of the few visual specialties; much can be seen with the naked eye, yet many tools and devices can facilitate the diagnosis of cutaneous maladies. There has been significant progress in diagnostic techniques in recent decades with the advent of artificial intelligence and teledermatology. Such advancements reflect principles of long-standing aids, whereas others embody novel techniques and concepts. These bedside tools range from simple magnifiers and binocular loupes to reflectance confocal microscopes and ultrasounds. The cornerstone diagnostic techniques, including the potassium hydroxide examination and the Tzanck smear, remain highly useful. Although visual examination often permits an accurate diagnosis of a skin disease, the clinician is now even further equipped. Just as the microscope did 4 centuries ago, newer advances will continue to revolutionize the practice of medicine.

The Impact of Field of View on Understanding of a Movie Is Reduced by Magnifying Around the Center of Interest.

PurposeMagnification is commonly used to reduce the impact of impaired central vision. However, magnification limits the field of view (FoV) which may make it difficult to follow the story. Most people with normal vision look in about the same place at about the same time, the center of interest (COI), when watching “Hollywood” movies. We hypothesized that if the FoV was centered at the COI, then this view would provide more useful information than either the original image center or an unrelated view location (the COI locations from a different video clip) as the FoV reduced.MethodsThe FoV was varied between 100% (original) and 3%. To measure video comprehension as the FoV reduced, subjects described 30-second video clips in response to two open-ended questions. A computational, natural-language approach was used to provide an information acquisition (IA) score.ResultsThe IA scores reduced as the FoV decreased. When the FoV was around the COI, subjects were better able to understand the content of the video clips (higher IA scores) as the FoV decreased than the other conditions. Thus, magnification around the COI may serve as a better video enhancement approach than simple magnification of the image center.ConclusionsThese results have implications for future image processing and scene viewing, which may help people with central vision loss view directed dynamic visual content (“Hollywood” movies).Translational RelevanceOur results are promising for the use of magnification around the COI as a vision rehabilitation aid for people with central vision loss.

Creating a More Accessible Environment in Anatomical Sciences

A growing number of students with disabilities are entering clinical programs that include anatomical sciences.1,2 Oftentimes, these students are insufficiently accommodated.3 Programs are seeking resources to ensure equal access to their curriculum. A combination of practice and research‐informed efforts have provided guidance to the greater scientific community.4–7 To assist programs with improving inclusion, we focus on three barrier‐removal practices: 1) accommodating the need for extra time in practical exams, 2) accommodating histology exams, and 3) reducing physical barriers in anatomy labs (with application for basic science laboratories), grounding each in legal guidance.Accommodating extra time in practical exams can be accomplished in two ways: First, groups who require additional time can rotate through the practical exam in the last group with traditional time, followed by a short break where all students are dismissed. After the break, the group requiring additional time can rotate through the practical stations a second time utilizing additional time for each station. With this approach, existing rotations are not disrupted and students’ accommodation‐related information is protected. A second approach is to rotate students in the final group through the practical exam in one sitting, at the accommodated time. The number of students with extra time as an accommodation may dictate the most efficient option.Histology exams may present barriers to students with low‐vision, color‐vision deficiency, or processing speed disorders. Leveraging principles of universal design for instruction (UDI) can ensure that practical exams do not serve as barriers. First, programs should maintain enlarged, high contrast, grey‐scale photos and simple magnifiers at each microscope station. If possible, slides should not be stained in blue or red. Instructors should also use letters or numbers to indicate the structure being queried, rather than color. When teaching structures, faculty should move towards greyscale and letter/number indications to introduce students to this approach prior to examination. Microscopes that magnify slides can ensure access for low‐vision students, however, traditional microscopes can also be attached to large monitors. This allows students to self‐select the appropriate size and contrast using built‐in monitor settings. These steps will reduce a myriad of barriers for the disability community. Even with a UDI approach, students may require additional time to adjust monitors.Finally, physical space barriers can be addressed to ensure greater access for all students. During practical exams, stools should be available at all stations. Embed inclusive practices, such as camera systems that project items onto a larger screen allows for closed captioning of instruction. Adjusted and modified equipment can reduce barriers for students with physical and chronic health disabilities, while alternative methods of anatomical instruction (e.g., Anatomage tables) can assist with sensory barriers and allergies.By incorporating principles of UDI and providing slight modifications to assessment structure, anatomical labs can transform to accessible and enhanced learning environments for all students.

Reading aids for adults with low vision.

Background The purpose of low-vision rehabilitation is to allow people to resume or to continue to perform daily living tasks, with reading being one of the most important. This is achieved by providing appropriate optical devices and special training in the use of residual-vision and low-vision aids, which range from simple optical magnifiers to high-magnification video magnifiers. Objectives To assess the effects of reading aids for adults with low vision. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 1), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE, (January 1950 to January 2013), EMBASE (January 1980 to January 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to January 2013), OpenGrey (System for Information on Grey Literature in Europe) (www.opengrey.eu/), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov/) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 31 January 2013. We searched the reference lists of relevant articles and used the Science Citation Index to find articles that cited the included studies and contacted investigators and manufacturers of low-vision aids. We handsearched the British Journal of Visual Impairment from 1983 to 1999 and the Journal of Visual Impairment and Blindness from 1976 to 1991. Selection criteria This review includes randomised and quasi-randomised trials in which any device or aid used for reading had been compared to another device or aid in people aged 16 or over with low vision as defined by the study investigators. Data collection and analysis At least two authors independently assessed trial quality and extracted data. Main results We included nine small studies with a cross-over-like design (181 people overall) and one study with three parallel arms (243 participants) in the review. All studies reported the primary outcome, results for reading speed. Two studies including 92 participants found moderate- or low-quality evidence suggesting that reading speed is higher with stand-mounted electronic devices or electronic devices with the camera mounted in a ‘mouse’ than with optical magnifiers, which in these trials were generally stand-mounted or, less frequently, hand-held magnifiers or microscopic lenses. In another study of 20 participants there was moderate-quality evidence that optical devices are better than head-mounted electronic devices (four types). There was low-quality evidence from three studies (93 participants) that reading using head-mounted electronic devices is slower than with stand-based electronic devices. The technology of electronic devices may have changed and improved since these studies were conducted. One study suggested no difference between a diffractive spectacle-mounted magnifier and either refractive (15 participants) or aplanatic (15 participants) magnifiers. One study of 10 people suggested that several overlay coloured filters were no better and possibly worse than a clear filter. A parallel-arm study including 243 participants with age-related macular degeneration found that custom or standard prism spectacles were no different from conventional reading spectacles, although the data did not allow precise estimates of performance to be made. Authors' conclusions There is insufficient evidence on the effect of different types of low-vision aids on reading performance. It would be necessary to investigate which patient characteristics predict performance with different devices, including costly electronic devices. Better-quality research should also focus on assessing sustained long-term use of each device. Authors of studies testing several devices on the same person should consider design and reporting issues related to their sequential presentation and to the cross-over-like study design.

A Simple and Practical Algorithm for Accurate Gravitational Magnification Maps

AbstractIn this brief communication, a new method is outlined for modelling magnification patterns on an observer’s plane using a first-order approximation to the null geodesic path equations for a point mass lens. For each ray emitted from a source, an explicit calculation is made for the change in position on the observer’s plane due to each lens mass. By counting the number of points in each small area of the observer’s plane, the magnification at that point can be determined. This allows for a very simple and transparent algorithm. A short Matlab code sample for creating simple magnification maps due to multiple point lenses is included in an appendix.

Measuring magnification of virtual images using digital cameras

The concept of virtual images and why they lead to angular rather than linear magnification of optical images can be vague for students. A particularly straightforward method of obtaining quantitative magnification for simple magnifiers, microscopes, and telescopes uses the technology that students carry in their backpacks—their camera phones.

Thrombus formation induced by laser in a mouse model.

Animal models are used for the development of techniques and/or models that aid the study of thrombosis pathophysiology. The aim of the present study was to modify the technique of in vivo thrombosis induction to make it more accessible. BALB/c mice were intraperitoneally anesthetized with 0.4 ml 2,2,2-tribromoethanol (266.6 mg/kg) and xylazine (13.3 mg/kg), whilst maintaining stable blood pressure and temperature. Through abdominal surgery, the mesentery was identified and isolated for the visualization of the arteries. A simple epifluorescence magnifier was used to detect the presence of thrombi. The results obtained indicate that using rose bengal at concentrations of 25 and 50 mg/kg and a laser power of 5 mW, thrombus formation occurred. In addition, formation of the thrombus occurred ~30 min following induction and the thrombus had a total area of 4,878.3 μm2, which caused total occlusion of the mesenteric artery. For visualization, platelets were labeled with calcein acetyloxymethyl ester for 1 h, which resulted in improved observation of thrombus formation in real time. Therefore, this technique may be used to perform in vivo studies simply and at low cost, and is suitable for use in a variety of studies of thrombosis.

Reading aids for adults with low vision.

The purpose of low-vision rehabilitation is to allow people to resume or to continue to perform daily living tasks, with reading being one of the most important. This is achieved by providing appropriate optical devices and special training in the use of residual-vision and low-vision aids, which range from simple optical magnifiers to high-magnification video magnifiers. To assess the effects of reading aids for adults with low vision. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 1), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE, (January 1950 to January 2013), EMBASE (January 1980 to January 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to January 2013), OpenGrey (System for Information on Grey Literature in Europe) (www.opengrey.eu/), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov/) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 31 January 2013. We searched the reference lists of relevant articles and used the Science Citation Index to find articles that cited the included studies and contacted investigators and manufacturers of low-vision aids. We handsearched the British Journal of Visual Impairment from 1983 to 1999 and the Journal of Visual Impairment and Blindness from 1976 to 1991. This review includes randomised and quasi-randomised trials in which any device or aid used for reading had been compared to another device or aid in people aged 16 or over with low vision as defined by the study investigators. At least two authors independently assessed trial quality and extracted data. We included nine small studies with a cross-over-like design (181 people overall) and one study with three parallel arms (243 participants) in the review. All studies reported the primary outcome, results for reading speed.Two studies including 92 participants found moderate- or low-quality evidence suggesting that reading speed is higher with stand-mounted electronic devices or electronic devices with the camera mounted in a 'mouse' than with optical magnifiers, which in these trials were generally stand-mounted or, less frequently, hand-held magnifiers or microscopic lenses. In another study of 20 participants there was moderate-quality evidence that optical devices are better than head-mounted electronic devices (four types).There was low-quality evidence from three studies (93 participants) that reading using head-mounted electronic devices is slower than with stand-based electronic devices. The technology of electronic devices may have changed and improved since these studies were conducted.One study suggested no difference between a diffractive spectacle-mounted magnifier and either refractive (15 participants) or aplanatic (15 participants) magnifiers.One study of 10 people suggested that several overlay coloured filters were no better and possibly worse than a clear filter.A parallel-arm study including 243 participants with age-related macular degeneration found that custom or standard prism spectacles were no different from conventional reading spectacles, although the data did not allow precise estimates of performance to be made. There is insufficient evidence on the effect of different types of low-vision aids on reading performance. It would be necessary to investigate which patient characteristics predict performance with different devices, including costly electronic devices. Better-quality research should also focus on assessing sustained long-term use of each device. Authors of studies testing several devices on the same person should consider design and reporting issues related to their sequential presentation and to the cross-over-like study design.

Why involve consumers in eye health research?

Why involve consumers in eye health research?

The Imperative and Benefits of Introducing Outcome Based Privatized Co-Regulation

Recent turmoil in the financial markets can be explained by the science of governance used by engineers to design the regulatory systems of devices operating in unknown, dynamic environments. Turmoil is the result of insufficient supplementary co-regulators. The laws of governance absolutely prohibits any direct and simple magnification but does not prohibit supplementation of regulation. This law creates an imperative for regulators to require that their regulatees establish a requisite variety of co-regulators. It is the stakeholders of regulatees that can provide the requisite variety of co-regulation required to avoid regulatory failure. Many stakeholders would typically include those individuals or organizations that government regulators are created to protect. The introduction of bottom up outcome based co-regulation by relevant stakeholders would result in the partial privatization of regulation. The resulting flexibility would allow regulatees to reduce compliance costs and obtain operating and competitive advantages. The paper identifies how bottom up private sector co-regulation by stakeholders could be introduced on an incremental basis. An example is presented on how a company efficiently raised new equity through changes in its constitution that also allowed the regulator to exempt it from the compliance processes and costs of changing auditors. A requirement for stakeholders to be effective co-regulators to reduce elements of public sector regulation is that they obtain the: (i) information, (ii) will and (iii) capability to act independently of regulatees to protect their own interests and that of the financial system as may be relevant. The role of government and its regulators would change from defining practices and processes to defining outcomes of the stakeholder and system protection required. An outcome based regime would introduce flexibility for regulatees to develop the most efficient and effective practices and process in their particular business to achieve the desired outcomes. A co-regulatory strategy would also reduce the cost to government as stakeholders complemented the monitoring role of regulators and reduced the need for regulators and the courts to take corrective action.

How do you use a magnifying glass?

At first blush, the title of this note may seem a little strange; doesn’t everyone know how to use a simple magnifier? Not if you believe what every elementary physics text I have ever seen says on the subject.

Optics and Photonics: An Introduction

First Page

Prescribing near magnification for low vision patients

Most patients with low vision request help with reading. Despite improvements in the assessment of visual functions, determining the appropriate magnification for reading still often involves a trial and error approach. Recent research has shown that with accurate and systematic assessments of vision, the required magnification can be predicted but this magnification needs to be much higher than has been previously recommended. This paper presents a systematic approach to enable practitioners to determine the power of a near addition or simple magnifier needed to assist patients with mild or moderate low vision who may present seeking help for reading. Guidelines for appropriate referral to low vision services are also provided.

Apparent Image Quality of Magnifiers Depends on Amplitude of Accommodation

We investigated the importance of the role of amplitude of accommodation in assessing the usefulness of magnifiers. Accommodation must be exerted to scan across the image produced by a magnifier that exhibits astigmatism and curvature of field. In general, increasing amounts of negative accommodation are required to scan from the center to the edge of the image field of view (FOV) when a simple magnifier is set for nominal magnification. It is necessary to refocus the magnifier (move it closer to the object plane) to convert the demand to positive accomodation. We used the OSLO program to design and evaluate the oblique astigmatism of four common types of magnifiers: Equiconvex, Best-form, Aspheric, and the Steinheil triplet, in powers of 10, 20, 40, 60, and 80 D. We found that the circle of least confusion (CLC), produced by the Equiconvex and Best-form lenses set at nominal magnification, lie on a surface that demands as much as 2.75 D of negative accommodation to view the CLC at the edge of a 30 degrees FOV. By refocusing the magnifier, the CLC at the edge of the field can be imaged at infinity, i.e., have zero vergence, and the demand for negative accommodation may be eliminated, but then about 2.4 D of positive accommodation is required to scan to the center of the field. The Aspheric and Steinheil magnifiers largely corrected the astigmatic errors and flattened the field. Less than 0.75 D of accommodation was sufficient to scan from the edge to the center of the object. Depending on the degree of uncorrected astigmatism and field curvature, presbyopic patients, lacking accommodative ability, will perceive constricted in-focus zones in the image field. They will continuously have to refocus the magnifier to bring adjacent zones into best-focus. This condition may cause a presbyope to reject a magnifier thought to be of good quality by a young clinician who can accommodate for best-focus across the entire FOV.

Primary success with low vision aids in age‐related macular degeneration

The benefit obtained from various low vision aids (LVAs) was studied in 65 consecutive patients with atrophic (70.3%) or disciform (29.7%) age-related macular degeneration (ARMD). 13.8% were able to read newsprint with age-related reading correction under proper lighting conditions. The primary success achieved with LVAs was good, 91.4% of patients being able to read newsprint. In most cases a simple magnifier (52.3%), high-powered reading glasses (10.8%) or Fonda's glasses (12.8%) were sufficient. The magnification preferred was 5x or less in 25.6% and greater than 5x to 9x in 48.8%. Patients with disciform degeneration required higher magnification than those with atrophic degeneration. It is concluded that most patients with ARMD found low vision aids useful for reading purposes and that a simple optical device was sufficient to achieve reading vision.

A survey of low vision patients in Hong Kong

This report provides some statistical information based on clinical data gathered on low vision patients who attended the low vision clinic of the Hong Kong Society for the Blind in the first three years of its operation. In this period, low vision devices were prescribed for 393 patients (46.5 per cent of the sample). The most commonly prescribed aids were simple magnifiers and distance telescopes. Cataract was the major cause of low vision.

Experimental Approaches to the Study of Regulatory Evolution

Examining the molecular aspects of regulatory evolution can add new insights to our understanding of evolutionary processes. It is already apparent that the mechanisms of transcription, translation, and protein processing place significant constraints on the types of regulatory polymorphism available for selection and that, at first glance, the regulatory differences between even closely related species appear to be more than a simple magnification of the polymorphisms found within each species. The power that molecular genetics brings to the analysis of regulatory evolution is the ability to analyze the coupling mechanisms between mutation and selectable phenotype, the ability to determine the DNA sequence changes that are the basis of the various mutations, and the ability to transcend genetic barriers between species in order to determine the genetic, as well as the phenotypic, differences between species. Each time the evolutionary process can be reduced to its more elemental components, the opportunity to gather new insights arises.

A fresh look at the open rhinoplasty technique.

Use of the open rhinoplasty technique (ORT) in certain nasal and septal deformities has proven to be an invaluable asset in the rhinoplasty armamentarium of the authors. Primarily owing to the markedly increased exposure with this technique, more accurate assessment of the deformities is possible and additional or improved surgical maneuvers become available, particularly in the tip. Sculpting the entire cartilaginous and/or bony vault, as well as correcting difficult septal malalignments, can be carried out under better direct vision with greater precision, accuracy, and predictability. This has led to improved and more consistent final results. Previous criticisms of unsightly columellar scars have been virtually eliminated through the use of improved surgical techniques and simple magnification. Overall, open rhinoplasty technique can provide many distinct advantages in certain nasal deformities with no real disadvantages over conventional closed techniques.

Nomographs for the Optical Properties of Simple Magnifiers

A general solution for equivalent power Fc magnification Mg and linear field of view W for the simple magnifier is presented in the form of two nomographs. The nomographs are useful in demonstrating graphically how a variation in a ‘user’ parameter for a simple magnifier, such as object distance, image vergence, accommodation or spectacle near addition, or eye-to-magnifier separation can change the equivalent power and theoretical field of view of the eye-magnifier system.

Simple Catadioptric Magnifiers

The present paper describes the basic principles and the geometries of certain simple catadioptric magnifiers that have been designed and fabricated. These magnifiers are made of moderately curved spherical surfaces and are capable of producing high visual magnifications with large eye-relief. Such magnifiers are found to be useful for reading microfiche having nominal frame sizes of 16mm X 12mm and 12mm X 9mm.