scholarly journals Inexpensive Binocular Indirect Ophthalmoscopy

2021 ◽  
Vol 15 (1) ◽  
pp. 243-245
Author(s):  
Aqeeda Singh ◽  
Sheng C. Hong ◽  
Kelechi Ogbuehi
Keyword(s):  
Light Source ◽  
Inexpensive Method ◽  
Indirect Ophthalmoscopy ◽  
Resource Poor ◽  
Indirect Ophthalmoscope

We aim to discuss an inexpensive method of conducting binocular indirect ophthalmoscopy without the binocular indirect ophthalmoscope headset. This technique only requires the examiner to hold a light source between their eyes and hold a condensing lens at an arm’s length. This may be particularly valuable in resource-poor settings.

scholarly journals Retinal Changes in Severe Malaria in Bangladeshi Children

2018 ◽  
Vol 42 (3) ◽  
pp. 118-124 ◽  
Author(s):  
Abul Kalam Azad ◽  
Sanat Kumar Barua ◽  
Farid Uddin Ahmed ◽  
Parvez Iqbal Sharif ◽  
Nasir Uddin Mahmud
Keyword(s):  
Severe Malaria ◽  
High Sensitivity ◽  
Plasmodium Falciparum Malaria ◽  
Retinal Hemorrhage ◽  
Clinical Tool ◽  
College Hospital ◽  
Indirect Ophthalmoscopy ◽  
Malarial Retinopathy ◽  
Direct Ophthalmoscopy ◽  
Indirect Ophthalmoscope

Background: In malaria endemic areas diagnosis of severe malaria by microscopy and immunodiagnostic test is confounded by asymptomatic peripheral blood parasitemia. In such settings, retinal changes by ophthalmoscopy showed some diagnostic utility. Contribution of ophthalmoscopy in diagnosis of severe malaria in children is not well studied in Bangladesh. The aim of this study was to describe the retinal findings in children of cerebral and non-cerebral severe malaria by direct and indirect ophthalmoscope and relate their outcome and to determine the course of changes in the fundus. Methodology: In this prospective observational study 130 consecutive children aged between 6 months to 12 years admitted with confirmed severe Plasmodium falciparum malaria in pediatrics ward of Chittagong Medical College Hospital, Chittagong, Bangladesh were assessed by both direct and indirect ophthalmoscopy during the period of April 2008 to March 2009. Results: Out of 130 patients 80 children had cerebral malaria and of these 49 (61.2%) had some degree of retinopathy; 24 (48%) of 50 with non cerebral severe malaria had retinopathy. Predominant retinal changes were Retinal hemorrhage and Macular whitening each in 53 (40.77%) patients, followed by peripheral whitening, Vessels changes and papilloedema in 50 (38.46%), 40 (30.77%) and 14 (10.78%) patients respectively. With indirect ophthalmoscope as reference, direct ophthalmoscopy had a high sensitivity to detect macular whitening, and papilloedema but was less sensitive to detect peripheral whitening and vessel changes. Patients with retinopathy had more chance to had unfavorable outcome (Death) in comparison to the patients who had not {Odds ratio:1.09 (95% CI:1.017-1.167)}. Most of these retinal changes were transient and resolved gradually as clinical condition improved. Conclusion:Features compatible with malarial retinopathy were commonly found in our children with severe malaria. Ophthalmoscopy is an important clinical tool to aid in diagnosis and prognosis in children. However, indirect ophthalmoscopy provides better information than direct ophthalmoscopy. Bangladesh J Child Health 2018; VOL 42 (3) :118-124

scholarly journals CONDENSING LENS ON BINOCULAR INDIRECT OPHTHALMOSCOPY AND SLIT-LAMP BIOMICROSCOPY

2019 ◽  
Vol 2 (2) ◽  
Author(s):  
Danang Yoga Wiguna ◽  
Sauli Ari Widjaja ◽  
Wimbo Sasono ◽  
Muhammad Firmansjah ◽  
Ima Yustiarini ◽  
...  
Keyword(s):  
Field Of View ◽  
Fundus Examination ◽  
Portable Instrument ◽  
Fundus Image ◽  
Slit Lamp ◽  
Advantages And Disadvantages ◽  
Illumination System ◽  
Indirect Ophthalmoscopy ◽  
Slit Lamp Biomicroscopy ◽  
Indirect Ophthalmoscope

Condensing lens is a lens used as an auxiliary lens in indirect instruments to examines the fundus. This lens is used with binocular indirect ophthalmoscope and slit-lamp biomicroscope to reach a stereopsis image of fundus. Optical principle of condensing lens is to make the eye in myopic condition, so it can producesa real, aerial, inverted and reversed image. This lens was placed between the instruments and the eye of the patient which located closer to patient’s eye. Optimalized position of the lens can produce a good fundus image. Condensing lens have so many power of dioptre that each power produces different magnification and field of view. High powered lenses produces wider field of view than low powered ones. High powered lens can also used in patient with small dilated pupil and shorter distance of examination. Low powered lenses offer more magnification. Fundus examination with binocular indirect ophthalmoscope and slit-lamp biomicroscope have purpose to produces stereopsis image because of the binocularity system. These two instruments have each advantages and disadvantages. The advantages of binocular indirect ophthalmoscope are a portable instrument, relatively can be used in uncooperative patient and it can be used with scleral indentation to reach more peripheral view of the fundus. Meanwhile slit-lamp biomicroscope has the advantages to offer more magnification and flexible illumination system. With higher powered lens use in biomicroscope, it also give advantages in shorter distance of examination and wider field of view.

A Method for Setting the Clearance Angle

1972 ◽  
Vol 30 ◽  
pp. 388-389
Author(s):  
Michael T. Bucek ◽  
Howard J. Arnott
Keyword(s):  
Experimental Evidence ◽  
Light Source ◽  
Black Spot ◽  
Critical Factor ◽  
Clearance Angle ◽  
Crude Approximation ◽  
Ultrathin Sections

It is believed by the authors, with supporting experimental evidence, that as little as 0.5°, or less, knife clearance angle may be a critical factor in obtaining optimum quality ultrathin sections. The degree increments located on the knife holder provides the investigator with only a crude approximation of the angle at which the holder is set. With the increments displayed on the holder one cannot set the clearance angle precisely and reproducibly. The ability to routinely set this angle precisely and without difficulty would obviously be of great assistance to the operator. A device has been contrived to aid the investigator in precisely setting the clearance angle. This device is relatively simple and is easily constructed. It consists of a light source and an optically flat, front surfaced mirror with a minute black spot in the center. The mirror is affixed to the knife by placing it permanently on top of the knife holder.

A confocal laser scanning microscope for fluorescence and reflection at video rates

1989 ◽  
Vol 47 ◽  
pp. 134-135
Author(s):  
P.M. Houpt ◽  
A. Draaijer
Keyword(s):  
Light Source ◽  
Laser Scanning ◽  
Focal Point ◽  
Confocal Laser Scanning Microscope ◽  
Confocal Laser ◽  
Point Light Source ◽  
Volume Of Interest ◽  
Ion Laser ◽  
Point Light ◽  
Point Detector

In confocal microscopy, the object is scanned by the coinciding focal points (confocal) of a point light source and a point detector both focused on a certain plane in the object. Only light coming from the focal point is detected and, even more important, out-of-focus light is rejected.This makes it possible to slice up optically the ‘volume of interest’ in the object by moving it axially while scanning the focused point light source (X-Y) laterally. The successive confocal sections can be stored in a computer and used to reconstruct the object in a 3D image display.The instrument described is able to scan the object laterally with an Ar ion laser (488 nm) at video rates. The image of one confocal section of an object can be displayed within 40 milliseconds (1000 х 1000 pixels). The time to record the total information within the ‘volume of interest’ normally depends on the number of slices needed to cover it, but rarely exceeds a few seconds.

Inter-Method Reliability of Pulse Volume Related Measures Derived Using Finger-Photoplethysmography

2018 ◽  
Vol 32 (4) ◽  
pp. 182-190 ◽  
Author(s):  
Kenta Matsumura ◽  
Koichi Shimizu ◽  
Peter Rolfe ◽  
Masanori Kakimoto ◽  
Takehiro Yamakoshi
Keyword(s):  
Light Intensity ◽  
Adverse Effects ◽  
Light Source ◽  
Direct Current ◽  
Resting State ◽  
Current Component ◽  
Psychophysiological Measures ◽  
Pulse Volume ◽  
Optical Paths ◽  
Sensor Positions

Abstract. Pulse volume (PV) and its related measures, such as modified normalized pulse volume (mNPV), direct-current component (DC), and pulse rate (PR), derived from the finger-photoplethysmogram (FPPG), are useful psychophysiological measures. Although considerable uncertainties exist in finger-photoplethysmography, little is known about the extent of the adverse effects on the measures. In this study, we therefore examined the inter-method reliability of each index across sensor positions and light intensities, which are major disturbance factors of FPPG. From the tips of the index fingers of 12 participants in a resting state, three simultaneous FPPGs having overlapping optical paths were recorded, with their light intensity being changed in three steps. The analysis revealed that the minimum values of three coefficients of Cronbach’s α for ln PV, ln mNPV, ln DC, and PR across positions were .948, .850, .922, and 1.000, respectively, and that those across intensities were .774, .985, .485, and .998, respectively. These findings suggest that ln mNPV and PR can be used for psychophysiological studies irrespective of minor differences in sensor attachment positions and light source intensity, whereas and ln DC can also be used for such studies but under the condition of light intensity being fixed.

X-ray microscopy by phase-retrieval methods at the advanced light source

2003 ◽  
Vol 104 ◽  
pp. 557-561 ◽  
Author(s):  
M. R. Howells ◽  
H. Chapman ◽  
S. Hau-Riege ◽  
H. He ◽  
S. Marchesini ◽  
...  
Keyword(s):  
Light Source ◽  
Phase Retrieval ◽  
X Ray ◽  
Advanced Light Source

Organic Light Emitting Diodes - Innovative Light Sources

2019 ◽  
pp. 101-107
Author(s):  
Sergei A. Stakharny
Keyword(s):  
Light Source ◽  
Organic Light Emitting Diodes ◽  
Organic Leds ◽  
Light Sources ◽  
High Quality ◽  
Light Emitting ◽  
Organic Light ◽  
Lighting Systems ◽  
Physical Principles ◽  
Prospects Of Application

This article is a review of the new light source – organic LEDs having prospects of application in general and special lighting systems. The article describes physical principles of operation of organic LEDs, their advantages and principal differences from conventional non-organic LEDs and other light sources. Also the article devoted to contemporary achievements and prospects of development of this field in the spheres of both general and museum lighting as well as other spheres where properties of organic LEDs as high-quality light sources may be extremely useful.

Hepatitis C Virus Infection: A Brief Review

JMS SKIMS ◽  
2020 ◽  
Vol 23 (1) ◽  
pp. 3-15
Author(s):  
Saleem Kamili ◽  
Hisham Qadri
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Basic Research ◽  
World Health ◽  
Hepatitis C Virus Infection ◽  
Poor Countries ◽  
Diagnostic Assays ◽  
Antiviral Therapies ◽  
Highly Sensitive ◽  
Resource Poor

Hepatitis C, caused by hepatitis C virus (HCV) was originally described as parenterally transmitted non-A non-B hepatitis. Since its discovery in 1989, the field of HCV research has become a shining example of successful translation of basic research wherein in a short of span of just 30 years the virus was discovered, highly sensitive and specific diagnostic assays were developed, epidemiology and clinical characteristics of the disease were well defined and now with the availability of highly efficacious antiviral therapies many countries are already on their way to achieving World Health Organization’s (WHO) elimination targets of hepatitis C by 2030.  However, much work needs to be done to eliminate hepatitis C especially in resource poor countries. Most recent data show an estimated 71 million people are currently infected with HCV worldwide and approximately 400,000 people die each year from causes related to HCV. Of these estimates, more than 13 million HCV infected persons are in India and Pakistan (Figure 1). Despite the availability of a cure for hepatitis C, only 20% of those infected patients have been diagnosed (1). In order to achieve the WHO targets of hepatitis C elimination, concerted efforts will have to made to make affordable and reliable diagnostics available worldwide.

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