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Investigative Ophthalmology & Visual... Apr 2014To quantify the angle of view, the magnification, and the quality of images acquired with an Optos 200Tx.
PURPOSE
To quantify the angle of view, the magnification, and the quality of images acquired with an Optos 200Tx.
METHODS
We obtained fundus images of a model eye with the Optos 200Tx and recorded the maximal scale imaged in each direction. We measured the length of the scale bar and the interval of the scale bars at each angle and calculated the magnification. We also measured the contrast between scale bars and the intervals between scale bars.
RESULTS
The fundus image obtained with the Optos 200Tx covered 96, 101, 76, and 102° in the up, right, down, and left directions, respectively. Quantitative measurement showed that the overall image is stretched 1.12-fold in the horizontal direction with respect to the vertical. The magnification with respect to the posterior pole increased quadratically in all directions, most steeply in the vertical direction, reaching 2.0 × 1.5 in the most extreme case. The image quality was best in the left part and was worse in the inferior and superior parts.
CONCLUSIONS
The Optos 200Tx can obtain an image duplicated, with an angular range of approximately 200° horizontally and 170° vertically, with greatest limitation in the inferior direction. It should be noted that the most peripheral part of the image is significantly and unequally magnified. In addition, the contrast is not the same at all positions. The present data would serve as a guide to correct the peripheral magnification in future studies.
Topics: Equipment Design; Fluorescein Angiography; Fundus Oculi; Humans; Image Processing, Computer-Assisted; Models, Theoretical; Ophthalmoscopes; Reproducibility of Results; Retina
PubMed: 24667862
DOI: 10.1167/iovs.13-13738 -
Klinische Monatsblatter Fur... Jun 1982A new indirect spectacle ophthalmoscope is described. Its main features are a fixed interpupillary distance (59, 62, 65, 68 mm.), a variable viewing beam stereoangle, a...
A new indirect spectacle ophthalmoscope is described. Its main features are a fixed interpupillary distance (59, 62, 65, 68 mm.), a variable viewing beam stereoangle, a precentered halogen lighting beam with Maxwellian view and an iris diaphragm to limit the viewing area, which has never been a feature of a binocular ophthalmoscope before. These features, on a lightweight spectacle frame, make indirect binocular ophthalmoscopy an easy-to-master method even for examining patients with small pupils and hazy media.
Topics: Humans; Ophthalmoscopes
PubMed: 7132187
DOI: 10.1055/s-2008-1055154 -
Eye (London, England) Nov 2021The Arclight is a novel, low-cost, solar-powered direct ophthalmoscope developed for low resource settings as an alternative to more expensive, conventional devices. The...
BACKGROUND/OBJECTIVES
The Arclight is a novel, low-cost, solar-powered direct ophthalmoscope developed for low resource settings as an alternative to more expensive, conventional devices. The Brückner reflex test (BRT) is a quick and effective means to screen for eye disease and amblyogenic risk factors. This test is however rarely performed in low resource settings due to the lack of access to ophthalmoscopes and trained health care workers. Our aim was to establish the sensitivity and specificity of the BRT when performed by a non-expert using an Arclight and compare to an expert as well as the results of a full clinic workup.
SUBJECTS/METHODS
In this prospective, blinded study, 64 patients referred to a paediatric ophthalmology clinic had the BRT performed by a 'non-expert' observer (medical student) then an 'expert' observer (consultant ophthalmologist). These results were then compared against the 'gold standard' outcomes of a full clinical workup.
RESULTS
BRT screening by the expert observer led to a sensitivity of 75.0% [95% CI: 57.9-86.8%] and a specificity of 90.6% [95% CI: 75.8-96.8%] in picking up media opacity, strabismus, refractive error or a combination of the above. For the non-expert, the sensitivity and specificity were 71.9% [95% CI: 54.6-84.4%] and 84.4% [95% CI: 68.3-93.1%], respectively.
CONCLUSIONS
The Arclight can be effectively used to perform the BRT and identify eye disease and common amblyogenic risk factors. Even when performed by a non-expert the results are highly specific and moderately sensitive. This study consequently offers support for the use of this low-cost ophthalmoscope in the expansion of eye screening by health care workers in low resource settings.
Topics: Child; Humans; Ophthalmoscopes; Prospective Studies; Reflex; Risk Factors; Strabismus
PubMed: 33414528
DOI: 10.1038/s41433-020-01341-9 -
British Medical Journal Mar 1965
Topics: Choroid; Diathermy; Equipment and Supplies; Eye Diseases; Humans; Lasers; Light Coagulation; Ophthalmoscopes; Ophthalmoscopy; Phototherapy; Retina
PubMed: 14258846
DOI: 10.1136/bmj.1.5438.823 -
BMC Medical Education Jun 2019Direct ophthalmoscopy (DO) is an essential skill for medical graduates but there are multiple barriers to learning this. Medical students and junior doctors typically... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Direct ophthalmoscopy (DO) is an essential skill for medical graduates but there are multiple barriers to learning this. Medical students and junior doctors typically lack confidence in DO. Most students do not own an ophthalmoscope and learn via ward devices that vary in design and usability. The Arclight ophthalmoscope (AO) is an easy to use, low-cost and portable device that could help address device access. This study aimed to assess the impact of personal ownership of an AO on DO skill acquisition and competency amongst medical students in the clinical environment.
METHODS
Method comparison study with 42 medical students randomised to either traditional device ophthalmoscope (TDO) control or AO intervention group during an 18-week medical placement. Three objective assessments of DO competency were performed at the beginning and end of the placement: vertical cup to disc ratio (VCDR) measurement, fundus photo multiple-choice questions (F-MCQ) and model slide examination (MSE). DO examinations performed during the placement were recorded via an electronic logbook.
RESULTS
Students in both groups recorded a median number of six examinations each during an eighteen-week placement. There was no statistically significant difference between the groups in any of the objective assessment measures (VCDR p = 0.561, MCQ p = 0.872, Model p = 0.772). Both groups demonstrated a minor improvement in VCDR measurement but a negative performance change in F-MCQ and MSE assessments.
CONCLUSIONS
Students do not practice ophthalmoscopy often, even with constant access to their own portable device. The lack of significant difference between the groups suggests that device access alone is not the major factor affecting frequency of DO performance and consequent skill acquisition. Improving student engagement with ophthalmoscopy will require a more wide-ranging approach.
Topics: Clinical Competence; Education, Medical, Undergraduate; Educational Measurement; Female; Humans; Male; Ophthalmology; Ophthalmoscopes
PubMed: 31196068
DOI: 10.1186/s12909-019-1644-5 -
Pediatric Emergency Care Jun 2001Thorough knowledge about the basic ophthalmic examination is instrumental in the emergency department (ED) to determine the severity of eye emergencies and to develop a... (Review)
Review
Thorough knowledge about the basic ophthalmic examination is instrumental in the emergency department (ED) to determine the severity of eye emergencies and to develop a plan for treatment, including the possible need for an ophthalmology consultation. The direct ophthalmoscope is undoubtedly the most practical instrument available to a pediatric emergency physician for ophthalmic examination. However, the information elicited by its use is dependent on the quality of the instrument and the competency of the user. A greater understanding of the range of possibilities of the direct ophthalmoscope as a diagnostic tool will facilitate more efficient care of the pediatric patient.
Topics: Child; Emergency Medical Services; Emergency Medicine; Eye Diseases; History, 19th Century; Humans; Ophthalmoscopes; Ophthalmoscopy; Pediatrics
PubMed: 11437148
DOI: 10.1097/00006565-200106000-00013 -
Transactions of the American... 1965
Topics: Ophthalmoscopes; Ophthalmoscopy
PubMed: 5859789
DOI: No ID Found -
American Journal of Ophthalmology Oct 1973
Topics: Animals; Europe; Fundus Oculi; Germany; History, 19th Century; History, 20th Century; Humans; Ocular Physiological Phenomena; Ophthalmoscopes; Ophthalmoscopy
PubMed: 4582793
DOI: 10.1016/0002-9394(73)90737-x -
A.M.A. Archives of Ophthalmology Nov 1957
Topics: Humans; Ophthalmoscopes; Ophthalmoscopy; Vision Tests
PubMed: 13468859
DOI: 10.1001/archopht.1957.00940010774016 -
Progress in Retinal and Eye Research Mar 2003In 1851 Helmholtz introduced the ophthalmoscope. The instrument allowed the observation of light reflected at the fundus. The development of this device was one of the... (Review)
Review
In 1851 Helmholtz introduced the ophthalmoscope. The instrument allowed the observation of light reflected at the fundus. The development of this device was one of the major advancements in ophthalmology. Yet ophthalmoscopy allows only qualitative observation of the eye. Since 1950 attempts were made to address the challenging, quantitative assessment of the amount of light reflected by the fundus. At first, only comparative measurements were possible, applied in the study of macular and visual pigments. With improvements in light detecting techniques, and with the advent of microprocessors, the measurement of spectral and spatial distribution of the reflectance became feasible. This led to the development of models that explained the observed wavelength dependence and the directional behavior of light reflected from the fovea. The models allowed a quantitative assessment of many parameters on absorption and reflection by structures in the human eye. This paper provides a review of both the experimental and theoretical progress, and summarizes the results of fundamental and clinical research using fundus reflectometry.
Topics: Diagnostic Techniques, Ophthalmological; Eye; Eye Diseases; History, 19th Century; History, 20th Century; History, 21st Century; Humans; Models, Biological; Ocular Physiological Phenomena; Ophthalmology; Ophthalmoscopes; Spectrophotometry
PubMed: 12604057
DOI: 10.1016/s1350-9462(02)00060-5