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Effect of off-axis retinoscopy on objective refractive measurement
Published in Jan-Tjeerd de Faber, 28th European Strabismological Association Meeting, 2020
E.A. Paysse, D.W. Jackson, K.R. Wilhelmus, M.A.W. Hussein, G. Rosby, D.K. Coats
Accurate retinoscopy is a key component of pediatric ophthalmologic examination. Optics textbooks have repeatedly stated that the accuracy of retinoscopy is improved when performed on-the-visual-axis.1–3,10 Uncooperative children, unsteady fixation, and problems with eye position during examination under anesthesia can make it difficult, if not impossible, to refract on-the-visual-axis.4 The true impact of eccentric retinoscopy in clinical situations has received little attention.
The Special Sense Organs and Their Disorders
Published in Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss, Understanding Medical Terms, 2020
Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss
Gonioscopy is the examination of the angle of the anterior chamber with a gonioscope (lens) or a contact prism lens and beam illumination from a slit lamp. This procedure is used to detect retinal or optic nerve disease. Applanation tonometry is used to measure intraocular pressure in millimeters of mercury (mmHg). If diagnosis is still in doubt, provocative procedures such as a water drinking test, darkroom test, or mydriatic tests are employed. Other diagnostic procedures may include gross visual fields and basic motor exam, fluorescent angioscopy (examination of the capillary vessels), slit lamp examination, keratometry, ophthalmodynamometry, needle oculo-electromyography, electro-oculography (EOG), and retinoscopy.
Optics and refractive errors
Published in Mostafa Khalil, Omar Kouli, The Duke Elder Exam of Ophthalmology, 2019
Nemat Ahmed, Omar Kouli, Mostafa Khalil, Obaid Kousha
Light from a retinoscope is shone into the patient's retina at a certain distance. The aim is to observe the patient's red reflex while adding plus/minus lenses until a complete red reflex is observed. In myopic patients, the direction of the reflex is against the direction of the light. In hypermetropic patients, the direction of reflex is with the direction of light.
A Novel Use of Retinoscopy for the Evaluation of Binocular Balance of Spherical Refractive Errors
Published in Seminars in Ophthalmology, 2022
Ebubekir Durmus, Veysel Aykut, Isil Karagoz, Mustafa Hepokur, Ozlem Turkyilmaz, Emine Savran Elibol, Fehim Esen, Halit Oguz
There were only 30 patients in this study. We did a post hoc power calculation with the G*Power 3.1 software for mac to understand whether the sample size was large enough for the intergroup comparisons of interocular spherical equivalent difference and the statistical power was sufficient (0.956). Therefore, we believe that this sample size was large enough to test our primary outcome measure, while it might not have been large enough for subgroup comparisons, which was not an outcome measure in this study. Further studies with larger sample sizes can be performed to better understand whether this technique also works well in patients with very high myopia or hyperopia. Although retinoscopy is the gold standard test for the objective evaluation of refractive errors, many eyecare practitioners refrain from the use of retinoscopy after the development of modern diagnostic tools, mainly because the use of the automated instruments is simpler and does not rely on clinical experience as much. Therefore, the results obtained here may not always be reached at every setting at the beginning since noticing small differences in refraction can only be achieved after a certain level of experience. However, many eyecare practitioners learn retinoscopy during their training and this skill gets weaker over time due to infrequent use. More frequent use of retinoscopy would improve the retinoscopy skills and deliver fast and reliable results for the objective evaluation of binocular balance.
The utility of a direct ophthalmoscope in estimating the magnitude of refractive error using a modification of the Brückner test
Published in Expert Review of Ophthalmology, 2021
Praveena S. Kumar, Yogish Subraya Kamath
Refractive errors are the second major cause of blindness in India [1]. Refractive errors in children are often missed due to challenges in evaluation, and may result in amblyopia if left untreated. Poor vision also hinders academic performance and the child’s over all development [2]. These events can be prevented by the early detection of advanced refractive errors, which can ensure timely management with spectacles. Various devices like automated refractometers and photo screeners have been developed for detection of refractive errors, but are not in widespread use as they are expensive and inaccessible in rural areas [3,4]. Simpler techniques like retinoscopy are time consuming and require personnel trained in Ophthalmology [3]. The direct ophthalmoscope is an instrument that is frequently used by Pediatricians and Internists, for viewing the ocular fundus. The utility of this device in estimation of the refractive error would help in early detection and referral of individuals with higher refractive errors.
Need for optical intervention in children attending a school for the blind in Eritrea
Published in Clinical and Experimental Optometry, 2018
Rajendra Gyawali, Vanessa R Moodley
Refractive status in each child was determined using objective and subjective refraction. Retinoscopy was performed in cases where a retinoscopy reflex was appreciable by the examiner. Control of accommodation during refraction was obtained either by fogging method or cycloplegic agents. In cases where retinoscopy could not be performed, subjective methods were applied to ascertain any improvement with refractive correction. Subjective refraction was performed using the trial frame and loose lens method with the magnitude of difference between the lens choices presented based on the differences discernible by the patient (just noticeable difference). A handheld ±0.50 Jackson crossed cylinder was used for astigmatic check. Other ancillary methods such as ‘hit and trial’ and eccentric viewing techniques were also tried in attempts to obtain best vision with the trial lenses. Myopia was defined as spherical equivalent (SE) error of at least −0.50 D or less, hyperopia as +1.00 D or more and astigmatism as 0.75 D or more in the better eye (and the eye with least error in cases with equal visual acuity).