China
Africa
Explore chapters and articles related to this topic
Clinical Examination in Neuro-Ophthalmology
Published in Vivek Lal, A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
Selvakumar Ambika, Krishnakumar Padmalakshmi
The standard recording of visual acuity is by Snellen notation which is a fraction. The numerator denotes the testing distance (6 m or 20 feet) and the denominator is the distance at which a normal person is able to read the letter (Figure 1.3). Variations in the Snellen chart for patients who are unable to read include the “Landolt C” or the Illiterate E chart, which allows testing of acuity based on the orientation of the letters. Other visual acuity charts with better specifications include ETDRS, logMAR and Bailey-Lovie charts.
Screening Programs
Published in Ching-Yu Cheng, Tien Yin Wong, Ophthalmic Epidemiology, 2022
Jakob Grauslund, Malin Lundberg Rasmussen
Visual acuity is measured using the Snellen, E chart, or similar charts. It can be easily tested by minimally trained personnel. In most children, visual acuity can be examined at the age of 4 or 5 or even younger. If any suspicion of visual impairment arises, patients should be referred to an ophthalmologist, where more detailed visual acuity can be measured.
Ophthalmic nursing procedures and investigations
Published in Mary E. Shaw, Agnes Lee, Ophthalmic Nursing, 2018
The tumbling E chart again is mainly used for patients who are illiterate. In the chart, the Es face in different directions. The patient is asked to hold a wooden E in his hand and to turn it the same way as the one the examiner is pointing to on the test chart.
Unilateral Vision Loss in Elderly People in Residential Care: Prevalence, Causes and Impact on Visual Functioning: The Hyderabad Ocular Morbidity in Elderly Study (HOMES)
Published in Ophthalmic Epidemiology, 2023
Srinivas Marmamula, Navya Rekha Barrenkala, Thirupathi Reddy Kumbham, Satya Brahmanandam Modepalli, Jill Keeffe
Trained examiners conducted the clinical assessments in ‘makeshift’ (temporary) clinics set up in each home for the aged. The clinical assessment protocol has been described in our previous publications.23,24 In brief, the clinical examination included visual acuity assessment, refraction, anterior and posterior segment examination. Distance and near visual acuity (VA) were assessed using a logMAR chart (logarithm of Minimum Angle of Resolution) at three metres and 40 centimetres, respectively. Tumbling E chart and English charts were used as needed. Also, presenting, pinhole, and best-corrected visual acuity were assessed. Anterior segment examination was done using a portable handheld slit lamp biomicroscope (BA 904 Haag-Streit Clement Clarke International, UK). Fundus images were taken using a non-mydriatic fundus camera (Zeiss Visuscout 100), and they were graded by trained graders. Participants having VI due to uncorrected refractive errors were provided with spectacles, and those who needed further care were referred to the L V Prasad Eye Institute for service provision. All eye care services and spectacles were provided at no cost to the participants.
Ultrasonic ocular dimensions and anthropometry in normal and myopic eyes: a case-control study
Published in Expert Review of Ophthalmology, 2022
Faosat Olayiwola Jinadu, Iskilu Adekunle Jolaoso, Modupe Balogun, Tawaqualit Abimbola Ottun, Ufuoma Oluwaseyi Olumodeji, Ayokunle Moses Olumodeji
The refractive statuses of all the study participants were determined at the ophthalmology unit of the study hospital by a senior optometrist; who at the outset identified participants with or without visual impairment after carrying out visual acuity test on them. Each participant was asked to read alphabets on the Snellen’s chart or E-chart (for illiterate subjects) from a distance of 6 meters using one eye at a time while the other eye was covered with a black cardboard. Participants that were unable to read down to the level of 6/6 were categorized as being visually impaired and such group of participants were asked to repeat the procedure using a pin-hole as a visual aid to determine whether the visual impairment was due to refractive error (if there was an improvement in the vision with the use of the pin-hole) or due to other ocular pathologies (if there was no improvement with the use of pin-hole).
Distribution of near Point of Convergence, near Point of Accommodation, Accommodative Facility and Refractive Errors in a Rural Population Living in Northern Iran
Published in Journal of Binocular Vision and Ocular Motility, 2021
Ali Zakian, Samira Heydarian, Ali Mirzajani, Ebrahim Jafarzadehpur, Abbasali Yekta, Mehdi Khabazkhoob
Visual acuity was measured with a Snellen E-chart at 6 m. Then, refraction was done for all subjects using the Topcon RM-8800 auto refractometer (Tokyo, Japan) and the results were used for objective and subjective refraction. The data obtained at this stage were used to measure the best-corrected visual acuity. Next, cycloplegic refraction was measured for all subjects 30 minutes after instilling cyclopentolate 1% drops twice 5 minutes apart. Refractive error was categorized according to cycloplegic refraction. Spherical equivalent (SE) was used for calculations of refractive error. Myopia was defined as an SE of at least −0.5 D and hyperopia was defined as an SE of +0.5 D or more. Emmetropia was defined if neither eye was myopic or hyperopic. Astigmatic subjects were a cylinder refraction of 0.75 D or more in at least one eye, which was recorded with a negative sign.