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Non-Organic Vision Loss
Published in Vivek Lal, A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
Ashwini Kini, Mangayarkarasi Thandampallayam Ajjeya, Padmaja Sudhakar
In an ophthalmologist's clinic, the lenses may be used on a phoropter; however, this equipment is unavailable in a neurologist's office and may not always be feasible to do this test. A trial frame with a few loose plus and minus lenses could be kept in the clinic which may be handy in testing in such cases.
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
The patients were placed in a plus cylinder phoropter that had been modified for the study. A barrier at the nose separated the right and left eyes. A second barrier with fixation lights at zero, 5, 10, 15, and 20 degrees to the left of fixation was placed 40 cm in front of the patient’s left eye. The study subjects were asked to direct the gaze of their left eye toward the illuminated fixation light and maintain fixation on the light until retinoscopy was complete. Cycloplegic refraction was performed by a single masked examiner at a constant working distance of 66 cm. Retinoscopy at all 5 gaze positions was completed within 1 hour on each subject. Patient order and eccentric gaze position tested were randomized.
The Procedure
Published in John William Yee, The Neurological Treatment for Nearsightedness and Related Vision Problems, 2019
For test purposes, rely on trial lenses instead of a phoropter to avoid the possibility of inducing instrument myopia. You want the crystalline lens to participate in the visual acuity test to help determine the weaker eye in Step 6 if the prescription of both eyes is the same or close to being the same. The information is necessary to establish the wearing sequence in Step 7. The correct wearing sequence for the specific drill synchronizes the right and left eye.
Three-Dimensional Choroidal Vascularity Index in High Myopia Using Swept-Source Optical Coherence Tomography
Published in Current Eye Research, 2022
Lu Liu, Chengcheng Zhu, Ying Yuan, Xiaojun Hu, Chaoyue Chen, Hong Zhu, Bilian Ke
We collected demographics (age, sex) and the ophthalmic parameters were also recorded. Each subject underwent a complete ophthalmic examination firstly, which included a slit-lamp examination of the anterior segment of the eye and an ophthalmoscopic examination of the fundus. The ophthalmic examinations of all subjects were normal, without any signs of myopic maculopathy or other ocular disorders. Refractive error was screened with autorefraction and then confirmed by an experienced optometrist with a standard phoropter. Refraction data were converted to SE, which was calculated as the spherical dioptric power plus one-half of the cylindrical dioptric power. BCVA was measured monocularly using a Snellen chart and then converted to log MAR (Logarithm of the Minimum Angle of Resolution) scale for statistical evaluation. Axial length (AL) and anterior chamber depth (ACD) were obtained from the IOLMaster (Zeiss 500; Carl Zeiss Meditec, Inc, Dublin, CA). All the measurements were taken three times by two skilled examiners independently who were masked to the clinical status of the subjects, and the results were averaged. According to refractive status, the 98 right eyes were organized into two groups. High myopia group (HM, SE≤-6D) consisted of 46 subjects; low to moderate myopia group (LMM, −6.0D<SE≤−0.5D) consisted of 52 subjects.
Convergence insufficiency in Chinese high school students
Published in Clinical and Experimental Optometry, 2019
Martin Ming‐leung Ma, Wen Long, Zhihui She, Wanping Li, Xuhui Chen, Lingmei Xie, Mitchell Scheiman, Yuling Liu, Xiang Chen
For distance measurements, the Maddox rod technique with phoropter, another reliable subjective method,1996 was used instead. These two phoria measurements were used to define convergence insufficiency. Positive fusional vergence was measured at 40-cm using a Risley rotating prism on the phoropter, and the average of three measures of break point was used for analysis. Blur point was not used because clinically many patients had difficulty recognising the blurring of a fixation target.2008 A column of 6/9 letters was used for the positive fusional vergence testing. The monocular accommodative amplitude (right eye only) was measured by using the push‐up method in free space; this test was repeated three times using a column of 6/9 letters as the fixation target. The patient was instructed to report the ‘first sustained blur’ as the target was moved slowly (1–2-cm/second) toward the eye. There was no specific requirement on the waiting time between repeated measurements or between different tests.
Barriers to eye care among participants of a mobile eye clinic
Published in Cogent Medicine, 2019
Kousanee Chheda, Rong Wu, Tosha Zaback, Mitchell V. Brinks
Participants completed a demographic and subjective visual function questionnaire inquiring about race/ethnicity, gender, health insurance coverage, zip code of residence, history of diabetes, and TLEE. Subjective measures of vision were collected. Participants indicated whether they had no, little, moderate, or severe difficulty reading a newspaper and reading street signs according to the National Eye Institute Visual Function Questionnaire (Crews et al., 2012; Mangione et al., 2001), a widely used tool in existing research. Near visual acuity was then measured with a hand held Snellen Eye chart and distance visual acuity with a Snellen Eye chart at 20 feet. Autorefraction (NIDEK ARK-530A/ARK-510A), pupil exam, tonometry (Reicher Tono-Pen AVIA), and lensometry (NIDEK LM-600P) were performed and dilation drops (Bausch + Lomb 1% tropicamide, Tampa, FL) were administered if anatomic narrow angles or risk factors for narrow angle glaucoma were not identified. An eye doctor performed manifest refractions using a phoropter (Recihert Phoroptor model 11635/11635B), and a comprehensive eye health exam with a slit lamp and indirect ophthalmoscope. Participants requiring prescriptive spectacle correction were provided a prescription and subsidized or free spectacles. If participants required further evaluation or medication based on abnormal exam findings, they were referred to a clinic-based eye doctor for further evaluation. Access to clinical eye care was managed by partner agencies. Interpreters were provided at each screening as needed through the partner agency. Paper charts were transcribed into OnBase® (version 15.0.1.84; Westlake, Ohio). Analysis was conducted on de-identified data to ensure confidentiality.