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Abraham CH, Sakyi-Badu G, Boadi-Kusi SB, Morny E, Darko-Takyi C, Ocansey S, Hope PKF, Dadzie AK, Aboagye MacCarthy A, Osei-Frimpong K, Nyarkoa Opoku E, Kwasi Abu E. Simulation of visual impairment in persons with normal vision for scientific research. Ophthalmic Physiol Opt 2024; 44:442-456. [PMID: 38223917 DOI: 10.1111/opo.13268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 01/16/2024]
Abstract
Simulation of visual impairment in healthy eyes has multiple applications in students' training, research and product development. However, due to the absence of an existing standard protocol, the method of simulation was left to the discretion of the researcher. This review aimed to outline the various methods of simulating visual impairment and categorising them. A scoping review of the relevant publications was conducted. Of the 1593 articles originally retrieved from the databases, 103 were included in the review. The characteristics of the participants, the method for simulation of the visual impairment in persons with normal vision and the level or type of visual impairment that was simulated were extracted from the papers. None of the methods of simulation can be judged as being superior to the others. However, electronic displays produced the most consistent form of visual impairment simulation.
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Affiliation(s)
- Carl Halladay Abraham
- Department of Optometry and Vision Science, University of Cape Coast, Cape Coast, Ghana
| | - Godfred Sakyi-Badu
- Department of Optometry and Vision Science, University of Cape Coast, Cape Coast, Ghana
| | | | - Enyam Morny
- Department of Optometry and Vision Science, University of Cape Coast, Cape Coast, Ghana
| | - Charles Darko-Takyi
- Department of Optometry and Vision Science, University of Cape Coast, Cape Coast, Ghana
| | - Stephen Ocansey
- Department of Optometry and Vision Science, University of Cape Coast, Cape Coast, Ghana
| | | | - Albert Kofi Dadzie
- Department of Optometry and Vision Science, University of Cape Coast, Cape Coast, Ghana
| | | | | | | | - Emmanuel Kwasi Abu
- Department of Optometry and Vision Science, University of Cape Coast, Cape Coast, Ghana
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Tanke N, Barsingerhorn AD, Goossens J, Boonstra FN. The Developmental Eye Movement Test Does Not Detect Oculomotor Problems: Evidence from Children with Nystagmus. Optom Vis Sci 2022; 99:711-717. [PMID: 35914094 PMCID: PMC9470044 DOI: 10.1097/opx.0000000000001930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 07/04/2022] [Indexed: 11/25/2022] Open
Abstract
SIGNIFICANCE The Developmental Eye Movement (DEM) test, a test purported to assess oculomotor skills, does not detect eye movement disorder in nystagmus syndromes. The test should not be used for the clinical evaluation of oculomotor disorders. PURPOSE The DEM test ratio compares a horizontal number naming subtest with a vertical one to identify oculomotor problems independent of a child's visual-verbal naming skills. Here, we tested the construct validity of this method by comparing scores of children with and without pathologic nystagmus. Such a nystagmus disturbs normal fixation and saccadic behavior because of the presence of involuntary rhythmic oscillations of the eyes. Therefore, if the ratio is indeed a comprehensive measure of oculomotor problems, children with nystagmus should show an increased ratio score. METHODS The DEM test performances of normally sighted children (n = 94), children with ocular visual impairments (VI o ; n = 33), and children with cerebral visual impairment (n = 30) were analyzed using linear regression. Part of the children with VI o and cerebral visual impairment had either fusion maldevelopment nystagmus syndrome (n = 8) or infantile nystagmus syndrome (n = 20), whereas the others showed no pathologic nystagmus. RESULTS The times needed for the horizontal and vertical subtests were significantly different between children with normal vision, VI o , and cerebral visual impairment ( P < .001). However, the presence of nystagmus did not add significantly to the horizontal and vertical times ( P > .20), nor did it have an effect on the ratio ( P > .10). CONCLUSIONS The DEM test ratio is not sensitive to fixation and saccade abnormalities associated with nystagmus, indicating that it does not have general construct validity to detect true eye movement disorders. Although not suitable for the evaluation of oculomotor disorders, the subtests do have clinical relevance in the diagnosis of cerebral visual impairment.
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Affiliation(s)
- Nouk Tanke
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Annemiek D. Barsingerhorn
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Centre, Nijmegen, the Netherlands
- Department of Biophysics, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Jeroen Goossens
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - F. Nienke Boonstra
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Centre, Nijmegen, the Netherlands
- Royal Dutch Visio, National Foundation for the Visually Impaired and Blind, Nijmegen, the Netherlands
- Behavioral Science Institute, Radboud University, Nijmegen, the Netherlands
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Neveu MM, Padhy SK, Ramamurthy S, Takkar B, Jalali S, Cp D, Padhi TR, Robson AG. Ophthalmological Manifestations of Oculocutaneous and Ocular Albinism: Current Perspectives. Clin Ophthalmol 2022; 16:1569-1587. [PMID: 35637898 PMCID: PMC9148211 DOI: 10.2147/opth.s329282] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 04/14/2022] [Indexed: 11/23/2022] Open
Abstract
Albinism describes a heterogeneous group of genetically determined disorders characterized by disrupted synthesis of melanin and a range of developmental ocular abnormalities. The main ocular features common to both oculocutaneous albinism (OCA), and ocular albinism (OA) include reduced visual acuity, refractive errors, foveal hypoplasia, congenital nystagmus, iris and fundus hypopigmentation and visual pathway misrouting, but clinical signs vary and there is phenotypic overlap with other pathologies. This study reviews the prevalence, genetics and ocular manifestations of OCA and OA, including abnormal development of the optic chiasm. The role of visual electrophysiology in the detection of chiasmal dysfunction and visual pathway misrouting is emphasized, highlighting how age-associated changes in visual evoked potential (VEP) test results must be considered to enable accurate diagnosis, and illustrated further by the inclusion of novel VEP data in genetically confirmed cases. Differential diagnosis is considered in the context of suspected retinal and other disorders, including rare syndromes that may masquerade as albinism.
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Affiliation(s)
- Magella M Neveu
- Department Electrophysiology, Moorfields Eye Hospital, London, EC1V 2PD, UK.,Institute of Ophthalmology, University College London, London, UK
| | | | | | - Brijesh Takkar
- Anant Bajaj Retina Institute, LV Prasad Eye Institute, Hyderabad, India
| | - Subhadra Jalali
- Anant Bajaj Retina Institute, LV Prasad Eye Institute, Hyderabad, India
| | - Deepika Cp
- Anant Bajaj Retina Institute, LV Prasad Eye Institute, Hyderabad, India
| | - Tapas Ranjan Padhi
- Anant Bajaj Retina Institute, LV Prasad Eye Institute, Bhubaneswar, India
| | - Anthony G Robson
- Department Electrophysiology, Moorfields Eye Hospital, London, EC1V 2PD, UK.,Institute of Ophthalmology, University College London, London, UK
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Tanke N, Barsingerhorn AD, Goossens J, Boonstra FN. The Developmental Eye Movement Test as a Diagnostic Aid in Cerebral Visual Impairment. Front Hum Neurosci 2021; 15:732927. [PMID: 34776905 PMCID: PMC8582923 DOI: 10.3389/fnhum.2021.732927] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 10/06/2021] [Indexed: 11/13/2022] Open
Abstract
The symptoms that characterize children with cerebral visual impairments (CVI) are diverse, ranging from extensive behavioral or physical disabilities to subtle changes that can easily be missed. A correct diagnosis of CVI is therefore difficult to make, but having a wide variety of tests available can be helpful. This study aims to determine if the developmental eye movement test (DEM) can be one of those tests. In this test, a fixed set of numbers has to be read aloud, first in vertical columns and then in horizontal lines. In order to measure differences between children with CVI compared to normally sighted age-matched controls and children with a visual impairment (VI), we determined DEM times, crowding intensities and the reaction time to a large visual stimulus for all three groups. We found that children with CVI or VI need significantly more time to read the DEM numbers than age-matched controls. Additionally, children with CVI need more time than children with VI to read the horizontal DEM, but not the vertical DEM. We also found a significant difference between the children with CVI and the other two groups in the relationship between horizontal DEM performance and crowding intensity. However, for the relationship between DEM performance and visual detection time, no group-differences were found. We conclude that the DEM can be a useful addition in the diagnosis of CVI, especially in combination with information about crowding.
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Affiliation(s)
- Nouk Tanke
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Annemiek D Barsingerhorn
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Centre, Nijmegen, Netherlands.,Department of Biophysics, Donders Institute for Brain, Cognition and Behavior, Radboud University, Nijmegen, Netherlands
| | - Jeroen Goossens
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Centre, Nijmegen, Netherlands
| | - F Nienke Boonstra
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Centre, Nijmegen, Netherlands.,Royal Dutch Visio, National Foundation for the Visually Impaired and Blind, Nijmegen, Netherlands.,Behavioral Science Institute, Radboud University, Nijmegen, Netherlands
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DeCarlo DK, Gao L, McGwin G, Owsley C, Kwon M. Repeatability and Validity of MNREAD Test in Children With Vision Impairment. Transl Vis Sci Technol 2020; 9:25. [PMID: 33384883 PMCID: PMC7757625 DOI: 10.1167/tvst.9.13.25] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 08/27/2020] [Indexed: 11/24/2022] Open
Abstract
Purpose To evaluate the test-retest reliability and validity of the MNREAD test for use in children with vision impairment (VI) and to compare their performance on the test to that of normally sighted children. Methods Children with VI (n = 62) and without VI (n = 40) were administered the MNREAD test and the Basic Reading Inventory (BRI) on two study visits, 1 to 3 weeks apart. The maximum reading rate, critical print size, and reading acuity were determined for the MNREAD test, and test-retest reliability was evaluated. The reading rate for the MNREAD test was compared to the BRI results. Results Strong correlations between visits were found for all MNREAD parameters (0.68-0.99). Older, but not younger, children with VI read significantly more slowly on both the MNREAD and the BRI than children with normal vision (P < 0.05). Reading rates between the two tests were strongly correlated (r = 0.88). For the MNREAD test, the reading rate increased 4.4 words per minute (wpm) per year for VI and 10.6 wpm/y for those with normal vision. For the BRI, the reading rate increased by 5.9 wpm/y for VI and 9.7 wpm/y for those with normal vision. Poorer visual acuity was associated with slower reading rates on the MNREAD test but not on the BRI, as the MNREAD relies largely on visual factors but the BRI also relies on linguistic and grammar skills. Conclusions The MNREAD test are reliable and valid for use in children with vision impairment. Translational Relevance The MNREAD test can be utilized by clinicians, as they are a quick, easy-to-administer method for evaluating reading vision in children with VI.
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Affiliation(s)
- Dawn K DeCarlo
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.,Department of Optometry, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Liyan Gao
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Gerald McGwin
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.,Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, AL, USA.,Department of Surgery, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Cynthia Owsley
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - MiYoung Kwon
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
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Current and emerging treatments for albinism. Surv Ophthalmol 2020; 66:362-377. [PMID: 33129801 DOI: 10.1016/j.survophthal.2020.10.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 10/07/2020] [Accepted: 10/21/2020] [Indexed: 12/24/2022]
Abstract
Albinism is a group of rare inherited disorders arising from impairment of melanin biosynthesis. The reduction of melanin synthesis leads to hypopigmentation of the skin and eyes. A wide range of ophthalmic manifestations arise from albinism, including reduction of visual acuity, nystagmus, strabismus, iris translucency, foveal hypoplasia, fundus hypopigmentation, and abnormal decussation of retinal ganglion cell axons at the optic chiasm. Currently, albinism is incurable, and treatment aims either surgically or pharmacologically to optimize vision and protect the skin; however, novel therapies that aim to directly address the molecular errors of albinism, such as l-dihydroxyphenylalanine and nitisinone, are being developed and have entered human trials though with limited success. Experimental gene-based strategies for editing the genetic errors in albinism have also met early success in animal models. The emergence of these new therapeutic modalities represents a new era in the management of albinism. We focus on the known genetic subtypes, clinical assessment, and existing and emerging therapeutic options for the nonsyndromic forms of albinism.
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Prakash E, McLean RJ, White SJ, Paterson KB, Gottlob I, Proudlock FA. Reading Individual Words Within Sentences in Infantile Nystagmus. Invest Ophthalmol Vis Sci 2019; 60:2226-2236. [PMID: 31112607 DOI: 10.1167/iovs.18-25793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Normal readers make immediate and precise adjustments in eye movements during sentence reading in response to individual word features, such as lexical difficulty (e.g., common or uncommon words) or word length. Our purpose was to assess the effect of infantile nystagmus (IN) on these adaptive mechanisms. Methods Eye movements were recorded from 29 participants with IN (14 albinism, 12 idiopathic, and 3 congenital stationary night blindness) and 15 controls when reading sentences containing either common/uncommon words or long/short target words. Parameters assessed included: duration of first foveation/fixation, number of first-pass and percentage second-pass foveations/fixations, percentage words skipped, gaze duration, acquisition time (gaze + nongaze duration), landing site locations, clinical and experimental reading speeds. Results Participants with IN could not modify first foveation durations in contrast to controls who made longer first fixations on uncommon words (P < 0.001). Participants with IN made more first-pass foveations on uncommon and long words (P < 0.001) to increase gaze durations. However, this also increased nongaze durations (P < 0.001) delaying acquisition times. Participants with IN reread shorter words more often (P < 0.005). Similar to controls, participants with IN landed more first foveations between the start and center of long words. Reading speeds during experiments were lower in IN participants compared to controls (P < 0.01). Conclusions People with IN make more first-pass foveations on uncommon and long words influencing reading speeds. This demonstrates that the "slow to see" phenomenon occurs during word reading in IN. These deficits are not captured by clinical reading charts.
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Affiliation(s)
- Esha Prakash
- University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Rebecca J McLean
- University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Sarah J White
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
| | - Kevin B Paterson
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
| | - Irene Gottlob
- University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Frank A Proudlock
- University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
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8
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Reading speed of patients with infantile nystagmus for text in different orientations. Vision Res 2019; 155:17-23. [DOI: 10.1016/j.visres.2018.12.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 12/02/2018] [Accepted: 12/12/2018] [Indexed: 11/20/2022]
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9
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Bradbury-Jones C, Ogik P, Betts J, Taylor J, Lund P. Beliefs about people with albinism in Uganda: A qualitative study using the Common-Sense Model. PLoS One 2018; 13:e0205774. [PMID: 30312349 PMCID: PMC6185843 DOI: 10.1371/journal.pone.0205774] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 09/25/2018] [Indexed: 11/30/2022] Open
Abstract
Albinism includes a group of inherited conditions that result in reduced melanin production. It has been documented across the world, with a high frequency in sub-Saharan Africa. There is very little published research about the lives of people with albinism, but available evidence shows that myths abound regarding their condition. They are feared, viewed with suspicion and believed to have supernatural powers. In this study we explored the links between beliefs, myths, traditions and positive/negative attitudes that surround people with albinism in Uganda. The study was located philosophically within Ubuntu—an Afrocentric worldview—and theoretically within the Common-Sense Model of self-regulation of health and illness that originates from the work of Leventhal in 2003. This qualitative study took place in eight districts of Busoga sub-region, Uganda between 2015 and 2017. Data collection comprised eight group discussions and 17 individual interviews with a range of informants, capturing the viewpoints of 73 participants. Findings lend support to previous research, highlighting the life-time discrimination and disadvantage experienced by many people with albinism. It shows that there is still much to be done to address the pervasive and potentially harmful beliefs and misconceptions about people with albinism.
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Affiliation(s)
| | - Peter Ogik
- Head Office, Source of the Nile Union for Persons with Albinism (SNUPA), Jinja, Uganda
| | - Jane Betts
- Advantage Africa, Olney, Buckinghamshire, United Kingdom
| | - Julie Taylor
- School of Nursing, University of Birmingham, Birmingham, United Kingdom
- Birmingham Women’s and Children’s Hospital NHS Foundation Trust, Birmingham, United Kingdom
| | - Patricia Lund
- School of Life Sciences, Albinism in Africa project, Coventry University, Coventry, United Kingdom
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Christen M, Abegg M. The Effect of Magnification and Contrast on Reading Performance in Different Types of Simulated Low Vision. J Eye Mov Res 2016; 10. [PMID: 33828652 PMCID: PMC7141081 DOI: 10.16910/jemr.10.2.5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Low vision therapy, such as magnifiers or contrast enhancement, is widely used. Scientific evidence proving its efficacy is scarce however. The objective of this study was to investigate whether the benefits of magnification and contrast enhancement depended on the origin of low vision. For this purpose we measured reading speed with artificially induced low vision in 12 healthy subjects in conditions of a simulated central scotoma, blurred vision and oscillopsia. Texts were either blurred, set in motion or blanked at the gaze position by using eye tracking and gaze contingent display. The simulated visual impairment was calibrated such that all types of low vision caused equal reading impairment. We then tested the effect of magnification and contrast enhancement among the different types of low vision. We found that reading speed improved with increasing magnification and with higher contrast in all conditions. The effect of magnification was significantly different in the three low vision conditions: The gain from magnification was highest in simulated blur and least in central scotoma. Magnification eventually led to near normal reading speed in all conditions. High contrast was less effective than high magnification and the effect of contrast enhancement was similar in all low vision conditions. From these results we conclude that the type of low vision determines the benefit that can be expected from magnification. Contrast enhancement leads to similar improved reading speed in all low vision types. We provide evidence that supports the use of low vision aids.
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Affiliation(s)
- Michael Christen
- Department of Ophthalmology, Inselspital, Bern University Hospital, and University of Bern, Switzerland
| | - Mathias Abegg
- Department of Ophthalmology, Inselspital, Bern University Hospital, and University of Bern, Switzerland
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