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Martin-Perez Y, Gonzalez-Montero G, Gutierrez-Hernandez AL, Blázquez-Sánchez V, Sánchez-Ramos C. Vision Impairments in Young Adults with Down Syndrome. Vision (Basel) 2023; 7:60. [PMID: 37756134 PMCID: PMC10536554 DOI: 10.3390/vision7030060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 08/24/2023] [Accepted: 09/08/2023] [Indexed: 09/29/2023] Open
Abstract
People with Down syndrome have more visual problems than the general population. They experience premature ageing, and they are expected to also have an acceleration in worsening visual function. A prospective observational study which includes visual acuity, refractive error, accommodation, binocular and colour vision was performed on young adults with (n = 69) and without (n = 65) Down syndrome and on a senior group (n = 55) without Down syndrome. Results showed significant differences in visual acuity between groups (p < 0.001), and it can be improved with a new prescription in 40% of the participants with Down syndrome. Regarding the accommodative state, no significant differences were found between groups of young people. Concerning binocular vision, 64.7% of strabismus was observed in the group with Down syndrome (p < 0.001). Visual abnormalities are significant in young adults with Down syndrome and are different from those of older people without Down syndrome, some of which can be improved by providing the optimal prescription as well as regular eye examinations.
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Affiliation(s)
- Yolanda Martin-Perez
- Faculty of Optic and Optometry, Department of Optometry and Vision Science, Complutense University of Madrid, 28040 Madrid, Spain; (G.G.-M.); (A.L.G.-H.); (V.B.-S.); (C.S.-R.)
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Ntodie M, Saunders K, Little JA. Accuracy and stability of accommodation and vergence responses during sustained near tasks in uncorrected hyperopes. Sci Rep 2023; 13:14389. [PMID: 37658084 PMCID: PMC10474059 DOI: 10.1038/s41598-023-41244-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 08/23/2023] [Indexed: 09/03/2023] Open
Abstract
This study investigated the accuracy and stability of accommodative and vergence functions in children with and without hyperopia while engaged in two sustained near tasks. The sustained accommodative and vergence characteristics of participants without refractive correction (n = 92, aged 5-10 years) with and without hyperopia (defined as cycloplegic retinoscopy ≥ + 1.00D and less than + 5.00D) were measured using eccentric infrared photorefraction (PowerRef 3; PlusOptix, Germany). Binocular measures of accommodation and eye position were recorded while participants engaged in 2 tasks at 25 cm for 15 min each: (1) reading small print on an Amazon Kindle and (2) watching an animated movie on liquid crystal display screen. Comprehensive visual assessment, including measurement of presenting visual acuity, amplitude of accommodation, and stereoacuity was conducted. The magnitude of accommodative and vergence responses was not related to refractive error (P > 0.05). However, there were inter-task differences in the accuracy and stability of the accommodative responses across refractive groups (P < 0.05). The relationship between accommodation and vergence was not significant in both tasks (P > 0.05). However, increased accommodative and vergence instabilities were associated with total accommodative response (P < 0.05). Despite having greater accommodative demand, uncorrected hyperopes accommodate comparably to emmetropic controls. However, uncorrected hyperopes have increased instabilities in their accommodative and vergence responses, which may adversely impact their visual experience.
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Affiliation(s)
- Michael Ntodie
- Department of Optometry and Vision Science, School of Allied Health Sciences, College of Health and Allied Sciences, University of Cape Coast, Cape Coast, Ghana.
- Centre for Optometry and Vision Science, Biomedical Sciences Research Institute, Ulster University, Coleraine, UK.
| | - Kathryn Saunders
- Centre for Optometry and Vision Science, Biomedical Sciences Research Institute, Ulster University, Coleraine, UK
| | - Julie-Anne Little
- Centre for Optometry and Vision Science, Biomedical Sciences Research Institute, Ulster University, Coleraine, UK
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The Ophthalmic Manifestations of Down Syndrome. CHILDREN (BASEL, SWITZERLAND) 2023; 10:children10020341. [PMID: 36832470 PMCID: PMC9955748 DOI: 10.3390/children10020341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/18/2023] [Accepted: 01/29/2023] [Indexed: 02/12/2023]
Abstract
Down Syndrome is one of the most common chromosomal conditions in the world, affecting an estimated 1:400-1:500 births. It is a multisystem genetic disorder but has a wide range of ophthalmic findings. These include strabismus, amblyopia, accommodation defects, refractive error, eyelid abnormalities, nasolacrimal duct obstruction, nystagmus, keratoconus, cataracts, retinal abnormalities, optic nerve abnormalities, and glaucoma. These ophthalmic conditions are more prevalent in children with Down Syndrome than the general pediatric population, and without exception, early identification with thoughtful screening in this patient population can drastically improve prognosis and/or quality of life.
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Bullaj R, Dyet L, Mitra S, Bunce C, Clarke CS, Saunders K, Dale N, Horwood A, Williams C, St Clair Tracy H, Marlow N, Bowman R. Effectiveness of early spectacle intervention on visual outcomes in babies at risk of cerebral visual impairment: a parallel group, open-label, randomised clinical feasibility trial protocol. BMJ Open 2022; 12:e059946. [PMID: 36130761 PMCID: PMC9494562 DOI: 10.1136/bmjopen-2021-059946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
INTRODUCTION Hypoaccommodation is common in children born prematurely and those with hypoxic ischaemic encephalopathy (HIE), with the potential to affect wider learning. These children are also at risk of longer-term cerebral visual impairment. It is also well recognised that early intervention for childhood visual pathology is essential, because neuroplasticity progressively diminishes during early life. This study aims to establish the feasibility and acceptability of conducting a randomised controlled trial to test the effectiveness of early near vision correction with spectacles in infancy, for babies, at risk of visual dysfunction. METHODS AND ANALYSIS This is a parallel group, open-label, randomised controlled (feasibility) study to assess visual outcomes in children with perinatal brain injury when prescribed near vision spectacles compared with the current standard care-waiting until a problem is detected. The study hypothesis is that accommodation, and possibly other aspects of vision, may be improved by intervening earlier with near vision glasses. Eligible infants (n=75, with either HIE or <29 weeks preterm) will be recruited and randomised to one of three arms, group A (no spectacles) and two intervention groups: B1 or B2. Infants in both intervention groups will be offered glasses with +3.00 DS added to the full cycloplegic refraction and prescribed for full time wear. Group B1 will get their first visit assessment and intervention at 8 weeks corrected gestational age (B1) and B2 at 16 weeks corrected gestational age. All infants will receive a complete visual and neurodevelopmental assessment at baseline and a follow-up visit at 3 and 6 months after the first visit. ETHICS AND DISSEMINATION The South-Central Oxford C Research Ethics Committee has approved the study. Members of the PPI committee will give advice on dissemination of results through peer-reviewed publications, conferences and societies. TRIAL REGISTRATION NUMBER ISRCTN14646770, NCT05048550, NIHR ref: PB-PG-0418-20006.
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Affiliation(s)
- Raimonda Bullaj
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
- University College London Hospitals NHS Foundation Trust, London, UK
- University College London, London, UK
| | - Leigh Dyet
- University College London Hospitals NHS Foundation Trust, London, UK
| | - Subhabrata Mitra
- University College London Hospitals NHS Foundation Trust, London, UK
| | - Catey Bunce
- The Royal Marsden NHS Foundation Trust, London, UK
| | - Caroline S Clarke
- Research Department of Primary Care and Population Health, University College London, London, UK
| | - Kathryn Saunders
- Biomedical Sciences Research Institute, Ulster University, Coleraine, UK
| | - Naomi Dale
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
- University College London, London, UK
| | - Anna Horwood
- School of Psychology, University of Reading, Reading, UK
| | - Cathy Williams
- Bristol Medical School, University of Bristol, Bristol, UK
| | | | | | - Richard Bowman
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
- Ophthalmology, University College London Institute of Child Health, London, UK
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Haseeb A, Huynh E, ElSheikh RH, ElHawary AS, Scelfo C, Ledoux DM, Maidana DE, Elhusseiny AM. Down syndrome: a review of ocular manifestations. Ther Adv Ophthalmol 2022; 14:25158414221101718. [PMID: 35795721 PMCID: PMC9252013 DOI: 10.1177/25158414221101718] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 04/27/2022] [Indexed: 02/01/2023] Open
Abstract
Down syndrome is the most common genetically mediated intellectual disability. Although many physiologic and pathologic features of Down syndrome are discussed at length in the literature, the ocular manifestations of Down syndrome have seldom been discussed in a comprehensive fashion. Given that Down syndrome has ocular manifestations from the front to the back of the eye, it is important for physicians to become familiar with these manifestations, especially given the prevalence of Down syndrome. This review aims to discuss the varied ophthalmologic manifestations of Down syndrome – including strabismus, amblyopia, nystagmus, accommodation deficits, nasolacrimal duct obstruction, keratoconus, optic nerve pathology, neoplastic disease, and retinal pathology – to facilitate better care and visual outcomes in this important patient population.
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Affiliation(s)
- Abid Haseeb
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Elisah Huynh
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Reem H ElSheikh
- Department of Ophthalmology, Kasr Al-Ainy Hospitals, Cairo University, Cairo, Egypt
| | | | - Christina Scelfo
- Department of Ophthalmology, Boston Children's Hospital, Hawthorne, NY, USA
| | - Danielle M Ledoux
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Daniel E Maidana
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Abdelrahman M Elhusseiny
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
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One-year effects of bifocal and unifocal glasses on executive functions in children with Down syndrome in a randomized controlled trial. Sci Rep 2021; 11:16893. [PMID: 34413362 PMCID: PMC8377071 DOI: 10.1038/s41598-021-96308-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 08/04/2021] [Indexed: 11/08/2022] Open
Abstract
Appropriate glasses can improve visual functioning of children with Down syndrome (DS), but it is unknown if such interventions influence their cognitive impairments. In a randomized controlled trial with 1-year follow-up. Children with DS (2-16 years) were provided either bifocal glasses (add +2.5 Dioptres; n = 50) or unifocal glasses (n = 52). Executive functions were assessed pre- and post-intervention with the task-based Minnesota Executive Function Scale (MEFS) and with questionnaires, BRIEF-P and BRIEF, parents' and teachers' version. Intervention effects and associations between executive functions, (near) vision and ocular alignment were analysed. Intervention improved MEFS-Total-scores in the bifocal group (p = 0.002; Cohen's d = 0.60) but not in the unifocal group (p = 0.191; Cohen's d = 0.24). Post-intervention, there was no intergroup difference (p = 0.120; Cohen's d = 0.34). Post-intervention, higher MEFS-scores were associated with better visual acuities (crowded near p = 0.025; uncrowded near p = 0.019; distant p = 0.045). Pre-post changes in MEFS-scores correlated significantly with improved ocular alignment (p = 0.040). Exploratory analysis of the questionnaires showed improved teacher-rated BRIEF-scores in both groups (bifocals: p = 0.014, Cohen's d = 1.91; unifocals: p = 0.022, Cohen's d = 1.46), with no intergroup difference (p = 0.594; Cohen's d = 0.23). These results demonstrate positive effects of wearing better-correcting glasses on executive functioning in children with DS, suggesting a link between their visual and executive functioning. However, the relative contributions of distant and near vision need further study.
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Ntodie M, Enimah EB, Akoto YO, Yennu JN, Abokyi S, Abu EK. Application and repeatability of ocular biometric measures for gaze position calibration in children. Ophthalmic Physiol Opt 2021; 41:1144-1151. [PMID: 34382223 DOI: 10.1111/opo.12866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 06/23/2021] [Accepted: 06/23/2021] [Indexed: 11/27/2022]
Abstract
PURPOSE The purpose of this study was to investigate the utility of two ocular biometric measurements to obtain Hirschberg ratios (HRs) in a binocularly normal paediatric population, and to assess the repeatability of this approach. METHODS Ocular biometry data from 80 participants (aged 5 to 14 years) was obtained using the KM-1 LED manual keratometer and the Tomey Biometer AL-100 A-scan. HRs were calculated from corneal curvature and anterior chamber depth measurements in the horizontal and vertical meridians of each eye using a regression equation based on a geometric optics model. To assess intrasubject variability in the HRs obtained from biometry, measurements were repeated approximately 1 h later. RESULTS At the initial measurement, mean (SD, range) HRs were 10.77 (0.79, 9.14-12.73) and 11.02 (0.82, 9.48-13.32) °/mm for the horizontal and vertical meridians, respectively. There was a significant difference between the horizontal and vertical HRs (p < 0.0001). Mean intrasubject variability of HR was 0.06 °/mm (95% Limit of Agreement [LOA]: -0.82 to 0.94 °/mm), and 0.05 °/mm (95% LOA: -1.05 to 1.15 °/mm) for the horizontal and vertical meridians, respectively. CONCLUSION The results indicated that HRs obtained through ocular biometry in a binocularly normal paediatric population are consistent with previous studies in both strabismic children and adult cohorts. The HRs obtained with this technique were highly repeatable in this study population. This approach to gaze position calibration could be used in lieu of other empirical techniques in children.
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Affiliation(s)
- Michael Ntodie
- Department of Optometry and Vision Science, School of Allied Health Sciences, College of Health and Allied Sciences, University of Cape Coast, Cape Coast, Ghana
| | | | - Yaw O Akoto
- Eye Unit, Our Lady of Grace Hospital, Breman Asikuma, Ghana
| | - Joseph N Yennu
- Eye Unit, Our Lady of Grace Hospital, Breman Asikuma, Ghana
| | - Samuel Abokyi
- Department of Optometry and Vision Science, School of Allied Health Sciences, College of Health and Allied Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Emmanuel K Abu
- Department of Optometry and Vision Science, School of Allied Health Sciences, College of Health and Allied Sciences, University of Cape Coast, Cape Coast, Ghana
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Postolache L, Monier A, Lhoir S. Neuro-Ophthalmological Manifestations in Children with Down Syndrome: Current Perspectives. Eye Brain 2021; 13:193-203. [PMID: 34321946 PMCID: PMC8311006 DOI: 10.2147/eb.s319817] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 07/11/2021] [Indexed: 12/03/2022] Open
Abstract
Down syndrome, caused by an extra copy of all or part of chromosome 21, is the most prevalent intellectual disability of genetic origin. Among numerous comorbidities which are part of the phenotype of individuals with Down syndrome, ocular problems appear to be highly prevalent. Neuro-ophthalmological manifestations, such as ocular alignment and motility disturbances, amblyopia, hypoaccommodation or optic nerve abnormalities, and other organic ocular anomalies frequently reported in Down syndrome, may lead to an overall decrease in visual acuity. Although numerous studies have reported ocular anomalies related to Down syndrome, it remains challenging to determine the impact of each anomaly upon the decreased visual acuity, as most such individuals have more than one ocular problem. Even in children with Down syndrome and no apparent ocular defect, visual acuity has been found to be reduced compared with typically developing children. Pediatric ophthalmological examination is a critical component of a multidisciplinary approach to prevent and treat ocular complications and improve the visual outcome in children with Down syndrome. This narrative review aims to provide a better understanding of the neuro-ophthalmological manifestations and discuss the current ophthalmological management in children with Down syndrome.
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Affiliation(s)
- Lavinia Postolache
- Department of Pediatric Ophthalmology, Queen Fabiola University Children's Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Anne Monier
- Department of Pediatric Neurology, Queen Fabiola University Children's Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Sophie Lhoir
- Department of Pediatric Ophthalmology, Queen Fabiola University Children's Hospital, Université Libre de Bruxelles, Brussels, Belgium
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de Weger C, Boonstra N, Goossens J. Bifocals reduce strabismus in children with Down syndrome: Evidence from a randomized controlled trial. Acta Ophthalmol 2020; 98:89-97. [PMID: 31313886 PMCID: PMC7003890 DOI: 10.1111/aos.14186] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 06/11/2019] [Indexed: 01/14/2023]
Abstract
PURPOSE Children with Down syndrome (DS) more often have strabismus, refractive errors, accommodative lags and reduced visual acuity (VA) than typically developing children. In this study, we compare the effects of bifocal glasses with those of unifocal glasses in children with DS. Changes in angle of strabismus, accommodation and refractive error were analysed in this paper. METHODS In a multicentre randomized controlled trial, 119 children with DS, aged 2-16, were randomly allocated for bifocal or unifocal glasses (with full correction of refractive error in cycloplegia). The 15 centres, all in the Netherlands, followed the participants for 1 year. Changes in refractive error, accommodative accuracy, strabismus, binocularity and stereopsis were compared across 4 subsequent visits. RESULTS Refractive errors and accommodative errors showed no significant change throughout the course of our study in either intervention group. The manifest angle of strabismus, however, reduced significantly in the bifocal group. This improvement was observed shortly after the children received their new correction (~6 weeks) (linear regression: t = 3.652, p < 0.001) and remained present in the final measurements after 1 year (linear regression: t = 3.604, p < 0.001). The percentage of children with positive binocularity and stereo tests showed no significant differences between the groups. CONCLUSION Bifocals with full correction of refractive error reduce the manifest angle of strabismus within a few weeks. No effects on accommodation, refractive error, stereopsis and binocularity occurred over the course of 1 year.
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Affiliation(s)
- Christine de Weger
- Donders Institute for BrainCognition and BehaviourDepartment of Cognitive NeuroscienceRadboud University Medical Centre NijmegenNijmegenThe Netherlands,BartiméusInstitute for the Visually ImpairedZeistThe Netherlands
| | - Nienke Boonstra
- Donders Institute for BrainCognition and BehaviourDepartment of Cognitive NeuroscienceRadboud University Medical Centre NijmegenNijmegenThe Netherlands,Royal Dutch VisioNational Foundation for the Visually Impaired and BlindHuizenThe Netherlands
| | - Jeroen Goossens
- Donders Institute for BrainCognition and BehaviourDepartment of Cognitive NeuroscienceRadboud University Medical Centre NijmegenNijmegenThe Netherlands
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Weger C, Boonstra N, Goossens J. Effects of bifocals on visual acuity in children with Down syndrome: a randomized controlled trial. Acta Ophthalmol 2019; 97:378-393. [PMID: 30367541 PMCID: PMC6587837 DOI: 10.1111/aos.13944] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 09/04/2018] [Indexed: 11/28/2022]
Abstract
Purpose Children with Down syndrome (DS) typically have reduced visual acuity (VA) and accommodation lag, but it is unclear whether prescribed glasses should correct both distance VA (DVA) and near VA (NVA) due to the lack of RCTs. We therefore conducted a multicentre RCT to compare the effects of bifocals designed to correct both DVA and NVA with distance‐correcting unifocal glasses in children with DS. Methods A total of 119 children with DS, aged 2–16, were randomly allocated for bifocal or unifocal glasses (with full correction of refraction error in cycloplegia) in 14 Dutch hospitals and followed during 1 year. VA data were analysed in relation to baseline VA with ancova. Results Treatment groups showed no differences at baseline. Shortly after receiving new corrections (~6 weeks), uncrowded NVA (bifocals 0.18 ± 0.33 LogMar; unifocals 0.09 ± 0.19 LogMar) and crowded NVA with bifocals (bifocals 0.13 ± 0.36 LogMar; unifocals 0.08 ± 0.33 LogMar) were significantly better than at baseline, but these short‐term improvements in NVA were not significantly different between the two treatments (p > 0.151). The 1‐year treatment differences were as follows: significantly larger improvement for bifocals compared to unifocals in both uncrowded NVA (bifocals 0.23 ± 0.29 LogMar, unifocals 0.12 ± 0.30 LogMar, p = 0.045) and crowded NVA (bifocals 0.31 ± 0.28 LogMar; unifocals 0.16 ± 0.30 LogMar, p = 0.017). Improvements in DVA were comparable (bifocals 0.07 ± 0.21 LogMar, unifocals 0.08 ± 0.22 LogMar, p = 0.565). Children with poor baseline VA improved more. Accommodation lag stayed unchanged. Conclusion After one year, bifocals with full correction of ametropia led to significantly larger improvement of both uncrowded NVA and crowded NVA in children with DS with accommodation lag compared to unifocals.
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Affiliation(s)
- Christine Weger
- Department of Cognitive Neuroscience Donders Institute for Brain, Cognition and Behaviour Radboud University Medical Centre Nijmegen Nijmegen The Netherlands
- Bartiméus Institute for the Visually Impaired Zeist The Netherlands
| | - Nienke Boonstra
- Department of Cognitive Neuroscience Donders Institute for Brain, Cognition and Behaviour Radboud University Medical Centre Nijmegen Nijmegen The Netherlands
- Royal Dutch Visio National Foundation for the Visually Impaired and Blind Huizen The Netherlands
| | - Jeroen Goossens
- Department of Cognitive Neuroscience Donders Institute for Brain, Cognition and Behaviour Radboud University Medical Centre Nijmegen Nijmegen The Netherlands
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Bharadwaj SR, Bandela PK, Nilagiri VK. Lens magnification affects the estimates of refractive error obtained using eccentric infrared photorefraction. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2018; 35:908-915. [PMID: 29877334 DOI: 10.1364/josaa.35.000908] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 04/10/2018] [Indexed: 06/08/2023]
Abstract
Positive- and negative-powered ophthalmic lenses are used in eccentric infrared photorefraction to calibrate the device, correct the subject's baseline refractive error before an experimental manipulation, or stimulate blur-driven accommodation. Through theoretical modeling of luminance gradients formed across the pupil and empirical measurements of the eye's refractive error using a commercial photorefractor, this study shows that image magnification by positive lenses and image minification by negative lenses under- and overestimates the refractive error, respectively, all independent of image defocus. The impact of image magnification/minification therefore appears non-trivial in experimental paradigms involving ophthalmic lenses to manipulate the eye's optics during photorefraction.
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