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Huang SY, Su HR, Hu YS, Lee CH, Tsai MS, Yeh SM, Chen YY, Tsai TH. Immediate Effects of Vergence Exercises Using Automatic Dual Rotational Risley Prisms on Accommodative Lag and Facility. Ophthalmol Ther 2023; 12:3361-3372. [PMID: 37853298 PMCID: PMC10640441 DOI: 10.1007/s40123-023-00832-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 10/03/2023] [Indexed: 10/20/2023] Open
Abstract
INTRODUCTION This study evaluated novel automatic dual rotational Risley prisms (ADRRPs) as a vergence exercise tool for patients with myopia to improve accommodative lag and accommodative facility. METHODS Participants with myopia aged 20-24 years were recruited. After vergence exercises with prisms (treatment group) or plano lenses (control group) using ADRRPs for 10 min, measurements were taken using an open-field autorefractor (Grand Seiko WAM-5500) at viewing distances of 0.4 m and 6.0 m. We measured accommodative facility using a ± 2.00 D accommodative flipper. RESULTS A total of 56 participants (treatment group, 39; control group, 17) performed vergence exercises using ADRRPs. Participants in the treatment group showed improvements in accommodative lag at a 0.4 m viewing distance, with measurements of 0.57 D (right eye; OD) and 0.53 D (left eye; OS) and 0.21 D (OD) and 0.27 D (OS) before and after the exercises, respectively (p < 0.001). Over-refractions using an open-field autorefractor with spherical equivalent contact lenses at a 6.0 m viewing distance were - 0.01 ± 0.30 D (OD) and 0.03 ± 0.34 D (OS) and 0.15 ± 0.32 D (OD) and 0.19 ± 0.28 D (OS) before and after the exercises, respectively (difference + 0.16 D; p < 0.001). Accommodative facility values before and after exercises were 14.88 ± 3.36 and 15.59 ± 3.60 cpm, respectively (p < 0.01). No significant differences in accommodative lag, relaxation, and accommodative facility before and after exercise were observed in the control group. CONCLUSIONS Using ADRRPs in vergence exercises can improve accommodative lag, accommodative facility, and accommodative relaxation in adults with myopia. Further research to evaluate persistent and long-term effects is needed.
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Affiliation(s)
- Shuan-Yu Huang
- Department of Optometry, Central Taiwan University of Science and Technology, Taichung, 402, Taiwan
| | - Hui-Rong Su
- Ph.D. Program of Electrical and Communications Engineering, Feng Chia University, Taichung, 407, Taiwan
| | - Yun-Shao Hu
- Department of Optometry, Chung Shan Medical University, Taichung, 402, Taiwan
| | - Chi-Hung Lee
- Department of Electrical Engineering, Feng Chia University, Taichung, 407, Taiwan
| | - Ming-Shan Tsai
- Department of Electrophysics, National Chiayi University, Chiayi, 600, Taiwan
| | - Shang-Min Yeh
- Department of Optometry, Da-Yeh University, Changhua, 515, Taiwan
| | - Ya-Yu Chen
- Department of Optometry, Da-Yeh University, Changhua, 515, Taiwan
| | - Tzu-Hsun Tsai
- Department of Ophthalmology, National Taiwan University Hospital Hsin-Chu Branch, Hsin-Chu, Taiwan.
- Department of Ophthalmology, National Taiwan University Hospital, Taipei City, 100225, Taiwan.
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Chen ST, Su KC, Wang PH, Zhong XY, Cheng CY. Routine binocular examination of young Taiwanese adults as a predictor of visual behavior performance. BMC Ophthalmol 2023; 23:47. [PMID: 36726067 PMCID: PMC9890884 DOI: 10.1186/s12886-022-02731-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 12/09/2022] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Morgan and Scheiman's Optometric Extension Program (OEP) expected binocular vision findings have longstanding use in optometry. With technological advances, the demands and standards of binocular function have changed. This study aimed to investigate which binocular visual functions can effectively predict visual behavior performance. METHODS Participants aged 15-24 years were recruited from two colleges and two universities. After completing the CSMU-Visual Behavioral Performance questionnaire (CSMU-VBP, with four components: near work, visual perception, visual comfort, and whole-body balance), participants were divided into symptomatic and asymptomatic groups based on questionnaire findings (cutoff: < 12 vs. ≥ 12 symptoms). Then a 24-step binocular visual examination was undertaken. Data were analyzed with one-sample, Student's, and paired t-tests. Additionally, receiver operating characteristic analysis was used to determine the predictors of binocular visual function required for near work, visual perception, visual comfort, and body balance dimensions. RESULTS Among 308 participants, 43 (14%) and 265 (86%) were symptomatic and asymptomatic, respectively. Among the 46 participants with abnormal binocular vision, 36 (78%) reported that they had no obvious symptoms. The commonest dysfunctions were accommodative excess and convergence excess. Most of the binocular visual findings significantly diverged from traditional normal values: amplitude of accommodation, as well as base-in prism to break and recovery points at distance were higher than traditional normal values, whereas others were lower than traditional normal values. Total CSMU-VBP scores indicated that the asymptomatic and symptomatic groups had significant differences in DBO recovery (t = 2.334, p = 0.020) and BAF (t = 1.984, p = 0.048). Receiver operating characteristic curve analysis yielded the following binocular visual functional cutoff points: near work (DBO blur < 7, DBO recovery < 5.5), visual perception (MAF < 10.5, BAF < 10.25), visual comfort (DLP < - 2.25, DBI break > 11.5, NBI blur > 15, NBI break > 17.5, NBI recovery > 13, NPC < 5.75), and body balance (NFD_H > - 0.5, gradient AC/A [minus] > 2.25, NPC < 4.75). CONCLUSIONS The mean values of binocular visual function among young Taiwanese adults were statistically different from traditional normative values. Further research is required to confirm whether these findings reflect impaired binocular vision or stringent criteria. Assessments of binocular visual function, especially binocular accommodation sensitivity, are crucial in routine optometric examination.
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Affiliation(s)
- Shyan-Tarng Chen
- grid.411641.70000 0004 0532 2041Department of Optometry, Chung Shan Medical University, Taichung, 402 Taiwan ,grid.411645.30000 0004 0638 9256Department of Ophthalmology, Chung Shan Medical University Hospital, Taichung, 402 Taiwan
| | - Kuo-Chen Su
- grid.411641.70000 0004 0532 2041Department of Optometry, Chung Shan Medical University, Taichung, 402 Taiwan ,grid.411645.30000 0004 0638 9256Department of Ophthalmology, Chung Shan Medical University Hospital, Taichung, 402 Taiwan
| | - Po-Hsin Wang
- grid.411641.70000 0004 0532 2041Department of Optometry, Chung Shan Medical University, Taichung, 402 Taiwan
| | - Xiang-Yin Zhong
- grid.411641.70000 0004 0532 2041Department of Optometry, Chung Shan Medical University, Taichung, 402 Taiwan
| | - Ching-Ying Cheng
- grid.411641.70000 0004 0532 2041Department of Optometry, Chung Shan Medical University, Taichung, 402 Taiwan ,grid.411645.30000 0004 0638 9256Department of Ophthalmology, Chung Shan Medical University Hospital, Taichung, 402 Taiwan
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Li S, Tang A, Yang B, Wang J, Liu L. Virtual reality-based vision therapy versus OBVAT in the treatment of convergence insufficiency, accommodative dysfunction: a pilot randomized controlled trial. BMC Ophthalmol 2022; 22:182. [PMID: 35448970 PMCID: PMC9027290 DOI: 10.1186/s12886-022-02393-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 04/11/2022] [Indexed: 02/08/2023] Open
Abstract
Background Virtual reality is being increasingly applied in vision therapy. However, the differences in effectiveness, optimal treatment cycle, and prognosis between virtual reality-based vision therapy and traditional therapies remain unknown. The purpose of this study was to compare the effectiveness of virtual reality-based vision therapy and office-based vergence/accommodative therapy in young adults with convergence insufficiency or accommodative dysfunction. Methods The patients were randomly assigned to either the virtual reality-based vision therapy group or the office-based vergence/accommodative therapy group. The vision therapy lasted 12 weeks (1 h/week) in both groups. Binocular visual functions (vergence and accommodation) were measured and a subjective questionnaire-based assessment was performed at baseline and after 6 and 12 weeks of therapy. Results In total, 33 patients with convergence insufficiency and 30 with accommodative dysfunction completed the study. After 12 weeks of treatment for convergence insufficiency, the Convergence Insufficiency Symptom Survey score (F2,31 = 13.704, P < 0.001), near point of convergence (F2,31 = 21.774, P < 0.001), positive fusional vergence (F2,31 = 71.766, P < 0.001), and near horizontal phoria (F2,31 = 16.482, P < 0.001) improved significantly in both groups. Moreover, the monocular accommodative amplitude (F2,25 = 22.154, P < 0.001) and monocular accommodative facility (F2,25 = 86.164, P < 0.001) improved significantly in both groups after 12 weeks of treatment. A statistically significant difference was observed in monocular accommodative facility (F1,25 = 8.140, P = 0.009) between the two groups, but not in other vergence and accommodative functions (0.098 < P < 0.687). Conclusion Virtual reality-based vision therapy significantly improved binocular vision functions and symptoms in patients with convergence insufficiency and accommodative dysfunction, thereby suggesting its effectiveness as a new optional or additional treatment for young adults with these conditions. Trial registration This study was registered at the Chinese Clinical Trials Registry on 16/04/2019 (identifier: ChiCTR1900022556). Supplementary Information The online version contains supplementary material available at 10.1186/s12886-022-02393-z.
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Affiliation(s)
- Shijin Li
- Department of Optometry, West China Clinical Medical College, Sichuan University, 37 Guoxue Xiang, Chengdu, Sichuan Province, China
| | - Angcang Tang
- Department of Ophthalmology, West China Hospital of Sichuan University, 37 Guoxue Xiang, Chengdu, Sichuan Province, China
| | - Bi Yang
- Department of Ophthalmology, West China Hospital of Sichuan University, 37 Guoxue Xiang, Chengdu, Sichuan Province, China
| | - Jianglan Wang
- Department of Ophthalmology, West China Hospital of Sichuan University, 37 Guoxue Xiang, Chengdu, Sichuan Province, China
| | - Longqian Liu
- Department of Optometry, West China Clinical Medical College, Sichuan University, 37 Guoxue Xiang, Chengdu, Sichuan Province, China. .,Department of Ophthalmology, West China Hospital of Sichuan University, 37 Guoxue Xiang, Chengdu, Sichuan Province, China.
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Huang Y, Li M, Shen Y, Liu F, Fang Y, Xu H, Zhou X. Study of the Immediate Effects of Autostereoscopic 3D Visual Training on the Accommodative Functions of Myopes. Invest Ophthalmol Vis Sci 2022; 63:9. [PMID: 35113140 PMCID: PMC8819359 DOI: 10.1167/iovs.63.2.9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Purpose Stereoscopic viewing has an impact on ocular dynamics, but its effects on accommodative functions are not fully understood, especially for autostereoscopic viewing. This study aimed to investigate the changes in dynamic accommodative response, accommodative amplitude, and accommodative facility of myopes after autostereoscopic visual training. Methods We enrolled 46 adults (men = 22 and women = 24; age = 21.5 ± 2.5 [range = 18–25] years, spherical equivalent: −4.52 ± 1.89 [−8.88 to −1.75] diopters [D]) who visited the Eye & ENT Hospital of Fudan University. The study population was randomly divided into three-dimensional (3D) and two-dimensional (2D) viewing groups to watch an 11-minute training video displayed in 3D or 2D mode. Dynamic accommodative response, accommodative facility, and accommodative amplitude were measured before, during, and immediately after the training. Accommodative lag and the variability of accommodation were also analyzed. Visual fatigue was evaluated subjectively using a questionnaire. Results Accommodative lag decreased from 0.54 ± 0.29 D to 0.42 ± 0.32 D (P = 0.004), whereas accommodative facility increased from 10.83 ± 4.55 cycles per minute (cpm) to 13.15 ± 5.25 cpm (P < 0.001) in the 3D group. In the 2D group, there was no significant change in the accommodative lag (P = 0.163) or facility (P = 0.975), but a decrease in accommodative amplitude was observed (from 13.88 ± 3.17 D to 12.71 ± 2.23 D, P = 0.013). In the 3D group, the accommodative response changed with the simulated target distance. Visual fatigue was relatively mild in both groups. Conclusions The immediate impact of autostereoscopic training included a decrease in the accommodative lag and an increase in the accommodative facility. However, the long-term effects of autostereoscopic training require further exploration.
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Affiliation(s)
- Yangyi Huang
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Meiyan Li
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Yang Shen
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Fang Liu
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Yong Fang
- Shanghai EVIS Technology Co. Ltd., Shanghai, China
| | - Haipeng Xu
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Xingtao Zhou
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
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Yoon HJ, Kim J, Park SW, Heo H. Influence of virtual reality on visual parameters: immersive versus non-immersive mode. BMC Ophthalmol 2020; 20:200. [PMID: 32448140 PMCID: PMC7245896 DOI: 10.1186/s12886-020-01471-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 05/13/2020] [Indexed: 11/10/2022] Open
Abstract
Abstract Background To investigate the differences in refraction, accommodative factors, visual parameters, and subjective symptoms after using two types of virtual reality (VR) content with different depths of perception. Methods Twenty-three volunteers, who played VR games in two modes (immersive and non-immersive) for 30 min, were enrolled. Visual parameters were examined before and after using VR. Accommodative factors were measured using static and dynamic methods. Subjective symptoms were assessed using a questionnaire. Differences according to VR content were compared, and correlations between each visual parameter were analyzed. Results There were no changes in refraction or accommodative factors after use of the VR. However, there was a significant increase in the near point of accommodation (NPA), the near point of convergence (NPC), and subjective symptom scores after using the immersive mode. Correlation analysis revealed a positive correlation between baseline values of near exophoria and mean accommodative lag of the dominant eye, and also revealed a negative correlation between NPA and mean accommodative lag in the non-dominant eye. Conclusions The use of VR for 30 min increased NPA and NPC, especially after the immersive mode was used. In addition, higher exophoria and smaller NPA is associated with increased accommodative lag after using VR.
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Affiliation(s)
- Hyeon Jeong Yoon
- Department of Ophthalmology, Chonnam National University Medical School and Hospital, 42 Jebong-ro, Dong-gu, Gwangju, 61469, Republic of Korea
| | - Jonghwa Kim
- Department of Ophthalmology, Chonnam National University Medical School and Hospital, 42 Jebong-ro, Dong-gu, Gwangju, 61469, Republic of Korea
| | - Sang Woo Park
- Department of Ophthalmology, Chonnam National University Medical School and Hospital, 42 Jebong-ro, Dong-gu, Gwangju, 61469, Republic of Korea
| | - Hwan Heo
- Department of Ophthalmology, Chonnam National University Medical School and Hospital, 42 Jebong-ro, Dong-gu, Gwangju, 61469, Republic of Korea.
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Vision Development Differences between Slow and Fast Motor Development in Typical Developing Toddlers: A Cross-Sectional Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17103597. [PMID: 32443815 PMCID: PMC7277625 DOI: 10.3390/ijerph17103597] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/14/2020] [Accepted: 05/18/2020] [Indexed: 11/17/2022]
Abstract
Many studies have established a relationship between visual function and motor development in toddlers. This is the first report to study two-year-olds via an assessment of their visual and motor skills. The purpose of this study is to describe the possible changes that can occur between visual and motor systems in typical developing toddlers. A total of 116 toddlers were included in this observational, descriptive, and cross-sectional study. Their mean age was 29.57 ± 3.45 months. Motor development variables studied were dominant hand/foot; stationary, locomotion, object manipulation, grasping, visual motor integration percentiles; gross motor, fine motor, and total motor percentiles; and gross motor, fine motor, and total motor quotients. Visual development variables were assessed including visual acuity, refractive error, ocular alignment, motor fusion and suppression, ocular motility, and stereopsis. Our findings demonstrated that typical developing toddlers with slow gross motor development had higher exophoria and further near point of convergence values compared to toddlers with fast gross motor development (p < 0.05). No statistically significant differences were found in visual acuity and stereopsis between slow and fast gross motor development toddlers.
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Hashemi H, Pakbin M, Ali B, Yekta A, Ostadimoghaddam H, Asharlous A, Aghamirsalim M, Khabazkhoob M. Near Points of Convergence and Accommodation in a Population of University Students in Iran. J Ophthalmic Vis Res 2019; 14:306-314. [PMID: 31660110 PMCID: PMC6815340 DOI: 10.18502/jovr.v14i3.4787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 02/21/2019] [Indexed: 11/24/2022] Open
Abstract
Purpose To determine the distribution of the near point of convergence (NPC) and near point of accommodation (NPA) in a young student population in Iran. Methods The subjects were selected using a cluster sampling method. All students underwent optometry tests, including visual acuity measurement, refraction, and cover test, as well as ophthalmic examinations. The NPC and NPA were measured using an accommodative target (near Snellen chart). Results Of 1,595 students, the data of 1,357 were analyzed. The mean NPC and NPA in the total sample were 7.25 cm (95% confidence interval [CI], 7.02 to 7.48) and 9.99 cm (95% CI, 9.69 to 10.29), respectively. Older age was associated with an increase in the NPC, which increased from 6.98 cm in 18-20 years olds to 9.51 cm in those over 30 years. The NPA was significantly associated with age and refractive errors in the multiple linear regression model, increasing from 9.92 cm in 18-20 years olds to 11.44 cm in those over 30 years ( P = 0.003). Hyperopic eyes had lower NPA than myopic and emmetropic eyes ( P = 0.001). In younger age groups, the mean accommodation amplitude was lower than the mean Hofstetter value. Moreover, with age, especially after 30 years, the mean values surpassed those determined using the Hofstetter formula. Conclusion The NPC values in this study were lower than those previously reported for identical age groups. The Hofstetter formula is not always an accurate predictor of the accommodation amplitude in the Iranian adult population.
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Affiliation(s)
- Hassan Hashemi
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran.,Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
| | - Mojgan Pakbin
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran.,Research and Technology Deputy, Tehran University of Medical Sciences, Tehran, Iran
| | - Babak Ali
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Abbasali Yekta
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hadi Ostadimoghaddam
- Refractive Errors Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amir Asharlous
- Refractive Errors Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Mehdi Khabazkhoob
- Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Sánchez-González MC, Pérez-Cabezas V, López-Izquierdo I, Gutiérrez-Sánchez E, Ruiz-Molinero C, Rebollo-Salas M, Jiménez-Rejano JJ. Is it possible to relate accommodative visual dysfunctions to neck pain? Ann N Y Acad Sci 2018. [PMID: 29524355 DOI: 10.1111/nyas.13614] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The aim of this study was to establish whether there is a relationship between conditions of accommodative visual dysfunctions and cervical complaints. Fifty-two participants were included. Variables were accommodative amplitude, positive and negative relative accommodation (NRA), accommodative response, and accommodative facility. Subjects were classified as accommodative insufficiency, accommodative excess, or normal. Neck complaints were measured with the Neck Disability Index, the Visual Analogue Scale, and by cervical range of motion, deep flexor muscle activation score, and performance index. We found the following significant relationships: between NRA and both performance index and left-side bending; accommodative amplitude right-eye with right-side bending and with left-side bending; accommodative amplitude left-eye with right-side bending; and accommodative facility left-eye with both performance index and left-side bending. In accommodative amplitude right-eye, aIl participants showed significant values and greater than those with accommodative excess. In both groups, performance index values were decreased. Greater pain and lower right-rotation were found in participants with accommodative excess than in those with accommodative insufficiency. We conclude that accommodative dysfunctions are related to low performance index, decreased range of motion, as well as greater neck pain.
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Affiliation(s)
| | - Verónica Pérez-Cabezas
- Department of Nursing and Physiotherapy, Faculty of Nursing and Physiotherapy, University of Cadiz, Cadiz, Spain
| | | | | | - Carmen Ruiz-Molinero
- Department of Nursing and Physiotherapy, Faculty of Nursing and Physiotherapy, University of Cadiz, Cadiz, Spain
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Upadhyaya S, Pullela M, Ramachandran S, Adade S, Joshi AC, Das VE. Fixational Saccades and Their Relation to Fixation Instability in Strabismic Monkeys. Invest Ophthalmol Vis Sci 2017; 58:5743-5753. [PMID: 29114840 PMCID: PMC5678548 DOI: 10.1167/iovs.17-22389] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 10/02/2017] [Indexed: 12/30/2022] Open
Abstract
Purpose To evaluate the contribution of fixational saccades toward fixation instability in strabismic monkeys. Methods Binocular eye movements were measured as six experimental monkeys (five strabismic monkeys and one monkey with downbeat nystagmus) and one normal monkey fixated targets of two shapes (Optotype, Disk) and two sizes (0.5°, 2°) during monocular and binocular viewing. Fixational saccades were detected using an unsupervised clustering algorithm. Results When compared with the normal monkey, amplitude and frequency of fixational saccades in both the viewing and nonviewing eye were greater in 3 of 5 strabismic monkeys (1-way ANOVA on ranks P < 0.001; median amplitude in the normal monkey viewing eye: 0.33°; experimental animals: median amplitude range 0.20-0.82°; median frequency in the normal monkey: 1.35/s; experimental animals: median frequency range 1.3-3.7/s). Increase in frequency of fixational saccades was largely due to quick phases of ongoing nystagmus. Fixational saccade amplitude was increased significantly (3-way ANOVA; P < 0.001) but by small magnitude depending on target shape and size (mean difference between disk and optotype targets = 0.02°; mean difference between 2° and 0.5° targets = 0.1°). Relationship between saccade amplitude and the Bivariate Contour Ellipse Area (BCEA) was nonlinear, showing saturation of saccade amplitude. Fixation instability in depth was significantly greater in strabismic monkeys (vergence BCEA: 0.63 deg2-2.15 deg2) compared with the normal animal (vergence BCEA: 0.15 deg2; P < 0.001). Conclusions Increased fixational instability in strabismic monkeys is only partially due to increased amplitude and more frequent fixational saccades. Target parameter effects on fixational saccades are similar to previous findings of target effects on BCEA.
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Affiliation(s)
- Suraj Upadhyaya
- College of Optometry, University of Houston, Houston, Texas, United States
| | - Mythri Pullela
- College of Optometry, University of Houston, Houston, Texas, United States
| | | | - Samuel Adade
- College of Optometry, University of Houston, Houston, Texas, United States
| | - Anand C. Joshi
- College of Optometry, University of Houston, Houston, Texas, United States
| | - Vallabh E. Das
- College of Optometry, University of Houston, Houston, Texas, United States
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