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  1. Free-space accommodative response and minus lens-induced accommodative response in pre-school children
    Chen AH, O'Leary DJ
    Optometry, 2000 Jul;71(7):454-8.
    PMID: 15326899
    The purpose of this study was to investigate and compare the accommodative accuracy of pre-school children between free-space accommodative stimulus and minus lens-induced accommodative stimulus.
    Matched MeSH terms: Accommodation, Ocular/physiology*
  2. Is there any difference in using blur as a stimulus for accommodation between emmetropes and myopes?
    Chen AH
    Documenta ophthalmologica. Advances in ophthalmology, 2002 Jul;105(1):33-9.
    PMID: 12152800
    The purpose of this study was to determine if there was any difference between myopes and emmetropes in using blur as a stimulus for accommodation when the chromatic aberration, size and proximal cues were eliminated. Twenty adults (10 myopes and 10 emmetropes) were examined for their accuracy of accommodation response for five different accommodation demands (OD, 1D, 2D, 3D, 4D) under two different light sources: achromatized white light versus monochromatic light. There was no significant difference in using blur stimulus between myopes and emmetropes when the chromatic aberration, size and proximal cues were eliminated.
    Matched MeSH terms: Accommodation, Ocular/physiology*
  3. Fulltext Vergence and accommodation system in malay primary school children
    Chen AH, Abidin AH
    Malays J Med Sci, 2002 Jan;9(1):9-15.
    PMID: 22969312
    Sixty primary school children, were measured for for accommodation and, vergence facility, accommodation accuracy, relative accommodation, fusional vergence / reserve and heterophoria.Analysis of Variance revealed that no - single factor was significant by involved among the six age groups for all the above (p>0.05). However, a significant age difference (p<0.05) was found in the fusional reserve. The mean and standard deviation was 20.08 (±6.43) cpm for the monocular accommodation facility, 19.77 (±6.26) cpm for the binocular accommodation facility, 20.18 (±5.00) cpm for the vergence facility, 0.44 (±0.27) D for the accommodation accuracy, -0.28 (±0.82) PD for the heterophoria at distance, -1.84 (±3.9) PD for the near heterophoria, 3.25 (±0.79) D for the negative relative accommodation, and -3.90 (±1.32) D for the positive relative accommodation.There was no age difference in the accommodation and the vergence status between years the ages of 7 and 12 years old but the fusional reserve component of the vergence system varied with age. The vergence and the accommodation findings in our subjects were discussed and compared with previous studies to serve as a guideline in clinical data interpretation and diagnosis for binocular vision problems in Malay children.
    Matched MeSH terms: Accommodation, Ocular*
  4. Fulltext Understanding and preventing computer vision syndrome
    Loh KY, Reddy SC
    Malays Fam Physician, 2008;3(3):128-30.
    PMID: 25606136 MyJurnal
    The invention of computer and advancement in information technology has revolutionized and benefited the society but at the same time has caused symptoms related to its usage such as ocular sprain, irritation, redness, dryness, blurred vision and double vision. This cluster of symptoms is known as computer vision syndrome which is characterized by the visual symptoms which result from interaction with computer display or its environment. Three major mechanisms that lead to computer vision syndrome are extraocular mechanism, accommodative mechanism and ocular surface mechanism. The visual effects of the computer such as brightness, resolution, glare and quality all are known factors that contribute to computer vision syndrome. Prevention is the most important strategy in managing computer vision syndrome. Modification in the ergonomics of the working environment, patient education and proper eye care are crucial in managing computer vision syndrome.
    Matched MeSH terms: Accommodation, Ocular
  5. Viewing distance with minimum heterophoria
    Chen AH, Aziz A
    Clin Exp Optom, 2002 12 17;82(5):182-186.
    PMID: 12482277
    BACKGROUND: The purposes of this study are to determine the viewing distance with minimum heterophoria and its relationship with refractive error and the resting position of accommodation. METHODS: The heterophoria and the accommodation responses of 36 optometry students (25 emmetropes and 11 myopes) were tested. Heterophoria was measured with the Free-Space Heterophoria Card at five different viewing distances (25 cm, 33 cm, 50 cm, 100 cm and 300 cm). The dioptric viewing distance with minimum heterophoria for each individual was estimated from the graph, where heterophoria in prism dioptres was plotted against viewing distance in centimetres. The Canon R-1 autore-fractor was used to determine the accommodation response at six different viewing distances (25 cm, 33 cm, 50 cm, 100 cm, 300 cm and 600 cm). The resting position of accommodation for each individual was estimated from the graph where the accommodative stimulus in dioptres was plotted against the accommodative response in dioptres. RESULTS: The dioptric viewing distance with minimum heterophoria ranges from 0.003 D to 0.65 D in emmetropes and ranges from 0.03 D to 2.36 D in myopes. There is no difference in the dioptric viewing distance with minimum heterophoria between myopes and emmetropes. Our results show a possible but not significant correlation between the dioptric viewing distance with minimum heterophoria and the resting position of accommodation. CONCLUSIONS: The viewing distance with minimum heterophoria is not affected by refractive error (stable early-onset myopia) and is poorly correlated with the resting position of accommodation.
    Matched MeSH terms: Accommodation, Ocular
  6. Virtual reality games on accommodation and convergence
    Mohamed Elias Z, Batumalai UM, Azmi ANH
    Appl Ergon, 2019 Nov;81:102879.
    PMID: 31422241 DOI: 10.1016/j.apergo.2019.102879
    Increasing popularity of virtual reality (VR) gaming is causing increased concern, as prolonged use induces visual adaptation effects which disturbs normal vision. Effects of VR gaming on accommodation and convergence of young adults by measuring accommodative response and phoria before and after experiencing virtual reality were measured. An increase in accommodative response and a decrease in convergence was observed after immersion in VR games. It was found that visual symptoms were apparent among the subjects post VR exposure.
    Matched MeSH terms: Accommodation, Ocular/physiology*
  7. Fulltext The effect of induced visual stress on three dimensional perception
    Abd-Manan F
    Malays J Med Sci, 2000 Jul;7(2):18-26.
    PMID: 22977386 MyJurnal
    Previous studies have shown that stress on the vergence and accommodation systems, either artificially induced or naturally occurring, results in small misalignment of the visual axes, reduces binocular visual acuity and produces symptoms of ocular discomfort. This study examines the effect of artificially induced visual stress using ophthalmic prisms on three dimensional perception on 30 optometry students ages ranging from 19 to 29 years old. 6D base-in prisms, equally divided between the eyes (3D base-in each) was used to induce stress on the visual system producing misalignment of visual axes known as fixation disparity. The fixation disparity is quantified using near vision Mallett Unit and an enlarged scaled diagram. Stereoscopic perception was measured with the TNO test, with and without the presence of stress and the results was compared. Wilcoxon's matched pair ranked tests show statistically significant difference in the stereo thresholds of both conditions, p = 0.01 for advancing stereopsis and p = 0.01 for receding stereopsis, respectively. The study concludes that visual stress induced by prisms, produce misalignment of the visual axes and thus reduces three dimensional performance.
    Matched MeSH terms: Accommodation, Ocular
  8. Fulltext Visual demands in modern Australian primary school classrooms
    Narayanasamy S, Vincent SJ, Sampson GP, Wood JM
    Clin Exp Optom, 2016 May;99(3):233-40.
    PMID: 26889920 DOI: 10.1111/cxo.12365
    BACKGROUND: The visual demands of modern classrooms are poorly understood yet are relevant in determining the levels of visual function required to perform optimally within this environment.

    METHODS: Thirty-three Year 5 and 6 classrooms from eight south-east Queensland schools were included. Classroom activities undertaken during a full school day (9 am to 3 pm) were observed and a range of measurements recorded, including classroom environment (physical dimensions, illumination levels), text size and contrast of learning materials, habitual working distances (distance and estimated for near) and time spent performing various classroom tasks. These measures were used to calculate demand-related minimum criteria for distance and near visual acuity, contrast and sustained use of accommodation and vergence.

    RESULTS: The visual acuity demands for distance and near were 0.33 ± 0.13 and 0.72 ± 0.09 logMAR, respectively (using habitual viewing distances and smallest target sizes) or 0.33 ± 0.09 logMAR assuming a 2.5 times acuity reserve for sustained near tasks. The mean contrast levels of learning materials at distance and near were greater than 70 per cent. Near tasks (47 per cent) dominated the academic tasks performed in the classroom followed by distance (29 per cent), distance to near (15 per cent) and computer-based (nine per cent). On average, children engaged in continuous near fixation for 23 ± 5 minutes at a time and during distance-near tasks performed fixation changes 10 ± 1 times per minute. The mean estimated habitual near working distance was 23 ± 1 cm (4.38 ± 0.24 D accommodative demand) and the vergence demand was 0.86 ± 0.07(Δ) at distance and 21.94 ± 1.09(Δ) at near assuming an average pupillary distance of 56 mm.

    CONCLUSIONS: Relatively high levels of visual acuity, contrast demand and sustained accommodative-convergence responses are required to meet the requirements of modern classroom environments. These findings provide an evidence base to inform prescribing guidelines and develop paediatric vision screening protocols and referral criteria.
    Matched MeSH terms: Accommodation, Ocular
  9. Fulltext Provision of Prosthetic Services Following Lower Limb Amputation in Malaysia
    Arifin N, Hasbollah HR, Hanafi MH, Ibrahim AH, Rahman WAWA, Aziz RC
    Malays J Med Sci, 2017 Oct;24(5):106-111.
    PMID: 29386978 MyJurnal DOI: 10.21315/mjms2017.24.5.12
    The incidence of lower limb amputation is high across the globe and continues to be a major threat to morbidity and mortality. Consequently, the provision of high quality and effective prosthetics services have been known as an essential component for a successful rehabilitation outcome. In Malaysia, amputation prevalence has been increasing in which several main components of service delivering aspects (such as service intervention, prosthetic personnel) should be anticipated to accommodate for the increasing demand. This article highlights the hurdles experienced in providing prosthetic services in Malaysia from multiple aspects such as financial burden to acquire the prosthesis and lack of expertise to produce quality prosthesis. This paramount issues consequently justify for the urgency to carry out national level survey on the current statistics of lower limb amputation and to ascertain the available workforce to provide a quality prosthetics services. Only with accurate and current information from the national survey, strategies and policies aimed at enhancing the outcome from prosthetics services can be achieved.
    Matched MeSH terms: Accommodation, Ocular
  10. The Cambridge Anti-myopia Study: variables associated with myopia progression
    Price H, Allen PM, Radhakrishnan H, Calver R, Rae S, Theagarayan B, et al.
    Optom Vis Sci, 2013 Nov;90(11):1274-83.
    PMID: 24100478 DOI: 10.1097/OPX.0000000000000067
    To identify variables associated with myopia progression and to identify any interaction between accommodative function, myopia progression, age, and treatment effect in the Cambridge Anti-Myopia Study.
    Matched MeSH terms: Accommodation, Ocular/physiology
  11. Critical review: effects of optical defocus on refractive development and ocular growth and relation to accommodation
    Chung KM
    Optom Vis Sci, 1993 Mar;70(3):228-33.
    PMID: 8483585
    Studies of optical defocus on refractive development and ocular growth in animals are presented and discussed in relation to the accommodation hypothesis. None of these studies fully support the accommodation hypothesis. The problems encountered in these studies are also discussed.
    Matched MeSH terms: Accommodation, Ocular*
  12. Effects of long-term visual display terminal usage on visual functions
    Yeow PT, Taylor SP
    Optom Vis Sci, 1991 Dec;68(12):930-41.
    PMID: 1787950
    Since their rapid introduction into the workplace visual display terminals (VDT's) have been the source of a number of studies aimed at detecting effects on office workers. The published studies have been either short-term or cross-sectional, with one exception. The results have shown varying degrees of relation but by not having a comparable control group all have been limited in their value. We set out to monitor at regular intervals over a 2-year period specific visual functions that have been reported to be affected by VDT usage, and to compare VDT and non-VDT users in the same office environment. By assessing the VDT operators from the time the systems were introduced we have an accurate baseline to work from when assessing change due to the introduction of the VDT.
    Matched MeSH terms: Accommodation, Ocular/physiology*
  13. Fulltext Amplitude of Accommodation among Students of a Malaysian Private University as Assessed Using Subjective and Objective Techniques
    Majumder C, Afnan H
    Korean J Ophthalmol, 2020 06;34(3):219-226.
    PMID: 32495530 DOI: 10.3341/kjo.2019.0138
    PURPOSE: The purpose of the study was to establish baseline data for amplitude of accommodation (AA) measured using both subjective and objective techniques in students at a private Malaysian university.

    METHODS: This cross-sectional study was conducted including 34 healthy participants with a mean age of 22.26 ± 1.88 years. AA was measured using dynamic retinoscopy and the push-up, pull-away, modified push-up, and minus-lens techniques.

    RESULTS: The mean AA scores for the push-up, pull-away, minus-lens, and modified push-up techniques and dynamic retinoscopy were 11.38 ± 2.03, 10.35 ± 1.64, 9.24 ± 1.18, 8.26 ± 1.44, and 7.2 ± 1.0 diopters, respectively. No AA measurements showed significant difference among ethnicities (Chinese, Malay, and Indian). This study suggested that AA obtained using push-up (p = 0.005) and pull-away (p = 0.017) methods and dynamic retinoscopy (p = 0.041) were significantly different according to sex. No significant difference was observed in AA for the minus-lens (p = 0.051) and modified push-up (p = 0.216) techniques by sex. A moderately negative correlation was found between AA and age for the push-up (r = -0.434, p = 0.010), pull-away (r = -0.412, p = 0.016), and minus-lens (r = -0.509, p = 0.002) techniques and dynamic retinoscopy (r = -0.497, p = 0.003). A weak negative correlation was found between age and AA measured using a modified push-up technique (r = -0.393, p = 0.022).

    CONCLUSIONS: Mean AA was highest for the push-up technique, followed by the pull-away technique, the minus-lens technique, the modified push up technique, and dynamic retinoscopy. The push-up and pull-away methods and dynamic retinoscopy showed a significant difference in measurement of AA between sexes.

    Matched MeSH terms: Accommodation, Ocular/physiology*
  14. The influence of age, refractive error, visual demand and lighting conditions on accommodative ability in Malay children and adults
    Chen AH, Ahmad A, Kearney S, Strang N
    Graefes Arch Clin Exp Ophthalmol, 2019 Sep;257(9):1997-2004.
    PMID: 31273509 DOI: 10.1007/s00417-019-04405-z
    PURPOSE: Near work, accommodative inaccuracy and ambient lighting conditions have all been implicated in the development of myopia. However, differences in accommodative responses with age and refractive error under different visual conditions remain unclear. This study explores differences in accommodative ability and refractive error with exposure to differing ambient illumination and visual demands in Malay schoolchildren and adults.

    METHODS: Sixty young adults (21-25 years) and 60 schoolchildren (8-12 years) were recruited. Accommodative lag and accommodative fluctuations at far (6 m) and near (25 cm) were measured using the Grand Seiko WAM-5500 open-field autorefractor. The effects of mesopic room illumination on accommodation were also investigated.

    RESULTS: Repeated-measures ANOVA indicated that accommodative lag at far and near differed significantly between schoolchildren and young adults [F(1.219, 35.354) = 11.857, p  0.05). Accommodative lag and fluctuations were greater under mesopic room conditions for all ages [all p 

    Matched MeSH terms: Accommodation, Ocular/physiology*
  15. Fulltext The effect of smartphone usage on accommodation status
    Wiki Safarina Narawi, Shaz’ Ain Razak, Nahdiyah Azman
    Malaysian Journal of Medicine and Health Sciences, 2020;16(2):244-247.
    MyJurnal
    Introduction: Usage of smartphones have increased rapidly because of its importance in our daily life. This led to an increase in incidence of ocular problems among smartphone users. This research was conducted to determine the effect of smartphone usage on accommodation status. Methods: A cross-sectional study was conducted among young adults aged 19 to 30 years old in Management and Science University, Shah Alam. All subjects were asked to use smartphone for 20 minutes. The symptoms and accommodation status were evaluated before and after the smartphone usage. Results: Total subjects showed the mean age of 23.60 ± 2.77 years, 50% (n = 20) were males and 50% (n = 20) were females. The mean smartphone usage per day was 8.60 ± 2.80) hours. After 20 minutes of smartphone usage, subjects complained of tired eyes (92.50%), dry eyes (90.00%), blurred vision (87.50%), and headache (82.50%). Paired t-test showed significant reduction in amplitude of accommodation, monocularly from 9.9 ± 1.9 D to 8.76 ± 2.50 D (p = 0.00), and binocularly from 12.01 ± 1.95 D to 10.96 ± 2.16 D (p = 0.00); monoc- ular accommodative facility from 13.93 ± 3.13 cpm to 11.10 ± 4.32 cpm (p = 0.00) and binocular accommodative facility from 12.70 ± 3.57 cpm to 9.70 ± 4.21 cpm (p = 0.00); positive relative accommodation from -2.72 ± 0.87 D to -2.13 ± 1.28 D (p = 0.00) and increase in lag of accommodation from 0.4 ± 0.26 D to 0.93 ± 0.48 D (p = 0.00). Conclusion: This study shows that there were significance changes on accommodation status after 20 minutes of smartphone usage which can lead to weakness of accommodation.

    Matched MeSH terms: Accommodation, Ocular
  16. Fulltext Accommodation response to Chinese and Latin characters in Chinese-illiterate young adults
    Radhakrishnan H, Hartwig A, Charman WN, Llorente L
    Clin Exp Optom, 2015 Nov;98(6):527-34.
    PMID: 26450168 DOI: 10.1111/cxo.12296
    BACKGROUND: Differences in accommodation when reading Chinese, as compared to Latin, characters have been suggested to have a role in the higher prevalence of myopia in some Asian countries. Yeo and colleagues (Optom Vis Sci 2013; 90: 156-163) found that, in Chinese-literate children, accommodation was marginally more accurate (by less than 0.05 D), when reading Chinese text. This was attributed to the additional cognitive demand associated with interpreting the more complex Chinese symbols. The present study compared responses to single Chinese and Latin characters, while controlling for cognitive demand.
    METHODS: The monocular accommodative response was measured in Chinese-illiterate adults (10 emmetropes, mean spherical equivalent: -0.07 ± 0.42 D, age: 29.9 ± 4.2 years; 11 myopes, mean spherical equivalent: -4.28 ± 2.84 D, age: 31.7 ± 4.6 years) with an open-field autorefractor. Four Chinese and three Latin characters (approximately 1.15 degrees subtense) were individually presented on a display screen one metre away from the subject, while their vergence was varied over the range zero to 5.00 D using spectacle trial lenses. The slope and the accommodative error index (AEI) were calculated from the accommodative stimulus/response curves (ASRC).
    RESULTS: No statistically significant differences were found between refractive groups or among characters within the same refractive group in ARSC slopes (Latin: 0.87 ± 0.14 for myopes versus 0.81 ± 0.12 for emmetropes; Chinese: 0.84 ± 0.12 for myopes versus 0.85 ± 0.12 for emmetropes). No significant differences were found between characters in accommodative error index either (Latin, 0.78 ± 0.42 D for myopes versus 1.15 ± 0.72 D for emmetropes; Chinese, 0.74 ± 0.37 D for myopes versus 1.17 ± 0.83 D for emmetropes). However, accommodative error indices and accommodative errors were significantly higher for emmetropes.
    CONCLUSION: Under controlled cognitive demand, Chinese and Latin characters elicited similar responses in both individual refractive groups. This study fails to support the hypothesis that development of myopia in some Asian populations is associated with larger lags of accommodation when reading or viewing Chinese characters.
    Study site: Manchester, United Kingdom
    Matched MeSH terms: Accommodation, Ocular/physiology*
  17. Transient loss of power of accommodation in 1 eye following inferior alveolar nerve block: report of 2 cases
    Ngeow WC, Shim CK, Chai WL
    J Can Dent Assoc, 2006 Dec;72(10):927-31.
    PMID: 17187708
    Unintended intravascular injection from inferior alveolar nerve blocks can result in frustrating distant complications affecting such structures as the middle ear and eyes. Possible complications affecting the eyes include blurring of vision, diplopia, mydriasis, palpebral ptosis and amaurosis (temporary or permanent). In this article, we present a complication that has been reported only rarely. Two patients developed transient loss of power of accommodation of the eye resulting in blurred vision after routine inferior alveolar nerve blocks on the ipsilateral side. Clear vision returned within 10-15 minutes after completion of the blocks. The possible explanation for this phenomenon is accidental injection into the neurovascular bundle of local anesthetic agents, which were carried via the blood to the orbital region. This resulted in paralysis of a branch of cranial nerve III, the short ciliary nerves that innervate the ciliary muscle, which controls accommodation.
    Matched MeSH terms: Accommodation, Ocular/drug effects*
  18. Effects of short-term VDT usage on visual functions
    Yeow PT, Taylor SP
    Optom Vis Sci, 1989 Jul;66(7):459-66.
    PMID: 2771333
    An on-site comparative study was carried out on the effects of video display terminal (VDT) and non-VDT work on visual functions in two working populations in the same office environment. Both continuous VDT usage in a training situation over a few days and intermittent VDT usage in a normal working situation were assessed and particular attention paid to their effects on the refractive error of different refractive groups and for different age populations. Other visual functions measured were visual acuity (VA), accommodation, and convergence. Results show that VDT work does not have a significantly greater effect on visual function than non-VDT work.
    Matched MeSH terms: Accommodation, Ocular
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