Investigation of amplitude of accommodation among Ghanaian school children

Background: Deficient amplitude of accommodation is the most frequently used criteria in an optometric practice in diagnosing whether a patient has accommodative insufficiency. This deficiency is determined based on an age‐related expected finding calculated using Hofstetter's equation derived from Donder's and Duane's data. The aim of the present study was to investigate the amplitude of accommodation among Ghanaian school children and to compare the findings with age‐expected norms predicted by Hofstetter's equation. Methods: The amplitude of accommodation was measured using the push‐up method in a random sample of 435 school children from the Cape Coast Municipality. The mean amplitude of accommodation was compared with the age‐expected amplitude of accommodation as predicted by Hofstetter's equation for average amplitude of accommodation. Results: The mean amplitude of accommodation was 16.86 ± 3.07 D (95% CI = 16.57, 17.15). This is significantly higher than age‐expected norms calculated using Hofstetter's equation. The amplitude of accommodation showed the characteristic decline with age. Conclusion: From the results, we conclude that the age‐expected norms for amplitude of accommodation using Hofstetter's equation might not be accurate for Ghanaian children.     

青年人近视眼与各调节因素的关系

目的分析眼屈光不正与调节各因素的关系,探讨近视眼与眼调节之间的相关性。方法分别对45名大学生的90眼进行屈光不正、调节幅度、调节灵活度和正相对调节检查,然后将各项结果与屈光不正状况进行相关性统计分析。结果45名大学生受试者调节幅度的平均值为(8.49±1.61)D(6.25~13.70 D)。调节灵活度平均值为(9.64±2.30)周/min。正相对调节平均值为(-2.19±0.84)D。其中调节幅度与眼屈光度有显著相关性(r=-0.885,P≤0.05)。调节灵活度与眼屈光度无相关性。结论眼屈光不正与眼调节幅度有显著关系,眼的调节灵活度与屈光不正无相关关系。     

近视患者LASIK术后早期单眼调节幅度的变化观察

目的:观察近视患者准分子激光原位角膜磨镶术(laser in situ keratomileusis,LASIK)术后早期单眼调节幅度(amplitude of accommodation,AMP)的变化。方法:用LASIK治疗近视患者53例,根据等效球镜度数分为轻度、中度和高度近视组,所有被测者均进行规范的主觉验光,采用移近法在术前、术后1wk;1mo和3mo测量左眼调节幅度,所得结果输入SPSS11.0统计软件包。结果:LASIK术后1wk和1mo调节幅度明显低于术前AMP(P<0.05),术后3mo不同近视程度患者调节幅度与术前比较无统计学差异(P>0.05)。结论:不同近视程度近患者LASIK术后早期单眼调节幅度变化趋势基本相同,即均表现为先下降,后上升,至术后3mo时AMP基本恢复到术前戴镜水平;LASIK手术对近视患者单眼调节幅度无明显不良影响。     

The amplitude of accommodation in 6–10-year-old children – not as good as expected!

The aim of this study was to measure the amplitude of accommodation for junior level school children and to compare it with age‐expected values. A junior level school in Göteborg, Sweden, was randomly chosen and the amplitude of accommodation among 76 children aged 6–10 years was examined using Donders’ push‐up method. The results showed lower amplitude than expected in a large group of children. Results also showed lower amplitude than previously reported for this age group, especially under monocular conditions, which revealed an average dioptric difference from the expected value of ?3.60 dioptres (D) right eye (mean 12.40 D, median 12.00 D, S.D. 3.7 D) and ?3.50 D left eye (mean 12.50 D, median 12.70 D, S.D. 3.8 D) (p < 0.001 for both eyes). Consequently, we conclude that it cannot be assumed that the amplitude of accommodation is in the expected amplitude range for all children of these ages.     

Lens fluorescence and accommodative amplitude in pre-presbyopic and presbyopic subjects

Accommodative amplitude (AA; the difference, measured in diopters, between the near and far points of vision) declines steadily with age such that, by midlife, most individuals are unable to focus clearly on near objects and, thus, are said to be presbyopic. Conversely, intrinsic lens fluorescence (LF) increases steadily with age. Previous studies have suggested that AA and LF are negatively correlated, independent of age. Were this to be the case, it might suggest that the biochemical modifications underlying increased tissue fluorescence (for example, glycation of lens proteins) contribute to presbyopia. We used quantitative techniques to re-evaluate the relationship between AA and LF in 161 healthy volunteers aged between 25 and 70. Our data confirmed that AA decreases with age, becoming essentially zero by age 55, and LF increases with age. However, in marked contrast to previous reports, statistical analysis failed to detect any correlation between LF and AA independent of age. Thus, the biochemical processes responsible for increased LF observed in the aged lens are unlikely to contribute directly to presbyopia.     

老视前期近视患者LASIK术后单眼调节幅度的变化

目的探讨老视前期近视患者准分子激光原位角膜磨镶术（laser in situ keratomileusis,LASIK）后单眼调节幅度的变化。方法随机选择接受LASIK手术治疗的老视前期近视患者29例（58眼）,按平时戴镜情况分为两组：角膜接触镜组（13例26眼）和框架眼镜组（16例32眼）,比较术前,术后第10天、第1个月和第3个月的单眼调节幅度（负镜片法）,并将第10天的调节幅度下降程度与术前屈光度数作相关分析。结果角膜接触镜组术前,术后第10天、第1个月和第3个月的调节幅度分别为（7．15±1．02）D、（6．14±1．32）D、（6．69±1．43）D和（7．17±1．15）D;框架眼镜组术前、术后第10天、第1个月和第3个月的调节幅度分别为（6．32±1．07）D、（5．49±1．06）D、（5．90±1．33）D和（6.31±1．19）D。术后第10天、第1个月的调节幅度与术前相比,两组均有显著性下降,差异有统计学意义（P〈0．05）;到术后第3个月时已恢复到术前水平,差异无统计学意义（P〉0．05）。术前角膜接触镜组的调节幅度明显高于框架眼镜组（P=0．004）．但是术后第10天调节幅度的下降值两组间差异无统计学意义（P=0．464）。术后第10天调节幅度的下降程度与术前屈光度数呈正相关（r=0．52,P〈0．01）。结论老视前期近视患者LASIK术后早期单眼调节幅度的降低是暂时性的。不会引起患者老视的提早出现。     

Effect of whiplash injury on accommodation

Background: Accommodative disturbance has been cited as one of the causes of visual disturbance following whiplash injury but to date, with one exception, none of the studies have incorporated a group of control subjects; none of the results have been statistically analysed. The aim of the present study was to examine the amplitude of accommodation in a group of whiplash subjects, the majority of whom had specifically complained of visual/ocular symptoms. Methods: The whiplash group consisted of 19 subjects and the control group consisted of 43 subjects. The amplitude of accommodation of the right and left eyes of the whiplash and control group subjects was measured and the results of the two groups compared. Results: There was reduced amplitude of accommodation of the right (P = 0.02) and left (P = 0.02) eyes in the whiplash group subjects compared to the control group subjects. Conclusion: These results indicate that whiplash was associated with defective accommodation in the present select group of whiplash subjects.     

Accommodation and the relationship to subjective symptoms with near work for young school children

The aim of this work was to study the relation between subjective symptoms at near and ocular accommodation in terms of the amplitude of accommodation and the relative accommodation. A secondary aim was to discuss the diagnosis of accommodative insufficiency. The chosen cohort was examined on two occasions with 1.8 years in between. The first examination included 72 children, 43 boys (mean age 8.1 years, ranging from 5.8 to 9.8) and 29 girls (mean age 8.3 years, ranging from 6.2 to 10.0). The second examination included 59 of these children, 34 boys (mean age 9.9 years, ranging from 7.8 to 11.7) and 25 girls (mean age 10.1 ranging from 8.0 to 11.8). Subjective symptoms at near work (headache, asthenopia, floating text, facility problems) were recorded and the amplitude and the relative accommodation, both positive and negative, were measured. The result from the questionnaire showed that at the first examination more than one‐third of the children (34.7%) reported at least one subjective symptom when doing near work and 42.4% at the second examination. No symptoms were found among children younger than 7.5 years, but for children between 7.5 and 10 years old at the first examination, the prevalence of at least one symptom was 47.2%. At the second examination, symptoms were reported also for the youngest children, i.e. from the age of 8 years. The discrimination ability for the amplitude of accommodation, both monocular and binocular, was significant. In the first examination the difference between the mean for the two groups (i.e. with and without at least one symptom) was around 2.00 D monocular and 3.00 D binocular. Corresponding figures from the second examination was a difference between the mean for the two groups of around 3.50 D monocular and nearly 4.00 D binocular. We suggest that accommodation measurements should be performed more routinely and regularly, maybe as screening, especially in children over 8 years of age.     

可调节型人工晶状体眼调节幅度的计算及其影响因素分析

目的①推导出计算可调节型人工晶状体(accom-modative intraocular lens,AIOL)植入术后眼的调节幅度(ac-commodative amplitude,AA)的数学公式。②探讨影响人工晶状体眼AA的相关因素,为研究AIOL植入手术的治疗效果提供理论依据。方法根据高斯近轴光线光学理论推导得出计算AIOL植入眼AA的理论计算公式,以人工晶状体(in-traocular lens,IOL)焦点的移动量(effective intraocular lensposition,ΔELP)、眼轴长(axial length,AL)、角膜屈光力(corneal power,K)、IOL的有效位置(effective lens position,ELP)、植入IOL的屈光力(power of the implanted IOL,IOLImp)计算AA,分别建立AA与ΔELP、AL、K、ELP、IOLImp的函数关系,分析以上各参数对AA的影响。结果①人工晶状体眼AA受ΔELP、AL、K、ELP、IOLImp的影响(AL=23.65mm、K=43.8D、ELP=5.8mm),屈光状态为正视、ΔELP...     

眼调节幅度与近视眼的关系研究

目的　评价不同屈光状态下的眼调节幅度特点 ,分析调节幅度在近视眼的发生发展中的作用 ,进一步明确眼调节幅度与近视眼的因果关系。方法　被测者共 3 5人 ,其中男 17人(4 8 6% ) ,女 18人 (5 1 4% ) ,年龄 19～ 3 5岁 ,平均 2 6 49± 3 3 3岁。所有被测者均进行规范的主觉验光 ,每眼矫正视力均≥ 1 0。移近法测得左眼调节幅度 ,采用SPSS9 0应用软件包对不同分组进行比较分析。结果　①近视组AMP明显高于正视组 ;②正视组、轻度近视和中度近视组三组之间AMP存在显著差异 ,其中正视组最低 ,其次是轻度近视和中度近视 ;③正视组、迟发性近视组和早发性近视组三组之间AMP存在显著差异 ,其中正视组最低 ,其次是迟发性近视和早发性近视。④对调节幅度和近视屈光度做相关分析后 ,可见AMP随着近视屈光度的不断加深呈现上升趋势 ,直线回归方程为AMP =9 95 2 -0 764 屈光度。⑤将AMP和近视发生与否做Logistic回归分析 ,结果认为AMP可能是近视发生的原因之一。结论　高调节幅度可能是引发近视的原因之一 ,而弱的交感神经和强的副交感神经可能是引发高调节幅度 ,继而引发近视的解剖学因素。     

Effect of timolol on the amplitude and dynamics of accommodation

There is still debate about whether the ciliary muscle is innervated by the sympathetic nervous system. We investigated the amplitude and the dynamics of accommodation under influence of the non-selective beta-blocker timolol. For this purpose the variations in thickness of the human lens during step-like changes in accommodation were measured with high-resolution A-scan echography. Results showed that the dynamics of accommodation, expressed in the time constants of the response, were affected as well as the amplitude.     

Correlation between ocular parameters and amplitude of accommodation

Aim:

To study the relationship between ocular parameters and amplitude of accommodation (AA) in the peri-presbyopic age group (35–50 years).

Materials and Methods:

Three hundred and sixteen right eyes of consecutive patients in the age group 35–50 years, who attended our outpatient clinic, were studied. Emmetropes, hypermetropes and myopes with best-corrected visual acuity of 20/20, J1 in both eyes were included. The AA was calculated by measuring the near point of accommodation. The axial length (AL), central anterior chamber depth (CACD) and lens thickness (LT) were also measured.

Results:

There was moderate correlation (Pearson’s correlation coefficient r = 0.56) between AL and AA as well as between CACD and AA (r = 0.53) in myopes in the age group 35–39 years. In the other age groups and the groups taken as a whole, there was no correlation. In hypermetropes and emmetropes, there was no correlation between AA and the above ocular parameters. No significant correlation existed between LT and AA across different age groups and refractive errors.

Conclusion:

There was no significant correlation between AA and ocular parameters like anterior chamber depth, AL and LT.     

计算机阅读后的调节幅度与屈光度优势眼的关系

目的 研究计算机阅读后的单眼调节幅度及其变化与屈光度、优势眼的关系.方法 30名受试者按不同屈光度、屈光参差状态、优势眼分组,均作连续计算机终端阅读2h,阅读前后分别查单眼调节幅度.结果 (1)连续2h计算机阅读前,调节幅度的大小与屈光度有相关性(r=0.439,P=0.003);阅读后,调节幅度的变化与屈光度无相关性(r=0.121,P=0.434).(2)计算机终端阅读前,优势眼的调节幅度大小与非优势眼调节幅度大小比较差异无统计学意义(P＞0.05);阅读后,优势眼的调节幅度变化比非优势眼调节幅度变化大(P＜0.05).(3)生理性屈光参差组和病理性屈光参差组两组内优势眼眼别与双眼中屈光不正度数较高或较低眼别之间无相关性(P＞0.05).结论 计算机阅读前,调节幅度的大小与屈光度有相关性;计算机阅读后优势眼的调节幅度变化比非优势眼调节幅度变化大;优势眼眼别与双眼中屈光不正度数较高或较低眼别之间无相关.高调节幅度及优势眼可能并不是近视进展中的主要因素.     

汉语发展性阅读障碍儿童调节功能与眼位的研究

目的 探讨汉语发展性阅读障碍儿童与正常儿童调节功能与眼位各参数的变化,明确影响汉语发展性阅读障碍儿童视觉效率的关键视觉因素.方法 病例对照研究.选取天津市12所小学五年级学生1458名.根据识字量和瑞文智力的测验结果,筛选出98名汉语发展性阅读障碍儿童为试验组,随机选取年龄、性别、瑞文智力与之匹配的98名正常儿童为对照...     

Repeatability intraexaminer and agreement in amplitude of accommodation measurements

Background  Clinical measurement of the amplitude of accommodation (AA) provides an indication of maximum accommodative ability. To determine whether there has been a significant change in the AA, it is important to have a good idea of the repeatability of the measurement method used. The aim of the present study was to compare AA measurements made using three different subjective clinical methods: the push-up, push-down, and minus lens techniques. These methods differ in terms of the apparent size of the target, the end point used, or the components of the accommodation response stimulated. Our working hypothesis was that these methods are likely to show different degrees of repeatability such that they should not be used interchangeably. Methods  The AA of the right eye was measured on two separate occasions in 61 visually normal subjects of mean age 19.7 years (range 18 to 32). The repeatability of the tests and agreement between them was estimated by the Bland and Altman method. We determined the mean difference (MD) and the 95% limits of agreement for the repeatability study (COR) and for the agreement study (COA). Results  The COR for the push-up, push-down, and minus lens techniques were ±4.76, ±4.00, and ±2.52D, respectively. Higher values of AA were obtained using the push-up procedure compared to the push-down and minus lens methods. The push-down method also yielded a larger mean AA than the negative-lens method. MD between the three methods were high in clinical terms, always over 1.75D, and the COA differed substantially by at least ±4.50D. The highest agreement interval was observed when we compared AA measurements made using minus lenses and the push-up method (±5.65D). Conclusions  The minus lens method exhibited the best repeatability, least MD (−0.08D) and the smallest COR. Agreement between the three techniques was poor. Presentation at ARVO 2007. This study was supported by grant PR1/07-14909 from the Universidad Complutense de Madrid.     

The repeatability and validity of dynamic retinoscopy in assessing the accommodative response

Dynamic retinoscopy (DR) is an objective technique that has been used successfully to examine accommodative function of non-communicative patients. However, there are few studies examining its repeatability and validity. This paper addresses the repeatability and validity of a form of DR (a modified Nott technique), by comparing results to the Shin-Nippon SRW-5000 Autorefractor whose validity and repeatability have previously been demonstrated. Accommodative responses of 41 subjects (aged 6-43 years) were assessed using DR and the Shin-Nippon SRW-5000 Autorefractor. Three different target demands were used (10, 6 and 4 D). DR was shown to be repeatable for all target demands (paired t-test, p > 0.05). The results demonstrated good agreement between the autorefractor and DR. The results of the present study suggest that DR is a repeatable and valid objective technique for assessing accommodative function.