Accommodative function in school children with reading difficulties

Background  Prior findings suggest correlation between reading problems and accommodative function, but few studies have assessed accommodation in children with poor reading skills. Our aim was to characterize monocular accommodative amplitude, relative accommodation and binocular accommodative facility in a population of healthy, non-dyslexic primary school children with reading difficulties. Methods  We conducted a cross-sectional study on 87 poor readers and 32 control children (all between 8 and 13 years of age) in grades three to six recruited from 11 elementary schools in Madrid, Spain. In each subject with best spectacle correction, negative relative accommodation (NRA) and positive relative accommodation (PRA) were measured using a phoropter, monocular accommodative amplitude (MAA) was determined using the minus lenses method, and binocular accommodative facility (BAF) was measured using the Bernell Acuity Suppression Slide (VO/9) and a ± 2.00 D accommodative demand for a period of 1 minute. Results  Monocular accommodative amplitude was significantly lower (p < 0.001) in the group of poor readers (right eye 9.1 D ± 2.3, left eye 9.0 D ± 2.3) than in the control group (right eye 10.5 D ± 1.7, left eye 10.5 D ± 1.7). Binocular accommodative facility values were significantly lower (p < 0.05) in the poor readers (4.9 cpm ± 3.1) than controls (6.3 cpm ± 2.9). Negative and positive relative accommodation values were similar in both groups of children. Conclusions  This study provides data on the accommodative capacity of a population of children with reading difficulties. Our findings suggest a reduced monocular accommodative amplitude and binocular accommodative facility, such that this function should be assessed by an optometric clinician in children whose reading level is below average. Human subjects and informed consent  The authors confirm that this research was performed followed the tenets of the Declaration of Helsinki, and that informed consent was obtained from the subjects after having explained to them in detail the nature of the study. The study protocol was approved by the Clinical Research Ethics Committee of the School of Optometry.     

Variation and correlation of clinical tests of accommodative function in a sample of school-age children.

Accommodative facility, lag of accommodation, accommodative response, and relative accommodation were measured in 244 school-age (7.9 to 15.9 years of age) children. The tests studied included monocular estimate method (MEM) dynamic retinoscopy, Nott dynamic retinoscopy, low neutral dynamic retinoscopy, the binocular cross cylinder test, lens accommodative rock (facility), distance (near-far) accommodative rock, negative relative accommodation (NRA), and positive relative accommodation (PRA). The mean, standard deviation, and range of test findings of each test are presented. Coefficients of correlation among the various tests are presented.     

MEM and Nott dynamic retinoscopy in patients with disorders of vergence and accommodation

The accommodative response in 34 patients with accommodative and binocular disorders was assessed with two different techniques of dynamic retinoscopy used in clinical practice: monocular estimate method (MEM) and Nott retinoscopy. The data obtained by both techniques were compared, evaluating the correlation and agreement between them. Results showed that there were statistically significant differences between the techniques with MEM values being more plus than Nott ones. There was a high correlation between the two techniques (0.90) and the regression analysis indicated that a linear relationship existed between MEM and Nott dynamic retinoscopy, so that accommodative lag value for Nott dynamic retinoscopy would be calculated by dividing the MEM result by 2. However, although both retinoscopies were related, there was a lack of agreement between them (+/-0.53 D) indicating that the two methods are not interchangeable for clinical purposes.     

间歇性外斜视的调节灵活度和调节反应

目的：比较间歇性外斜视和正常眼位人群之间,间歇性外斜视注视眼和非注视眼之间的调节灵活度和调节反应。方法：病例对照研究。选取2016年10月至2017年1月在温州医科大学附属眼视光医院门诊就诊的35例间歇性外斜视患者作为间歇性外斜视组,另选取24例正位眼或外隐斜斜视度≤6 △ 的门诊患者作为对照组。采用±2.00 D的反转拍和开放视野式自动验光仪分别测量受试者在单眼和双眼注视近距视标时的调节灵活度和调节反应。采用t检验对数据进行分析。结果：间歇性外斜视组的双眼调节灵活度为（8.8±4.1）cpm,显著低于对照组[（10.9±3.1）cpm],两者差异有统计学意义（t=-2.165,P=0.035）。间歇性外斜视组的非注视眼调节灵活度显著低于注视眼（t=4.657,P<0.001）。双眼注视40 cm处视标时,间歇性外斜视组的注视眼调节反应高于对照组的主导眼（t=-2.163,P=0.035）。双眼注视状态下,间歇性外斜视组注视眼的调节反应为（1.89±0.30）D,高于其在单眼注视状态下的调节反应[ （1.64±0.34）D],两者差异有统计学意义（t=3.801,P=0.001）。结论：间歇性外斜视患者的双眼调节灵活度低于对照人群,其注视眼和非注视眼的调节灵活度和调节反应均不一致,且双眼注视时调节反应高于单眼注视状态。     

Statistical normal values of visual parameters that characterize binocular function in children

A wide range of visual parameters used to evaluate binocular function were evaluated in a paediatric population (1056 subjects aged 6-12 years). Mean values are provided for these ages in optometric tests that directly assess the vergence system, horizontal phorias for near and far vision (measured by a modified version of the Thorington method), negative and positive vergence amplitude for near and far vision (step vergence testing), vergence facility (flippers 8 Delta BI/8 Delta BO), and near-point of convergence (penlight push-up technique and red-lens push-up technique), as well as stimulus accommodative convergence/accommodation ratio and stereoacuity (Randot test) which provide an overall evaluation of the vergence, accommodative and oculomotor systems. A statistical comparison (anova and Bonferroni post hoc test) of these values between ages was performed. The differences, although statistically significant, were not clinically meaningful, and therefore we identified two trends in the behaviour of these parameters. For all parameters, except for vergence facility, we established a single mean reference value for the age range studied. The difference between the means for vergence facility indicated the need to divide the population into two age ranges (6-8 and 8-12 years). This study establishes statistical normal values for these parameters in a paediatric population and their means are a valuable instrument for separating children with binocular anomalies from those with normal binocular vision.     

儿童和青少年远视性屈光参差调节功能的研究

目的研究远视性屈光参差患儿的调节幅度和调节滞后量,并比较其主导眼和非主导眼的差别。方法18例远视性屈光参差患几,年龄6．5～15（10．5±2．6）岁,屈光参差度＋1．75～5．0（＋3．5±0．9）D．7例伴有单眼轻中度弱视,11例不伴弱视。采用动态检影法检查患者40cm处的调节滞后情况．移近法测量调节幅度,区分主导眼和非主导眼,并与同期就诊的25例远视屈光不正患儿[年龄7—14（9．8±2．4）岁,屈光度（＋4．5±2．3）D1和20例正视儿童[年龄7～12（9．5±2．6）岁]进行对照比较。采用t检验对所得数据进行统计学分析。结果远视性屈光参差患儿主导眼的调节幅度和调节滞后量分别为（13．3±3．2）D和（0．79±0．39）D．与正视儿童及远视屈光不正患儿无明显差别;非主导眼的调节幅度为（11．3±3．3）D,与正视儿童及远视屈光不正患儿无明显差别：调节滞后量为（1．10±0．12）D,与正视儿童及远视屈光不正患儿差异均有统计学意义（t=2．79,P=0．03;t=2．95,P=0．02）。远视性屈光参差患儿主导眼和非主导眼的调节幅度和调节滞后量不同,差异均有显著的统计学意义（t=3．12,P=0．006;t＝4．10,P＝0．001）。伴弱视者主导眼调节滞后量比无弱视者主导眼调节滞后量大。差异有统计学意义（t=2．43,P=0．027）,而两组非主导眼的调节滞后量的差异无统计学意义（t=0．78,P=0．45）。结论儿童和青少年远视性屈光参差的主导眼和非主导眼的调节幅度和调节滞后不同：其主导眼的调节功能与同龄儿童无明显差别．非主导眼的调节功能存在缺陷。伴弱视者．其主导眼的调节功能也存在缺陷。     

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名正常儿童为对照组。对两组儿童进行调节近点、调节幅度、调节灵活度以及眼位的检查,并进行统计学分析。结果　两组儿童的双眼调节灵活度、近距离水平眼位差异均有统计学意义（均为P＜0.05）,而单眼或双眼的调节近点及调节幅度、单眼的调节灵活度、近距离垂直眼位、远距离水平眼位及垂直眼位差异均无统计学意义（均为P＞0.05）。结论　汉语发展性阅读性障碍组儿童的双眼调节灵活度下降,双眼近距离水平眼位偏大,提示这些视觉因素可能是引起汉语发展性阅读障碍儿童视觉效率下降的原因。     

Diagnostic signs of accommodative insufficiency.

PURPOSE: To determine which are the most sensitive tests, together with accommodative amplitude, to classify accommodative insufficiency (Al), we analyzed the relation between monocular estimated method (MEM) dynamic retinoscopy, monocular and binocular accommodative facility (MAF, BAF), and positive relative accommodation (PRA) with or without the presence of reduced amplitude of accommodation. METHODS: We studied 328 symptomatic patients who presented consecutively to an optometric clinic. From this sample, we selected the 41 patients who presented amplitude of accommodation at least 2 D below the minimum age-appropriate amplitude according to Hofstetter's formula: 15 - 0.25 x age. We also selected data from 40 consecutive subjects (control group) with no general binocular disorders and normal accommodative amplitudes. We studied the specificity and sensitivity of the four signs related with the accommodative insufficiency: high MEM dynamic retinoscopy, failing MAF and BAF with minus lenses of +/- 2 D flipper lenses, and low PRA. RESULTS: Using the standard deviation as the cutoff, the specificity values were MEM = 0.88, MAF = 1, BAF = 0.93, and PRA = 1. When using the mean value as the cutoff, the specificity diminished, fundamentally for MEM. The sensitivity for the 41 patients using standard deviation as the cutoff was MEM = 0.44, MAF = 0.34, BAF = 0.27, and PRA = 0.27, and when using the mean value as the cutoff the four, sensitivity values increased. CONCLUSIONS: According to the sensitivity results, with both cutoffs used, failing the +/- 2 D MAF test seems to be the sign that is most associated with the accommodative insufficiency.     

The relation between accommodative facility and general binocular dysfunction

This study was designed to evaluate the relation between accommodative facility and accommodative and binocular dysfunctions. We determined whether failure to achieve 8 cycles per minute of binocular accommodative facility or 11 cycles per minute of monocular accommodative facility tends to be associated with these dysfunctions. Forty eight subjects, ages 10–30 years were examined and classified into four groups: 13 subjects with accommodative dysfunctions, 11 patients with binocular dysfunctions, 12 subjects with accommodative and binocular dysfunctions and 12 control subjects with refractive errors but no accommodative or binocular anomalies. Monocular and binocular accommodative facility was conducted using ±2.00 D flip lenses. In general, statistical analysis indicates that subjects with binocular and accommodative (ocular motor) anomalies performed significantly poorer than subjects of normal group on monocular and binocular facility tests. Monocular accommodative facility results showed more information about the dysfunction of the patient compared with the results of the binocular accommodative facility. In general data supported a relation between reduced accommodative facility and a general binocular dysfunction (accommodative or binocular) which demonstrates the importance of the accommodative facility test in diagnosing an accommodative or binocular anomaly.     

Intra-examiner repeatability and agreement in accommodative response measurements

Purpose: Clinical measurement of the accommodative response (AR) identifies the focusing plane of a subject with respect to the accommodative target. To establish whether a significant change in AR has occurred, it is important to determine the repeatability of this measurement. This study had two aims: First, to determine the intraexaminer repeatability of AR measurements using four clinical methods: Nott retinoscopy, monocular estimate method (MEM) retinoscopy, binocular crossed cylinder test (BCC) and near autorefractometry. Second, to study the level of agreement between AR measurements obtained with the different methods. Methods: The AR of the right eye at one accommodative demand of 2.50 D (40 cm) was measured on two separate occasions in 61 visually normal subjects of mean age 19.7 years (range 18–32 years). The intraexaminer repeatability of the tests, and agreement between them, were estimated by the Bland–Altman method. We determined mean differences (MD) and the 95% limits of agreement [coefficient of repeatability (COR) and coefficient of agreement (COA)]. Results: Nott retinoscopy and BCC offered the best repeatability, showing the lowest MD and narrowest 95% interval of agreement (Nott: ?0.10 ± 0.66 D, BCC: ?0.05 ± 0.75 D). The 95% limits of agreement for the four techniques were similar (COA = ± 0.92 to ±1.00 D) yet clinically significant, according to the expected values of the AR. The two dynamic retinoscopy techniques (Nott and MEM) had a better agreement (COA = ±0.64 D) although this COA must be interpreted in the context of the low MEM repeatability (COR = ±0.98 D). Conclusions: The best method of assessing AR was Nott retinoscopy. The BCC technique was also repeatable, and both are recommended as suitable methods for clinical use. Despite better agreement between MEM and Nott, agreement among the remaining methods was poor such that their interchangeable use in clinical practice is not recommended.     

SMILE术后调节功能变化

目的 研究飞秒激光小切口角膜基质透镜取出术（SMILE）后双眼视及调节功能的变化特点。方法 回顾性研究。选取2015年3-12月在天津市眼科医院屈光手术中心接受SMILE的近视散光患者25例。分别在术前,术后1周、1个月、3个月测量调节功能参数,包括单眼调节幅度（MAA）、单眼调节灵敏度（MAF）、双眼交叉柱镜法（BCC）测量的调节反应、正相对调节（PRA）及负相对调节（NRA）。不同时间段之间参数的差异比较采用重复测量方差分析,两两比较采用LSD-t检验。结果 MAA在SMILE手术后1周下降,术后3个月时恢复到术前水平,差异有统计学意义（F=5.418,P=0.002）;MAF及PRA在SMILE术后1周轻微下降,术后3个月较术前显著增加（F=8.090,P<0.001;F=5.466,P=0.002）。BCC测量的调节反应及NRA在术后各个时期差异无统计学意义（F=2.445,P=0.071;F=0.536,P=0.659）。结论 SMILE可暂时性降低调节功能,但随着时间推移逐渐好转。     

Horizontal saccade disconjugacy in strabismic monkeys

PURPOSE: Previous studies have shown that binocular coordination during saccadic eye movement is affected in humans with large strabismus. The purpose of this study was to examine the conjugacy of saccadic eye movements in monkeys with sensory strabismus. METHODS: The authors recorded binocular eye movements in four strabismic monkeys and one unaffected monkey. Strabismus was induced by first occluding one eye for 24 hours, switching the occluder to the fellow eye for the next 24 hours, and repeating this pattern of daily alternating monocular occlusion for the first 4 to 6 months of life. Horizontal saccades were measured during monocular viewing when the animals were 2 to 3 years of age. RESULTS: Horizontal saccade testing during monocular viewing showed that the amplitude of saccades in the nonviewing eye was usually different from that in the viewing eye (saccade disconjugacy). The amount of saccade disconjugacy varied among animals as a function of the degree of ocular misalignment as measured in primary gaze. Saccade disconjugacy also increased with eccentric orbital positions of the nonviewing eye. If the saccade disconjugacy was large, there was an immediate postsaccadic drift for less than 200 ms. The control animal showed none of these effects. CONCLUSIONS: As do humans with large strabismus, strabismic monkey display disconjugate saccadic eye movements. Saccade disconjugacy varies with orbital position and increases as a function of ocular misalignment as measured in primary gaze. This type of sensory-induced strabismus serves as a useful animal model to investigate the neural or mechanical factors responsible for saccade disconjugacy observed in humans with strabismus.     

初发近视儿童调节反应与近视屈光度的关系

目的 探讨初发近视儿童调节反应与近视屈光度的关系。设计 回顾性病例系列。研究对象 北京同仁验光配镜中心视力下降在6个月内的8～10岁儿童96例,复方托吡卡胺散瞳测双眼近视低于-1.00 D。方法 散瞳前采用综合验光仪进行调节反应、调节灵活度以及正、负相对调节检查。选取双眼中较低度数眼的参数进行统计学分析。主要指标 屈光度、调节反应、调节灵活度、正负相对调节。结果 受试者屈光度为（-0.66±0.25）D,调节反应为（0.25±0.36）D;调节灵活度为（6.31±2.54）cpm;负相对调节为（2.20±0.40）D;正相对调节为（-1.96±1.32）D。调节反应与近视屈光度呈负相关（r=-0.34,P=0.001）;调节反应与调节灵活度、负相对调节无相关性（r=0.027,P=0.798,r=-0.140,P=0.174）;调节反应与正相对调节呈正相关（r=0.231,P=0.023）。结论 初发近视儿童已存在调节反应滞后,调节反应滞后和正相对调节的降低,可能是近视发生发展的原因。（眼科, 2014, 23: 319-322）     

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.     

Reduced accommodation in children with cerebral palsy

Accommodation in 43 subjects with cerebral palsy was measured objectively using a dynamic retinoscopy technique, which has already been shown to be reliable and repeatable. The subject's ages ranged from 3 to 35 years. Of these, 42% were found to have an accommodative response pattern which was different from the normal control group for his/her age. Nearly 29% had an estimated amplitude of accommodation of 4 D or less. The presence of reduced accommodation was found to be associated with reduced visual acuity, but was not associated with cognitive or communication ability, refractive error or age. The prevalence of other ocular disorders in this group is also high. These findings have developmental and educational implications.     

Age-related changes in static accommodation and accommodative miosis

An attempt was made to explore the validity of the Hess-Gullstrand and Duane-Fincham models of presbyopia development, on the assumption that accommodative miosis could be used as an indicator of ciliary muscle effort. Monocular accommodation response and pupil size were measured as a function of accommodation demand over the range 0-4 D, in 48 normal subjects with ages between 17 and 56 years. The slope of the response/stimulus curve was found to decrease only slowly with age up to about 35 years and then to decline more rapidly. Accommodative miosis per dioptre of accommodation response did not change systematically with age up to about 35 years, this being apparently more in accord with the Hess-Gullstrand model. However, accommodative miosis varied very widely between younger subjects of similar age and accommodative amplitude (from zero to around 1 mm per dioptre of accommodation response for subjects in their twenties). It is concluded that miosis does not necessarily accompany accommodation and that its magnitude is not related in any simple general way to ciliary muscle contraction. Hence it cannot be used to support or refute particular theories of presbyopia.     

Binocular eye movements during accommodative vergence

Binocular eye position was monitored by the photoelectric technique during accommodative vergence. Contrary to previous reports indicating that accommodative vergence was a uniocular phenomenon, without exception, binocular accommodative vergence movements were recorded. The total vergence amplitude in the viewing eye was reduced, on the average, by approximately 88% with respect to the vergence movement measured in the covered eye. Some saccadic eye movements that occurred during vergence movements were likewise reduced in amplitude in the viewing eye by up to 20%. Smooth eye movements were utilized to counteract the vergence movement in the viewing eye. This smooth movement alone, or in conjunction with a late saccade, returned the eye to the target and helped to maintain the retinal image of the target coincident with the foveal center for the duration of the accommodative vergence movement. Thus, there appears to be a fixation-holding mechanism which produced a general attenuation of both vergence and some saccadic movements in the viewing eye. Although this control strategy produced violations of Hering's law with respect to the magnitude of the movements in the eyes but not with respect to the direction of the movement, it was implemented in the interest of retaining the target within the sensitive foveal region.     

Clinical testing of accommodative facility: Part 1. A critical appraisal of the literature.

BACKGROUND: Accommodative facility testing is used in clinical care to assess functioning of the ocular accommodative system. The current clinical standard (binocular assessment using +/- 2.00 D lenses at 40 cm with a vectographic suppression check) was first described nearly 20 years ago as part of the last comprehensive review of the literature. The standard accommodative facility test imposes a variable requirement on patients of different ages who have a wide range of accommodative amplitudes. METHOD: In this article, we critically reviewthe present body of literature on accommodative facility testing, with emphasis on the relation between symptoms, accommodative amplitude, and the results found during accommodative facility testing. RESULT: We include discussion of the five broad categories of accommodative facility studies: (11 recommendations for testing criteria; (2) normative data investigations; (3) reliability and variability assessment; (4) relation between accommodative facility and symptoms; and (5) other relationships (e.g., effect of test parameters on accommodative facility). CONCLUSION: Given the substantial variation in demand when testing patients of different ages (amplitudes), it is not surprising that a significant variation in responses has been reported in the clinical accommodative facility literature. Future clinical investigation of accommodative facility would benefit from a systematic investigation into the relationship between age and amplitude. The presence or absence of symptoms needs to be considered so that results of testing can be analyzed in relation to the severity of binocular vision-related symptoms.     

儿童近视进展与视功能相关性的研究

我国青少年近视发病率逐年上升,呈现逐渐低龄化的趋势。本文旨在系统梳理各个视功能对近视及其进展的影响,聚焦调节功能、集合功能以及眼位这三个因素。通过对调节功能的调节幅度、调节灵敏度、调节反应、正相对调节和负相对调节等方面的深入研究,探讨了调节功能对近视进展的影响; 同时,从单纯性内、外隐斜,集合不足和集合过度,融像性功能聚散障碍,散开不足和过度几个方面,详细剖析了集合功能对近视进展的影响。最后通过对知觉性眼位和间歇性外隐斜两个方面介绍了眼位对近视进展的影响,以及其他因素对其的影响。文章旨在揭示影响近视及其进展的多方面视功能因素,明确调节功能、集合功能和眼位在其中的重要性。     

屈光性调节性内斜视眼位回退的临床观察

目的:观察分析屈光性调节性内斜视矫正后眼位回退。方法:选120例患者,初诊年龄1.5～3岁,初诊时用10g/L阿托品眼膏每晚点眼,1wk后散瞳检影,屈光度在+2.00～+10.00D,散光在0～+4.00D,屈光参差0～+4.00D,在散瞳检影的度数上最多减去+0.50D作最大量的光学矫正。戴镜最小年龄为1.5岁,有弱视者同时治疗弱视。每3mo复诊重新用阿托品散瞳验光,根据验光结果调整屈光度。结果:随访5a,在120例中19例发生眼位回退,回退内斜度>+15°,回退发生年龄在4～12岁。结论:屈光性调节性内斜视眼位回退率13%～17%,发生原因主要与发病年龄、发病后未及时戴镜矫正和无双眼单视功能有关。早期发现,早期戴镜矫正是减少屈光性调节性眼位回退的重要手段。