影响近视性屈光不正调节滞后的相关因素探讨

目的 探讨近视眼在不同状态下,调节刺激与调节滞后的变化关系.方法 临床病例对照研究.对2011年4～7月在天津眼科医院就诊病人,选取25只正视眼,72只近视眼,并按屈光度数分成低中高三组.注视调节E视标,同时使用开视野红外验光仪,测量不同距离以及不同近用附加状态下双眼的实际调节反应;应用综合验光仪测量近用隐斜度,比较近用隐斜与调节滞后的关系.结果 双眼视状态下,高度近视组和正视组在4 D (P =0.049)、5 D(P=0.018)的调节刺激下,调节滞后量差异有统计学意义(P＜0.05),而正视组、低度近视组、中度近视组间的调节滞后量无统计学意义;受试者40 cm处右眼的调节滞后量与40cm处的隐斜量呈线性相关(y=O.0606x+0.9655,r=0.483 P=0.001,P＜0.05); 比较正视眼组和近视眼组在40cm处无附加,+1 D以及-1 D附加的三种情况下的平均调节反应,在-1 D附加时,正视组(-1.74±0.47)与近视组(-2.02±0.35)的调节反应差异有统计学意义(P =0.000).结论 在相同调节刺激下,近视眼的调节滞后量大于正视眼,其中高度近视眼表现尤为明显;近用隐斜度数影响近用调节滞后的幅度,外隐斜使调节滞后量相对减少,内隐斜使调节滞后量相对增多;正性近用附加使调节滞后量减小,负性附加使调节滞后量增大,且近视组的滞后量明显大于正视组.     

近距隐斜视与屈光不正的关系研究

目的 探讨近距隐斜视的发生、类型与屈光不正的关系.方法 连续收集近距隐斜视患者267例,男145例,女122例,年龄(8.05+5.0)岁(3～44岁),分别进行近距隐斜视检测,静态检影.结果 正视者63例,其中发生近距外隐斜60例,近距内隐斜3例,近距外隐斜所占比重明显高于内隐斜(P=0.000).近距内隐斜47例,其屈光状态构成分别为正视和近视各3例,远视41例;近距外隐斜220例,其屈光状态构成分别为正视60例,近视64例,远视96例,经卡方检验,近距隐斜视类型与屈光状态有关(X2=29.47,P=0.000).就137例远视患者而言,发牛近距内隐斜41例,其不同程度屈光构成分别为轻度远视12例,中度远视18例,重度远视11例;发生近距外隐斜96例,其不同程度屈光构成分别为轻度远视56例,中度远视27例,重度远视13例,经卡方检验,对远视患者而言,近距隐斜视类型与远视的程度有关(X2=16.61,P=0.000),近距内隐斜多发生于中度远视,而近距外隐斜多发生于轻度远视.结论 近距隐斜视类型与屈光状态相关,其中近距内隐斜主要为远视眼未经屈光矫正引致;一定范嗣内的近距外隐斜可能是一种,圭理性眼位,而近距内隐斜则可能是一种病理性眼位,并与近视的发生发展相关.     

集合不足型外隐斜合并调节不足三种治疗方法的比较

目的 比较集合调节训练、三棱镜配戴矫正和近视屈光过矫在集合不足型外隐斜合并调节不足患者中的疗效.方法 横断面研究,将10～35岁的60名确诊为集合不足型外隐斜合并调节不足患者随机分为3组,每组20例,A组行三棱镜配戴矫正,B组行近视屈光过矫-0.50 D戴镜矫正,C组行集合调节视功能训练,于3个月后复查隐斜度和视功能采用配对t检验和单因采方差分析 结果 复查各项视功能参数3组患者之间差异有统计学总义 A组患者隐斜度增加(t=1 2.65,P＜0.01),近距正相对融合范围减小(t=12.65,P＜0.01),症状先短暂缓解后加重;B组患者隐斜度增加(t=4.63,P＜0.01),近距正E相对融合范围减小(t＝6.71,P＜0.01),调节幅度减小(t=14.3,P＜0.01),症状明显加重;C组患者隐斜度显著减小(t=-11.61,P＜0.01),近距正相对融合范围显著增大(t=-22.40,P＜0.01),调节幅度显著增大(t=-31.06,P＜0.01),症状明显改善 结论 集合不足型外隐斜合并调节不足患者采用集合调节视功能训练能明显改善症状,减少近距隐斜度,增加近距正相对融合范围和调节幅度,是一种有效可行的治疗方法.     

近距离工作眼动参数与青少年近视进展的相关性研究

目的 探讨近距离眼动参数与青少年近视进展的关系.方法 以28名近视青少年为研究对象跟踪随访8～19个月,每3个月记录近距水平隐斜、AC/A、负相对调节、正相对调节、调节滞后、调节幅度等近距离眼动参数,检测双眼平均等效球镜值,根据首次与末次双眼平均等效球镜值计算年近视进展量作为近视加深速度,分析各近距离眼动参数与年近视进展量之间的相关性.结果 AC/A、调节滞后及调节幅度与年近视进展量均呈负相关(相关系数r分别为-0.416,-0.495及-0.463,P均小于0.05);考虑到AC/A与调节滞后相互关联,将AC/A作为控制因素再行分析,调节滞后与年近视加深量仍有相关性(r=-0.383,P<0.05).结论 近距离工作时高调节滞后可能是导致近视进展的原因之一.     

不同屈光状态下反应性AC/A值的比较

目的 探讨进展性近视、稳定性近视及正视之间反应性AC/A值的关系,并对其成因进行分析.方法 病例对照研究.门诊选取10～22岁病例,根据随访资料以及主觉验光结果分为进展性近视组、稳定性近视组以及正视组各17例,在全矫基础上分别测量9个调节刺激水平下的调节反应以及隐斜值,计算调节误差指数(AEI)和反应性AC/A值.数据采用单因素方差分析.结果 3组屈光组的反应性AC/A值之间的差异有统计学意义(F=4.051,P＜O.05),进展性近视组的AC/A值高于稳定性近视组和正视组.3组的AEI值之间无显著性差异(F=2.579,P＞0.05);在高调节刺激水平(3.21～4.12 D),进展性近视组显示出较大的内隐斜,但只有在4.12 D水平,3组之间的差异具有统计学意义(F=3.828,P＜0.05).结论 和稳定性近视以及正视相比,进展性近视具有较高的AC/A值和较大的近距内隐斜,提示较大的近距内隐斜可能是高AC/A的成因,高AC/A值和较大的近距内隐斜可能是近视进展的危险因素.     

使用计算机终端及不同休息方案对调节聚散功能影响分析

目的 研究使用计算机终端及不同的休息方案对调节、聚散功能的影响.方法 30名受试者均接受5种不同阅读方案:(1)连续计算机终端阅读2h后休息10min.(2)连续书本阅读2h后休息10min.(3)连续计算机终端阅读1h后休息10min(休息1方案).(4)计算机终端阅读总时间1h,每30min间隔休息5min(休息2方案).(5)计算机终端阅读总时间1h,每15min间隔休息2min(休息3方案).每次阅读前后分别查眼部屈光、调节反应(调节滞后度)、单眼调节幅度、聚散功能(集合近点、调节性集合/调节[accommodative convergence/accommodation,AC/A]、远近距水平隐斜、远近距融像性水平聚散力).结果 (1)连续2h计算机终端阅读后较书本阅读更易出现调节滞后值增加、调节幅度下降、集合近点远移、近距水平外隐斜增加内隐斜减小、近距融像性水平聚合力减弱(P＜0.05).(2)连续计算机终端阅读2h较1h更易出现调节滞后值增加、调节幅度下降、集合近点远移(P＜0.05).(3)调节滞后值、调节幅度、集合近点、近距离水平内外隐斜在三种休息方案之间的差异具有统计学意义(P＜0.05),休息3方案优于其它方案.结论 使用计算机终端阅读较书本阅读更易对调节、聚散功能产生影响,且随时间的不同出现差异.三种不同休息方案比较,每使用计算机终端阅读15min间隔休息2min对调节、聚散功能影响最小.     

近视的屈光矫正对近外周融合和水平位均衡的影响

目的 探讨青少年近视眼的屈光矫正与近外周融合功能的关系以及评价双眼水平位均衡状态.方法 利用综合验光仪检测97名青少年近隐斜、近外周融合力和双眼水平位均衡的情况,将近视青少年按照近视程度.矫正情况分类,分组为A组,0.50～1.50D;B组,-1.75～-3.00D;C组,-3.25～-4.50D,分别同正常青少年进行近外周融合力的比较和双眼水平位均衡的评估,分析屈光矫正对近外周融合范围和双眼水平位均衡的影响,以及近隐斜和近外周融合范围的关系.结果 未矫组与正视祖和足矫组在近隐斜度(f=33.43,P=0.000)和近正融像性集合(F=90.55,P=0.000)方面差异均有统计学意义,而近负融合像集合间均值差别无统计学意义(F=2.78,P=0.07).未矫近视青少年表现为近融合范围的变小,近融合范围的均值为(+11.22～-16.51).近正融像性集合与近隐斜存在负的直线关系(r=-0.785,P=0.00).正视组,足矫组.未矫组的双眼水平位均衡的异常率差别有统计学意义(x2=12.467,P=0.002).结论 近视如不矫正,双眼水平失衡率显著增高;对近融合范围的影响在低度近视就已经非常显著,主要表现为对近正融像性集合的影响.对近融合范围的影响是近视程度越高影响越大.     

儿童和青少年近视调节功能的临床分析

目的 探讨发病早期的儿童和青少年近视的调节功能状态,分析主导眼和非主导眼的调节功能水平.方法 应用动态检影法和移近法分别测量50例发病1～2年的学龄期儿童和青少年近视患儿调节滞后和调节幅度;同样方法测量20例正视儿童和25例远视屈光不正患儿;检测其主导眼和非主导眼.结果 近视患儿的主导眼和非主导眼的调节幅度和调节滞后与正视儿童均差异无统计学意义;而其主导眼和非主导眼的调节幅度比远视患儿明显更大(t=2.21,P=0.03＜0.05;t=2.83,P=0.006＜0.05);两组的调节滞后差异无统计学意义.50例近视患儿主导眼和非主导眼的调节滞后值分别为(0.73±0.31)D和(0.81±0.38)D,主导眼和非主导眼间差异有统计学意义(t=2.14,P=0.038＜0.05);调节幅度分别为(13.39±3.51)D和(13.26±3.60)D,差异无统计学意义.95例观察对象(近视、正视和远视患儿)的主导眼的调节滞后度为(0.68±0.36)D,非主导眼调节滞后度为(0.75±0.34)D,主导眼和非主导眼间的差异有统计学意义(t=2.06,P=0.042＜0.05);主导眼调节幅度(12.9±3.09)D,非主导眼为(12.6±3.09)D,差异无统计学意义(t=1.49,P=0.14).结论 发病早期的儿童和青少年近视的调节滞后值和调节幅度与正视儿童无明显差别;调节幅度比远视儿童的更大.儿童和青少年主导眼的调节滞后比非主导眼的更小,进行调节滞后相关研究时应注意主导眼和非主导眼的区别.     

近视儿童眼调节功能的客观检查与分析

目的 对假性近视和真性近视儿童注视近距与远距视标时的调节功能进行客观检查分析,探讨眼调节功能与近视发生发展的关系。方法 选取2021年4月济南市某小学眼健康筛查中符合纳入标准的105例(105眼)学龄期儿童为研究对象,根据睫状肌麻痹验光结果分为正视眼组(40例)、假性近视组(33例)、真性近视组(32例)。首先所有受试者检测主观调节反应(BCC)与正/负相对调节(PRA/NRA),然后应用近远调节功能检测系统测量受试者在注视近点25 cm处与远点250 cm处时眼客观调节反应(AR)、调节微波动(AM)与调节滞后(AL),最后所有受试者进行睫状肌麻痹验光。结果 3组受试者BCC、NRA差异均无统计学意义(均为P>0.05)。3组受试者PRA差异有统计学意义(P<0.05)。两两比较结果显示,正视眼组与真性近视组、假性近视组与真性近视组受试者PRA比较,差异均有统计学意义(均为P<0.05),正视眼组与假性近视组受试者PRA差异无统计学意义(P>0.05)。在近点25 cm处,3组受试者AR值差异有统计学意义(P<0.001)。两两比较结果显示,正视眼组受试...     

双眼协动参数在近视眼的差异研究

目的　探讨调节和辐辏的关系在近视发生、发展中的作用。方法　本研究对象包括 31例成人正视者与 4 6例成人近视者 ,近视者又分为高度近视者 (>- 6 0 0D)、中度近视者 (- 6 0 0～ -3 2 5D)和轻度近视者 (- 3 0 0～ - 0 5 0D)。双眼协动参数测量包括远距隐斜、近距隐斜及正、负相对调节 ,对不同屈光度数组的计算性调节 (AC/A)进行分析和比较。结果　近视组的计算性AC/A高于正视组 ,且计算性AC/A有随近视程度加深而增加的趋势。近视组和正视组的远隐斜及负相对调节差异无显著意义 (P >0 0 5 ) ,但近视组的正相对调节其绝对值显著低于正视组 (P <0 0 5 ) ,且近视组的近隐斜较正视组的近隐斜有内隐斜倾向 (P <0 0 5 )。结论　调节、辐辏及其相互作用协动参数在近视者中有明显的差异 ,AC/A为该差异的关键参数 ,并因近视度数增高而呈上升趋势 ,AC/A增高表明近视者在近距离工作时存在视网膜离焦趋势。     

Relationship of accommodative response and nearpoint phoria in a sample of myopic children.

Esophoria has been associated with onset and progression of myopia in children. The induction of myopia by optical defocus shown by animal models suggests that a high lag of accommodation during near work may contribute to myopia in children. This paper examines the relationship of nearpoint phoria and accommodative response in a sample of children with myopia. Accommodative response was measured under binocular conditions with the Canon Autoref R-1 autorefractor with a 40 cm viewing distance. Phorias were measured with the von Graefe method using a 40 cm test distance. In the statistical analysis exophoria was scored as a negative number and esophoria was scored as a positive number. The coefficient of correlation of accommodative response with phoria was -0.32 (n = 73; p<0.01), thus showing an association of a more positive (more convergent) near phoria with lower accommodative response. The correlation coefficient increased to -0.39 when an exponential function was used. When only esophores were considered, the correlation coefficient was -0.59 (n = 44; p<0.001). Lower accommodative response (higher lag of accommodation) was associated with greater esophoria.     

青少年隐斜视对近视眼发生发展的影响

目的 了解隐斜视与调节性集合/调节比值（AC/A）、调节滞后量之间的关系,探讨隐斜视在近视发生发展中的可能作用。方法 横断面研究。选取近视伴隐斜视青少年62例,检测其屈光度、近距离水平隐斜度及AC/A、调节滞后量。按低、中、高度近视分组,分别对这3组中内隐斜患者与外隐斜患者的AC/A、调节滞后量进行比较,并对隐斜度与AC/A、调节滞后量进行相关性分析。结果 低度近视组内隐斜患者的AC/A、调节滞后量分别为（4.72±0.38）△/D、（-0.50±0.20）D,外隐斜患者分别为（3.4±0.31）△/D、（-0.20±0.10）D;中度近视组,内隐斜患者的AC/A、调节滞后量分别为（4.25±0.55）△/D、（-0.58±0.12）D,外隐斜患者分别为（3.26±0.25）△/D、（-0.30±0.13）D;高度近视组,内隐斜患者的AC/A、调节滞后量分别为（3.63±0.21）△/D、（-0.60±0.10）D,外隐斜患者分别为（2.50±0.29）△/D、（-0.28±0.12）D;3组中内隐斜患者与外隐斜患者的AC/A及调节滞后量差异均有统计学意义。内隐斜度与AC/A呈正相关（r=0.670,P<0.05）,与调节滞后量呈正相关（r=0.430,P<0.05）;外隐斜度与AC/A呈负相关（r=-0.331,P<0.05）,与调节滞后量呈正相关（r=0.423,P<0.05）。结论 近视患者中,内隐斜的AC/A、调节滞后量均大于外隐斜。内隐斜可能比外隐斜更易促进近视发展,隐斜度越大,近视发展越快。较大度数的外隐斜因伴随较大的调节滞后量对近视发生、发展起重要作用。     

Accommodation and related risk factors associated with myopia progression and their interaction with treatment in COMET children

PURPOSE: To examine baseline measurements of accommodative lag, phoria, reading distance, amount of near work, and level of myopia as risk factors for progression of myopia and their interaction with treatment over 3 years, in children enrolled in the Correction of Myopia Evaluation Trial (COMET). METHODS: COMET enrolled 469 ethnically diverse children (ages, 6-11 years) with myopia between -1.25 and -4.50 D. They were randomly assigned to either progressive addition lenses (PALs) with a +2.00 addition (n = 235) or single vision lenses (SVLs; n = 234), the conventional spectacle treatment, and were observed for 3 years. The primary outcome measure was progression of myopia by autorefraction after cycloplegia with 2 drops of 1% tropicamide. Other measurements included accommodative response (by an open field of view autorefractor), phoria (by cover test), reading distance, and hours of near work. Independent and interaction analyses were based on the mean of the two eyes. Results were adjusted for important covariates with multiple linear regression. RESULTS: Children with larger accommodative lags (>0.43 D for a 33 cm target) wearing SVLs had the most progression at 3 years. PALs were effective in slowing progression in these children, with statistically significant 3-year treatment effects (mean +/- SE) for those with larger lags in combination with near esophoria (PAL - SVL progression = -1.08 D - [-1.72 D] = 0.64 +/- 0.21 D), shorter reading distances (0.44 +/- 0.20 D), or lower baseline myopia (0.48 +/- 0.15 D). The 3-year treatment effect for larger lags in combination with more hours of near work was 0.42 +/- 0.26 D, which did not reach statistical significance. Statistically significant treatment effects were observed in these four groups at 1 year and became larger from 1 to 3 years. CONCLUSIONS: The results support the COMET rationale (i.e., a role for retinal defocus in myopia progression). In clinical practice in the United States children with large lags of accommodation and near esophoria often are prescribed PALs or bifocals to improve visual performance. Results of this study suggest that such children, if myopic, may have an additional benefit of slowed progression of myopia.     

不同程度近视青少年儿童双眼视功能的差异

目的通过比较不同程度近视儿童双眼协动参数的差异性及其与近视程度相关性,进一步探索近视发展的原理。方法横断面研究。研究对象包括128例7～14岁近视青少年儿童,根据等效球镜度分为低度近视组（-0.50～-3.00 D）、中度近视组（-3.25～-6.00 D）和高度近视组（>-6.00 D）。双眼协动参数测量包括远距及近距水平聚散力,远距及近距水平隐斜,梯度性调节性集合与调节的比率（AC/A比率）。采用单因素方差分析和卡方检验对3组数据进行分析。结果在融像性聚散范围中,远距散开力的破裂点、近距散开力的恢复点、远距集合力的恢复点、近距集合力的模糊点及破裂点随近视程度加深而减小（F=3.271、3.579、4.931、6.507、4.887,P<0.05）,其余参数的差异无明显统计学意义（P>0.05）;在隐斜视类型的构成比中,远距及近距隐斜类型构成比例的差异在3组中无明显统计学意义（P>0.05）,总体上近距内隐斜构成比例高于远距内隐斜（χ²=6.609,P<0.05）;梯度性AC/A随近视程度的增加而增加（F=3.625,P<0.05）,其中高度近视组明显高于低度近视组（P<0.05）。结论随着青少年儿童近视程度的增加,融像性聚散范围减少,梯度性AC/A比率增高。近视儿童表现出的近距内隐斜可能与近视发展相关。     

The effect of positive-lens addition and base-in prism on accommodation accuracy and near horizontal phoria in Chinese myopic children.

The effect of positive-lens addition (0, +0.75, +1.50, +2.25, +3.00 D each eye) and base-in prism power (0, 1.5, 3 Delta each eye) on both near focusing errors and latent horizontal deviations was evaluated in 29 Chinese myopic children (age: 10.3 +/- 1.9 years, refractive error: -2.73 +/- 1.31 D). Accommodation response and phoria were measured by the Shin-Nippon auto-refractor (right eye) and Howell-Dwyer near phoria card at 33 cm with each of the 15 lens/prism combinations in random order. The initial accommodative error was -0.96 +/- 0.67 D (lag) and near phoria was -0.8 +/- 5.0 Delta (exophoria). The positive-lens addition decreased the accommodative lag but increased the exophoria as the power increased (e.g. up to -9.1 +/- 4.1 Delta with +3 D). A 6-Delta base-in prism totally controlled the exophoria induced by a +1.50 D addition (-0.3 +/- 4.3 Delta), but the accommodative lag was still considerable (-0.69 +/- 0.54 D). In the graphical analysis of the data, a lens addition of +2.25 D combined with a 6-Delta base-in prism minimized both the lag and lens-induced exophoria to -0.33 D and -2.4 Delta respectively (regression analysis). This lens and prism combination decreased the lens-induced exophoria by 4.5 Delta compared with that measured with +2.25 D alone (-2.4 Delta vs -6.9 Delta). The results suggest that incorporating near base-in prism when prescribing bifocal lenses for young progressing myopes with exophoria could reduce the positive lens-induced oculomotor imbalance.     

近视青少年配戴角膜塑形镜前后调节参数变化

目的：:观察近视青少年配戴角膜塑形镜前后调节参数及隐斜度的变化,探讨角膜塑形镜延缓近视进展的机制及近视发病病因。方法：:回顾性研究。收集2011年1月至2019年3月在中国医科大学附属第一医院眼科门诊进行角膜塑形镜配戴前后调节参数资料完整的患者51例（102眼）,比较角膜塑形镜配戴前、配戴后1、12个月或以上的正负相对...     

Near esophoria is associated with high myopia

Background : A retrospective study was undertaken to examine the hypothesis that esophoria is associated with higher amounts of myopia. Methods : One hundred and forty‐four subjects were selected from the files of optometry clinics at the Department of Optometry, National University of Malaysia, from the years 1995 to 1998 inclusive. These subjects were matched in terms of age group, sex, race and near phoria group. Near phorias were determined by Maddox wing technique and were classified into three groups: more than six prism dioptres exophoria, zero to six prism dioptres exophoria and any esophorias. Results : One way analysis of variance revealed that there were significant differences in mean myopias between the three phoria groups (ANOVA, F(2,141) = 5.34, p < 0.01). Further analysis with the Student‐Newman‐Keuls test showed that the amount of myopia is significantly higher in the esophoric group than in the other two groups. Conclusions : The results support the hypothesis that near esophoria is associated with high myopia. This study suggests that near phoria might be an important factor in myopia development.     

Referral rates for a functional vision screening among a large cosmopolitan sample of Australian children

The aim of this study was to investigate the incidence of functional vision problems in a large unselected cosmopolitan population of primary school-age children and to investigate whether constant clinical criteria for functional vision problems would be implemented by the practitioners involved in the screening. Refractive errors, near point of convergence, stereopsis, strabismus, heterophoria and accommodative facility were assessed for 2697 children (3-12 years) of varying racial backgrounds living in Australia. The spherical component of the refractive error ranged from -7.75 to +9.50 D (mean +0.54 D, +/-0.79) with a distribution skewed towards hypermetropia; astigmatism ranged from 0 to 4.25 D (mean -0.16 D, +/-0.35). There was a trend towards less hypermetropia and slightly more astigmatism with age. Mean near point of convergence was 5.4+/-2.9 cm, heterophoria at far and near was 0.12+/-1.58delta exophoria and 1.05+/-2.53delta exophoria, respectively, 0.55% of children exhibited vertical phoria at near >0.5delta, accommodative facility ranged from 0 to 24 cycles per minute (cpm) (mean 11.2 cpm, +/-3.7), stereopsis varied from 20 to 800 s (") of arc with 50% of children having 40" or better. The prevalence of strabismus was particularly low (0.3%). Twenty percent of the children were referred for further assessment based on criteria of one or more of: stereopsis >70", accommodative facility <8 cpm, near point of convergence (NPC) >9 cm, near exophoria >10delta or near esophoria >5delta, shift in eso or exophoria > or = 4delta between distance and near, astigmatism > or = 1 D, myopia more than -0.75 D, or hyperopia >+1.50 D. Post-hoc analysis of the record cards seeking the reason for further assessment indicates that referrals appear to have been based upon clinical intuition rather than on a set number of borderline or unsatisfactory results.     

Accommodative lag before and after the onset of myopia

PURPOSE: To evaluate accommodative lag before, during the year of, and after the onset of myopia in children who became myopic, compared with emmetropes. METHODS: The subjects were 568 children who became myopic (at least -0.75 D in each meridian) and 539 children who were emmetropic (between -0.25 D and +1.00 D in each meridian at all visits) participating between 1995 and 2003 in the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study. Accommodative lag was measured annually with either a Canon R-1 (Canon USA., Lake Success, NY; no longer manufactured) or a Grand Seiko WR 5100-K (Grand Seiko Co., Hiroshima, Japan) autorefractor. Subjects wore their habitual refractive corrections while viewing a letter target accommodative stimulus of 4 D (either in a Badal system or at 25 cm from the subject, designated Badal and near, respectively) or of 2 D (Badal only). Refractive error was measured with the same autorefractor in subjects under cycloplegia. Accommodative lag in children who became myopic was compared to age-, gender-, and ethnicity-matched model estimates of emmetropic values for each annual visit from 5 years before, through 5 years after, the onset of myopia. RESULTS: In the sample as a whole, accommodative lag was not significantly different in children who became myopic compared with model estimates in emmetropes in any year before onset of myopia for either the 4-D or 2-D Badal stimulus. For the 4-D near target, there was only a greater amount of accommodative lag in children who became myopic compared with emmetropes 4 years before onset (difference, 0.22 D; P = 0.0002). Accommodative lag was not significantly elevated during the year of onset of myopia in any of the three measurement conditions (P < 0.82 for all three). A consistently higher lag was seen in children after the onset of their myopia (range, 0.13-0.56 D; P < 0.004 for all comparisons). These patterns were generally followed by each ethnic group, with Asian children typically showing the most, African-American and white children showing the least, and Hispanic children having intermediate accommodative lag. CONCLUSIONS: Substantive and consistent elevations in accommodative lag relative to model estimates of lag in emmetropes did not occur in children who became myopic before the onset of myopia or during the year of onset. Increased accommodative lag occurred in children after the onset of myopia. Elevated accommodative lag is unlikely to be a useful predictive factor for the onset of myopia. Increased hyperopic defocus from accommodative lag may be a consequence rather than a cause of myopia.     

Monocular estimate method retinoscopy: central tendency measures and relationship to refractive status and heterophoria.

BACKGROUND: Monocular estimate (estimation) method (MEM) is a widely used clinical test of accommodative response. Normative data for MEM are available based on the central tendency measures from a population of schoolchildren but not a clinical population. Also, the relationship of accommodative response to refractive status and heterophoria has been researched, but not with MEM as the determinant of the manifestation of accommodative response. METHODS: A group of 211 pre-presbyopic clinical subjects were tested with MEM for purposes of comparing the central tendency measures of a clinical population to established normative data and determining whether MEM varied with refractive status or near phoria. RESULTS: A lag of about one-third diopter was the mean MEM result for this clinical population. The median was +0.25 D. Myopia and near esophoria have a statistically significant relationship to MEM. CONCLUSIONS: The central tendency measures derived from MEM administered to this population replicate the central tendency measures found in a previous normative study. This study provides preliminary evidence that the difference between accommodative response and accommodative stimulus, as measured by MEM, may be influenced by myopia and esophoria.