Characteristics of accommodative behavior during sustained reading in emmetropes and myopes

Accommodation has long been suspected to be involved in the development of myopia because near work, particularly reading, is known to be a risk factor. In this study, we measured several dynamic characteristics of accommodative behavior during extended periods of reading under close-to-natural conditions in 20 young emmetropic and stable myopic subjects. Accommodative responses, errors, and variability (including power spectrum analysis) were analyzed and related to accommodative demand and subject refractive error. All accommodative behaviors showed large inter-subject variability at all of the reading demands. Accommodative lags and variability significantly increased with closer demands for all subjects (ANOVA, p<0.05). Myopes had significantly greater variability in their accommodation responses compared to emmetropes (ANOVA, p<0.05) and had larger accommodative lags at further reading distances (unpaired t test p<0.05). Power spectrum analysis showed a significant increase in the power of accommodative microfluctuations with closer demands (ANOVA, p<0.05) and with increasing myopia at the closest reading demand (ANOVA, p<0.01). The difference in the stability of the accommodative behavior between individuals with different refractive states suggests a possible relationship between variability in accommodation and the development of myopia.     

儿童远视性弱视眼调节幅度及调节灵活度的研究

目的　比较不同程度远视性弱视眼与正视眼之间调节幅度及调节灵活度的差别.方法　临床病例对照研究.对2009年1～12月在河北大学附属医院眼科门诊能配合检查的远视性弱视儿童50例92只眼,按弱视程度分为中度弱视组(A组),轻度弱视组(B组),弱视治愈组(C组).正常儿童组(对照组)20人40只眼,采用改良移近法测量调节幅度(AMP),正负球镜翻转测量调节灵活度.结果　A组、B组、C组及对照组AMP平均值分别为(13.07±1.72)D、(14.17±1.60)D、(15.55±1.26)D、(16.09±1.11)D,调节灵活度平均值分别为(5.77±2.00)次/分、(5.13±1.67)次/分、(5.06±1.56)次/分、(5.45±2.19)次/分,结果显示A组和B组AMP均分别显著低于C组及对照组(P＜0.05).C组与对照组差异无统计学意义(P =0.247).各组调节灵活度差异无统计学意义(P=0.723).A组及B组中AMP与矫正视力呈正相关(r=0.487,P=0.007),AMP与屈光度无显著相关性(r=-0.236,P=0.218).结论　与同年龄正常眼相比,远视性弱视儿童眼调节幅度降低,调节幅度与弱视程度有显著相关性.调节灵活度差异无统计学意义.     

两种矫正方式对调节滞后量和调节灵敏度的对比研究

目的研究青少年近视患者在佩戴角膜塑形镜与佩戴框架眼镜后各自调节滞后量和调节灵敏度的变化情况,并进行对比分析,进一步明确角膜塑形镜与框架眼镜对近视患者视功能的影响及对青少年近视的控制作用。方法随机选取60例来我院成功验配角膜塑形镜的青少年近视患者作为实验组,随机选取60例门诊就诊并给予框架眼镜的青少年近视患者作为对照组,观察两组患者屈光矫正前后调节滞后量、调节灵敏度和等效球镜度的变化并进行对比研究。随访时间依次为1个月、6个月、1年。结果 (1)调节滞后量:实验组戴镜前和戴镜后1个月、6个月、1年分别为:1.05±0.28、0.92±0.16、0.62±0.13、0.64±0.18,差异有统计学意义(P<0.05)。对照组戴镜前和戴镜后1个月、6个月、1年分别为:1.03±0.27、1.03±0.19、0.82±0.11、1.08±0.16。两组戴镜前差异无统计学意义(P>0.05),戴镜后差异均有统计学意义(P<0.05)。(2)调节灵敏度:实验组戴镜前和戴镜后1个月、6个月、1年分别为:9.33±2.65、10.82±2.06、10.90±2.48、11.05±2.55,差异有统计学意义(P<0.05)。对照组戴镜前和戴镜后1个月、6个月、1年分别为:9.56±2.32、10.76±1.88、10.85±2.08、9.02±1.97。两组戴镜前差异无统计学意义(P>0.05);戴镜后1个月、6个月两组差异无统计学意义(P>0.05);戴镜后1年两组差异有统计学意义(P<0.05)。(3)观察1年:实验组等效球镜度增加了(0.38±0.35)DS,对照组增加了(0.84±0.56)DS,两组差异有统计学意义(P<0.05)。结论 (1)实验组戴镜后对调节滞后量的改善较明显,并使其逐渐趋于正常化;对照组对调节滞后量改善较慢,不能使其达到正常值,且近视度数增长后调节滞后量会变大。(2)实验组对调节灵敏度的改善更快,对照组较慢,在近视度数没有明显增长的情况下,两组的调节灵敏度相似,近视度数增长后调节灵敏度下降。(3)角膜塑形镜对中低度近视的矫正有效,它较框架眼镜能更有效地控制青少年近视的增长速度,是目前控制近视的一种有效方法。     

The association of wavefront aberration and accommodative lag in myopes

Accommodative lags, induced by a target at 33 cm (distance-induced condition) and by a -3.0 D lens (lens-induced condition), and wavefront aberrations were measured in 27 young myopic eyes. The accommodative lags and Strehl ratios derived from the wavefront aberrations in myopes were compared with those from 57 emmetropes. Accommodation was measured using a Canon R-1 autorefractor, while aberrations were measured using a psychophysical ray-tracing technique. In accord with previous results, larger accommodative lags were found for the myopes than the emmetropes in both the lens-induced and distance-induced conditions. The mean Strehl ratio was smaller in the myopes (0.079) than the emmetropes (0.091); this difference approached significance (p = 0.055). In addition, for myopes the accommodative lag was significantly correlated with the Strehl ratio in the lens-induced condition (r = -0.45, p < 0.02) and approached significance in the distance-induced condition (r = -0.35, p = 0.07). No significant correlations were found for emmetropes. Possible reasons to account for these results are discussed.     

远视性屈光参差性弱视眼调节功能的临床研究

目的 研究单眼远视性屈光参差性弱视患儿的调节幅度及调节灵活度,比较其弱视眼和非弱视眼的差别.方法 23例能配合检查的单眼远视性屈光参差性弱视患儿,采用改良移近法及正负球镜翻转法分别测量调节幅度及调节灵活度.并与同期就诊的12例(24只眼)正视儿童作对照比较.结果 远视性屈光参差性弱视患儿非弱视眼的调节幅度和调节灵活度分别为(15.43±1.33)D和(6.45±2.19)次/min,与正视儿童眼无明显差别(t=0.781,P=0.451;t=1.072,P=0.293).弱视眼的调节幅度为(13.22±1.61)D,与正视儿童眼的差异有统计学意义(t=3.020,P=0.006),弱视眼的调节灵活度为(6.36±1.40)次/min,与正视儿童眼无明显差别(t=1.542,P=0.137).远视性屈光参差性弱视患儿非弱视眼与弱视眼调节幅度的比较差异有统计学意义(t =2.394,P=0.032),调节灵活度的比较无明显差别(t =1.286,P=0.212).结论 儿童远视性屈光参差性弱视眼的调节幅度明显低于非弱视眼及同龄正视儿童,其非弱视眼的调节幅度与同龄正视儿童无明显差别.弱视眼与非弱视眼的调节灵活度无明显差别.     

LASIK术后眼调节状态的改变及其与视疲劳的关系

目的探讨准分子激光原位角膜磨镶术（LASIK）对近视患者眼调节状态的影响,同时对眼调节状态的变化与视疲劳症状的关系进行探讨。方法回顾性研究。选取2009年3月至8月来东风总医院眼科行LASIK的双眼近视患者60例（120眼）,年龄18-35岁,术前等效球镜值为（-5．52±1．60）D,散光度〈2．00D．最佳矫正视力（BCVA）≥1．0。选择正视者20例（40眼）作为对照组。术前及术后1周、2周、1个月,分别对两组测定其单眼及双眼调节幅度,并对其进行近距工作视疲劳症状的问卷调查。采用独立样本t检验对两组的调节幅度和视疲劳评分进行比较,对近视组各时间点的调节幅度行单因素方差分析．并对术后1周调节幅度下降程度与术前屈光度的关系采用Pearson相关分析。结果①调节状态：LASIK术后第1周,近视组单眼及双眼调节幅度分别为（7．82±0．58）D和（8．10±0．54）D,较术前下降（P均〈0．05）,之后逐渐恢复,至术后1个月时超过术前水平,且与正视组相比差异无统计学意义。②视疲劳症状：LASIK术后第1周,近视患者视疲劳症状均较术前明显加重,之后症状逐渐减轻,至术后1个月时视疲劳症状较术前明显减轻。③相关性分析：术后1周时,调节幅度的降低程度与术前屈光度呈正相关（r=0．83,P〈0．01）;近视组视疲劳症状与双眼调节幅度呈负相关（r＝-0．79,P〈0．01）。结论LASIK术后患者视近时调节需求增加,且单眼及双眼调节幅度均有短暂下降,术后第1周显著下降,之后逐渐恢复。LASIK术后视疲劳症状和眼调节状态的变化有关。     

角膜塑形镜对近视眼调节微波动幅度和调节滞后的影响

目的 研究近视眼配戴角膜塑形镜后调节微波动幅度和调节滞后的改变.方法 横断面研究.选取在视光门诊规范验配、随诊、配戴角膜塑形镜者15例作为观察组,框架眼镜者15例作为对照组;使用开放视野型红外验光仪(WAM-5500)测量两组在0～4 D的调节刺激下的调节反应,计算相应的调节微波动幅度、调节滞后值和调节误差指数.对两组相关数据进行独立样本t检验.结果 在0、1、2、3、4D调节刺激下,角膜塑形镜组的调节微波动幅度均大于框架眼镜组,且差异有统计学意义(t=3.704、3.277、2.365、2.179、2.591,P均＜0.05).角膜塑形镜组的调节滞后值均小于框架眼镜组,在2,3和4D调节刺激下,两组差异有统计学意义(t=-2.208,-2.244,-2.098,P均＜0.05);而在0和1 D调节刺激下,两组差异无统计学意义(t=-1.974、-1.758,P＞0.05).角膜塑形镜组的调节误差指数小于框架眼镜组,且差异有统计学意义(t=-2.098,P＜0.05).结论 近视眼配戴角膜塑形镜后,调节微波动幅度增大;在高调节需求时,调节滞后值减小,这为其延缓近视的进展提供了一定依据.     

青少年近视眼配戴RGPCL、Ortho—K及框架眼镜一年后调节滞后的差异

目的探讨青少年近视眼配戴硬性透气性角膜接触镜（rigid gas permeable contact lens,RGPCL）、角膜塑型镜（orthokeratology,Ortho—K,OK镜）及框架眼镜后调节滞后的差异。方法70名（70眼）9～14岁中低度青少年近视眼患儿,行医学验光、角膜曲率、角膜地形图检查后,根据检查结果、患儿及家长依从性等综合评估,对其中25名患儿选择配戴RGPCL,25名患儿配戴Ortho—K,其余20名患儿配戴框架眼镜。配戴期间每3个月复查1次,1年以后测定RGPCL组戴镜屈光度、Ortho—K组脱镜后的残余屈光度及框架眼镜组的屈光度．并使用开放视野型红外验光仪测量其在2～5D调节刺激下的调节反应．计算相对应的调节滞后和调节反应／刺激（AR／AS）斜率。对相关数据采用单因素方差分析的LSD检验。结果总共有57人完成测量。在2D调节刺激水平下,RGPCL、Ortho—K和框架眼镜组的调节滞后值间差异无统计学意义（P〉0．05）;在3D、4D、5D调节刺激水平下,3组问的调节滞后值差异均具有统计学意义（F=4．373,P〈0．05;F=5．833,P〈0．01;F=6．157,P〈0．01）,Ortho—K组的调节滞后值最小,RGPCL组次之,而框架眼镜组的调节滞后值最大。调节反应／刺激（AR／AS）斜率也呈现同样趋势,但3组间差异无统计学意义（P〉0．05）。结论配戴RGPCL和Ortho—K1年后,患儿在高调节需求时的调节滞后值明显低于框架眼镜组,其在延缓青少年近视进展中可以起到积极的作用。     

角膜塑形镜对近视眼调节微波动幅度和调节滞后的影响

目的 研究近视眼配戴角膜塑形镜后调节微波动幅度和调节滞后的改变。方法 横断面研究。选取在视光门诊规范验配、随诊、配戴角膜塑形镜者15例作为观察组,框架眼镜者15例作为对照组;使用开放视野型红外验光仪（WAM-5500） 测量两组在0~4 D的调节刺激下的调节反应,计算相应的调节微波动幅度、调节滞后值和调节误差指数。对两组相关数据进行独立样本t检验。结果 在0、1、2、3、4 D调节刺激下,角膜塑形镜组的调节微波动幅度均大于框架眼镜组,且差异有统计学意义（t=3.704、3.277、2.365、2.179、2.591,P均<0.05）。角膜塑形镜组的调节滞后值均小于框架眼镜组,在2,3和4 D调节刺激下,两组差异有统计学意义（t=-2.208,-2.244,-2.098,P均＜0.05）;而在0和1 D调节刺激下,两组差异无统计学意义（t=-1.974、-1.758,P＞0.05）。角膜塑形镜组的调节误差指数小于框架眼镜组,且差异有统计学意义（t=-2.098,P<0.05）。结论 近视眼配戴角膜塑形镜后,调节微波动幅度增大;在高调节需求时,调节滞后值减小,这为其延缓近视的进展提供了一定依据。     

Dynamics of accommodative facility in myopes

PURPOSE: To evaluate the dynamic changes in refraction during the accommodative facility test in myopes and emmetropes. METHODS: Ten myopes and 10 emmetropes participated in the study. All were young adults, and refractive error in the myopes was corrected with soft contact lenses. Monocular accommodative facility measurements were taken for a 40-cm and a 6-m working distance with +2.00/-2.00-D and Plano/-2.00-D flippers, respectively. Subjective facility was recorded with automated flippers and objective measurements of dynamic accommodation response were simultaneously taken with a photorefractor. RESULTS: Subjective and objective facility measurements showed a significantly lower facility rate in myopes when compared with emmetropes at distance (P < 0.05) but not at near (P > 0.05). The response amplitude of accommodation during facility tasks was found to be similar in the two refractive groups. However, the velocity of accommodation was found to be lower in myopes than in emmetropes for distance facility (P < 0.05) but not for near facility (P > 0.05). Velocity of disaccommodation was lower in myopes than in emmetropes at both distance and near (P < 0.05). CONCLUSIONS: During distance accommodative facility testing, myopes exhibited a lower velocity of accommodation and disaccommodation, which led to a lower distance accommodative facility rate. For near facility measurements, however, although velocity of disaccommodation was lower in myopes, velocity of accommodation was found to be similar in the two refractive groups. A variety of factors that contribute to these differences are discussed.     

近视眼LASIK术后调节灵洁度变化与视觉疲劳的关系

目的研究近视眼LASIK术后调节灵活度(accommodative facility,AF)的变化情况以及与视觉疲劳关系。方法 32例(64眼)近视患者按年龄分成30岁以下组和30岁以上组,行标准LASIK手术,术前及术后1周、1个月分别测量双眼AF,术后1个月对术后视觉疲劳症状情况行问卷调查,采用配对t检验比较手术前后AF的变化,用Logistic回归分析法分析手术前后AF、年龄以及屈光度等对术后视觉疲劳的影响。结果 30岁以下组术前双眼AF为(7.12±2.02)c·min-1,术后1周为(6.22±1.73)c·min-1,与术前相比差异无统计学意义(P>0.05);术后1个月为(9.46±1.97)c·min-1,与术前相比差异有统计学意义(P<0.05)。30岁以上组术后1周AF由术前(5.68±2.51)c·min-1显著降低至(4.02±1.59)c·min-1,差异有统计学意义(P<0.05),术后1个月恢复至(6.03±1.61)c·min-1,与术前相比差异无统计学意义(P>0.05)。问卷调查发现,术后视觉疲劳症状阳性者13例(40.6%),阴性者19例(59.4%);回归分析表明,患者术前及术后1周AF、年龄以及术前等效球镜度数与视觉疲劳症状显著相关。结论近视眼LASIK术后早期AF下降,以后逐渐恢复,可能是术后视觉疲劳的重要原因之一。     

Analysis of head position used by myopes and emmetropes when performing a near-vision reading task

The aim of the study was to compare head posture in young, adult emmetropes and corrected myopes during a reading task. Thirty-two (32) myopes (mean spherical equivalent: −3.46 ± 2.35 D) and 22 emmetropes (mean spherical equivalent: −0.03 ± 0.36 D) participated in the study. Of the myopes, 16 were progressing (rate of progression ?−0.5 D over the previous 2 years), 12 were stable (changes of −0.25 D or less over 2 years) and four could not be classified. Seated subjects were asked to read a text binocularly in their habitual posture. To measure head posture, two simultaneous images were recorded from different directions. In a separate study with the same subjects and conditions, a motion monitor was used to track head posture for 1 min. The habitual reading distance was measured in both studies, together with the stereoscopic acuity and fixation disparity for each subject.The results of the photographic study showed no significant differences in head posture or reading distance between the myopic and emmetropic groups (p > 0.05) but there was some evidence that downward pitch angles were greater in progressing myopes than in non-progressing myopes (p = 0.03). No correlations were observed between the binocular parameters and head posture. Reading distances were systematically shorter with the helmet-mounted eye tracker and it was concluded that posture was affected by the weight of the equipment. With this reservation, it appeared that the rate of change of downward pitch angle over the 1-min recording session increased with the subject’s rate of myopia progression (correlation between myopia progression and slope of pitch: r² = −0.69, p = 0.001), implying a greater reliance on head movements when reading down a page.Overall, while no differences in mean head posture were found between myopes and emmetropes, there was some evidence that head posture and movement during reading may differ in progressing myopes.     

Differences in the accommodation stimulus response curves of adult myopes and emmetropes

While the accommodation system has been implicated in myopia development, the nature of this relationship remains obscure. This study investigated the differences in accommodation stimulus response curves between adult myopes and emmetropes. Myopic subjects were classified according to age of onset and stability of their myopia. Accommodation stimulus response curves were measured using three different methods: (i) real targets presented at viewing distances of 4 m to 0.25 m, (ii) a target at 4 m viewed through negative lenses of increasing power, and (iii) a target at 0.25 m viewed through positive lenses of decreasing power. A Canon Autoref R-1 measured the accommodation responses at 5 levels of demand (increasing from 0 D to 4 D in 1 D steps). We found significant differences between the three methods used to stimulate an accommodation response in all subject groups, for example, accommodation lags at high accommodative demands were greatest for the negative lens series and least for the positive lens series. In addition, while differences between early-onset myopes, late-onset myopes and emmetropes were not observed, we did observe differences when myopic subjects were reclassified according to whether their myopia was progressing or stable. A reduced accommodation response to negative lens-induced accommodative demand was found in progressing myopes but not in stable myopes. These results provide further evidence for the link between myopia progression and inaccurate accommodation. The data also suggest that adult myopes with stable refractive errors show accommodation responses similar to that of emmetropes.     

LASIK对近视患者调节和隐斜的影响

目的　探讨LASIK手术对近视患者调节和隐斜的影响。方法　对LASIK手术的近视患者 60人在术前和术后一个月进行调节力和看近隐斜度的测定 ,并进行对比分析。结果　术前调节力平均值为 6 77D± 1 41D ,术后调节力平均值为 7 3 9D± 1 2 5D。统计学分析二者之间的差异有非常显著性意义 (t =6 887,P <0 0 1)。术前裸眼隐斜度的平均值为 -10 18± 5 0 7Δ。术前戴矫正镜片隐斜度的平均值为 -1 99± 6 49Δ ;术后裸眼隐斜度的平均值为 -4 92± 4 46Δ。统计学分析 ,术前裸眼与戴矫正镜片隐斜度平均值之间的差异有非常显著性意义 (t =11 898,P <0 0 1) ;术前裸眼与术后裸眼隐斜度平均值之间的差异有非常显著性意义 (t =11 10 1,P <0 0 1) ;术后裸眼与术前戴矫正镜片隐斜度平均值之间的差异有非常显著性意义 (t =3 0 45 ,P <0 0 1)。结论　LASIK手术后近视患者的调节力有一定增加。矫正眼镜和LASIK手术可以减少近视患者看近外隐斜。较长期的影响尚有待于观察。     

Axial length and choroidal thickness changes accompanying prolonged accommodation in myopes and emmetropes

The time course of elongation and recovery of axial length associated with a 30 min accommodative task was studied using optical low coherence reflectometry in a population of young adult myopic (n = 37) and emmetropic (n = 22) subjects. Ten of the 59 subjects were excluded from analysis either due to inconsistent accommodative response, or incomplete anterior biometry data. Those subjects with valid data (n = 49) were found to exhibit a significant axial elongation immediately following the commencement of a 30 min, 4 D accommodation task, which was sustained for the duration of the task, and was evident to a lesser extent immediately following task cessation. During the accommodation task, on average, the myopic subjects exhibited 22 ± 34 μm, and the emmetropic subjects 6 ± 22 μm of axial elongation, however the differences in axial elongation between the myopic and emmetropic subjects were not statistically significant (p = 0.136). Immediately following the completion of the task, the myopic subjects still exhibited an axial elongation (mean magnitude 12 ± 28 μm), that was significantly greater (p < 0.05) than the changes in axial length observed in the emmetropic subjects (mean change −3 ± 16 μm). Axial length had returned to baseline levels 10 min after completion of the accommodation task. The time for recovery from accommodation-induced axial elongation was greater in myopes, which may reflect differences in the biomechanical properties of the globe associated with refractive error. Changes in subfoveal choroidal thickness were able to be measured in 37 of the 59 subjects, and a small amount of choroidal thinning was observed during the accommodation task that was statistically significant in the myopic subjects (p < 0.05). These subfoveal choroidal changes could account for some but not all of the increased axial length during accommodation.     

The value of training accommodative facility for ball sports

We address the issue of training accommodative facility as a means of improving performance in ball sports. Presenting examples from the game of baseball, we show that dynamic accommodation is unlikely to play an important role in ball skills. The movement speed of the ball combined with the last possible time at which visual information can be converted to motor action means that accommodation cannot provide useful information on the time to contact of the ball. In addition, we question whether altering accommodation to provide a clear retinal image of an approaching target is necessary for most ball sport skills.     

Cognition, ocular accommodation, and cardiovascular function in emmetropes and late-onset myopes

PURPOSE: To investigate objectively and noninvasively the role of cognitive demand on autonomic control of systemic cardiovascular and ocular accommodative responses in emmetropes and myopes of late-onset. METHODS: Sixteen subjects (10 men, 6 women) aged between 18 and 34 years (mean +/- SD: 22.6 +/- 4.4 years), eight emmetropes (EMMs; mean spherical equivalent [MSE] refractive error +/- SD: 0.05 +/- 0.24 D) and eight with late-onset myopia (LOMs; MSE +/- SD: -3.66 +/- 2.31 D) participated in the study. Subjects viewed stationary numerical digits monocularly within a Badal optical system (at both 0.0 and -3.0 D) while performing a two-alternative, forced-choice paradigm that matched cognitive loading across subjects. Five individually matched cognitive levels of increasing difficulty were used in random order for each subject. Five 20-second, continuous-objective recordings of the accommodative response measured with an open-view infrared autorefractor were obtained for each cognitive level, whereas simultaneous measurement of heart rate was continuously recorded with a finger-mounted piezoelectric pulse transducer for 5 minutes. Fast Fourier transformation of cardiovascular function allowed the relative power of the autonomic components to be assessed in the frequency domain, whereas heart period gave an indication of the time-domain response. RESULTS: Increasing the cognitive demand led to a significant reduction in the accommodative response in all subjects (0.0 D: by -0.35 +/- 0.33 D; -3.0 D: by -0.31 +/- 0.40 D, P < 0.001). The greater lag of LOMs compared with EMMs was not significant (P = 0.07) at both distance (0.38 +/- 0.35 D) and near (0.14 +/- 0.42 D). Mean heart period reduced with increasing levels of workload (P < 0.0005). LOMs exhibited a relative elevation in sympathetic system activity compared to EMMs. Within refractive groups, however, accommodative shifts with increasing cognition correlated with parasympathetic activity (r = 0.99, P < 0.001), more than with sympathetic activity (r = 0.62, P > 0.05). CONCLUSIONS: In an equivalent workload paradigm, increasing cognitive demand caused a reduction in accommodative response that was attributable principally to a concurrent reduction in the relative power of the parasympathetic component of the autonomic nervous system (ANS). The disparity in accommodative response between EMMs and LOMs, however, appears to be augmented by changes in the sympathetic nervous component of the systemic ANS.     

Reduction of asthenopia after accommodative facility training

Five patients reporting asthenopia secondary to accommodative deficiencies underwent automated accommodative facility training. A matched-subjects, crossover design was used to control for placebo effects. All patients receiving automated accommodative training showed a marked increase in accommodative amplitude along with a concurrent reduction of asthenopia. Decreases of blur and increases of reading time were the most frequently reported changes by patients. This experiment shows the effectiveness of automated accommodative training in reducing asthenopia and improving accommodative facility.     

准分子激光原位角膜磨镶术后调节训练疗效观察

目的 观察调节训练法治疗准分子激光原位角膜磨镶术(Laser in situ keratomileusis,LASIK)后患者视疲劳的临床效果.方法 选择行LASIK术后3个月仍有视疲劳症状的患者28例,年龄34～45岁(平均38.32岁),进行调节灵敏度训练(即±1.0 D、±2.0 D反转透镜),每日2次,每次15 min.15 d为一疗程,一般为2个疗程.观察治疗前后视疲劳评分及调节灵敏度.结果 LASIK术后患者视疲劳评分治疗前为10.04±0.22,治疗后为4.00±0.15,治疗后较治疗前显著降低有统计学意义(P＜0.05).调节灵敏度治疗前为( 5.27±1.22) cpm,治疗后为(8.98±1.69) cpm,治疗后较治疗前明显提高,差异显著有统计学意义(P＜0.05).结论 调节灵敏度是一种简单、有效的调节与双眼视觉训练方法,能改善LASIK术后患者视疲劳症状.