The relation between visual sensitivity and intraocular pressure in normal eyes

Intraocular pressure and flicker modulation sensitivity at 25 and 40 Hz were measured in 22 normal observers, with an age range from 20-71 years. Significant correlations up to 0.67 were found between intraocular pressure and flicker sensitivity at several points in the visual field. There was no correlation between flicker sensitivity and age of the observers. Thus intraocular pressure may affect neuronal function in the normal eye.     

Associated convergence and accommodative insufficiency

Nine patients were described with a syndrome consisting of accommodative and convergence insufficiency. All but two had received extensive orthoptic therapy without benefit in the past. Near points of convergence and accommodation, fusional amplitudes and the AC/A ratio were determined and the data compared with those from a group with ordinary convergence insufficiency. The results show that this syndrome is a distinct and separate entity from ordinary convergence insufficiency. Special therapeutic measures include base in prisms and bifocal correction.From the Wilmer Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland.This study was supported by Research Grant EY-00274 from the National Eye Institute, Bethesda, Maryland.     

The synkinetic interaction of convergence accommodation and accommodative convergence

An experimental paradigm is presented to test the long-standing theory that binocular vergence is supported by an addition of tonic, proximal and accommodative convergence (as measured monocularly) along with a supplemental fusional component. Results show accommodative convergence is less than, and the fusional component greater than, predicted by this traditional theory. An alternative theory is presented which includes the influence of convergence accommodation and which correctly predicts the experimental results.     

Proximal and accommodative convergence and age

The authors have estimated the phoria for distant and near fixation in two groups of subjects (mean age 27.5 ± 4.4 and 59.2 ± 8.2 years). Different accommodative stimuli were induced by adding minus lenses for distant fixation and plus lenses for near fixation. Statistical analysis of the experimental data indicates that, for distant fixation, the value of phoria per unit of accommodative stimulus is significantly lower in presbyopic than in nonpresbyopic subjects. Also, during near fixation, the accommodative convergence (AC/A ratio) is more reliable in the presbyopic subjects when the accommodative stimulus is progressively reduced. This varying behavior indicates in presbyopic subjects that proximal convergence is of greater relative importance in the determination of the fusion-free position. In nonpresbyopic subjects, accommodative convergence is the more important component.     

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.     

近视与调节功能的相关性研究现状

眼的调节是指睫状肌通过改变晶状体的屈光力，使物体在视网膜形成清晰像的过程，当眼的调节能力不足时，成像焦点落于视网膜后的区域，容易形成远视离焦，引起眼轴增长，导致近视的发展，且研究发现多数近视患者通常存在一定程度的调节功能障碍。近视已成为我国的公共健康问题，青少年近视的患病率急剧升高，如何预防及阻止近视的发生、发展是一大难题。既往研究发现眼调节功能障碍与近视的发生、发展存在一定联系，调节功能相关参数的测量对近视的防控有一定的指导意义。本文旨在综述近视与眼调节功能的相关性，以期为近视的防控和治疗提供新思路。     

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.     

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.     

Gain changes in the accommodative convergence cross-link

The output of the accommodative vergence cross-link, the AC/A ratio, was measured before and after subjects viewed through a telestereoscope which increased their interocular separation (pd) approximately fourfold. The initial paradigm was designed to force an increase in the AC/A ratio in that subjects alternately fixated targets set at differing distances. In this paradigm, the varying vergence demands could not be met by a constant increase in phasic or tonic vergence responses. In a second paradigm, only one target was viewed at a fixed position from the eye. Now the constant vergence demand could be met by a set increase in phasic and/or tonic vergence. A significant increase in the AC/A ratio was found in the two-target study but not in the single-target study. Increases in the accommodative vergence gain did show considerable individual differences. Tonic vergence changes were interpolated from the data. This parameter increased significantly in both cases but more so when two targets were alternately fixated. This finding is consistent with current near triad models which predict that accommodative convergence input acts along with disparity vergence input to increase tonic levels of convergence. When AC/A ratios were calculated using clinical measures of the phoria at 6 and 0.4 m, increases were found in the two-target study and to a lesser degree in the single-target study. This clinical method of AC/A measure appears to have been confounded by changes in tonic vergence.     

眼挫伤30例视力的恢复与视觉诱发电位变化相关性的分析

目的探讨将诱发电位技术应用于眼外伤后视力评估的可行性。方法眼挫伤致视力受损者30例（48眼）进行视觉诱发电位检查,每例受检对象均记录3次,检测时间分别为伤后1月、3月及1年,以刺激模式空间频率、P100波幅和潜伏期作为检测指标,检测与记载各受检眼P100波幅和潜伏期的变化,以盲测的视力表视力为参照,分析不同时期视觉诱发电位结果与视力恢复状况的相关性。结果一定的视觉刺激模式空间频率大小与视力表现出一致性,P100波幅与视力水平呈正相关,P100波潜伏期长短与视力状况未见必然联系,视觉诱发电位变化与眼挫伤后视力的恢复状况有关,视力表筛查与VEP检测结果比较无差异。结论应用视觉诱发电位技术可对眼挫伤后视力的恢复状况进行客观评估。     

The first and second order dynamics of accommodative convergence and disparity convergence

Main sequences, the function describing the relationship between eye movement amplitude and velocity, have been used extensively in oculomotor research as an indicator of first-order dynamics yet it is difficult to find main sequence analyses for accommodative vergence or for disparity vergence in isolation when all mitigating factors have been well controlled and there are no studies in which accommodative vergence and disparity vergence main sequences have been generated for the same group of subjects. The present study measured main sequences in: (1) accommodative vergence with disparity vergence open loop, (2) disparity vergence with accommodation open loop, and (3) combinations of accommodative and disparity vergence. A dynamic AC/A ratio was defined and was found to be similar to the traditional static AC/A ratio. Vergence acceleration was measured for all conditions. A pulse-step model of accommodation and convergence was constructed to interpret the dynamics of the crosslinked interactions between the two systems. The model supports cross-coupling of both the pulse and step components and simulates the primary empirical findings that: (1) disparity vergence has a higher main sequence slope than accommodative vergence, (2) both accommodative and disparity vergence acceleration increase with response amplitude whereas accommodation acceleration does not.     

可调节折叠人工晶状体临床应用初步报告

目的：通过植入一种新型的可调节折叠人工晶状体1CU，观察患者术后远近视力，观察改型人工晶状体的拟调节力。方法：对10眼单纯老年性白内障患者实施超声乳化联合囊袋内可调节折叠人工晶状体植入术，同期随机抽取10眼单纯老年性白内障行超声乳化及单焦点折叠晶状体植入术作为对照，于术前、及术后1wk；1，3mo查裸眼远近视力、矫正视力，并进行主客观验光。结果：1CU组裸眼近视力优于对照组（0．01〈P〈0．02），裸眼远视力及矫正远近视力无显著差异（P，0．2），两组手术前后散光无显著差异（P〉0．05）。结论：植入可调节折叠人工晶状体后，术眼具有一定的假晶状体调节。     

客观调节性集合/调节比率的研究

目的利用眼动追踪仪和红外自动验光仪获得刺激性调节性集合/调节（accommodative convergence/accommodation,AC/A）和反应性AC/A值,分析两者相关性及差异。方法选取34名健康在校学生和年轻工作人员[年龄为20～35岁,平均（25.8±3.4）岁],在集合反馈回路打开（遮盖左眼）的条件下,用310型眼动追踪仪分别记录调节性集合;用wv500红外自动验光仪测量注视眼在各调节刺激下的调节反应,从而分别得出刺激性AC/A和反应性AC/A,对两者数据采用配对t检验进行分析。结果用眼动追踪仪法测量所有受试者所得的刺激性AC/A和反应性AC/A有显著相关性（r=0.871,P=0.000）和明显差异,反应性AC/A为（7.50±3.60）△/D,刺激性AC/A为（4.77±1.84）△/D,反应性AC/A平均值与刺激性AC/A平均值相比为1.57,两者差异有显著统计学意义（P=0.000）。结论反应性AC/A高于刺激性AC/A,大多数个体均有一定程度的调节滞后量。     

可调节折叠人工晶状体临床应用初步手报告

目的:通过植入一种新型的可调节折叠人工晶状体1CU,观察患者术后远近视力,观察改型人工晶状体的拟调节力.方法:对10眼单纯老年性白内障患者实施超声乳化联合囊袋内可调节折叠人工晶状体植入术,同期随机抽取10眼单纯老年性白内障行超声乳化及单焦点折叠晶状体植入术作为对照,于术前、及术后1wk;1,3mo查裸眼远近视力、矫正视力,并进行主客观验光.结果:1CU组裸眼近视力优于对照组(0.01＜P＜0.02),裸眼远视力及矫正远近视力无显著差异(P＞0.2),两组手术前后散光无显著差异(P＞O.05).结论:植入可调节折叠人工晶状体后,术眼具有一定的假晶状体调节.