Functional lid surgery in Down''s syndrome.

Down's syndrome is associated with characteristic eyelid abnormalities. Ten patients presented with lid abnormalities leading to corneal problems. Five patients had ectropion, four of whom required skin grafting to correct the abnormality. One patient had entropion and four had chronic blepharoconjunctivitis leading to trichiasis, which was treated with double freeze thaw cryotherapy.     

Amblyopia and visual acuity in children with Down''s syndrome

BACKGROUND/AIMS: Amblyopia in people with Down's syndrome has not been well investigated. This study was designed to determine the prevalence and associated conditions of amblyopia in a group of home reared children with Down's syndrome. METHODS: All children in the study group underwent an evaluation of visual acuity. In addition, previous ophthalmological records were reviewed, and a subgroup of children was examined. For the purposes of this study, amblyopia was defined quantitatively as a difference of two Snellen acuity lines between eyes or if unilateral central steady maintained (CSM) vision and a clear fixation preference was observed. A high refractive error was defined as a spherical equivalent more than 3 dioptres and astigmatism more than 1.75 dioptres. Anisometropia was defined as a difference of at least 1.5 dioptres of sphere and/or 1.0 dioptre of cylinder between eyes. 68 children with Down's syndrome between the ages of 5 and 19 years were enrolled in the final study group. RESULTS: Amblyopia was observed in 15 (22%) of 68 patients. An additional 16 (24%) patients had bilateral vision less than 20/50. Strabismus, high refractive errors, and anisometropia were the conditions most commonly associated with decreased vision and amblyopia CONCLUSION: This study suggests that the prevalence of amblyopia is higher than previously reported. Fully 46% of these children with Down's syndrome had evidence of substantial visual deficits. These patients may be at higher risk for visual impairment and should be carefully examined for ophthalmological problems.     

Visual development in infants and young children with Down''s syndrome

Purpose: To compare reading performance as mediated by the healthy eye and the affected eye of individuals with recent onset, unilateral, exudative age-related macular degeneration.
Methods: The reading performance of eight subjects (76.3 ± 5.3 years) was assessed under monocular viewing conditions with the affected and the healthy eye. Eye movements were recorded using a spectacle-mounted, infrared limbal reflection system whilst the subjects read short stories (65 words) printed in 16 point Times Roman font at a working distance of 25 cm. Comprehension was assessed by 'free' recall at the end of each story.
Results: Acuity in the affected eyes ranged from 0.40 to 0.80 (log MAR) and in the healthy eyes from 0.00 to 0.20. When using the affected eye, reading speed was reduced by 50%, compared to reading with the healthy eye, though comprehension scores were similar. There was also a significant increase ( P < 0.01) in the durations of fixation pauses, the time between the initiation of the return sweep and the first forward saccade on the subsequent line and the numbers of regressive saccades, with each forward saccade covering fewer letters. Fixation durations were positively correlated with the mean depth of the field defect.
Conclusions: The results seem to indicate that although the motor aspects of reading are affected in the initial stages of the visual loss, comprehension is relatively unaffected for short, simple passages of text.     

Transient pattern Visual Evoked Potentials in children with Down''s syndrome

Visual acuity and contrast sensitivity are lower in children with Down's syndrome than in those developing normally. In many cases, this difference might be accounted for by the relatively high incidence of ocular abnormalities (including refractive error and strabismus) in Down's syndrome. However, abnormal spatial vision persists in children with Down's syndrome in the absence of ocular abnormality, suggesting that abnormal retino-cortical visual processing explains reduced visual function in this group. The aim of the present study was to assess retino-cortical function in children with Down's syndrome by recording transient visual evoked potentials (VEPs) in response to pattern stimuli. Responses from children with Down's syndrome were compared with those recorded from children developing normally. Response latency is similar in the two groups, but morphology differs, with the N75 component being clearly present in the normal responses, but diminished or undetectable in responses from children with Down's syndrome. Our findings may suggest a cortical abnormality specific to the source of the N75 component of pattern-reversal achromatic VEPs.     

儿童屈光不正与立体视觉

目的探讨儿童屈光不正对立体视觉的影响。方法采用颜少明等《立体视觉检查图》对60例正常儿童及115例矫正视力正常的屈光不正患儿进行立体视阈值检查并进行统计学处理。结果远视眼立体视阈值明显高于正常组及近视眼组（P＜0．005），且随屈光度增高而增高，随发生年龄增高而降低，近视眼组与正常组之间无差异（P＞0．05）。近视眼之间戴眼镜前后立体视阈值无显著性，而远视眼戴镜后立体视阈值明显下降（P＜0．005）。结论屈光不正对立体视功能影响是由于视力下降引起。提示及早发现屈光不正，及时预防、矫正屈光不正性弱视，对保证立体视功能的正常发育具有重要意义     

挫伤性屈光不正的眼超声生物学检测

对１１２例挫伤性屈光不正患者进行了超声生物学检测。结果提示，挫伤性近视患者眼球解剖结构存在两大变，即晶体前移和厚度增加，超声前房深度、晶本厚度在伤后的检测结果与对照组相比具显著性差异。并对挫伤屈光不正的发生机制进行了探讨。     

In focus: the use of bifocal spectacles with children with Down''s syndrome

PURPOSE: Over 75% of children with Down's syndrome fail to accommodate accurately on near targets. This deficit must result in optically blurred images for near work. This present study set out to evaluate the controlled use of bifocal spectacles as an aid to near focusing. Although sometimes used clinically, no systematic studies of bifocals for children with Down's syndrome have been reported. METHODS: This was a comparative non-randomised interventional study. Thirty-four children with Down's syndrome of primary school age (5-11 years) took part, assigned in equal numbers to form two matched groups. All children received a full optometric assessment prior to entering the study. The treatment group was prescribed bifocal spectacles with a +2.50 addition, and the control group provided with single vision lenses to correct any clinically significant refractive error. Three follow-up visits were made over a 5-month period after spectacle provision. RESULTS: The treatment group showed consistently more accurate accommodation than the control group both through the bifocal segment, and, unexpectedly, through the distance part of the lens (p < 0.05). Compliance with new spectacles was high in both groups (>82% fully compliant). CONCLUSIONS: Bifocals confer benefit to children with Down's syndrome who under-accommodate, both directly (better focusing through the bifocal) and indirectly (by encouraging improved accommodation through the distance part of the lens). Based on the results of this study, eye examinations of children with Down's syndrome should routinely include a measure of accommodation at near, and bifocal spectacles should be considered for those who show under-accommodation.     

屈光不正患者伴有偏高角膜曲率46例的临床分析

目的：探讨术前检查中发现屈光不正患伴有偏高角膜曲率时的归属和对策。方法：利用角膜地形图对拟接受准分子激光手术的46例屈光不正患进行角膜曲率的检查和分析。结果：因出现圆锥角膜或角膜薄、度数高而不能手术10例(18眼),初查曲率偏高、随查3mo后行LASIK矫正术3例(6眼),初查曲率偏高、需进一步随查而暂未手术33例(63眼)。结论：单纯角膜曲率偏高不能作为准分子激光手术的禁忌症,但也不能盲目手术。角膜曲率的检查对选择治疗方式具有一定的意义。     

屈光不正眼弥散斑变化的实验研究

提出一种应用激光技术测定屈光不正眼弥散斑变化的方法,并将其初步应用结果与理论计算值进行了比较对照。结果表明:屈光不正眼弥散斑随眼离焦量的增加而增大。比较理论值和实测值,两者间存有一定差异。认为实测值比理论值更能准确地评价屈光不正眼的成象质量。     

儿童多瞬症与屈光不正的关系

目的 探讨儿童多瞬症与屈光不正的关系.方法 选取240例多瞬症儿童为观察组,240例健康儿童为对照组,比较两组儿童的屈光状态,分析其屈光度、配镜合适度和屈光性眼位异常的差异.结果 多瞬症儿童屈光不正的比例为60.8﹪,高于对照组的32.9﹪,差异有统计学意义(P＜0.05);屈光不正儿童中,多瞬症儿童高度近视和高度远视的比例分别为23.1﹪和51.1﹪,高于对照组的15.8﹪和16.7﹪,配镜不适者和屈光性眼位异常的比例分别为63.0﹪和65.1﹪,高于对照组的2.6﹪和48.1﹪,差异均有统计学意义(P＜0.05).结论 屈光不正可能诱导儿童产生多瞬症,应该尽可能及早纠正屈光不正.     

有晶状体眼后房型人工晶状体植入矫正屈光不正的临床进展

后房型人工晶状体又称可植入式隐形眼镜（ICL），它为屈光不正的治疗提供了角膜手术以外的新途 径，可应用于高度近视、屈光参差、圆锥角膜等患者。目前临床最常用的是V4c型ICL，其特点是带 有中央孔，可改善房水的引流并增加晶状体前表面的房水循环，且术前或术中不再需要行周边虹膜 切除术。ICL植入术可有效提高裸眼及矫正视力，且术后眼压长期稳定。V4c型ICL植入术后白内障 发生率较传统V4型更低，其长期安全性及有效性高，在目前的临床应用中取得了良好的疗效，可作 为矫正上述屈光不正的主要方法。随着ICL的临床应用与研究进展，有关ICL植入术的疗效及并发 症的讨论越来越多，明确手术的安全有效性，以及对术后并发症的评估和处理是临床医师面临的重 要问题。现就ICL植入术的临床研究进展进行综述。