Factors influencing visual outcome in anisometropic amblyopes

Aim: To identify which factors influence the final visual acuity in children with anisometropic amblyopia. METHODS: A retrospective analysis of 112 children with anisometropic amblyopia, identified from examining all case notes of children who had failed preschool or school screening. RESULTS: The age at presentation had no effect on the final visual outcome (p=0.804). Both the degree of refractive error and the degree of anisometropia at presentation correlated with final visual acuity (p<0.001 and p=0.001). Those with strabismus had a poorer final outcome. CONCLUSIONS: The age at presentation of a child with anisometropic amblyopia appears to have no significant effect on the final visual acuity. The amount of refractive error and degree of anisometropia at presentation do correlate strongly with final visual acuity. This would suggest, firstly, that children with poorer visual acuity at presentation and higher degrees of anisometropia should be treated more aggressively and that, secondly, children with anisometropic amblyopia should be treated regardless of age.     

学龄前儿童弱视的防治

目的:探讨学龄前儿童弱视防治的关键。方法:对6500例学龄前儿童进行眼部的健康普查,对检出弱视的个体进行系统治疗。结果:弱视患病率4.38%;屈光不正性弱视356眼(76.1%),斜视性弱视47眼(10.0%),屈光参差性弱视65眼(13.9%)。弱视总治愈率为98.1%,其中轻度弱视有效率100%,中度弱视有效率96.6%,重度弱视有效率80.8%。结论:学龄前儿童弱视以轻中度弱视为主,弱视程度越轻,治疗越早,治疗效果越佳。     

A retrospective analysis of children with anisometropic amblyopia in Nepal

Purpose: Anisometropia is one of the main causes of amblyopia. This study was conducted to investigate the association between the depth of amblyopia and the magnitude of anisometropia.

Methods: A retrospective record review was conducted at the Nepal Eye Hospital between July 2006 and June 2011. Those children included in this study were aged ≤13 years and diagnosed with unilateral anisometropic amblyopia, no strabismus and ocular pathology. Associations between the depth of amblyopia and the age and/or gender of the subjects, the laterality of the amblyopic eyes, the type and magnitude of refractive error of amblyopic eyes, and the magnitude of anisometropia were statistically analyzed.

Results: Out of the 189 children with unilateral anisometropic amblyopia (mean age 9.1?±?2.8 years), 59% were boys. Amblyopia was more commonly found in left eye (p?p?=?0.864) or age (p?=?0.341) of the subjects or the laterality of the eyes (p?=?0.159), but it was associated with the type (p?=?0.049) and magnitude (p?=?0.013) of refractive error of the amblyopic eye and the magnitude of anisometropia (p?=?0.002).

Conclusion: Nepalese anisometropic amblyopic children were presented late to hospital. The depth of amblyopia was highly associated with the type and magnitude of refractive error of the amblyopic eye and the magnitude of anisometropia. So, basic vision screening programs may help to find out the anisometropic children and reefer them to the hospital for timely management of anisometropic amblyopia if present.     

Original papers: Prevalence of amblyogenic diseases in a preschool population sample of Valladolid, Spain

Objectives: Amblyopia is the leading cause of monocular vision loss in people under 40 years, and especially in children. The purpose of the present investigation is to determine the prevalence of amblyopia and ocular pathology, specially the most common causes of amblyopia, in a population of 3-to 6-year-old children. Patients and methods: From a total of 8167 children, a geographically defined population of 3-to 6-year-old children, 2000 were randomly selected, and 1179 (58.9%) examined. Ophthalmologic examination included: Personal and familial history, visual acuity, extraocular motility, cover test at near distance, cycloplegic refraction with autorefractometer and fundus eye examination. Amblyopia was considered when corrected visual acuity was < 0.5 with Marquez optotypes and difference in visual acuity of 0.2 or more between eyes. Pathology considered as amblyogenic were strabismus, visual acuity asymmetry and anisometropia. Results: The family history showed amblyopia in 249 (21.1%), strabismus in 227 (19.2%), and refractive errors in 808 (65.5%). Cover test was positive in 78 children (6.7%). A visual acuity difference of 0.2 or more between eyes was present in 88 (7.5%) children, and anisometropia over 1.5 diopters (in spherical equivalent) was present in 17 (1.4%) subjects. One hundred and twenty-two (10.35%) children did not achieve a normal visual acuity: visual acuity in the better eye was less than 0.5 in 55 children under 5 years and less than 0.6 in 67 children over 5 years. The prevalence of amblyopia was 7.5%. Conclusions: The data support the importance of early detection and treatment of amblyopia and the need for visual screening at an early age.     

Hyperacuity deficits in anisometropic and strabismic amblyopes with known ages of onset

In order to evaluate the influence of etiology of amblyopia and of age at onset of amblyopia on the resulting constellation of spatial vision deficits, resolution/vernier and recognition/resolution acuity ratios were measured in groups of children with either strabismic amblyopia or anisometropic amblyopia with known ages of onset. Strabismic amblyopia with infantile onset (<9 months) and strabismic amblyopia with late onset (18-30 months) were both associated with abnormally low resolution/vernier and abnormally high recognition/resolution acuity ratios. Among amblyopes with infantile onset (<9 months), moderate amblyopia was associated with different resolution/vernier and recognition/resolution acuity ratios in anisometropic and strabismic groups. Infantile amblyopes with poor acuity outcomes included children who initially presented with anisometropia but later developed strabismus and children who initially presented with esotropia but later developed anisometropia; both subgroups with mixed amblyopia had poor resolution/vernier acuity ratios. Data from moderate amblyopes support the hypothesis that anisometropia and strabismus disrupt visual maturation in fundamentally different ways rather than simply at different stages in visual development.     

先天性上睑下垂患者100例弱视致病原因的探讨

目的:评估先天性上睑下垂患者的弱视发病情况。方法:在本横断面研究中,包括1岁以上的先天性上睑下垂患者100例(114眼)。最佳矫正视力小于10/10或两眼之间至少相差2/10者定义为弱视。年幼患者不能进行斯内伦视力表检测者,观察其注视情况。不同弱视患者的类型:1)屈光参差性弱视:散光性屈光参差≥1.00D;远视性球镜屈光参差≥1.00D,近视性球镜屈光参差≥-3.00D(睫状肌麻痹);2)斜视性弱视,3)形觉剥夺性弱视(SDA)。观察弱视的总发病率及类型,并对单侧和双侧上睑下垂患者进行比较。结果:弱视的发生率在上睑下垂患者为39/114(34.2%),其具体原因:屈光参差性弱视占29.8%,SDA占10.5%,斜视性弱视4.3%,严重的上睑下垂患者弱视发病率更高,视轴遮盖者(OA)占76%,而视轴未遮盖者只占22%。在视轴遮盖的单侧眼睑下垂患者,散光屈光参差性弱视发生率更高,在双侧眼睑下垂至少1眼视轴遮盖者,球镜屈光参差性弱视发生率更高。无论单侧和双侧上睑下垂,如果有视轴遮盖,则SDA比较多见。结论:由于屈光参差性弱视比SDA发生率更高,关注导致的弱视所有原因对于预防儿童上睑下垂所致的弱视极其重要。     

影响儿童屈光参差性弱视疗效的相关因素分析

目的 探讨影响儿童屈光参差性弱视疗效的相关因素.方法 113例3～10岁屈光参差性弱视儿童给予综合疗法治疗,观察其治疗效果,并对年龄、治疗依从性、弱视程度、屈光参差程度及类型等影响疗效的相关因素进行分析.结果 治愈77只眼(68.1%).进步24只眼(21.2%),无效12只眼(10.6%).其中不同治疗依从性、弱视程度及屈光参差程度各组间的疗效差异有统计学意义,而不同年龄及屈光参差类型各组间的疗效差异无统计学意义.结论 儿童屈光参差性弱视的治疗效果较好,其疗效与治疗的依从性、弱视的程度、屈光参差的程度密切相关,而与患儿的年龄、屈光参差的类型无明显的相关性.     

屈光参差性弱视儿童视力与立体视的关系

目的探究相同屈光参差范围内不同类型屈光参差性弱视儿童的视力与立体视情况,以及视力、屈光参差类型对拥有立体视与否的影响。方法回顾性研究。收集56例屈光参差性弱视儿童和52例伴有斜视的屈光参差性弱视儿童以及20例正常儿童相应检查数据,检查包括矫正视力、屈光程度、随机点动态2阶粗糙立体视。采用多元方差分析3类儿童的视力差异,统计立体视分布情况,运用非条件logistic回归分析视力与屈光参差类型对拥有立体视与否的影响。结果单纯屈光参差性弱视儿童与伴有斜视的屈光参差性弱视儿童的视力差异无统计学意义（F=3.58,P=0.0314,校正α=0.016）。单纯及伴有斜视的屈光参差性弱视儿童粗糙立体视拥有率分别为96%,71%。在双眼视力一致的条件下,伴有斜视的屈光参差性弱视与单纯屈光参差性弱视儿童相比,拥有2阶立体视的OR估计值为0.132（95%CI：0.034~0.503）。在屈光参差类型一致的条件下,高、中双眼视力平衡度与低双眼视力平衡度相比,拥有2阶立体视的OR估计值分别为5.161（95%CI：0.868~30.675）和3.939（95%CI： 0.920~16.858）。结论相同屈光参差程度范围中不同类型屈光参差性弱视儿童的视力差异不明显;伴有斜视的屈光参差性弱视儿童立体视缺损的可能性更高,并且双眼不平衡度越高引起的立体视下降越明显。     

Anisometropic amblyopia treated with spectacle correction alone: possible factors predicting success and time to start patching

PURPOSE: To evaluate factors predicting resolution of amblyopia and the time course of improvement in VA in children 3 to 7 years old with anisometropic amblyopia treated with spectacles alone. DESIGN: Prospective, noncomparative intervention. METHODS: Measurement of corrected amblyopic logMAR visual acuity (VA) in newly diagnosed children at four-weekly intervals until VA stabilized or amblyopia resolved. The time course of improvement in VA and the factors related to amblyopia resolution were assessed. RESULTS: Sixty children with a mean age of 5.3 years and mean anisometropia of 2.95 diopters (D) were included. Amblyopia improved by 2 or more logMAR lines in 56 patients (93%) and resolved in 27 patients (45%), with a mean improvement in VA of 0.38 logMAR. The improvement in VA in the amblyopic eye was considerable at four to 12 weeks then reached a plateau, after which it improved only slowly. Resolution of amblyopia was related to better initial VA (0.2 to 0.6 logMAR) and lesser amounts of anisometropia (<4 D). The time to resolution ranged from four to 40 weeks, but no patient with residual amblyopia showed an improvement in VA of more than 0.1 logMAR over four consecutive visits. CONCLUSIONS: With spectacle correction alone, 3- to 7-year-old children with previously untreated anisometropic amblyopia achieved approximately four-line improvement and resolved nearly in half. The nearly two-month plateau periods during improvement of VA should be noticed. After four months with no improvement in VA, occlusion therapy or atropine penalization may be considered.     

屈光参差性弱视患者LASIK术后矫正视力和立体视觉的变化

目的:探讨屈光参差性弱视患者在准分子激光原位角膜磨镶术(laser-assisted in situ keratomileusis,LASIK)治疗弱视中矫正视力和立体视觉的变化.方法:回顾性分析屈光参差性弱视患者84例84眼临床资料,分析不同性别、年龄、屈光参差性弱视类型患者治疗前和治疗后3、6mo,1a矫正视力和立体视觉的变化,分析矫正视力与立体视觉的相关性.结果:患者84 例84眼经LASIK术治疗3、6mo,1a后矫正视力较治疗前提高,立体视锐度值较治疗前降低(P<0.05).男性患者与女性患者治疗后3、6mo,1a矫正LogMAR视力和立体视锐度值差异无统计学意义(P>0.05).年龄<30岁组治疗后3、6mo,1a矫正视力明显高于年龄≥30岁组(P<0.05).远视性屈光参差性弱视患者治疗后3、6mo,1a立体视锐度值较近视性屈光参差性弱视患者显著下降(P<0.05),而两组患者治疗后矫正LogMAR视力比较无统计学差异(P>0.05).屈光参差性弱视患者在LASIK术治疗过程中矫正视力的提高与立体视力下降值无显著相关性(P>0.05).结论:LASIK术能有效改善屈光参差性弱视患者矫正视力及立体视觉,但患者治疗过程中矫正视力和立体视觉受年龄与弱视类型影响.     

The burden of pure anisometropic amblyopia: a cross-sectional study on 2800 Iranians

Purpose

To assess the proportion of pure anisometropic amblyopia in a sample Iranian (white) population.

Methods

A total of 2800 consecutive individuals who presented at a referral eye clinic for any reason were examined for the presence of pure anisometropic amblyopia. Anisometropia was reported when a spherical equivalent refraction difference of at least 1.0 D with or without a cylinder refraction difference of at least 1.0 D was present between the two eyes. Amblyopia was defined as the best-corrected visual acuity of 20/30 or worse or a two-line interocular visual acuity difference between eyes that could not be attributed to any structural ocular pathology or visual pathway abnormality.

Results

Subjects were 1528 females and 1272 males with a mean age of 30.25 ± 14.93 years (range, 5–65). Amblyopia was diagnosed in 192 cases (6.9%), significantly more frequent among females (7.9 vs. 5.7%, p = 0.02). Pure anisometropic amblyopia was present in 6.1% of the study population, significantly more common in patients with spherical hyperopic anisometropia (37.7%) compared to patients with spherical myopic anisometropia (21.3%), cylindrical myopic anisometropia (4.1%), and cylindrical hyperopic anisometropia (15%) (p < 0.001).

Conclusions

Pure anisometropic amblyopia is a common finding in Caucasians seeking eye care, particularly when anisometropia is of spherical hyperopic subtype.

     

儿童屈光参差与弱视、立体视相关性的研究

目的　探讨屈光参差对儿童视力和立体视功能的影响以及屈光参差、弱视、立体视三者之间的相关关系。方法　选择不伴有斜视的 4 5～ 13 8岁屈光参差儿童 186例 ,无屈光参差和弱视的同龄正常儿童 2 0例。对以上所选病例 ,测定裸眼视力、屈光状态、最佳的矫正视力及矫正后Tit mus立体视 ,并对测量数据进行统计学分析。结果　①当远视参差 >1D ,近视参差 >2D ,散光参差 >1 0D ,弱视的发生率分别为 43 %、 43 %、 3 6% ;立体视异常百分比分别为 43 %、 2 9%、 3 6% :屈光参差 >3D ,弱视及异常立体视发生率均 10 0 %。②屈光参差与弱视的相关性及立体视与弱视的相关性均大于屈光参差与立体视的相关性。结论　儿童屈光参差可严重损害患儿的视力及双眼视功能 ,随着屈光参差程度的增加 ,弱视及异常立体视的发生率明显增多 ,并且 ,立体视功能的下降与弱视相伴行 ,二者之间存在显著相关性     

Contact lenses in the management of high anisometropic amblyopia

Poster at College Congress, Birmingham 2001.Oral presentation at European Strabismus Association, Florence 2001. PURPOSE: Anisometropia of more than one dioptre during the sensitive visual period may cause amblyopia. Its management requires refractive correction, and occlusion. Compliance with treatment is critical if visual improvement is to obtained. High anisometropia, poor initial acuity and mixed strabismic/anisometropia amblyopia are predictive factors for a poor outcome. We evaluated contact lens use in the management of high anisometropic amblyopia. METHODS: Retrospective analysis of anisometropic amblyopia managed in a paediatric contact lens clinic (July 1996-July 2000), after standard amblyopia therapy of spectacles and occlusion therapy had been tried. Presenting age, acuity and refraction, duration of lens wear and occlusion, and final visual outcomes were noted. RESULTS: Seven children (four male, three female) presented at age 3.5-6 years (mean 4.5). Six had myopic anisometropia 6.0-18.4 dioptres (mean 10.4 dioptres) and one 6.75 dioptres hypermetropic anisometropia. The initial corrected acuities of the amblyopic eyes were 6/18 to 1/60. Five patients used contact lenses with a range from 5 months to 4 years. Final acuities were 6/12-1/60. Two myopes with 6 dioptres anisometropia improved three to four Snellen lines, one with 8.8 dioptres improved one line. Three with >10 dioptres anisometropia did not improve. The hypermetropic patient improved part of one Snellen line. CONCLUSIONS: High anisometropic amblyopia is challenging to treat. In our study contact lenses improved visual acuity in myopic anisometropia of up to 9 dioptres.     

屈光参差性弱视与斜视性弱视临床疗效的比较

目的:分析比较屈光参差性与斜视性弱视的治疗效果。方法:前瞻性研究。2018-07/2020-01在我院门诊确诊的并首次接受治疗的单眼弱视患者46例,平均年龄9±3岁,其中男26例,女20例,按照临床诊断分为斜视性弱视组(无屈光不正),共23例,平均年龄9±3岁,其中男12例,女11例。以及屈光参差性弱视组,共23例,平均年龄9±3岁,其中男14例,女9例。对两组患者采用遮盖及精细训练治疗弱视,于治疗前及治疗后采用国际标准视力表检测视力、用Titmus图谱行立体视锐度的检测。比较两组患者经弱视治疗前后最佳矫正视力及立体视恢复的差异。结果:治疗前两组患者弱视眼的最佳矫正视力无差异(t=-0.475,P>0.05),但斜视性弱视患者的立体视功能明显低于屈光参差性弱视患者(t=-3.919,P<0.001);通过2mo的治疗,两组患者最佳矫正视力提高值有明显差异(t=-2.946,P<0.01),而两组患者立体视提高值无差异(t=1.305,P>0.05);通过6mo的治疗,两组患者最佳矫正视力提高差值有明显差异(t=-2.353,P<0.05),两组患者立体视提...     

Amblyopia in myopia in patients with strabismus and without strabismus

PURPOSE: To determine factors, which have influence on presence of strabismus among myopic patients with amblyopia. MATERIAL AND METHODS: Material covers 21 myopic patients with amblyopia, aged 6-15. All children presented have a different amount of anisometropia, 12 of them had strabismus. Authors, compared the group of patients with amblyopia and strabismus (12) with the group of patients with pure anisometropic amblyopia (9), according to the following criteria: age of presentation, best corrected visual acuity, mean refraction error of amblyopic eye, mean amount of anisometropia, percentage of patients with central fixation and binocular vision. RESULTS: Patients with strabismus presented oneself earlier than patients without squint. Best corrected visual acuity was better in patients without strabismus. Refraction error in both groups has similar value. Amount of anisometropia was slightly smaller in the group with squint. Central fixation and binocular vision were better preserved among patients without strabismus. Authors didn't find the following correlations too: correlation between amount of anisometropia and amount of amblyopia in both groups, correlation between amount of anisometropia and the amount of the deviation of squinting eye, correlation between depth of amblyopia and the amount of deviation of the squinting eye. CONCLUSION: It seems, that primary factor leading to presence of strabismus among patients with anisometropic myopia, is motor dysfunction of extraocular muscles.     

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.     

The Prevalence of Anisometropia,Amblyopia and Strabismus in Schoolchildren of Shiraz,Iran

Purpose: To determine the prevalence of amblyopia, anisometropia, and strabismus in schoolchildren of Shiraz, Iran.

Materials and Methods: A random cluster sampling was used in a cross-sectional study on schoolchildren in Shiraz. Cycloplegic refraction was performed in elementary and middle school children and high school students had non-cylcoplegic refraction. Uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) were recorded for each participant. Anisometropia was defined as spherical equivalent (SE) refraction difference 1.00D or more between two eyes. Amblyopia was distinguished as a reduction of BCVA to 20/30 or less in one eye or 2-line interocular optotype acuity differences in the absence of pathological causes. Cover test was performed for investigating of strabismus.

Results: Mean age of 2638 schoolchildren was 12.5 years (response rate?=?86.06%). Prevalence of anisometropia was 2.31% (95% confidence interval [CI], 1.45 to 3.16). 2.29% of schoolchildren (95% CI, 1.46 to 3.14) were amblyopic. The prevalence of amblyopia in boys and girls was 2.32% and 2.26%, respectively (p?=?0.945). Anisometropic amblyopia was found in 58.1% of the amblyopic subjects. The strabismus prevalence was 2.02% (95% CI, 1.18 to 2.85). The prevalence of exotropia and esotropia was 1.30% and 0.59%, respectively.

Conclusions: Results of this study showed that the prevalence of anisometropia, amblyopia, and strabismus are in the mid range. The etiology of amblyopia was often refractive, mostly astigmatic, and non-strabismic. Exotropia prevalence increased with age and was the most common strabismus type.     

Assessing amblyogenic factors in 100 patients with congenital ptosis

AIM: To study the frequency of amblyogenic factors in patients with congenital ptosis. METHODS: In this cross-sectional study, 114 eyes of 100 patients with congenital ptosis more than 1 year old were included. Amblyopia was defined as best-corrected visual acuity (BCVA) less than 10/10 or a difference between the two eyes of at least 2/10. In patients too young to be measured by the linear Snellen E test, fixation behavior was observed. Different types of amblyopia were assessed for each patient as: 1) anisometropic amblyopia: astigmatic anisometropia ≥1 dpt, hyperopic spherical anisometropia ≥1 dpt, myopic spherical anisometropia ≥-3 dpt (with cycloplegia); 2) strabismic amblyopia, and 3) stimulus deprivation amblyopia (SDA). Then the total incidence of amblyopia and each type of it were obtained. Patients with uni- and bi-lateral ptosis were also compared. RESULTS: The incidence of amblyopia in ptotic eyes was 39/114 (34.2 %), and for each specific cause was: refractive amblyopia in 29.8%, SDA in 10.5%, strabismic amblyopia in 4.3%. Amblyopia was more frequent in severe ptosis, 76% in patients with covered optical axes (OA), compared to non-covered OA (22.5%). In unilateral ptosis with covered OA, astigmatic anisometropic amblyopia was more frequent, and in bilateral ptosis with at least one eye covered OA, spherical anisometropic amblyopia was more frequent. In both unilateral and bilateral ptosis, SDA was more common if the OA was covered. CONCLUSION: As refractive anisometropic amblyopia is more prevalent than SDA, paying attention to all causes of amblyopia may be important in preventing amblyopia in a child with a ptotic eye.     

The relationship between anisometropia and amblyopia

This review aims to disentangle cause and effect in the relationship between anisometropia and amblyopia. Specifically, we examine the literature for evidence to support different possible developmental sequences that could ultimately lead to the presentation of both conditions. The prevalence of anisometropia is around 20% for an inter-ocular difference of 0.5D or greater in spherical equivalent refraction, falling to 2–3%, for an inter-ocular difference of 3D or above. Anisometropia prevalence is relatively high in the weeks following birth, in the teenage years coinciding with the onset of myopia and, most notably, in older adults starting after the onset of presbyopia. It has about one-third the prevalence of bilateral refractive errors of the same magnitude. Importantly, the prevalence of anisometropia is higher in highly ametropic groups, suggesting that emmetropization failures underlying ametropia and anisometropia may be similar.Amblyopia is present in 1–3% of humans and around one-half to two-thirds of amblyopes have anisometropia either alone or in combination with strabismus. The frequent co-existence of amblyopia and anisometropia at a child's first clinical examination promotes the belief that the anisometropia has caused the amblyopia, as has been demonstrated in animal models of the condition. In reviewing the human and monkey literature however it is clear that there are additional paths beyond this classic hypothesis to the co-occurrence of anisometropia and amblyopia. For example, after the emergence of amblyopia secondary to either deprivation or strabismus, anisometropia often follows. In cases of anisometropia with no apparent deprivation or strabismus, questions remain about the failure of the emmetropization mechanism that routinely eliminates infantile anisometropia. Also, the chronology of amblyopia development is poorly documented in cases of ‘pure’ anisometropic amblyopia. Although indirect, the therapeutic impact of refractive correction on anisometropic amblyopia provides strong support for the hypothesis that the anisometropia caused the amblyopia. Direct evidence for the aetiology of anisometropic amblyopia will require longitudinal tracking of at-risk infants, which poses numerous methodological and ethical challenges. However, if we are to prevent this condition, we must understand the factors that cause it to develop.     

Facilitation of amblyopia management by laser in situ keratomileusis in high anisometropic hyperopic and myopic children

PURPOSE: To assess the efficacy of laser in situ keratomileusis (LASIK) in facilitating amblyopia management of children from 6 to 14 years old, with high hyperopic and myopic anisometropia. PATIENTS AND METHODS: Between 2000 and 2005, 42 children with high hyperopic anisometropic amblyopia and 32 children with high myopic anisometropic amblyopia underwent LASIK to reduce their anisometropia. LASIK was performed under topical or general anesthesia. Pre- and postoperative best-corrected visual acuity, cycloplegic refraction, and binocular vision were recorded. Follow-up ranged from 6 months to 3 years, the averages of which were 17.45 months in the hyperopic group and 18.31 months in myopic group. RESULTS: Hyperopic anisometropia correction ranged from +3.50 D to +7.75 D, and the mean postoperative anisometropia was +0.56 +/- 0.75 D at 3 years. Myopic anisometropia correction ranged from -15.75 to -5.00 D and the mean postoperative anisometropia at 3 years was -2.20 +/- 1.05 D. The best-corrected visual acuity for distance and reading in the myopic group improved from 0.4 +/- 0.25 and 0.58 +/- 0.27, respectively, before surgery to 0.59 +/- 0.28 and 0.96 +/- 0.35, respectively, 3 years after surgery. In the hyperopic group, best-corrected visual acuity for distance and reading improved from 0.23 +/- 0.21 and 0.34 +/- 0.32, respectively, before surgery to 0.53 +/- 0.31 and 0.80 +/- 0.33, respectively, 3 years after surgery. The proportion of patients who had stereopsis increased from 19.1% preoperatively to 46.7% postoperatively in the hyperopic group and from 19% to 89% in the myopic group. CONCLUSIONS: LASIK reduced high hyperopic and myopic anisometropia in children, thus facilitating amblyopia management and improving their visual acuity and stereopsis.