Refraction changes in children developing convergent or divergent strabismus.

Strabismus and amblyopia were studied in a cohort of children born in 1979 or 1980 in the area of Västerås, Sweden. Forty percent of the children had participated in a voluntary eye examination at 1 year of age. All children diagnosed as strabismic and/or amblyopic between 1979 and 1988 at any of the three eye clinics in the area were included in this study. Strabismic cases were mostly detected by the parents while microstrabismus and straight eye amblyopia were found at the general 4 years of age screening at children''s health centres. In 57 cases with (n = 31) and without amblyopia (n = 41) it was possible to obtain several refraction values between 1 and 6 years of age. In this study we concentrated on manifest esotropia and exotropia. The aim of the study was to describe changes of refraction before and after onset of strabismus and to establish risk indicators that identified populations at risk of developing strabismus. We found that patients with esotropia show a more pronounced hypermetropia than exotropic cases at the time of detection of strabismus. This difference becomes more definite over time, since hypermetropia increased in the deviating eye in the esotropic cases while refractive errors remained stationary in most of the exotropic eyes. It was also apparent that anisometropia frequently developed after onset of strabismus in esotropic cases in contrast to exotropic cases. An increasing refractive error in the deviating esotropic eye could be combined with an emmetropisation of the fixating eye.     

Prediction of amblyopia and squint by means of refraction at age 1 year.

In this series amblyopia, uncorrectable by spectacles and occlusion, was highly likely (48%) if a child had +3.50 or more dioptres of meridional hypermetropia at age 1 year. 45% of children with this refraction also had a squint. All those who remained with severely defective acuity in spite of treatment had either +3.50 or more dioptres of meridional hypermetropia or 4 or more dioptres of meridional myopia at age 1 year. These children were identifiable in the 3.7% of the population at age 1 year who showed high refractive errors. Squint as such was not so accurately predictable. Of those children with squint 71% had less than +3.50 dioptres of meridional hypermetropia at age 1 year--an incidence of 4.4% of the population. Apart from two 'congenital myopes' only 16% of these had residual amblyopia after treatment, and their last known acuity was never less than 6/12. Astigmatism in infancy or later is not significantly associated with squint or amblyopia.     

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.     

Visual Outcome in 879 Children Treated for Strabismus: Insufficient Accommodation and Vision Deprivation,Deficient Emmetropisation and Anisometropia

Purpose: To identify the effect of infant hypermetropia on residual amblyopia in children remaining after treatment.

Materials and Methods: 879 strabismic children had cycloplegic retinoscopy at the age of 6 months and later when strabismus was diagnosed. A total of 26 hypermetropes consistently wore glasses from the age of 6 months, and 305 other hypermetropes had their accommodation periodically assessed by dynamic retinoscopy before strabismus was diagnosed. The relation between the last known visual acuity after treatment and all other clinical findings was analysed using t-tests and regression analysis.

Results: Vision less than 6/12 in nonfixing eyes was associated with infantile hypermetropia > +5.0D, and in rare instances in excess of -3.0D of myopia. In hypermetropes only, anisometropia was associated with worse amblyopia. Astigmatism was associated with myopia and low levels of hypermetropia but not with worse vision. The vision of fixing eyes that were hypermetropic was significantly worse than that of emmetropic or myopic eyes. Wearing spectacles from the age of 6 months was associated with better vision in the nonfixing eye. Vision in the nonfixing eye of 19 hypermetropic heterotropes who started wearing glasses between 6 and 18 months of age also was better than that of those who started wearing glasses after 18 months of age. Insufficiency of accommodation was related to the degree of infantile hypermetropia, to worse vision and to failure to emmetropise. Difference in amplitude of accommodation between the eyes was largest in hypermetropes with anisometropia > +1.50 D and was marginally associated with worse vision in microtropes who became anisometropic after infancy. Hypermetropia decreased more in fixing eyes than in nonfixing eyes, thereby causing anisohypermetropia to increase after infancy. This change was most pronounced in hypermetropic microtropes. Conversely, failure of fixing eyes to emmetropise was associated with an increase in their inability to accommodate and heterotropia.

Conclusions: On the basis of these findings, severe residual amblyopia in children remaining after treatment could be explained by additional vision deprivation. It can be reduced by starting spectacle correction of hypermetropia before the age of 18 months. Anisometropia seemed the result of deficient emmetropisation.     

Reduction of astigmatism after infancy in children who did and did not wear glasses and have strabismus

The purpose of this study was to record and explain the changes in astigmatism as normal and strabismic infants grew. Two-hundred-and-eighty-nine hypermetropic infants were randomly allocated to wear glasses from the age of six months. Changes in astigmatism and in hypermetropia of the horizontal and vertical meridia were compared in those who did and did not wear glasses and have strabismus. Mean astigmatism decreased significantly (p < 0.001) in both eyes of normal and strabismic children, but the ‘last’ astigmatism was significantly (p < 0.001) larger in both eyes of those who had strabismus. There was a similar progressive decrease of hypermetropia in both meridia of both eyes within each diagnostic group, but with the exception of the vertical meridian of the non-fixating eyes (in which the difference approached statistical significance), this was significantly (p < 0.01) larger in the normal children. The consistent wear of glasses was not associated with change in both meridia of both eyes in the normal children (p < 0.005), but had no significant effect on the changes in astigmatism. Since the changes in the two meridia were proportional to the starting level, hypermetropia decreased more in the meridian which was, initially, the more hypermetropic one, and the difference between them, i.e. astigmatism, tended to disappear whether or not the child eventually had strabismus.     

弱视儿童散光变化的动态检测

对３９５例３－１２岁弱视儿童散光变化进行了动态检测，进一步了解弱视儿童的散光变化规律。全部病例球镜的主要变化远视度数减或近视数增加。散光的主要变化为：复性远视散光大部分转变为单纯远视散光，单向转变占２５％；混合性散光大部分单向转变。本文并对产生原因及散光变化的意义进行了详细讨论。     

学龄前儿童弱视及斜视的调查

目的早期发现并及时治疗弱视、斜视及其他眼病,减少可预防盲及低视力。方法济南市部分幼儿园内随机检查健康3～6岁6085例学龄前儿童,检查其标准远视力、近视力、屈光、眼位、眼前节及眼底。结果3～6岁儿童远视力低常率为12．16%,近视力低常率为4．40%；弱视患病率为5．23%,其中初次发现者占86．48%；共发现斜视患儿96例,其治疗率仅为14．58%。结论近视力可作为发现患儿视力不佳的线索之一,发现后重点核实其远视力。我市3～6岁儿童的弱视斜视的漏诊漏治情况相当严重,对幼儿尽早进行眼科普查意义重大,保健预防及宣教工作亟待加强。     

Final report of the early vs. late infantile strabismus surgery study (ELISSS), a controlled, prospective, multicenter study

BACKGROUND: The optimal age for surgery for infantile esotropia is controversial. Proponents of early surgery believe that further loss of binocular vision can be prevented by early surgery, a minority believes that binocular vision can even be restored by early surgery. The ELISSS compared early with late surgery in a prospective, controlled, non-randomized, multicenter trial. METHODS: Fifty-eight clinics recruited children aged 6-18 months for the study. Each clinic operated all eligible children either 'early', i.e. at age 6-24 months, or 'late', i.e. at age 32-60 months. At baseline the angle of strabismus, refraction, degree of amblyopia and limitation of abduction were assessed. Intermediate examinations took place every six months. Children were evaluated at age six in the presence of independent observers. Primary endpoints were (i) level of binocular vision, (ii) manifest angle of strabismus at distance and (iii) remaining amblyopia. Secondary endpoints were number of operations, vertical strabismus, angle at near and the influence of surgical technique. RESULTS: A total of 231 children were recruited for early and 301 for late surgery. Age at entry examination was 11.1 months (SD 3.7 months) in the early group and 10.9 (SD 3.7) months in the late group. Refraction, amblyopia and limitation of abduction were distributed equally in the early and late groups, but the angle of strabismus was slightly larger in the early group. Dropout-rates were 26.0% in the early and 22.3% in the late group. At age six, 13.5% of the early vs. 3.9% of the late group recognized the Titmus Housefly; 3.0% of the early and 3.9% of the late group had stereopsis beyond Titmus Housefly. No significant difference was found for angle of strabismus. 35.1% of the early group and 34.8% of the late group did not have an angle between 0 degrees and 10 degrees , the thresholds set for re-operation. For ratio of the visual acuities (remaining amblyopia) there was a small but significant advantage for the early group. There was hardly any correlation between the baseline parameters and the primary endpoints. Children scheduled for early surgery had first been operated at 20 (SD 8.4) months, but 8.2% had not been operated at age six. Children scheduled for late surgery had been operated at 49.1 (SD 12.7) months, but 20.1% had not been operated at age six. The number of operations per child was 1.18 (SD 0.67) in the early and 0.99 (SD 0.64) in the late group. Age at recruitment, age that strabismus reportedly had started and refraction at entry examination were similar among operated and non-operated children. Only the angle of strabismus at entry predicted, to some extent, whether a child had been operated at age six. DISCUSSION: Children operated early had better gross stereopsis at age six as compared to children operated late. They had been operated more frequently, however, and a substantial number of children in both groups had not been operated at all.     

儿童眼睑血管瘤眼屈光状态及其变化规律分析

目的探讨儿童眼睑血管瘤的屈光状态及其变化规律。方法对66例眼睑血管瘤患儿，于治疗前及治疗后第1年和第2年进行双眼散瞳检影验光。结果（1）66只患眼（血管瘤）中，初诊时以远视散光最多（68．2％），3年后远视散光的例数和散光度数明显减少（P〈0．05）；（2）66只健眼中，初诊时以远视最多（57．6％），3年后其屈光状态及屈光度的变化无显著性差异（P〉0．05）。结论及时治疗儿童眼睑血管瘤，可以减少远视散光、避免弱视和斜视。     

Screening for refractive errors at age 1 year: a pilot study.

Cycloplegic refraction of 1-year-old children is technically possible and is acceptable to mothers as a method for screening children for visual defects. The range of refractions found in a sample of 186 1-year-old children is reported. Prediction of which children are significantly at risk for squint and/or amblyopia is possible on the basis of refractions at age 1 year according to the criteria selected for an 'abnormal' refraction. Bilateral hypermetropia and/or astigmatism or anisometropia at age 1 year was significantly (P less than 1 in 10 000) associated with a child eventually being found to have squint or amblyopia. Both the age of screening and criteria of abnormality will probably need modification. +2.50 or more D hypermetropia in any one meridian of either eye at age 1 year was even more significantly (P = 0.000 000 05%) associated with squint and/or amblyopia. The possibility that meridional hypermetropia could be the basic defect in squint and amblyopia is discussed.     

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.     

A longitudinal study of a population based sample of astigmatic children. I. Refraction and amblyopia

The refraction changes in 310 children with astigmatism greater than or equal to 1.0 D in at least one eye at one year of age were followed during a period of 3 years. At the age 4 years amblyopia was found in 23 children (7%). The refraction data of these children were compared to the rest of the sample. We found that an increasing astigmatism during the test period was associated with an increased risk to develop amblyopia. The majority of children (n = 280) showed a decrease of their astigmatism, whereas all cases with a marked amblyopia (V.A. less than 0.5) or binocular amblyopia, except one, had an increasing or unchanged astigmatism during the age period 1 to 4 years. Strabismus and oblique astigmatism at any time during the test period was also strongly related to amblyopia. The incidence of strabismus (1%) was unexpectedly low. The study also showed that independent of age there was no simple relationship between amblyopia and refraction errors measured at a single test session. The main conclusion of this study is that failure of emmetropization may play an important role in visual development.     

Refraction as a basis for screening children for squint and amblyopia.

+2-00 to +2-75 dioptres of spherical hypermetropia in the more emmetropic of a pair of eyes is significantly associated with esotropia (P less than 0-001) and the presence of amblyopia (P less than 0-01). Anisometropia is not significantly associated with esotropia (P = 0-31) unless there is spherical hypermetropia of +2-00 dioptres or more in the more emmetropic eye (P less than 0-001). Hypermetropic anisometropia of +1-00 DS or +1-00 D.Cyl. is associated with the presence of amblyopia (P less than 0-001). In the absence of esotropia there is also a significant association between the amount of anisometropia and the initial depth of amblyopia (P less than 0-01). The additional presence of esotropia increases the depth of amblyopia further (P less than 0-05) but not the incidence of amblyopia (P greater than 0-30). The level of significance of the association of refractive errors with squint/amblyopia was itself significantly higher (P less than 0-01) than that between a family history of squint or "lazy eye" on the one hand and squint and/or amblyopia on the other hand. 72 +/- 3% of all cases of esotropia and/or amblyopia in this sample of children had a refractive error of +2-00 DS or more spherical hypermetropia in the more emmetropic eye, or +1-00 D. or more spherical or cylindrical anisometropia. Since there is a close association between the refraction and how, when, and whether a child presents with squint and/or amblyopia, it would seem reasonable to reconsider refraction as a basis for screening young children for visual defects.     

昆明市婴幼儿屈光状态的调查

目的　调查和了解婴幼儿的屈光状态,并予以合理矫正,以期尽早治疗和预防弱视、斜视。方法　采用随机整群抽样方法,对1146例（2291只眼）生后1个月至3岁的婴幼儿用托品酰胺眼液麻痹睫状肌后行视网膜检影验光,并对其结果进行统计学分析。结果　正视89只眼（3.88%）;远视2139只眼（93.37%）;近视38只眼（1.66%）;散光560只眼（24.44%）;其中混合散光25只眼（1.09%）;各类型屈光不正均以轻度为主,中、高度屈光不正97只眼（4.23%）;屈光参差34例(2.97%);斜视7例（11只眼,0.48%)。随年龄增长,远视度逐渐减低,散光眼数逐渐减少（χ     

Earlier detection of amblyopia and strabismus by ophthalmologic screening card attached to the vaccination card

BACKGROUND: In 1983, in Rijeka, Croatia, an ophthalmologic screening card was introduced for the detection and prevention of ophthalmologic diseases, including amblyopia and strabismus, in children. The card was attached to the vaccination card. The main goal of this study was to investigate whether this model of screening decreased the age at which children were first admitted to our Department of Strabismus and Pediatric Ophthalmology. METHODS: We randomly selected 100 of the 225 children who underwent examination for the first time in the Department of Pediatric Ophthalmology and Strabismus of a clinical hospital centre in Rijeka in 1980, and 100 of the 412 examined for the first time in 1990. Only children aged 5 years or less who were born in the maternity hospital in Rijeka were included in the study. We reviewed the records for these groups, noting the sex, age, diagnosis, refraction and visual acuity. RESULTS: The average age of the children examined in 1980 was 4.4 (standard deviation 1.4) years, compared with 2.5 (standard deviation 1.2) years in 1990, a statistically significant difference (p < 0.01, Student's t-test). In 1980, 17% of the children were under 3 years, compared with 80% in 1990 (p < 0.01). INTERPRETATION: The ophthalmologic screening card contributed to reducing the age at which strabismus and amblyopia are detected. This method of detection has been applied to the entire child population, and detection is performed continuously.     

Amblyopia without strabismus in context of research on concomitant strabismus

PURPOSE: To evaluate pathogenic factors for unilateral amblyopia in the group of amblyopic patients without strabismus. MATERIAL AND METHODS: In the study 141 patients with unilateral amblyopia without strabismus were evaluated according to age, sex, visual acuity, refraction error, presence of anisometropia, age of mother on delivery, weight on birth, hereditary transmission of strabismus or refractive error, pregnancy and delivery complications, response to treatment. RESULTS: Serious birth and pregnancy complications were noted only in 14.2% of cases, hereditary transmission might be suspected in 41.2% of patients. Anisometropia was found in 72% of cases. No significant difference in prevalence of possible pathogenic or risk factors such as age, sex, birth-weight, age of mother on delivery, hereditary transmission, pregnancy or delivery complications were found between anisometropic and isometropic group. Anisometropic group had bigger refractive error and deeper amblyopia, but responded better to treatment. CONCLUSION: Etiology of amblyopia without strabismus, particularly in the group of patients with isometropia, should be associated with trauma to central nervous system either in pre-natal or early after birth period.     

Effect of spectacles on changes of spherical hypermetropia in infants who did, and did not, have strabismus

AIM: To explore why emmetropisation fails in children who have strabismus. METHODS: 289 hypermetropic infants were randomly allocated spectacles and followed. Changes in spherical hypermetropia were compared in those who had strabismus and those who did not. The effect of wearing glasses on these changes was assessed using t tests and regression analysis. RESULTS: Mean spherical hypermetropia decreased in both eyes of "normal" children (p<0.001). The consistent wearing of glasses impeded this process in both eyes (p<0.007). In the children with strabismus, there were no significant changes in either eye, irrespective of treatment (p>0. 05). CONCLUSIONS: In contrast with normal infants, neither eye of those who had strabismus emmetropised, irrespective of whether the incoming vision was clear or blurred. It is suggested that these eyes did not "recognise" the signal of blurred vision, and that they remained long sighted because they were destined to squint. Hence, the children did not squint because they were long sighted, and glasses did not prevent them squinting.     

Long term effect of hypermetropic anisometropia on the visual acuity of treated amblyopic eyes

AIM—To evaluate the effect of the extent of hypermetropic anisometropia on the long term visual acuity results in amblyopic eyes following their treatment by occlusion.
METHODS—The visual acuity of 86 patients, who had been treated for unilateral amblyopia by occlusion of the fellow eye and followed up at least to the age of 9 years, was examined 6.4 years, on average, after cessation of treatment. Patients were divided into two groups—those with a small amount of hypermetropic anisometropia, where the spherical equivalent difference between the eyes ranged between 0 and +1.50 dioptres, and those with a large amount of hypermetropic anisometropia, where the difference was +1.75 dioptres or greater.
RESULTS—Deterioration of visual acuity after cessation of occlusion treatment occurred in 51% of the patients in the group with a small amount of anisometropia and in 75% of the patients in the group with a large amount. At cessation of treatment, the average visual acuity in both groups was 20/40+. At the long term follow up examination, however, the average visual acuity was 20/40− and 20/70, respectively. This difference was statistically significant.
CONCLUSIONS—Hypermetropic anisometropia greater than 1.50 dioptres appears to be a risk factor for deterioration of visual acuity in the long term, following treatment of amblyopic eyes by occlusion of the fellow eye.

Keywords: amblyopia; hypermetropic anisometropia; strabismus     

Long term follow up of premature infants: detection of strabismus, amblyopia, and refractive errors

AIM: To establish recommendations for long term ophthalmological follow up of prematurely born infants. METHODS: 130 infants with a gestational age (GA) <37 weeks and born between 1 November 1989 and 31 October 1990 were enrolled in a prospective study about the development of strabismus, amblyopia, and refractive errors. Infants were subdivided in three groups according to GA: A <28 weeks (n=32), B >/=28-32-<37 weeks (n=34). Ophthalmological assessment took place at the postconceptional age of 32 weeks, at term and at 3, 6, 12, and 30 months post term. At the age of 5 years parents received a questionnaire and a majority of the children was examined again (n=99). RESULTS: At the age of 5 years 46 infants were known to have strabismus (n=29) and/or amblyopia (n=22) and/or refractive errors (n=22). Statistical analysis showed that gestational age, duration of supplementary oxygen, and duration of hospitalisation were important predictive variables for the development of strabismus, amblyopia, or refractive errors (SAR) at the age of 5 years (p<0.05). Infants with a GA 32 weeks, who developed an incidence comparable with the normal population. Strabismus developed mainly in the first year of life and at the age of 5 years. Most infants with amblyopia were detected at the age of 2-3 years. Refractive errors were found in the first year of life and at the age of 2.5 and 5 years. CONCLUSION: Infants with a GA <32 weeks should be selected for long term ophthalmological follow up. These infants should be screened at the age of 1 year, in the third year of life (preferably at 30 months), and just before school age (including testing of visual acuity with optotypes).     

Botulinum treatment of childhood strabismus

Four hundred thirteen children ranging in age from 2 months to 12 years were treated for strabismus by botulinum injection of extraocular muscles. An average of 1.7 injections per patient was given. Follow-up at an average of 26 months after the last injection (minimum, 6 months) was available on 362 children (88%). The frequency of correction of 10 prism diopters (PD) or less in various groups of strabismus cases was: all 362 cases, 61%; all esotropia, 66%; infantile esotropia, 65%; and exotropia, 45%. Smaller deviations (10-20 PD) were more frequently corrected (73%) than were larger deviations (20-110 PD, 54%). The frequency of correction to 10 PD or less of previously operated cases was not different from that of unoperated cases. There was no globe perforation, amblyopia, or visual loss produced by the injection treatment in this series.