Risk factors for the development of accommodative esotropia following treatment for infantile esotropia.

PURPOSE: One aim of the study was to determine whether accommodative esotropia after surgical alignment in infantile esotropia occurs because a pre-existing accommodative component is unmasked at the time of surgery or whether it occurs as a sequela of infantile esotropia. A second aim of the present study was to examine risk factors for accommodative esotropia after surgery for infantile esotropia. METHODS: A total of 80 consecutive patients who were enrolled in a prospective study of infantile esotropia had been followed for more than 4 years and had achieved orthoposition were included. Twelve potential risk factors were examined: age at onset, initial esodeviation, initial refractive error, age at alignment, delay in alignment, presurgical glasses, amblyopia, additional surgical procedures, unstable alignment, increase in hypermetropia, peripheral fusion, and stereopsis. Mantel-Haenszel odds ratios were computed for each factor and were corrected to relative risks. RESULTS: Overall, 48 of 80 children (60%) developed accommodative esotropia at a mean age of 33 months. Increasing hypermetropia, delay in alignment, and poor stereopsis posed significant risks for accommodative esotropia. The remaining 9 factors were not associated with increased risk for accommodative esotropia. CONCLUSIONS: Accommodative esotropia is unlikely to be a pre-existing condition in most cases because the mean age of onset was 23 months postoperative and the prevalence of preoperative hypermetropia greater than +3.00 D was low. Both delay in alignment and stereopsis risk factors may reflect compromised binocular sensory status that allows accommodative esotropia to occur at low to moderate levels of hypermetropia. Identification of children treated for infantile esotropia who are at risk for accommodative esotropia may allow for prevention or early treatment.     

Association between accommodative accuracy, hypermetropia, and strabismus in children with Down's syndrome.

PURPOSE: A significant proportion of children with Down's syndrome have been shown to have reduced accommodation. The purpose of this study was to investigate any association between reduced accommodation and refractive error, strabismus, visual acuity, and other ocular parameters. METHODS: Subjects were children with Down's syndrome enrolled in a longitudinal cohort to monitor visual development. Twenty-seven children with accurate accommodation were age-matched to children with reduced accommodation based on their most recent assessment for which a full, reliable data set was available. Each child was used only once for matching. Cross-sectional ocular and visual data were analyzed using chi or Fisher's exact test, or the Mann-Whitney U test for (non-normally distributed) quantitative data. RESULTS: Children with under-accommodation were statistically more likely to have moderate/high hypermetropia (> or = +3.00 D) and to be strabismic (most with esotropia). No significant difference between the groups was found for any other ocular parameters. CONCLUSIONS: This study demonstrates the marked association between under-accommodation, hypermetropia, and strabismus in children with Down's syndrome. No causal relation can be demonstrated with these data, but findings suggest that the link between under-accommodation and hypermetropia (and between accurate accommodation and emmetropia) is present in early infancy.     

Risk factors for accommodative esotropia among hypermetropic children

PURPOSE: Identification of risk factors for accommodative esotropia may help to determine which children with hyperopia may benefit from early spectacle correction or preventive therapy. METHODS: Participants in the family history study were 95 consecutive patients, aged 18 to 60 months, with accommodative esotropia. Participants in the binocular sensory function study were a subgroup of 41 children enrolled in the family history study within 1 month of onset, while the esodeviation was still intermittent. Participants in the hypermetropia study were 345 consecutive patients, ages 12 months to 8 years, with refractive error of +2.00 D or greater and no esodeviation before age 12 months. RESULTS: In the family history study, 23% of children with accommodative esotropia had an affected first-degree relative, and 91% had at least one affected relative. In the binocular sensory function study, random-dot stereoacuity was abnormal in 41% of children, whereas an abnormal motion VEP, Worth 4-dot, or positive 4-PD base-out prism responses were present in 4% or less of the children. In the hypermetropia study, patients with a mean spherical equivalent of < +3.00 D and significant anisometropia had a 7.8-fold increased risk for accommodative esotropia over nonanisometropic patients. CONCLUSIONS: A positive family history, subnormal random-dot stereopsis, and hypermetropic anisometropia each pose a significant risk for the development of accommodative esotropia. Assessment of these risk factors in conjunction with refractive screening should help to identify those children who are most likely to benefit from early spectacle correction or preventive treatment.     

Emmetropisation in normal and strabismic children and the associated changes of anisometropia

The purpose of this study was to measure whether emmetropisation failed in children who had strabismus irrespective of their refraction in infancy, and to record simultaneous changes in anisometropia. We also report how often hypermetropia increased before these children presented with esotropia. A total of 2920 infants had a cycloplegic retinoscopy at age 5-7 months and again at 42 months or when defective vision was identified. Changes of refraction in 210 children with strabismus are compared with the remaining 2710 who did not. When the spherical equivalent of the fixing eyes was > +2.75 D in infancy, hypermetropia decreased less in both eyes of those who had microtropia (p <.001) and heterotropia (p <.001) than in normal children. When it was < +2.75 D, the spherical and/or cylindrical refraction more often remained outside the 'normal' range in both eyes of those who had microtropia and heterotropia (p <.05). Emmetropisation was deficient in both eyes of at least 80% of these strabismic children irrespective of their refraction in infancy. Furthermore, in the strabismic children, the mean change of refraction was less (p <.05) in their fellow eyes than in their fixing eyes, the difference between the two eyes being on average three times greater than that in those who had normal vision. Thus, anisometropia increased in 53% of those who had strabismus but remained within normal limits (< ca. 0.75 D spherical equivalent) in 94 % of those who did not. 'Abnormal' anisometropia in infancy did not, per se, permanently affect vision because 72% of all those who had it did not have strabismus. Finally, the spherical hypermetropia of fixing eyes increased in only 35% of the children with esotropia - similar to the incidence in those who had a microtropia (p =.36). This does not obviously support the concept that increasing hypermetropia causes accommodation to increase before convergence.     

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.     

Emmetropisation in normal and strabismic children and the associated changes of anisometropia

The purpose of this study was to measure whether emmetropisation failed in children who had strabismus irrespective of their refraction in infancy, and to record simultaneous changes in anisometropia. We also report how often hypermetropia increased before these children presented with esotropia. A total of 2920 infants had a cycloplegic retinoscopy at age 5-7 months and again at 42 months or when defective vision was identified. Changes of refraction in 210 children with strabismus are compared with the remaining 2710 who did not. When the spherical equivalent of the fixing eyes was &gt; +2.75 D in infancy, hypermetropia decreased less in both eyes of those who had microtropia (p &lt;. 001) and heterotropia (p &lt;. 001) than in normal children. When it was &lt; +2.75 D, the spherical and/or cylindrical refraction more often remained outside the ‘normal’ range in both eyes of those who had microtropia and heterotropia (p &lt;. 05). Emmetropisation was deficient in both eyes of at least 80% of these strabismic children irrespective of their refraction in infancy. Furthermore, in the strabismic children, the mean change of refraction was less (p &lt;. 05) in their fellow eyes than in their fixing eyes, the difference between the two eyes being on average three times greater than that in those who had normal vision. Thus, anisometropia increased in 53% of those who had strabismus but remained within normal limits (&lt; ca. 0.75 D spherical equivalent) in 94 % of those who did not.‘Abormal’ anisometropia in infancy did not, per se, permanently affect vision because 72% of all those who had it did not have strabismus. Finally, the spherical hypermetropia of fixing eyes increased in only 35% of the children with esotropia – similar to the incidence in those who had a microtropia (p =. 36). This does not obviously support the concept that increasing hypermetropia causes accommodation to increase before convergence.     

Form vision deprivation amblyopia: Further observations

Nine cases of esotropia occurring in deprivation amblyopia, where exotropia rather than esotropia is usually found, showed a refractive error of hypermetropia. This fact suggested that an accommodative factor is largely responsible for the development of esotropia. A- or V-pattern strabismus was encountered in a higher incidence in deprivation amblyopia than in ordinary strabismus. Pattern-reversal VEP showed more prominent abnormality than flash VEP did. Studies of the sensitive period of the visual system revealed that the sensitivity is likely to be low for a month or two after birth and increases with a peak around the 18th month of age, decreasing thereafter with a waning slope to the end of the 8th year of life.Dedicated to Dr. G.K. von Noorden on the occasion of his 60th birthday     

Age at strabismus diagnosis in an incidence cohort of children

PURPOSE: To compare the age at diagnosis of children with esotropia, exotropia, and hypertropia. DESIGN: Retrospective, population-based cohort study. METHODS: The medical records of all Olmsted County, Minnesota, residents < 19 years diagnosed with esotropia, exotropia, or hypertropia from January 1, 1985 through December 31, 1994 were reviewed. RESULTS: The median age at diagnosis of esotropia (n = 380), exotropia (n = 205), and hypertropia (n = 42) was 3.1 years, 7.2 years, and 6.1 years, respectively (P = .001). In the first six years of life, esotropia had the highest incidence and was more likely to occur than either exotropia or hypertropia; exotropia predominated between age seven and 12 years; and each form was similarly likely to occur between 13 and 18 years of age (P = .001). CONCLUSIONS: The age at diagnosis was significantly different for the various forms of strabismus in this population. Esotropia is the most common form in the first six years of life; beyond this age exotropia predominates until the teenage years when the three forms have a similar but decreased incidence.     

Long-term outcome and predictor variables in the treatment of acquired esotropia with botulinum toxin

PURPOSE: To determine the long-term results of botulinum therapy in acquired esotropia and to identify predictors of a satisfactory outcome. METHODS: Sixty-eight children (age range, 8-64 months) with acquired esotropia were enrolled in a prospective study. Botulinum toxin A was injected in the two medial recti. Motor and sensory statuses were evaluated at 1 and 2 weeks; 3, 6, and 12 months; and every year after the last injection. Univariate and multivariate logistic regression analyses were performed to relate motor and sensory outcome to variables recorded as potential predictors. RESULTS: After an average follow-up of 4.8 years since the last injection, motor success was obtained in 36 children with one injection (52.9%), increasing to 48 (70.6%) and 60 (88.2%) children after two and three injections, respectively. Forty-eight (70.6%) patients had at least peripheral fusion (category 1 binocularity) and 32 (47.1%) had stereoacuity of at least 400 seconds of arc (category 2 binocularity). Higher hypermetropia, less severe amblyopia, and a smaller angle of esotropia were the best predictors of motor success. Minimal amblyopia and favorable motor alignment were associated with better binocularity outcome. CONCLUSIONS: Botulinum is an effective long-term treatment of acquired esotropia. It is especially useful in children with high hypermetropia, minimal amblyopia, and small esotropic deviation.     

A longitudinal study of children with a family history of strabismus: factors determining the incidence of strabismus.

A longitudinal study of ocular refraction, position, and fixation was performed in children with a family history of strabismus. The children were examined at regular intervals between 3 months and 4 years of age, and the results are discussed in terms of changes in refraction between different ages and correlations between refraction and development of strabismus and amblyopia. Six of 34 children (17.6%) developed constant or intermittent esotropia. The strabismus was first noted between 18 and 30 months of age except in one case. All esotropic children were 4 dioptres hypermetropic or more at 6 months, and their hypermetropia remained almost unchanged through the years. Seven additional children were 4 dioptres or more hypermetropic at 6 months but did not develop a squint. In contrast to the squinting children the hypermetropia in these children changed towards emmetropia. This emmetropisation was most pronounced during the first 2 years of age. The implications of these results for an early diagnosis of strabismus amblyopia are discussed.     

A family of squints: the differing effects of hypermetropia on four siblings

Four siblings in a family of five were found to be affected with hypermetropia in differing degrees and with differing effects. These were unilateral hypermetropia, producing amblyopia; hypermetropia inducing an accommodative esotropia with minimal amblyopia and fully controlled with glasses; hypermetropia producing an accommodative esotropia with a high AC/A ratio, fully controlled with bifocals; and hypermetropia producing esotropia which was only partially corrected with glasses, therefore partially accommodative, with a residual squint which required surgery. This family of four nicely demonstrates all the permutations and combinations possible in accommodative-type esotropia and the pitfalls therein.     

A FAMILY OF SQUINTS: THE DIFFERING EFFECTS OF HYPERMETROPIA ON FOUR SIBLINGS

Four siblings in a famil of five were found to be affected with hypermetropia in differing degrees and with differing effects. dese were (i) unilateral hypermetropia, producing amblyopia; (ii) hypermetropia inducing an accommodative esotropia with minimal amblyopia and fully controlled with glasses; (iii) hypermetropia producing an accommodative esotropia with a high AC/A ratio, fully controlled with bifocals; and (iv) hypermetropia producing esotropia which was only partially corrected with glasses, therefore partially accommodative, with a residual squint which required surgery.
This family of four nicely demonstrates all the permutations and combinations possible in accommodative-type esotropia and the piifalls therein.     

NONACCOMMODATIVE FACTORS OF REFRACTIVE ACCOMMODATIVE ESOTROPIA

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Use of atropine to predict the accommodative component in esotropia with hypermetropia

This cohort study included children with esotropia and hypermetropia of ≥ +2.0 diopters (D). The deviation was measured at presentation, under atropine cycloplegia and 3 months after full refractive correction. Of 44 children with a mean age of 5.2 ± 2.4 years, 25 were males. Eighteen (41%) had fully refractive accommodative esotropia (RAE), 10 (23%) had partial accommodative esotropia (PAE), and 5 (11%) had nonaccommodative esotropia (NAE). Eleven (25%) had convergence excess (CE). Under cycloplegia, all with RAE and RAE with CE had orthotropia. There was no significant change in the deviation in the patients with NAE. The deviation under cycloplegia and that with full refractive correction in PAE and PAE with CE (with +3.0 D addition) were not different. The intraclass correlation coefficient for deviation under cycloplegia and after full refractive correction (+3.0 D addition for CE) was 0.89. It was concluded that ocular deviation under cycloplegia can help to predict the accommodative component in esotropia with hypermetropia.     

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.     

内斜视相关因素分析

目的探讨影响内斜视的因素。方法观察136例远视度大于 2D的儿童,年龄2～14岁,随访至少2年(24月),观察其发生内斜视的可能性及内斜视矫正的情况。结果1.未被矫正的远视并不都过度使用调节引起集合过强而致内斜视;2.高度远视合并内斜视其内斜视的矫正满意度明显较中低度远视差;3.斜视矫正满意与否与发病到就诊时间明显相关;4.斜视矫正满意与否与弱视程度有关;5.斜视矫正满意与否与立体视有一定关系。结论影响内斜视的因素包括弱视程度,双眼视功能,屈光参差,远视的程度等。     

Accommodative Esotropia Long Range Follow-up

Thirty-nine adult patients treated for typical (refractive) accommodative esotropia in childhood continue to have problems because they have not outgrown their hypermetropia, and the majority have not developed stable binocular vision. Their hypermetropia became maximal (median 5.7 diopters) by age 6, decreased in adolescence, and then stabilized (median 4 diopters). Thirty-eight of the 39 adults wear correcting lenses full-time. Nearly all depend on relaxed accommodation to maintain alignment when they remove their glasses. Ten patients, all of whom received treatment before a constant esotropia developed are essentially orthophoric with glasses and have normal binocular vision. The remainder have small-angle deviations with glasses, 14 with varying degrees of amblyopia and peripheral fusion and 15 with anomalous correspondence and suppression. As adults, only one patient with normal binocular function has required surgery whereas 13 of the patients lacking normal fusion have had surgery for increasing esotropia, postoperative exotropia, or consecutive exotropia.     

Strabismus and binocular function in children with Down syndrome. A population-based, longitudinal study

PURPOSE: We have performed a population-based, longitudinal study on strabismus in children with Down syndrome. The aims of the study were to examine the frequency and type of strabismus, the age at onset, and the binocular potential. METHODS: An unselected population of 60 children with Down syndrome born 1988-1999 was followed with repeated examinations. Mean follow-up time was 55+/-23 months (range 24--115). The alignment of the eyes was examined using Hirschberg corneal reflex test and cover test for near fixation. To evaluate binocular function, Titmus House Fly Test and Lang's stereo test were used. RESULTS: Twenty-five patients (42%) had strabismus (21 esotropias, two exodeviations and two vertical deviations). Only one case of infantile esotropia was found, the other esotropias were acquired forms. The mean age at "onset" (e.g. when strabismus was first noticed) was 54+/-35 months. In the acquired esotropia group (n=20), 15 (75%) were associated with hypermetropia (mean spherical equivalent +4.3+/-1.7 D). Seventeen of the strabismic patients had an accommodation weakness. Eleven of the strabismus patients gave a clearly positive response to one or both stereotests. CONCLUSIONS: The majority of the Down syndrome children with strabismus have an acquired esotropia and hence a potential for binocularity. Hypermetropia and accommodation weakness are probably important factors in esotropia in Down syndrome patients.     

Acquired nonaccommodative esotropia in childhood.

PURPOSE: Acquired nonaccommodative esotropia (ANAET) in childhood is reported to occur infrequently and is often associated with an underlying neurologic or neoplastic disorder. The primary objective of this study was to ascertain the prevalence and clinical characteristics of this form of childhood esotropia. METHODS: A cohort of all children younger than 11 years with esotropia from a predominantly rural Appalachian region was prospectively identified from August 1, 1995, through July 31, 1998. The age at onset, family history of strabismus, perinatal and medical history, ophthalmologic findings, and surgical results were reviewed for all patients with ANAET. RESULTS: Twenty-three (10.4%) of 221 consecutive children with esotropia were diagnosed with ANAET compared with 12 (5.4%) diagnosed with congenital esotropia. The median age at esotropia onset for the 23 children with ANAET was 31.4 months (range, 8-63 months) with a mean initial angle of esotropia of 24 PD. Although at least 2 children presented with diplopia, none of the 23 patients were known to have harbored intracranial tumors or other lesions of the central nervous system during the follow-up period. Fourteen of the 19 patients who underwent surgery attended follow-up visits for at least 6 months after their last surgical procedure: 13 were within 8 PD or less of orthotropia, whereas the final patient had persistent esotropia. Twelve of the 13 patients within 8 PD of orthotropia demonstrated some level of stereopsis, including 2 children with bifoveal fixation. Two (10.5 %) of the 19 operated patients later required a low hyperopic spectacle correction to control their deviation. CONCLUSIONS: ANAET was more prevalent than congenital esotropia in this cohort of children with esotropia. This clinically distinct form of strabismus typically begins between 1 and 5 years of age and appears to be infrequently associated with underlying disease. The angle of deviation is relatively small and early surgical correction is more likely to achieve bifoveal fixation for these patients than for those with congenital esotropia.     

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.