Detection of Strabismus by Non-Health Care Professionals in an Ethnically Diverse Set of Images.

IMPORTANCE: Understanding the criteria for when strabismus becomes detectable by non-health care professionals could influence the goals for determining the success of surgical intervention and how patients with such misalignments are counseled. OBJECTIVE: To examine the magnitude at which strabismus is detectable by lay observers in an ethnically diverse set of images. DESIGN, SETTING, AND PARTICIPANTS: Photographs of 12 ethnically diverse models (black, white, and Asian) were simulated to have strabismus from esotropia of 21 prism diopters (∆) to exotropia of 21∆. From July 1, 2007, to October, 1, 2008, images were presented to 120 non-health care professionals aged 21 years or older from the general community in Boston, Massachusetts, who were asked whether strabismus was present. Analysis was conducted from November 1, 2008, to March 31, 2009. MAIN OUTCOMES AND MEASURES: The threshold angle for detecting strabismus to enable 70% of lay observers to make a positive determination whether strabismus is present. RESULTS: In white and black models, the threshold allowing a 70% positive detection rate was higher for esotropia than for exotropia (P < .001 for both). For white models, the threshold was 23.2∆ (95% CI, 21.0∆ to 26.5∆) for esotropia and 13.5∆ (95% CI, 12.5∆ to 14.6∆) for exotropia. For black models, the threshold was 20.8∆ (95% CI, 19.2∆ to 22.2∆) for esotropia and 16.3∆ (95% CI, 15.5∆ to 17.2∆) for exotropia. Asian models showed an opposite trend, with the threshold allowing a 70% positive detection rate for esotropia (14.3∆; 95% CI, 13.2∆ to 15.7∆) being lower than that for exotropia (20.9∆; 95% CI, 18.0∆ to 24.6∆) (P < .001). CONCLUSIONS AND RELEVANCE: Esotropia was easier for lay observers to detect than exotropia in Asian models, and exotropia was easier to detect than esotropia in white and black models. This information should be considered when managing patients who have concerns about the social significance of their strabismus. Future studies should include diverse individuals and make an effort to account for individual factors that may alter the perception of strabismus.

Comitant horizontal strabismus in South African black and mixed race children--a clinic-based study.

PURPOSE: To examine the types of comitant horizontal strabismus in children belonging to the two largest ethnic groups of the Western Cape, South Africa. METHODS: Retrospective review of 2371 children presenting with comitant horizontal strabismus to a single, large, pediatric tertiary referral center in Cape Town, South Africa, between 1997 and 2007. RESULTS: 81% of children were of mixed race and 19% were black. The overall esotropia:exotropia ratio was 73:27. For black children this was 85:15 and for mixed race, 71:29. The overwhelming majority of black children had congenital esotropias (74%), whereas accommodative esotropia was rare (9%). In mixed race children, esotopias were more equally divided between congenital (46%) and accommodative types (35%). Exotropias were uncommon in black children, and were mainly constant (61%). Intermittent exotropias predominated in mixed race children (55%). CONCLUSION: Congenital esotropia remains common in South African black children, and of the few who presented with exotropia, most had constant type. Accommodative esotropias were more prevalent in South African mixed race children, but in smaller proportions than in other studies. Exotropias were mostly intermittent in this ethnic group, and showed a similar profile to that in white American children.

Characteristics of divergence excess type intermittent exotropia in Asian children.

BACKGROUND: Exotropia is twice as common as esotropia in Asian children, with divergence excess intermittent exotropia contributing more than one half of exotropia cases. In this study, distance-near relationships and ratios of accommodative convergence to accommodation (AC/A) are compared using different measurement methods in Asian children with divergence excess intermittent exotropia. METHODS: Children with intermittent exotropia and a distance deviation exceeding the near by at least 10(Δ) were consecutively recruited. After prism cover test measurements at 6 m and 33 cm, AC/A ratios were calculated using the heterophoria method and the gradient method with -2.0 D and +3.0 D lenses at 6 m and 33 cm, respectively. AC/A ratios were recalculated after 1 hour of monocular patching. RESULTS: A total of 42 children (mean age, 6.9 years; range, 3-16 years) were included. The mean difference between distance and near deviation was 22(Δ) before occlusion and 14(Δ) after (P < 0.001). Approximately one third had a distance-near difference <10(Δ) after occlusion. With the heterophoria method, 100% of patients had high AC/A ratios before occlusion, with 71% continuing to have high AC/A ratios after. With the gradient method, 52% of patients had high AC/A ratios before occlusion, with 68% of this subgroup continuing to have high AC/A ratios after. CONCLUSIONS: Pseudo-divergence excess was found in one third of the subjects. More children were diagnosed with high AC/A ratios using the heterophoria method than with the gradient method. Without monocular occlusion, approximately one third of the children with normal AC/A ratios may be mistaken to have high AC/A ratios when measured with either method. Identification of high AC/A ratio exotropic patients is critical due to the risk of developing consecutive esotropia at near after strabismus surgery.

Risk factors associated with childhood strabismus: the multi-ethnic pediatric eye disease and Baltimore pediatric eye disease studies.

OBJECTIVE: To investigate risk factors associated with esotropia or exotropia in infants and young children. DESIGN: Population-based cross-sectional prevalence study. PARTICIPANTS: Population-based samples of 9970 children 6 to 72 months of age from California and Maryland. METHODS: Participants were preschool African-American, Hispanic, and non-Hispanic white children participating in the Multi-Ethnic Pediatric Eye Disease Study and the Baltimore Eye Disease Study. Data were obtained by parental interview and ocular examination. Odd ratios and 95% confidence intervals were calculated to evaluate the association of demographic, behavioral, and clinical risk factors with esotropia and exotropia. MAIN OUTCOME MEASURES: Odds ratios (ORs) for various risk factors associated with esotropia or exotropia diagnosis based on cover testing. RESULTS: In multivariate logistic regression analysis, esotropia was associated independently with prematurity, maternal smoking during pregnancy, older preschool age (48-72 months), anisometropia, and hyperopia. There was a severity-dependent association of hyperopia with the prevalence of esotropia, with ORs increasing from 6.4 for 2.00 diopters (D) to less than 3.00 D of hyperopia, to 122.0 for 5.00 D or more of hyperopia. Exotropia was associated with prematurity, maternal smoking during pregnancy, family history of strabismus, female sex, astigmatism (OR, 2.5 for 1.50 to <2.50 D of astigmatism, and 5.9 for ≥2.5 D of astigmatism), and anisoastigmatism in the J0 component (OR, ≥2 for J0 anisoastigmatism of ≥0.25 D). CONCLUSIONS: Prematurity and maternal smoking during pregnancy are associated with a higher risk of having esotropia and exotropia. Refractive error is associated in a severity-dependent manner to the prevalence of esotropia and exotropia. Because refractive error is correctable, these risk associations should be considered when developing guidelines for the screening and management of refractive error in infants and young children. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Evidence for frequent divergence impairment in French dyslexic children: deficit of convergence relaxation or of divergence per se?

AIM: There is a controversy as to whether dyslexic children present visuo-motor disabilities such as vergence and accommodative problems assessed with orthoptic tests. The purpose of this study is to re-examine this issue in a large population of children. METHODS: Extensive orthoptic evaluation was made in 57 dyslexic and 46 non-dyslexic ("normal") age-matched children. Convergence and divergence capacities were evaluated at two distances (30 cm and 400 cm). RESULTS: Binocular vision measured with stereo-acuity tests was normal in dyslexics. In contrast, the near point of convergence was significantly more remote in dyslexics; most importantly, divergence at both far and near distance was significantly more reduced in dyslexics (median value 4 pD and 10 pD, respectively, at far and near) than in "normals" (median value 6 pD and 12 pD, at far and near). CONCLUSION: The existence of the divergence deficit at far distance indicates the presence of deficit of divergence per se, independently from convergence and accommodation relaxation. This result is novel and corroborated by physiological studies indicating distinct control of convergence and divergence, both at the cortical and subcortical premotor level. We conclude that vergence deficits are frequently present in dyslexics, and that dyslexics should be re-educated; training should address distinctively convergence and divergence subsystems.

Risk factors for esotropia and exotropia.

OBJECTIVE: To identify risk factors associated with the two major types of strabismus--esotropia and exotropia--in a cohort of children followed up from gestation to age 7 years. DESIGN: Pregnant women were enrolled in the Collaborative Project of the National Institute of Neurological Disorders and Stroke, Bethesda, Md, from 1959 to 1965 at 12 university centers. This large multidisciplinary study was designed to evaluate the developmental consequences of complications during pregnancy and the perinatal period. Data on maternal, socioeconomic, perinatal, and neonatal characteristics were collected from 39,227 children and their mothers by medical examination and interview. Examinations of the children were performed at birth, 4 months, 8 months, 1 year, and 7 years. OUTCOME MEASURES: The evaluation of the presence of strabismus was performed during follow-up examinations and confirmed at the 7-year follow-up visit. Potential risk factors for strabismus were evaluated from the maternal, socioeconomic, perinatal, and neonatal characteristics. RESULTS: Esotropia developed in 1187 children (3.0%), and exotropia developed in 490 children (1.2%). Esotropia was more common in whites (3.9% in whites vs 2.2% in blacks, P < .0001). The occurrence of exotropia was similar in the two races (1.2% in whites and 1.3% in blacks). Results of multivariable logistic regression models showed that the risk of strabismus increased with low birth weight (P < .0001). For infants weighing 1500 g at birth compared with those weighing 4000 g at birth, the odd ratios were 3.26 (95% confidence interval, 2.50 to 4.25) for esotropia and 4.01 (95% confidence interval, 2.77 to 5.80) for exotropia. Maternal cigarette smoking during pregnancy also increased the risk of each type of strabismus (P < .0001). For offspring of mothers who smoked more than two packs of cigarettes per day compared with those whose mothers did not smoke, the odds ratios were 1.83 (95% confidence interval, 1.51 to 2.22) for esotropia and 2.32 (95% confidence interval, 1.72 to 3.13) for exotropia. Maternal age was also a significant risk factor for esotropia (P = .0005). The risk of esotropia increased with increasing age until age 34 years. In particular, the odds ratio for mothers aged 30 to 34 years relative to that for mothers aged 20 to 24 years was 1.43 (95% confidence interval, 1.19 to 1.70). CONCLUSIONS: Esotropia was more common in whites than in blacks. The occurrence of exotropia was similar in the two races. Maternal cigarette smoking during pregnancy and low birth weight were independent and important risk factors for both esotropia and exotropia. There was an increased risk of esotropia with increasing maternal age.