Visual acuity, amblyopia, and ocular pathology in 12- to 13-year-old children in Northern Mexico.

PURPOSE: The aim of this study was to establish visual acuity (VA) and the prevalence of amblyopia and other ocular disorders in a population of 12- to 13-year-old children in Mexico who have not been vision screened. METHODS: A total of 1,035 12- to 13-year-old children were examined in a field study. The examination included VA, stereopsis, cover testing, refractive retinoscopy, and examination of the red reflex and posterior pole. In cases with unexplained subnormal VA, visually evoked potential/visually evoked response was also performed. RESULTS: A >or=20/20 in at least one eye was found in 93% of the subjects. Bilateral VA 相似文献   

Visual screening of Swedish children: an ophthalmological evaluation

PURPOSE: This study describes the various ophthalmological conditions detected in the Swedish visual screening program for children. METHODS: The study was longitudinal and retrospective. All children (3126) born in 1982 in three Swedish municipalities have been followed from birth to ten years of age. Visual acuity was examined at the ages of 4, 5.5, 7 and 10 years. Before the age of 4, a gross examination of the eyes was performed. RESULTS: The prevalence of ametropia in the population was 7.7%, the prevalence of strabismus 3.1%, and the prevalence of organic lesions 0.6%. Seven children (0.2%) were visually handicapped (visual acuity 相似文献   

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.     

Amblyopia screening for first and second-grade children in Jordan

AIM: To share the results of a national screening program for amblyopia in school children in the north of Jordan. METHODS: This is a prospective national screening study for amblyopia. The program rolls first and second-grade children (6 to 7 years old) in the north of Jordan. The eye examination included: best-corrected visual acuity, cover-uncover test, and cycloplegic retinoscopy. Monocular visual acuity was tested using an ETDRS visual acuity chart without correction. Moreover, children were tested with full cycloplegic refraction when the test criteria were met. Unilateral amblyopia was defined as a best-corrected visual acuity difference of 2 or more lines. In comparison, bilateral amblyopia was defined as a best-corrected visual acuity of 20/40 or worse in the best eye. RESULTS: The prevalence of amblyopia for the total sample tested (n=17 203) was 2.78% (n=479). The most common cause of amblyopia was hypermetropia (64.45%), followed by previous ocular surgeries (15.1%), myopia (10.43%), strabismus (9.39%), and congenital cataract (0.63%). CONCLUSION: This is the first and only study, identi?ng modifiable risk factors in Jordanian children with amblyopia. In their first couple of years of elementary education, many Jordanian children are affected by amblyopia and pass unnoticed. A more governmental effort is needed into screening programs to improve vision in the Jordanian population.     

Amblyopia and binocular vision

Amblyopia is the most common cause of monocular visual loss in children, affecting 1.3%–3.6% of children. Current treatments are effective in reducing the visual acuity deficit but many amblyopic individuals are left with residual visual acuity deficits, ocular motor abnormalities, deficient fine motor skills, and risk for recurrent amblyopia. Using a combination of psychophysical, electrophysiological, imaging, risk factor analysis, and fine motor skill assessment, the primary role of binocular dysfunction in the genesis of amblyopia and the constellation of visual and motor deficits that accompany the visual acuity deficit has been identified. These findings motivated us to evaluate a new, binocular approach to amblyopia treatment with the goals of reducing or eliminating residual and recurrent amblyopia and of improving the deficient ocular motor function and fine motor skills that accompany amblyopia.     

Screening for amblyopia and strabismus with the Lang II stereo card

PURPOSE: To evaluate the effectiveness of the Lang II stereo card as a screening test for amblyopia and/or strabismus. METHODS: A total of 1046 children aged 12-13 years were examined in a field study in the G?teborg area, Sweden. In addition to the Lang II stereo card, the examination included visual acuity, cover testing, cycloplegic refraction, and inspection of the optical media and posterior pole. RESULTS: If every incorrect subject response was considered a reason for referral, the Lang II test would have correctly identified 82% (23 subjects) of the 28 children with manifest strabismus and 38% (11 subjects) of the 29 children with amblyopia. The test failed to refer 45% (21 subjects). Of all subjects referred, 44 (63%) were found to be ophthalmologically normal. CONCLUSIONS: The Lang II stereo card is neither a reliable nor an efficient method of screening for amblyopia and/or strabismus.     

Subnormal visual acuity syndromes (SVAS): albinism in Swedish 12-13-year-old children

BACKGROUND: The vision of 12-13-year-olds in Sweden was examined in a field study. The study was designed as being a part of a large European-Latin American study, the DESAMI project. The objective was to evaluate the prevalence of residual amblyopia and ocular disorders, aetiologies of subnormal vision and some normal visual parameters in this group of children. The children had to be born in Sweden in 1985 in order to have the opportunity to be included in the voluntary screening visual examinations. The full results of the study will be presented elsewhere. This paper presents clinical and VEP data of those children who had visual acuity of 0.8 or below in one or both eyes which could not be increased with glasses, or other visual/eye disturbances not explained as common amblyopia, i.e., subnormal visual acuity or pathological visual states of unknown cause, SVAS (subnormal visual acuity syndromes). SUBJECTS AND METHODS: In all, 1046 children were examined: 76 had visual disturbances of such severity that they were referred to a paediatric ophthalmologist (AS). Eighteen children could not be pathologically classified, and they were referred to another ophthalmological examination and VEP (visual evoked potential) recordings. VEP reveals an asymmetric response after monocular stimulation in albinism. RESULTS: Twelve children turned up for a second examination and VEP was recorded from 10 children. Nine children showed iris translucency. Seven children showed an asymmetric VEP and were classified as albinos. The albinoic VEPs could be subdivided into two types, (1) including all parts of the response and (2) partly excluding the P1/P100 potential complex. The VEP response was normal, showing symmetry and no other abnormality, in three of the children. CONCLUSIONS: The results indicate that albinism is common in Sweden. A prevalence value of approximately 1% is about 100 times higher than previous figures. This high prevalence may indicate another form of heredity, with genetical contribution to albinism from a varying number of albino genes and varying expression in the phenotypes, in the Scandinavian population. It is emphasised that in investigations of children with SVAS, electrophysiological examinations are important, not only to reveal albinism but also to exclude or verify neurometabolic conditions, for example.     

Subnormal visual acuity syndromes (SVAS): albinism in Swedish 12-13-year-old children

BACKGROUND: The vision of 12-13-year-olds in Sweden was examined in a field study. The study was designed as being a part of a large European-Latin American study, the DESAMI project. The objective was to evaluate the prevalence of residual amblyopia and ocular disorders, atiologies of subnormal vision and some normal visual parameters in this group of children. The children had to be born in Sweden in 1985 in order to have the opportunity to be included in the voluntary screening visual examinations. The full results of the study will be presented elsewhere. This paper presents clinical and VEP data of those children who had visual acuity of 0.8 or below in one or both eyes which could not be increased with glasses, or other visual/eye disturbances not explained as common amblyopia, i.e., subnormal visual acuity or pathological visual states of unknown cause, SVAS (subnormal visual acuity syndromes). SUBJECTS AND METHODS: In all, 1046 children were examined: 76 had visual disturbances of such severity that they were referred to a paediatric ophthalmologist (AS). Eighteen children could not be pathologically classified, and they were referred to another ophthalmological examination and VEP (visual evoked potential) recordings. VEP reveals an asymmetric response after monocular stimulation in albinism. RESULTS: Twelve children turned up for a second examination and VEP was recorded from 10 children. Nine children showed iris translucency. Seven children showed an asymmetric VEP and were classified as albinos. The albinoic VEPs could be subdivided into two types, (1) including all parts of the response and (2) partly excluding the P1/P100 potential complex. The VEP response was normal, showing symmetry and no other abnormality, in three of the children. CONCLUSIONS: The results indicate that albinism is common in Sweden. A prevalence value of approximately 1% is about 100 times higher than previous figures. This high prevalence may indicate another form of heredity, with genetical contribution to albinism from a varying number of albino genes and varying expression in the phenotypes, in the Scandinavian population. It is emphasised that in investigations of children with SVAS, electrophysiological examinations are important, not only to reveal albinism but also to exclude or verify neurometabolic conditions, for example.     

Early screening for amblyogenic risk factors lowers the prevalence and severity of amblyopia.

PURPOSE: To evaluate the efficacy of a mass screening program for amblyopia and amblyogenic risk factors in infants. METHODS: Since 1968, children between the ages of 1 and 2(1/2) years in the city of Haifa, Israel, have been systematically screened for amblyopia and amblyogenic risk factors. The screening is performed by the Ophthalmology Department of Bnai-Zion Medical Center (formerly known as Rothchild Hospital). In 1995, we compared the prevalence and severity of amblyopia in two populations of 8-year-old children in elementary school: one group was a cohort of 808 children from the city of Haifa and its vicinity, who had been screened in infancy (between 1988 and 1990); and the second group, the control group, was a cohort of 782 children from Hadera and its vicinity, where this early screening program is not conducted. Amblyopia was defined as corrected visual acuity of < or =5/10 (20/40), or >1 line difference in corrected visual acuity between the two eyes. Referral rate, treatment rate, sensitivity, specificity, and positive predictive value and negative predictive value of the screening test in detecting factors that later resulted in the development of amblyopia were examined. RESULTS: The prevalence of amblyopia in the 8-year-old population screened in infancy was found to be 1.0% compared with 2.6% in the 8-year-old population that had not been screened in infancy (P =.0098). The prevalence of amblyopia with visual acuity of < or =5/15 (20/60) in the amblyopic eye was 0.1% in the screened population compared with 1.7% in the non-screened population (P =.00026). In the screened infant population, 3.6% were referred from the screening examination to a confirmatory examination and 2.2% were treated. The screening examination had a sensitivity of 85.7% and a specificity of 98.6% for amblyopia. The positive predictive value of the screening examination was 62.1% and the negative predictive value was 99.6%. CONCLUSIONS: The screening program for amblyopia and amblyogenic risk factors in infants, followed by appropriate treatment, is effective in significantly reducing the prevalence and severity of amblyopia in children.     

Isoametropic amblyopia due to high hyperopia in children.

PURPOSE: To identify children with isoametropic amblyopia due to moderate to high hyperopia and evaluate associated findings and visual acuity outcome. METHODS: Charts from two university's pediatric ophthalmology clinics were reviewed retrospectively. Healthy children with > or = +4.5 D spherical equivalent who did not have anisometropia > or = 1.5 D were selected for data collection. The charts of qualifying children with bilateral amblyopia (visual acuity of 20/40 or less) were further analyzed. RESULTS: Identified were 418 children with the above set of criteria for hyperopia; 36 of these children had isoametropic amblyopia (bilateral amblyopia). This gives an estimated prevalence of isoametropic amblyopia of 8.6% in children with at least 4.5 D of hyperopia in one or both eyes. The children with isoametropic amblyopia presented at a later age (5 years, 1 month) than the overall group of hyperopes (3 years, 5 months). Strabismus was less prevalent in this group (64%) than in the entire population of children with high hyperopia (81%). These children's amblyopia responded well to treatment with glasses, and patching in 13 (36%) cases. Surgical intervention for residual strabismus was necessary in very few cases (2 of 36, 5.5%). CONCLUSION: Children with hyperopia > or = 4.5 D have an increased risk of amblyopia and strabismus that further threatens their future visual function. Isoametropic amblyopia is a real risk in these children. Based on these results, hyperopic correction should be prescribed for children with > or = 4.5 D of hyperopia even if no strabismus or fixation preference is detected, to reduce this risk. Screening programs should also be in place to identify these children at an early age.     

Visual results in children treated for macular retinoblastoma

PURPOSE: To evaluate the results of patching treatment in children with macular retinoblastoma in one eye. METHODS: Fifteen children affected by macular retinoblastoma received instructions for patching treatment for amblyopia. Data were collected on age at diagnosis of the tumor, presence of unilateral or bilateral disease, area of posterior pole involvement by the scar of the regressed tumor and its relationship to the fovea; and the onset, duration, and compliance of patching. The visual acuities recorded were expressed in logMAR (logarithm minimum angle of resolution) equivalents. RESULTS: Twelve children (80%) had bilateral retinoblastoma with the macular involved in one eye and three children had unilateral macular tumors. The median age at which patching was initiated was 15 months (range 4-36). Compliance to patching was good in 80% of children, with a median duration of 4 h (range 0.5-8) per day, 7 days per week, with total occlusion of the better eye. The median percentage of posterior pole involvement was 34% (range 11-100%). Eighty percent of children had some improvement in their visual acuity, and of the children in whom final logMAR acuity was recorded, 73% had an acuity of 1.0 logMAR or better and 53% an acuity of 0.5 logMAR or better after patching. There was no evidence of association between age of patient, sex, duration of patching, or percentage of posterior pole involvement and the improvement in visual acuity. CONCLUSIONS: In spite of the macular involvement of eyes with retinoblastoma, some visual recovery was achieved in 80% of children. Hence a trial of patching therapy is recommended for all children with involvement of the macula by retinoblastoma.     

Risk of visual impairment in children with congenital toxoplasmic retinochoroiditis

PURPOSE: Reliable information is needed to counsel parents of children with congenital toxoplasmosis regarding the long-term risk of visual impairment resulting from ocular toxoplasmosis. DESIGN: Prospective cohort study of children with congenital toxoplasmosis identified by prenatal or neonatal screening. METHODS: After three years of age, ophthalmologists reported the site of retinochoroidal lesions and visual acuity and parents reported visual impairment. An ophthalmologist predicted the child's vision based on the last retinal diagram. Selection biases were minimized by prospective enrollment and data collection, high rates of follow-up, and exclusion of referred cases. RESULTS: Two hundred and eighty-one of 284 infected children who underwent ophthalmic examinations were followed up to a median age of 4.8 years. One in six children (49/281; 17%) had at least one retinochoroidal lesion, two-thirds of whom (32/49; 65%) had a lesion at the posterior pole. In children with retinochoroiditis who had visual acuity measured after 3 years of age, 94% (31/33) had normal vision in the best eye (6/12 Snellen or better), as did 91% of those with a posterior pole lesion (21/23). Analyses based on affected eyes showed that 42% (29/69) had a posterior pole lesion, of which just more than half (15/29, 52%) had normal vision, as did 84% (16/19) of eyes with a peripheral lesion alone. Vision predicted by the ophthalmologist was moderately sensitive (59%) but overestimated impairment associated with posterior pole lesions. Of 44 children with information on acuity, four (9%) had bilateral visual impairment worse than 6/12 Snellen. CONCLUSIONS: Severe bilateral impairment occurred in 9% of children with congenital toxoplasmic retinochoroiditis. Half the children with a posterior pole lesion and one in six of those with peripheral lesions alone were visually impaired in the affected eye.     

The polaroid suppression test in a pediatric population with ophthalmologic disorders.

PURPOSE: The Polaroid suppression test (PST) is a new method for early detection of amblyogenic factors by screening for suppression. The apparatus can elicit suppression with the use of Polaroid filters. The aim of the present study was to examine a population of children with known ophthalmologic disorders using the PST to determine the rate of false-negative results of the PST. METHODS: Six hundred four children, varying in age between 3 and 15 years (mean, 7.9) were examined using the PST. Ophthalmologic disorders ranged from strabismus and amblyopia to refractive disorders. RESULTS: Mean testing time for the PST was 43 seconds. The PST could not be administered to 34 children (5.6%); 443 children (73.3%) had abnormal results; and 127 children (22.2%) showed no suppression. The suppression in constant strabismus was detected in almost all cases. The sensitivity for accommodative forms of strabismus was lower, but amblyopia was never missed in these cases. In children with normal eye alignment, only 2.7% with an interocular acuity difference of more than 0.1 logMAR had no suppression. Of all 119 children with clinical defined amblyopia, only 1 (0.8%) did not have suppression. Overall sensitivity of the PST for strabismus and/or abnormal interocular acuity difference was 96.2% and specificity was 41.1%. CONCLUSIONS: The PST has great potential as a visual screening tool in young children. Only few children with amblyogenic factors were missed. Thus, the test can differentiate those children at risk for amblyopia from normally sighted children. Because specificity is lower, all children showing suppression with the PST in a screening situation should have further examination by the health care worker before being referred to the ophthalmologist.     

早产对无早产儿视网膜病变的早产儿眼发育和发病的影响

目的调查无早产儿视网膜病变（ROP）的学龄前和学龄期早产儿的眼球发育和发病率。方法对26名5～7岁无ROP的早产儿童进行全面的眼科检查,包括矫正视力、散瞳验光、色觉以及眼前后段检查。测量数据包括前房深度、晶体厚度、玻璃体长度和眼轴长度。结果早产儿视力和屈光状态之间没有相关性。2名（7.7%）有斜视,2名（7.7%）有弱视,3名（11.5%）有屈光参差。眼轴长与胎龄（r=0.822,P〈0.001）和胎重（r=0.569,P=0.003）有相关性,玻璃体长度与胎龄（r=0.744,P〈0.001）和胎重（r=0.553,P=0.004）有相关性。讨论本研究显示眼球的增长是因为胎龄和胎重增加,但这种情况不会导致明显的屈光不正。通过文献对比,无ROP的早产儿童的斜视、弱视和屈光参差的发病率要明显高于同年龄段的正常儿童。     

Reduction of deviation angle during occlusion therapy: in partially accommodative esotropia with moderate amblyopia

PURPOSE: To evaluate changes in ocular alignment in partially accommodative esotropic children age ranged from 3 to 8 years during occlusion therapy for amblyopia. METHODS: Angle measurements of twenty-two partially accommodative esotropic patients with moderate amblyopia were evaluated before and at 2 years after occlusion therapy. RESULTS: Mean deviation angle with glasses at the start of occlusion treatment was 19.45+/-5.97 PD and decreased to 12.14+/-12.96 PD at 2 years after occlusion therapy (p<0.01). After occlusion therapy, 9 (41%) cases were indications of surgery for residual deviation but if we had planned surgery before occlusion treatment, 18 (82%) of patients would have had surgery. There was a statistical relationship between increase of visual acuity ratio and decrease of deviation angle (r=-0.479, p=0.024). CONCLUSIONS: There was a significant reduction of deviation angle of partially accommodative esotropic patients at 2 years after occlusion therapy. Our results suggest that occlusion therapy has an influence on ocular alignment in partially accommodative esotropic patients with amblyopia.     

Loss of visual acuity due to eye injuries among 6292 school children in the Sultanate of Oman

PURPOSE: In 1992-94 a nation-wide survey in primary schools in the Sultanate of Oman for ocular disorders was conducted. This report focuses on the prevalence of visual acuity loss after injury. METHODS AND MATERIAL: A random selection of 6,292 children from Grades 1 and 6 from all primary schools in the country provided the research sample. Children who failed the visual acuity screening test received a complete "on the spot" eye examination by the pediatric ophthalmologist. Results: 12 children were found to have monocular low vision (VA <0.3 to amaurosis) caused by injury. Total prevalence for loss of vision in one eye was 0.19%, with 0.15% in 6-year-olds and 0.25% in 12-year-olds Traumatic cataracts were noted in 4 children, 3 of these were in need of surgery. One child had aphakia after trauma surgery and needed a secondary lens implant. CONCLUSION: Altogether the prevalence of traumatic monocular visual damage in our study was 0.19%. Next to amblyopia, injury is the main reason for monocular loss of vision in childhood, however, both are preventable. Information about trauma prevention and the need for adequate ophthalmic care should be emphasized. Regular and repeated screening of visual acuity in children is essential.     

Change in vision disorders among Hong Kong preschoolers in 10 years

Background: To determine the change in refractive error and the prevalence of amblyopia and strabismus among preschool children in Hong Kong over a period of 10 years. Design: Two cross‐sectional population‐based studies conducted in 1996 to 1997 (part A) and 2006 to 2007 (part B) Participants: Children attending randomly selected kindergarten participated in the study. Methods: Ocular alignment, visual acuity, cover and uncover tests, cycloplegic refraction, slit‐lamp and fundi examination were performed under a standardized testing environment. Main Outcome Measures: The prevalence of amblyopia (best‐corrected visual acuity ≤6/12 in one or both eyes, or a bilateral difference of ≥2 best‐corrected visual acuity lines), strabismus and significant refractive error (hyperopia ≥+2.50 D; myopia ≥?1.00 D; astigmatism ≥2.00 D) among preschool children. Results: Of the 601 children in part A of the study, reduced visual acuity was presented in 3.8%; whereas strabismus was found in 1.8%. The commonest type of refractive error was astigmatism in 6.3% of children, followed by hyperopia (5.8%) and myopia (2.3%). Among 823 children in part B, reduced visual acuity was presented in 2.7% of children, and strabismus was found in 1.7%. The commonest type of refractive error was myopia (6.3%), followed by astigmatism (5.7%) and hyperopia (5.1%). The percentage of children having myopia has significantly increased (P = 0.001). Conclusion: A significant increase in myopia has been noted in Hong Kong preschoolers. Visual screening programmes may need to be tailored to correspond to the local population and be adjusted accordingly from time to time.     

Ocular alterations associated with bungee jumping: case report

The popularization of bungee jumping is causing an increase in occurrences of lesions associated with its practice, including ocular lesions. The purpose of this study is to describe a case of acute decrease in vision and visual field defects following a bungee jump. The authors present a case of a 48-year-old woman, without history of systemic or ocular disorders, seen at an ophthalmologic emergency service with visual loss complaint following a bungee jump. On initial ophthalmologic evaluation, hemorrhages in the posterior pole of both eyes were found. Fluorescein angiography showed hypofluorescent areas, without other vascular alterations. The patient was evaluated after 14 weeks, the hemorrhages cleared up and there was atrophy of the pigmented epithelium of the retina in the posterior pole, but the patient remained with complaint of scotoma and visual field defects even 5 months after the initial event. The occurrence of body lesions, including ocular lesions, with risk of decrease in visual acuity should be informed to candidates for the practice of this sport, and the ophthalmologist would do well to provide information to the population about possible ocular disorders, in this sport and in daily life.     

Screening merits of the Lang II, Frisby, Randot, Titmus, and TNO stereo tests.

PURPOSE: Previous works show a pronounced disagreement on the reliability of stereo tests as screening tools for amblyopia and strabismus. This study's aim was to compare the ability of the Lang II, Frisby, Randot, Titmus, and TNO stereo tests to detect amblyopia and strabismus with visual acuity testing and cover testing. METHODS: A total of 1035 school children aged 12 to 13 years were examined in a field study in Monterrey, Mexico. In addition to the 5 stereo tests, the examination included visual acuity, cover testing, refraction (skiascopy), and inspection of the red reflex and posterior pole. RESULTS: Sensitivity ranged from 17% to 47% (Frisby-Titmus-Lang II-Randot-TNO, in order of occurrence). Of the 60 subjects with strabismus and/or amblyopia, only 8 subjects were identified by all 5 stereo tests. A considerable number of subjects (25), the majority of whom were amblyopic (23 subjects), were not identified by any of the tests. All stereo tests showed higher sensitivities for strabismus than for amblyopia. CONCLUSION: None of the 5 stereo tests studied is suitable for screening for amblyopia or strabismus. The results of both ocularly normal subjects and subjects with strabismus and/or amblyopia are variable, and there is no way of separating normal response from abnormal response.     

The multi-ethnic pediatric eye disease study: design and methods

PURPOSE: To summarize the study design of the Multi-Ethnic Pediatric Eye Disease Study (MEPEDS). METHODS: The objectives of the MEPEDS are to: (1) estimate age- and ethnicity-specific prevalence of strabismus, amblyopia, and refractive error; (2) evaluate the association of selected risk factors with these ocular disorders; and (3) evaluate the association of ocular conditions on limitations in health-related functional status in a population-based sample of 12,000 children aged 6-72 months from four ethnic groups--African-American, Asian-American, Hispanics/Latinos and non-Hispanic White. Each eligible child undergoes an eye examination, which includes an interview with his/her parent. The interview includes an assessment of demographic, behavioral, biological, and ocular risk factors and health-related functional status. The examination includes fixation preference testing, visual acuity, stereoacuity, axial length measurement, cycloplegic refraction, keratometry, eye alignment, and anterior and posterior segment examination.