Childhood Amblyopia Research Articles

Movement hyperacuity deficit in childhood amblyopia

Besides a loss in resolution acuity, amblyopia results in deficits in a number of visual functions in the amblyopic eye. We describe impairment in oscillatory movement displacement thresholds (OMDT) in childhood amblyopia. 50 subjects (aged 74 ± 16 months) with strabismic, anisometropic or mixed aetiology amblyopia were compared to a group of 24 age‐matched controls. Thresholds were demonstrated to be in the hyperacuity range and were not related to the visual acuity. OMDT was significantly reduced in the amblyopic eye compared to the dominant and control eyes (P < 0.05) only when no stereoscopic responses were demonstrated. When gross stereopsis was present, thresholds for the amblyopic eyes were comparable with both the dominant and control eyes. The results are discussed in terms of binocular competition and developmental anomaly.

Movement hyperacuity deficit in childhood amblyopia

Movement hyperacuity deficit in childhood amblyopia

Epidemiology of blindness and eye disease.

Introduction: historical aspects objectives of the study. Materials and methods: research strategy evaluation evolutionary trends classification of the causes of blindness determining the cause of blindness definitions of blindness material for studies on the number of blind and the causes of blindness, Results: blindness rate in Germany number of visually handicapped degree of disability demographics of the onset blindness sex distribution age distribution age at the onset of blindness duration of blindness macular degeneration as a cause of blindness diabetes mellitus as a cause of blindness cataract as a cause of blindness glaucoma as a cause of blindness high-grade myopia as a cause of blindness retinal detachment as a cause of blindness `tapetoretinal' degeneration (retinitis pigmentosa) as a cause of blindness optic atrophy (degeneration of the optic nerve) as a cause of blindness infections as causes of blindness disorders of the uvea as a cause of blindness injuries as a cause of blindness. Blindness in childhood: prevalence and incidence of childhood blindness bupthalmia as a cause of blindness congenital cataract as a cause of blindness malformation as causes of blindness retinopathy of prematurity as a cause of blindness amblyopia in childhood.

SKILL card results in amblyopic children.

Two experiments were undertaken to assess high contrast-high luminance (HCHL) and low contrast-low luminance (LCLL) visual acuity as measured with the Smith-Kettlewell Institute Low Luminance (SKILL) card, in childhood amblyopia. In experiment 1, HCHL and LCLL visual acuity was measured in 11 amblyopic children and in 12 normal children of similar age. The results revealed that HCHL visual acuity was similar in the normal eyes and in the amblyopes' dominant eyes, and was abnormal in 91% of the amblyopic eyes. LCLL visual acuity was significantly worse in normal eyes compared to the amblyopes' dominant eyes, and was abnormal in only 64% of the amblyopic eyes. In experiment 2, HCHL and LCLL visual acuity was measured in seven previously tested amblyopic children, after a 5-month interval, and in six additional amblyopic children. In the amblyopic children who were tested twice, significant test-retest reliability for HCHL and LCLL visual acuity was found and visual acuity varied by 3.6%. The results of experiment 2 corroborated the results of experiment 1 from the amblyopic children. It is concluded that visual acuity in the amblyopic eye tends to normalize under low contrast-low luminance conditions. In addition, the mechanism(s) underlying amblyopia appear also to influence the dominant eye, resulting in superior visual acuity under low contrast-low luminance conditions.

Levodopa and childhood amblyopia.

A pilot study was undertaken to address the tolerance and efficacy of levodopa/carbidopa treatment for amblyopia in older amblyopic children who failed to respond to conventional occlusion therapy. Five amblyopic children, between the ages of 7 and 12 years, and two normal adults were given between 100 mg/25 mg and 400 mg/100 mg of levodopa/carbidopa, respectively, depending on body weight. A symptoms questionnaire was completed, with temperature, respiration, heart rate, and blood pressure taken periodically to assess tolerance. Blood samples were taken, via a heparin well, to assess the pharmacokinetics of levodopa, dopamine, noradrenaline, and DOPAC. Snellen visual acuity, contrast sensitivity, stereo acuity, and pattern VERs were measured periodically to assess efficacy. The results revealed a high prevalence of side effects including emesis and nausea (four of seven subjects). Pharmacokinetics revealed that maximum serum levels of levodopa occurred 30 minutes to 1 hour after drug ingestion and decreased by 50% after 2 to 4 hours. One hour after drug ingestion, Snellen visual acuity temporarily improved from an average of 20/159 to 20/83 in the amblyopic eyes. Contrast sensitivity and pattern VERs (10-minute checks) temporarily improved in both dominant and amblyopic eyes, whereas visual function remained stable in normal eyes. The improvements in visual function started to decrease 5 hours after drug ingestion. The results are discussed in the context of developing a therapeutic trial of levodopa/carbidopa for childhood amblyopia.

Factors Associated With Delay in Diagnosis of Childhood Amblyopia

The prevention of permanent visual impairment from amblyopia is an important goal of pediatric vision screening. Unfortunately, many cases of amblyopia are not diagnosed until the child is too old to benefit maximally from treatment. A review of patient records from the practice of a private pediatric ophthalmologist confirmed that late detection is a frequent occurrence among children with amblyopia who have had good access to health care. A case-control study was then used to identify factors associated with delayed diagnosis, in which children with an adverse outcome (diagnosed at or after 5 years of age) were compared with those with an optimal outcome (diagnosed before 5 years of age). The chart review identified 161 children with amblyopia who participated in this study; 75 had late diagnoses (case patients) and 86 served as control patients. Children with early diagnoses more often had the following characteristics: a positive family history of strabismus, greater degrees of strabismus (when strabismus was present), higher maternal educational level, greater parental suspicion that an eye problem existed, and an increased chance that the parents requested the eye examination that led to the diagnosis. The parents of children with late diagnoses expressed less concern over the seriousness of amblyopia but were more likely to report that their children had suffered adverse consequences of amblyopia. When diagnosed early, amblyopia was more often detected by the child's primary health care provider. Physicians of the children with early diagnoses more often reported compliance with both the American Academy of Pediatrics guidelines for vision screening in infancy and referral for vision problems.(ABSTRACT TRUNCATED AT 250 WORDS)

The Contrast Sensitivity Function and Childhood Amblyopia

We measured contrast sensitivity function and visual acuity in both eyes of strabismic and anisometropic amblyopic patients. There was a linear relationship between contrast sensitivity function and visual acuity in the amblyopic eye. As visual acuity decreased, the contrast sensitivity function decreased along the contrast sensitivity axis, and peak sensitivity shifted to lower spatial frequencies. After patching therapy, when visual acuity reached 20/20 in each eye, suggesting that the amblyopia was cured, there continued to be statistically significant difference in the contrast sensitivity functions between the eyes. The contrast sensitivity function from the previously amblyopic eye was depressed compared to the nonamblyopic eye. A comparison between patients with strabismic and anisometropic amblyopia showed that, when matched for visual acuity, the contrast sensitivity functions were similar for both the nonamblyopic and amblyopic eyes. However, a large difference was found between the amblyopic and nonamblyopic eyes of each group.

Ophthalmic screening of 38,000 children, age 1 to 2 1/2 years, in child welfare clinics.

Screening of 38,000 infants, age 1 to 2 1/2 years, showed a prevalence of 1.3% of strabismus and 0.5% of strabismic amblyopia. Esotropia was more than three times as frequent as exotropia. Approximately half of the cases with esotropia were amblyopic. Eighty-one percent of the cases with exotropia were intermittent, and in 29% the V-pattern was found. Significant ametropia was found in over 50% of the cases with strabismus. Although hypermetropia was the most frequent refraction in children with esotropia, myopia was a frequent finding in both esotropia and exotropia. Anisometroia was particularly frequent in constant unilateral esotropia. Accommodative strabismus was found in 7% of cases with infantile esotropia. In cases with paralytic strabismus, the most frequent muscle involved was the lateral rectus. Significant organic pathology, other than strabismus or amblyopia, was revealed in 0.2% of the series. "Rapid retinoscopy" through undilated pupils is an efficient method in detecting high refractive errors and candidates for nonstrabismic amblyopia in childhood. Since this method of examination is easy to perform, its adoption as a part of screening projects in childhood is recommended. "Rapid retinoscopy" performed by a trained orthoptist is also a useful method for detecting opacities in the ocular media.