Unilateral visual impairment and neurodevelopmental performance in preschool children.

BACKGROUND: Unilateral visual impairment (UVI) as a result of amblyopia or refractive error is common in childhood, but its functional significance remains largely unexplored. AIM: To investigate the influence of visual acuity and stereoacuity on the performance of preschool children on tasks requiring visuomotor skills and visuospatial ability. METHODS: Children with normal (6/6) visual acuity (VA) in both eyes and children with UVI ranging from 6/9 to 6/60, with no strabismus and normal vision in the fellow eye, were assessed on a neurodevelopmental test battery of visually guided tasks. RESULTS: 50 children (mean age (SD): 52.4 (5.7) months; median (range) VA: 6/9 (6/6 to 6/60); median (range) stereoacuity: 70 seconds arc (40-absent)) completed the test battery. UVI and stereoacuity correlated moderately (Pearson's r = 0.537, p < 0.001) but seven of 28 children with impaired VA had normal stereoacuity (< 70 seconds arc) while five of 22 with normal VA had abnormal stereoacuity. Stereoacuity correlated with performance on a task requiring fine hand-eye coordination and a task measuring visuomotor integration. UVI did not correlate with performance on any test battery items. CONCLUSIONS: UVI itself does not appear to relate to visuomotor actions, except when associated with reduced stereoacuity. Stereoacuity appears to have an influential role in fine visuomotor actions and spatial representation in preschool children.

Frisby Davis distance stereoacuity values in visually normal children.

AIMS: To establish the range of normal distance stereoacuity in young children using the Frisby Davis distance stereo test (FD2). METHODS: Children passing preschool vision screening assessments underwent measurement of distance stereoacuity with the FD2 using a standard testing protocol. RESULTS: 59 visually normal children aged between 36 months and 68 months were recruited to this study. All 59 were able to understand the test requirements and were examined with the FD2 stereo test. Four (6.8%) had no measurable stereoacuity; 13 (24%) had stereoacuity measurable only at a 3 metre testing distance (mean 92.3 seconds of arc; SD 52.6). These children were significantly younger than the remaining 42 (76%) who demonstrated a stereoacuity response at a 6 metre testing distance (mean 29.6 seconds of arc; SD 13.1, p=0.008). CONCLUSION: The FD2 stereo test enables the measurement of distance stereoacuity in young children. There appears to be a maturational effect with distance stereoacuity improving between 36 months and 68 months. The data on age related normal values will provide a baseline from which to compare outcomes in clinical populations.

The emotional impact of amblyopia treatment in preschool children: randomized controlled trial.

PURPOSE: To investigate the emotional status of children undergoing active treatment for amblyopia. DESIGN: Postal survey, in the context of a prospective, multicenter, randomized controlled trial. PARTICIPANTS: Parents of 177 children with a unilateral visual impairment referred from preschool vision screening. The children had been recruited to a randomized controlled trial of treatment for unilateral visual impairment and randomly assigned to receive either glasses with or without patches, glasses alone, or treatment deferred for 1 year. METHODS: A self-completion questionnaire, including a psychometric behavioral scale, was sent to the parents of all children recruited to the trial at age 4 years, to 66 whose deferred treatment began at age 5 years, and finally to 151 remaining in the trial at the end of follow-up. MAIN OUTCOME MEASURES: Mean scores per treatment group on the Revised Rutter Parent Scale for Preschool Children. Comparison of parent responses to questions assessing the child's general well-being and difficulties associated with treatment. RESULTS: Completed questionnaires were returned for 144 of 177 (81%) children at a mean age (standard deviation) of 48 months (5.0), for 45 of 66 (68%) at a mean age of 61 months (5.8), and for 78 of 151 (52%) at a mean age of 67 months (5.0). Most parents reported having difficulty with patching their child regardless of age (77% at age 4 years and 73% at age 5 years), with fewer reporting difficulties with glasses alone (42% and 53%, respectively). Children were significantly more upset by patching than by glasses only (chi-square test, P = 0.03 for age 4 years and P = 0.01 for age 5 years), as were the parents of 4-year-olds (chi-square test, P = 0.01). Most parents thought their children were happy, cooperative, and good tempered, and behavioral scores did not differ between treatment groups. CONCLUSIONS: Treatment for unilateral visual impairment is not easy to implement and is commonly associated with some degree of distress. Despite this, no impact on the child's global well-being or behavior was seen either during or after the treatment period.

The Newcastle Control Score: a new method of grading the severity of intermittent distance exotropia.

AIM: To describe the development and application of a novel scoring system for grading the severity of intermittent distance exotropia (IDEX) and its potential application as an intervention criterion for surgical intervention. METHODS: The Newcastle Control Score (NCS) for IDEX was developed by incorporating both subjective (home control) and objective (clinic control) criteria into a scale to grade severity. The score structure described was evaluated for interobserver and test-retest reliability. To determine an optimal score threshold for surgical intervention, 170 cases of IDEX were scored retrospectively. Cure rates for surgical and non-surgical cases were then compared according to preoperative or presenting scores. RESULTS: Interobserver and test-test reliability were good (r = 0.82 and r = 0.89 respectively). Total cure rate with surgery was 54% and without surgery 18% (chi(2) = 23.093, df = 1, p<0.001). Significantly fewer patients with NCS >/=3 achieved cure without surgery than those with NCS 2 (chi(2) = 3.362, df = 1, p<0.047). CONCLUSIONS: The NCS is a reliable method for grading the severity of IDEX and aids decisions regarding intervention. Patients with a score of 3 or more are unlikely to attain a cure without surgery.

Randomised controlled trial of treatment of unilateral visual impairment detected at preschool vision screening.

OBJECTIVES: To test the efficacy of treatment for unilateral visual loss detected by preschool vision screening and the extent to which effectiveness varies with initial severity. DESIGN: Randomised controlled trial of full treatment with glasses and patching, if required, compared with glasses only or no treatment. Masked assessment of best corrected acuity after one year of follow up. SETTING: Eight UK eye departments. PARTICIPANTS: 177 children aged 3-5 years with mild to moderate unilateral impairment of acuity (6/9 to 6/36) detected by screening. RESULTS: Children in the full and glasses treatment groups had incrementally better visual acuity at follow up than children who received no treatment, but the mean treatment effect between full and no treatment was equivalent to only one line on a Snellen chart (0.11 log units; 95% confidence interval 0.050 to 0.171; P < 0.0001). The effects of treatment depended on initial acuity: full treatment showed a substantial effect in the moderate acuity group (6/36 to 6/18 at recruitment) and no significant effect in the mild acuity group (6/9 to 6/12 at recruitment) (P = 0.006 for linear regression interaction term). For 64 children with moderate acuity loss the treatment effect was 0.20 log units, equivalent to one to two lines on a Snellen chart. When all children had received treatment, six months after the end of the trial, there was no significant difference in acuity between the groups. CONCLUSIONS: Treatment is worth while in children with the poorest acuity, but in children with mild (6/9 to 6/12) unilateral acuity loss there was little benefit. Delay in treatment until the age of 5 did not seem to influence effectiveness.

Do experienced diagnosticians agree about the diagnosis of dementia from survey data? The effects of informants' reports and interviewers' vignettes.

Dementia in community settings is often diagnosed by computerized algorithms. This study examines the extent to which independent diagnosticians agreed among themselves in diagnosing dementia, severity and type when presented with data obtained during a population-based incidence study of cognitive decline and dementia. Secondly, it examines how judgements, based initially on respondents' self-reports and cognitive performance, were affected first by informants' reports and then by short case-vignettes written by trained lay interviewers. Thirdly, it compares diagnosticians' diagnosis of dementia with the algorithmic diagnosis (AGECAT). The items presented were selected from two screening interviews at wave 1 and wave 2 separated by an interval of 2 years and from wave 2 assessment and informant interviews, and included medical, psychiatric and ADL items and interviewers' own observations. The sample (N = 42) was derived from the first year of the wave 2 assessments, potential dementia cases entering consecutively while presumed normals were selected randomly. Informants were available in 30. Agreement on diagnosis and type of dementia improved with increasing information, particularly from informants, but remained poor regarding severity. The number of cases of dementia, defined operationally, increased from 10 to 12 and uncertain cases fell from eight to six, but no respondent initially diagnosed as a dementia case was rediagnosed as a non-case, or vice versa. Dementia type changed from agreement about Alzheimer's disease to agreement about vascular dementia in one case. Operational and algorithmic diagnoses showed good agreement. Causes of disagreement, the role of vignettes and the relevance of the results for population surveys are discussed.