OKN-Fast: Objective visual acuity threshold measurement using the optokinetic response.

Visual acuity (VA) is the gold-standard measure for the assessment of visual function, but it is challenging to obtain in non-verbal adults and young children. We present OKN-Fast, an objective, automated method for estimation of VA using a reflexive eye movement called optokinetic nystagmus (OKN) that does not require a verbal response from the patient (VA-OKN). We tested the method in a cohort of healthy adults (n=12) with good vision, who were also blurred using a lens. On average OKN-Fast reduced the number of trials needed to determine threshold by half, as compared to a gold standard trial-by-trial assessment. The VAs determined by OKN and ETDRS were similar when blurred (no statistically significant difference). However, a significant bias of logMAR 0.2 was observed for the good vision condition. VA-OKN was highly repeatable with limits of agreement (LOA) similar to those found for ETDRS charts when blurred. However, this VA-OKN was only moderately correlated with VA measured using a ETDRS chart (r2 = 0.55). These results suggest that further optimization is warranted.Clinical Relevance- This work provides an automated approach for the estimation of visual acuity in non-verbal populations such as young children or non-verbal adults.

Vision screening in New Zealand pre-school children: Is it equitable?

AIM: This study aimed to investigate the variability by ethnicity, socio-economic status and location in coverage and testability of the universal B4 School Check vision screening in children aged 4-5 years in New Zealand. METHODS: Aggregated data from 1 July 2011 to 30 June 2015 were sourced from the Statistics New Zealand Integrated Data Infrastructure. Sourced data were attendance at vision screening and record of visual acuity measurement stratified by ethnicity, socio-economic status and region. Children who attended screening were compared with the eligible population (n = 252 279) to calculate coverage. Testability was determined by comparing the children with a recorded visual acuity measurement in each eye with those who attended screening. RESULTS: Overall vision screening coverage was 89.5% and testability was 97.8%. Ethnic differences were evident for coverage (85.7% in Pacific children, 92.5% in European children) and testability (96.4% in Maori children, 98.4% in European children). Socio-economic differences were also observed for coverage (86.4% in most deprived areas, 92.4% in least deprived), testability (most deprived 96.3%, least deprived 98.7%) and by region (coverage range of 80.4-96.4% and testability range of 93.2-99.3%). CONCLUSIONS: Significant disparities exist in vision screening coverage and testability for New Zealand pre-school children. Equity-focused initiatives are required to improve outcomes for children from Maori and Pacific families, and those from households in lower socio-economic areas. Understanding region-specific challenges and successes could support more equitable access to vision screening between regions. Further research is required to determine sources of inequities and to investigate interactions between ethnicity, socio-economic status and location.

Diagnostic accuracy of the Parr vision test, single crowded Lea symbols and Spot vision screener for vision screening of preschool children aged 4-5 years in Aotearoa/New Zealand.

PURPOSE: Preschool children in New Zealand undergo vision screening to detect amblyopia at 4-5 years of age. The current test, the Parr vision test, does not meet international visual acuity chart guidelines and has not been validated against other commonly used paediatric vision tests. New Zealand vision screening protocols are also not targeted for detecting other eye conditions such as uncorrected refractive error, which may affect school performance. We compared the Parr vision test with the single crowded Lea symbols and the Spot vision screener for detecting ocular pathology, refractive error and amblyopic risk factors in preschool children. METHODS: A cross-sectional diagnostic accuracy study recruited children aged 4-5 years via convenience sampling from the University of Auckland Optometry Clinic and through primary schools in Auckland, New Zealand. Participants received vision screening with the three different instruments administered by a lay screener. Comprehensive eye examinations were completed by a paediatric optometrist to determine the presence of vision disorders. RESULTS: Of 197 children who received a comprehensive eye examination, 14 (7.1%) had amblyopic risk factors and 43 (21.8%) had significant refractive error (15.7% with astigmatism, 9.1% with hyperopia). The sensitivity for detecting any ocular condition did not differ significantly between the tests (50.0% for Parr, 43.5% for Lea, 42.5% for Spot). Specificity was significantly lower for the Parr vision test (80.8%) than for the Lea symbols (93.4%) and Spot vision screener (98.0%). Adding the Spot vision screener to measurements of visual acuity significantly improved sensitivity in detecting any ocular condition with the Parr vision test (67.5% for Parr/Spot vs 50% for Parr alone), but not with the Lea symbols (52.5% for Lea/Spot vs 43.5% for Lea alone). CONCLUSION: The sensitivity of the Parr vision test for detecting ocular conditions in preschool children does not vary significantly from that achieved by the Lea symbols or the Spot vision screener. However, current New Zealand vision screening protocols could be improved by expanding the target conditions to include significant refractive error and incorporating the use of the Spot vision screener to increase the accuracy with which children with refractive error are identified. Future research should include longitudinal studies to determine the effect of preschool vision screening on later ocular and academic outcomes.

The effect of induced blur on the Beery-Buktenica developmental test of visual-motor integration and its supplemental tests.

BACKGROUND: The Beery-Buktenica Test of Visual-Motor Integration (Beery VMI) is a commonly used standardized test of visual-motor integration. Performance on the test is related to academic achievement, but the effect of reduced visual acuity on test results is unknown. This study determined the visual acuity demand and the spacing of the test forms for the Beery VMI and its supplemental tests and investigated the effect of induced optical blur on test results in both adults and children. METHODS: The overall size and critical detail size of each form and the distance between the center of each form and its adjacent crowding source were measured. The visual acuity demand and angular separation of forms were calculated. Two groups of participants (adults aged ≥18 years [n = 19] and children aged 7-12 years [n = 20]) completed four sessions in which they performed the Beery VMI and the supplemental tests under different blur conditions (habitual near correction, monocular spherical blur, binocular spherical blur and binocular astigmatic blur) in a randomized order. RESULTS: Stroke width, overall form size and box size remained constant throughout the Beery VMI, whereas these reduced with increasing difficulty for the supplemental tests. Reduced near visual acuity from simulated blur resulted in reduced mean scores for the Beery VMI and its supplemental tests, compared with habitual near vision in both adults and children. Binocular spherical blur had the most detrimental effect (p<0.001), followed by binocular astigmatic blur (p<0.001) then monocular spherical blur (p = 0.022). CONCLUSIONS: In individuals with uncorrected spherical or astigmatic ametropia, reduced scores on the Beery VMI and its supplemental tests may be due to impaired near visual acuity and not reflect reduced visual-motor abilities. This highlights the importance of excluding reduced near visual acuity as a cause of reduced performance before diagnosing impairment and initiating treatment strategies for visual-motor integration.

The prevalence of refractive error and visual impairment among New Zealand children in a community with significant socioeconomic disadvantage: is current preschool vision screening effective?

AIM: To examine the prevalence of refractive error and visual impairment and evaluate the efficacy of B4 School Check (B4SC) vision screening, in a cohort of predominantly New Zealand Maori and Pacific children from a community with socioeconomic disadvantage. METHOD: A cross-sectional investigation of children in the Welcome-to-School study. Participants received a comprehensive eye examination at six to seven years of age. Refractive error and amblyopia were identified and compared with B4SC vision screening results. RESULTS: One-hundred and fourteen children were assessed: 21.9% Maori, 57.9% Pacific and 20.2% Other. Over 30% of children had significant refractive error. Eighty-nine percent received a B4SC; 26.3% of children who passed the B4SC had significant refractive error. Seven children (6.1%) had amblyopia risk factors: none passed the B4SC, four were referred, one was identified for rescreening and two were not screened. CONCLUSION: Refractive errors were common in this cohort. For those screened, the B4SC was effective at identifying children with amblyopia risk factors but poor at detecting refractive errors potentially affecting academic performance. The efficacy of the programme was limited by the number of children screened, inequity of screening and the mismatch between the aims of the vision screening test and the overall rationale for the B4SC.

Community-wide vaccination with the heptavalent pneumococcal conjugate significantly alters the microbiology of acute otitis media.

BACKGROUND: Community-wide use of conjugated heptavalent pneumococcal vaccine (PCV7) in children <2 years of age could affect the microbiology of acute otitis media (AOM) in vaccinees, particularly for penicillin-nonsusceptible Streptococcus pneumoniae (PNSP). SETTING: Since Summer 2000, 94% of young children cared for by this 7-clinician, pediatric practice in rural central Kentucky received 3 or 4 doses of PCV7 in the first 18 months of life. OBJECTIVE: To determine changes in microbiology of AOM before and after community-wide routine implementation of PCV7. METHODS: Among children 7-24 months old with severe or refractory AOM, we compared 336 AOM isolates from 1992-1998 with 83 AOM isolates from 2000-2003 in children who had received 3 or 4 doses of PCV7. RESULTS: Comparing each cohort (1992-1998 versus 2000-2003), the proportion of S. pneumoniae decreased from 48% to 31% (P = 0.009; relative risk, 0.754; 95% confidence interval, 0.628-0.906), and nontypable Haemophilus influenzae increased from 41% to 56% (P = 0.01; relative risk, 1.87; 95% confidence interval, 1.15-3.04; beta-lactamase-positive, 56% versus 64%, not significant). The proportions of intermediate PNSP and resistant PNSP, respectively, were 16% and 9% versus 13% and 6% pre- and post-PCV7, respectively. Vaccine and vaccine-related serotypes, respectively, comprised 70% and 8% versus 36% and 32% of S. pneumoniae strains (P = 0.003). Post-PCV7, Gram-negative bacteria and beta-lactamase-producing organisms accounted for two-thirds and one-half of all AOM isolates, respectively. DISCUSSION: The overall proportion of S. pneumoniae isolates and vaccine serotypes in AOM were significantly reduced by community-wide use of PCV7 vaccine in our practice. The proportion of Gram-negative bacteria became 2-fold more frequent than S. pneumoniae in AOM in PCV7-vaccinated young children where PCV7 uptake was community-wide and supply was adequate.

Pneumococcal serotypes from acute otitis media in rural Kentucky.

OBJECTIVE: Acute otitis media (AOM) accounts for most infections caused by, but few data are available regarding the incidence of pneumococcal serotypes recovered from children with AOM in the United States. METHODS: Between January 1992 and March 1998, 777 middle ear pathogens from AOM were obtained from 701 patients by tympanocentesis (84.6%) or by culture of otorrhea (15.4%) from spontaneous perforation or draining tubes. The ambulatory patient population was mostly white and cared for by a sole private pediatric practice in rural Kentucky. RESULTS: Penicillin-nonsusceptible (penicillin MIC > or = 0.1 microg/ml) (PNSP) isolates accounted for 18% [6% resistant PNSP (rPNSP) and 12% intermediate resistant PNSP], and penicillin-susceptible strains accounted for 35% of the pathogens recovered from children with culture-proved AOM. Comparing the frequency of isolates between 1992 and 1993 with those between 1994 and 1998, overall rates of PNSP strains remained remarkably stable (32.2% 37.3%), but intermediate resistant PNSP strains doubled from 14% to 27% ( < 0.01), whereas rPNSP strains fell by one-third. Serotypes 19F (34%), 23F (30%), 6B (26%) and 14 (8%) accounted for nearly all rPNSP isolates. Two cross-reactive serotypes (6A and 19A) not included in the available pneumococcal conjugate vaccine comprised 8.4 and 15% of all serotypes and PNSP serotypes, respectively. Nearly all PNSP strains recovered in children < or =24 months are included in the vaccine serogroups. CONCLUSION: Depending on rates of efficacy and serotype cross-protection, the current pneumococcal conjugate vaccine could potentially protect against most PNSP strains in all ages, particularly in those < or =24 months.