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Biomedical subjects

Graham Quinn

Publications and source records attributed to Graham Quinn.

9 recordsLinked to original sources
PubMed2006

Random Dot E stereotest: testability and reliability in 3- to 5-year-old children.

PURPOSE: To determine the proportion of preschoolers testable with the Random Dot E (RDE) stereotest and the between-tester reliability. METHODS: Subjects were 1257 3- to 5-year-olds who were participants in Head Start programs in five communities. The sample was over-weighted with children who failed the routine Head Start vision screening (58% failures; 42% nonfailures). Each child had stereotesting attempted by two licensed eye care professionals using the RDE test, first in a screening setting and later in a comprehensive eye examination. Pretesting was performed at 50 cm. Children who discriminated between the nonstereo E and blank cards on 4 of 4 or 4 of 5 presentations were considered testable. Stereotesting was conducted at 50, 100, and 150 cm corresponding to 504, 252, and 168 arcsec disparity). Extent of agreement beyond chance between the screening and examination test results was assessed using the kappa (kappa) and weighted kappa (kappa(w)) statistics. RESULTS: Testability increased with age at both the first (86% of 3-, 89% of 4-, and 93% of 5-year-olds; p = 0.02) and the second (90% of 3-, 94% of 4-, and 98% of 5-year-olds; p = 0.0001) sessions. Overall, stereopsis was better at the second session. Agreement between sessions was moderate (kappa(w) = 0.43; 59% identical scores). While identical scores increased with age (53% of 3-, 59% of 4-, and 63% of 5-year-olds), kappa(w) statistics did not differ with age (p = 0.49). CONCLUSIONS: Child testability on the RDE stereotest was significantly better for older than younger preschool-age children. Overall, test-retest agreement was moderate and did not differ according to age. Testability rates of 98% and higher have been achieved in the same population with other screening tests including another random dot stereotest.

Age Factors↗
PubMed2005

Characteristics of infants with severe retinopathy of prematurity in countries with low, moderate, and high levels of development: implications for screening programs.

OBJECTIVE: Retinopathy of prematurity (ROP) is a potentially avoidable cause of blindness in children. The proportion of blindness as a result of ROP varies greatly among countries depending on their level of development, being influenced by the availability of neonatal care, neonatal outcomes, and whether effective screening and treatment programs are in place. The objective of this study was to compare characteristics of premature infants who developed severe ROP between 1996 and 2002 in highly developed countries with less developed countries. METHODS: This was an observational study. A questionnaire was completed by ophthalmologists in countries with low, moderate, and high development rankings (3 highly developed countries and from 10 less well-developed countries) who screen for ROP in which they supplied birth weights and gestational ages (GAs) of infants who were treated for threshold ROP or identified with more advanced stages of the disease. Birth weights and GAs of infants with severe ROP were measured. RESULTS: The mean birth weights of infants from highly developed countries ranged from 737 to 763 g compared with values ranging from 903 to 1527 g in less developed countries. Mean GAs of infants from highly developed countries ranged from 25.3 to 25.6 weeks compared with 26.3 to 33.5 weeks in less developed countries. A total of 13.0% of 1091 infants from poorly developed countries exceeded United Kingdom screening criteria; 3.6% exceeded a criteria of <34 weeks' GA and/or <1750 g birth weight. CONCLUSIONS: These findings suggest that larger, more mature infants are developing severe ROP in countries with low/moderate levels of development compared with highly developed countries. ROP screening programs need to use criteria that are appropriate for their local population.

Birth Weight↗
PubMed2004

Comparison of preschool vision screening tests as administered by licensed eye care professionals in the Vision In Preschoolers Study.

PURPOSE: To compare 11 preschool vision screening tests administered by licensed eye care professionals (LEPs; optometrists and pediatric ophthalmologists). DESIGN: Multicenter, cross-sectional study. PARTICIPANTS: A sample (N = 2588) of 3- to 5-year-old children enrolled in Head Start was selected to over-represent children with vision problems. METHODS: Certified LEPs administered 11 commonly used or commercially available screening tests. Results from a standardized comprehensive eye examination were used to classify children with respect to 4 targeted conditions: amblyopia, strabismus, significant refractive error, and unexplained reduced visual acuity (VA). MAIN OUTCOME MEASURES: Sensitivity for detecting children with > or =1 targeted conditions at selected levels of specificity was the primary outcome measure. Sensitivity also was calculated for detecting conditions grouped into 3 levels of importance. RESULTS: At 90% specificity, sensitivities of noncycloplegic retinoscopy (NCR) (64%), the Retinomax Autorefractor (63%), SureSight Vision Screener (63%), and Lea Symbols test (61%) were similar. Sensitivities of the Power Refractor II (54%) and HOTV VA test (54%) were similar to each other. Sensitivities of the Random Dot E stereoacuity (42%) and Stereo Smile II (44%) tests were similar to each other and lower (P<0.0001) than the sensitivities of NCR, the 2 autorefractors, and the Lea Symbols test. The cover-uncover test had very low sensitivity (16%) but very high specificity (98%). Sensitivity for conditions considered the most important to detect was 80% to 90% for the 2 autorefractors and NCR. Central interpretations for the MTI and iScreen photoscreeners each yielded 94% specificity and 37% sensitivity. At 94% specificity, the sensitivities were significantly better for NCR, the 2 autorefractors, and the Lea Symbols VA test than for the 2 photoscreeners for detecting > or =1 targeted conditions and for detecting the most important conditions. CONCLUSIONS: Screening tests administered by LEPs vary widely in performance. With 90% specificity, the best tests detected only two thirds of children having > or =1 targeted conditions, but nearly 90% of children with the most important conditions. The 2 tests that use static photorefractive technology were less accurate than 3 tests that assess refractive error in other ways. These results have important implications for screening preschool-aged children.

Amblyopia↗
PubMed2004

The electronic visual acuity tester: testability in preschool children.

PURPOSE: To evaluate the ability of preschool children to have their threshold visual acuity assessed using a standardized, computer-based letter test. METHODS: Participants were 1195 3.5- to 5-year-old children enrolled in the Vision in Preschoolers Study. Monocular visual acuity was assessed by licensed eye care professionals (optometrists and pediatric ophthalmologists experimented in the examination of children), using the Electronic Visual Acuity tester, which uses the letters H, O, T, and V with a crowded surround. RESULTS: Overall, 99.1% of children passed the training that consisted of identifying the letters H, O, T, and V by naming or matching the letters at 60 cm. Among those who passed the training, 99.6% completed the binocular pretest at 3 m, and 97.6% of those passing the training and the pretest completed monocular threshold visual acuity testing of each eye with the Electronic Visual Acuity tester. Testability increased with age for training (p = 0.03), pretesting (p = 0.04), and acuity testing (p = 0.07). Overall, 93.3% of 3.5-year-olds, 96.7% of 4-year-olds, and 98.8% of 5-year-olds completed training, pretesting, and monocular threshold acuity testing of each eye using standard letter optotypes. CONCLUSION: Using the computer-based Electronic Visual Acuity system, nearly all 3.5- to 5-year-old children can complete monocular acuity testing of each eye.

Child, Preschool↗
PubMed2003

Threshold visual acuity testing of preschool children using the crowded HOTV and Lea Symbols acuity tests.

PURPOSE: To compare the testability and threshold acuity levels for very young children on the crowded HOTV logMAR distance visual acuity test presented on the BVAT apparatus and the Lea Symbols logMAR distance visual acuity chart. METHODS: Subjects were 87 Head Start children from age 3 to 3.5 years. Testing consisted of binocular pretraining at near using a lap card as needed, binocular pretraining at 3 m, and threshold testing for each eye. The testing procedure, adapted from the Amblyopia Treatment Study, presented optotypes until the child was unable to correctly name or match three of three or three of four optotypes of a given size. Threshold acuity was the smallest size for which at least three optotypes were correctly identified. RESULTS: Both near and distance pretraining were completed by 71% of children for HOTV and by 75% for Lea Symbols (P =.39). The distribution of threshold acuities differed between the two tests. For the 69 eyes of 53 children who were successfully tested with both optotypes, results from the crowded HOTV acuity test were on average 0.25 logMar (2.5 lines) better than those from the Lea Symbols acuity test (P <.001). CONCLUSIONS: The proportion of children between 3 and 3.5 years of age whose monocular visual acuity could be assessed was high and was similar for the two charts tested. Crowded HOTV acuity results were better on average than results using Lea symbols. The different formats of the two tests may explain the observed differences in threshold acuity level.

Amblyopia↗
PubMed2003

Visual acuity results in school-aged children and adults: Lea Symbols chart versus Bailey-Lovie chart.

PURPOSE: To compare visual acuity results obtained using the Lea Symbols chart with visual acuity results obtained with the Bailey-Lovie chart in school-aged children and adults using a within-subjects comparison of monocular acuity results. METHODS: Subjects were 62 individuals between 4.5 and 60 years of age, recruited from patients seen in five optometry clinics. Each subject had acuity of the right eye and the left eye tested with the Lea Symbols chart and the Bailey-Lovie chart, with order of testing varied across subjects. Outcome measures were monocular logarithm of the minimum angle of resolution (logMAR) visual acuity and inter-eye acuity difference in logMAR units for each test. RESULTS: Correlation between acuity results obtained with the two charts was high. There was no difference in absolute inter-eye acuity difference measured with the two acuity charts. However, on average, Lea Symbols acuity scores were one logMAR line better than Bailey-Lovie acuity scores, and this difference increased with worse visual acuity. CONCLUSIONS: The Lea Symbols chart provides a measure of inter-eye difference that is similar to that obtained with the Bailey-Lovie chart. However, the monocular acuity results obtained with the Lea Symbols chart differ from those obtained with the Bailey-Lovie chart, and the difference is dependent on the individual's absolute level of visual acuity.

Adolescent↗