Biomedical subjects

S A Cotter

Publications and source records attributed to S A Cotter.

9 recordsLinked to original sources

PubMed1999

Evaluation of a new color vision test: "color vision testing made easy".

PURPOSE: A new pseudoisochromatic color plate test, "Color Vision Testing Made Easy" (CVTMET) has recently been introduced. Said to be designed for all age groups, including pre-school children, it uses the identification of simple shapes and objects to detect red-green color deficiencies. We evaluated the CVTMET to determine if the test is suitable for color vision screening of young children. METHODS: Forty-one adults predetermined to be color normal (n = 20) or to have hereditary red-green color deficiency (n = 21), served as subjects. A battery of color vision tests including the Ishihara, Panel D-15, and the anomaloscope were used for diagnosis and color deficiency classification. Subjects were then tested with Part I and Part II of the CVTMET test and results were compared to the Ishihara, Panel D-15, and anomaloscope. In addition, the CVTMET was used to screen for color vision deficiency in 152 kindergarten children 5 to 7 years of age. RESULTS: The pass/fail results for the adult subjects were the same for Parts I and II and compared favorably with the anomaloscope. There were no false positives (100% specificity) and only a few (2 of 21) false negatives (90.5% sensitivity). The two color-deficient subjects who passed the CVTMET had the mildest color deficiencies (simple deuteranomaly) and also passed the Ishihara test. Testability of kindergarten children was found to be 100%. Color vision deficiency occurred in 5.06% of the boys, which is about the same frequency found in older boys of similar ethnic background. CONCLUSION: This preliminary study indicates that the CVTMET appears to be an excellent screening instrument for red-green color deficiency in adults and has been shown to be useful for examining color vision in children 5 to 7 years of age.

Adult↗

PubMed1999

Frequency of convergence insufficiency among fifth and sixth graders. The Convergence Insufficiency and Reading Study (CIRS) group.

PURPOSE: To estimate the frequency of convergence insufficiency (CI) and its related clinical characteristics among 9- to 13-year-old children. METHODS: Fifth and sixth graders were screened in school settings at three different study sites. Eligible children with 20/30 or better visual acuity, minimal refractive error, no strabismus, and exophoria at near were evaluated according to a standardized protocol to determine the presence and severity of CI. These children were classified according to the presence and number of the following clinical signs: (1) exophoria at near > or =4delta than far, (2) insufficient fusional convergence, and (3) receded nearpoint of convergence. Also, children were classified as accommodative insufficient (AI) if they failed Hofstetter's minimum amplitude formula or had greater than a + 1.00 D lag on Monocular Estimate Method retinoscopy. RESULTS: Of 684 children screened, 468 (68%) were eligible for further evaluation. Of these, 453 had complete data on CI measurements and were classified as: no CI (nonexophoric at near or exophoric at near and < 4delta difference between near and far) (78.6%); low suspect CI (exophoric at near and one clinical sign: exophoria at near > or =4delta than far) (8.4%); high suspect CI (exophoric at near and two clinical signs) (8.8%); and definite CI (exophoric at near and three clinical signs) (4.2%). CI status varied according to ethnicity and study site (p < 0.0005), but not gender. The frequency of AI increased with the number of CI-related signs. For CI children with three signs, 78.9% were classified as also having AI. CONCLUSIONS: These findings suggest that CI (defined as high suspect and definite) is frequent (13%) among fifth and sixth grade children. In addition, there is a high percentage of CI children with an associated AI.

Accommodation, Ocular↗

PubMed1997

Orientation anisotropy and strabismus.

Monocular contrast sensitivity (CS) measurements were obtained in the two principal meridians of eight constant unilateral strabismic subjects and four subjects diagnosed with alternating strabismus. The results indicated that: (1) the CS of both the fellow and deviating eyes of patients with a constant unilateral deviation is significantly less than that of visually normal eyes at high spatial frequencies; (2) both the fellow and deviating eyes reveal a significant reduction in CS to vertically oriented gratings. This effect is frequency-specific, occurring only at the highest spatial frequencies; (3) the magnitude of the orientation anisotropy did not vary systematically with the degree of amblyopia; and (4) a mild orientation anisotropy was observed in only three of the eight alternating strabismic eyes tested. The etiology of the vertical effect is examined with respect to the role of anomalous binocular competition, suppression and abnormal eye movements.

Amblyopia↗

PubMed1997

Evaluation of Kojima-Matsubara color vision test plates: validity in young children.

PURPOSE: We examined a pseudoisochromatic color plate test by Kojima and Matsubara for young children which uses drawings of familiar objects rather than letters or numbers. First, we evaluated the test's efficacy as a color deficiency screener and its validity in classifying the types of color deficiencies by comparing its results with those from the Moreland anomaloscope. Second, we eliminated the chromatic factor and evaluated the functional ability of young children to perform the task by determining how many correct responses were obtained using modified black/white replicas of the test plates. METHODS: Part 1: Twenty color-normal and 13 color-deficient adults were diagnosed and classified with the Ishihara test, Panel D-15 test, and anomaloscope. Subjects were then tested with the Kojima-Matsubara test and result were compared with those from the anomaloscope. Part 2: Fifty children aged 3 to 7 years were tested with modified black/white test plate replicas. The number of correct responses for each plate was determined for five different age groups. RESULTS: Part 1: Among the 20 color-normal subjects, 18 read all 10 plates correctly and 2 subjects missed 1 of the 10. Only 1 of the 13 color-deficient subjects exhibited the expected responses for plates 2 to 6 (used for color deficiency screening). The color-deficient subjects' responses for plates 7 to 10, which are used to classify red-green defects, were varied and only the protanomalous subjects (n = 2) followed the expected response pattern. Part 2: Of the 10 black/white modified plates, only 2 were correctly identified by all 50 children. The other plates had a recognition rate that ranged from 32 to 98%. CONCLUSIONS: Because the response patterns given by most of the color-deficient adult subjects were different from those in the test manual, ambiguous results would occur if the Kojima-Matsubara test were used for color vision screening or the diagnosis of color deficiency. In addition, the difficulty that many of the young children exhibited in identifying the objects in the black/white replica plates suggests that there would be a large number of false positive errors (classifying a color normal as color deficient) when using this test in young children.

Adult↗

PubMed1992

Re-evaluation of the four prism diopter base-out test.

The four prism diopter base-out (4 delta BO) test is often recommended for use as an objective assessment of binocular visual function in patients with suspected microstrabismus or central suppression; however, many aspects of the test are unknown. In this series of investigations we evaluated: (1) inter-observer agreement between 2 examiners, using 15 subjects; (2) types of eye movements made and prevalence of the various response types demonstrated in 212 children and 116 adults with normal binocular vision, and 10 children and 4 adults with abnormal binocular vision; and (3) repeatability of test results for 22 subjects evaluated on two separate occasions. In addition, using an SRI Eye-tracker, we documented the eye movements made while testing 2 subjects with small angle strabismus and 4 subjects with normal binocular vision. We found the following results: (1) inter-observer agreement is high; (2) both children and adults exhibit many atypical responses, whether or not they have normal binocular vision; (3) diplopia awareness does not differentiate between subjects with normal and abnormal binocular vision; and (4) 4 delta BO test results are not repeatable. Due to frequent atypical and variable responses in subjects with or without normal binocular vision, we suggest the examiner use caution when making a diagnosis based solely on the 4 delta BO test.

Adult↗

PubMed1990

Normative contrast sensitivity data for young children.

Contrast sensitivity (CS) was measured in children ages 3 to 7 years using the Vistech Contrast Sensitivity distance chart (VCTS 6500). The purpose of the study was to determine how effectively the technique could be used with young children and to establish normative data for this age group. Of 286 children participating in a vision screening, the contrast sensitivity function (CSF) was measurable on 241 (84%) under binocular conditions and 229 (80%) under both binocular and monocular conditions. The 219 binocular CSF's and 208 monocular CSF's obtained from visually normal children were used to establish normative data and then compared to similar data from 50 visually normal young adults. The results indicated that there is an effect of age between 3 and 7 years, children are significantly less sensitive than adults, and adult-like levels of CS are not yet reached at 7 years of age. In addition, although the children's mean contrast thresholds fell within the norms provided with the VCTS 6500, the variability in the children's CSF's precludes using the Vistech data for diagnostic purposes in the young. The normative data are presented to assist the clinician in evaluating CS in young children when using the VCTS 6500.

Adult↗

PubMed1987

Comparative study of the Jordan left-right reversal test, the reversals frequency test, and teachers' observations.

The intertest pass/fail reliability of the Jordan left-right reversal test (JRT) and reversals frequency test (RFT) was compared on 510 "regular classroom" and 126 "learning handicapped" children. Children were divided into two age groups, 5 to 8 years and 9 to 13 years. Teachers completed a questionnaire assessing whether they felt a reversal problem existed. Statistical analysis showed low to moderate agreement between the pass/fail rate of the two tests (p less than 0.001) for both age groups of normal children; however, no statistical agreement was found for either age group of learning handicapped children. There was only very low agreement between the teacher's assessment of reversals and the pass/fail rates for both age groups of normals and the 9- to 13-year-old learning handicapped group. No agreement was found for the 5- to 8-year-old learning handicapped group. The effect of test design and recommendations for the clinical investigation of reversals are discussed.

Adolescent↗

PubMed1986

The Brückner test: evaluation of clinical usefulness.

A quick and simple clinical test for detection of strabismus was evaluated for three groups of subjects. The test reliably detected the strabismic eye in the first group of strabismic subjects when observers discriminated between brightness of the right and left fundus reflex. The test reliably detected strabismus in the second group of strabismic subjects when observers decided if brightness of the fundus reflexes were equal or unequal. However, the Brückner test yielded false positives when it indicated strabismus in the third group of nonstrabismic subjects. The Brückner test is recommended only as an adjunct to testing for use by professionals, but not as a single test for strabismus detection by lay screeners.

Adolescent↗

PubMedDate not supplied

Erroneous findings in polarized testing caused by plastic prisms.

Certain plastic prisms, when used with polarized tests (eg, stereopsis), can destroy the uniqueness of each eye's view. We investigated this effect by administering the Randot stereotest to 12 visually normal observers. The test was administered monocularly (simulating suppression), under habitual conditions, and through six representative prisms, both fused and monocularly. Whereas stereo thresholds with an anaglyphic random dot stereogram (TNO) were not significantly affected by the prism, fusing through some of the prisms resulted in significantly poorer stereo thresholds and a failure to detect random dot stereopsis (RDS) on the polarized stereotest. Furthermore, some subjects appreciated RDS viewing monocularly through each of the prisms. Thus, it is important to conduct polarized testing through prisms that are known not to interfere with polarization. This optical phenomenon is explained here.

Adult↗