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At least 109 records · Page 6Linked to original sources
PubMed1995

Colorimetric analyses of various light sources for the D-15 color vision test.

Colorimetric analyses were performed in both normal trichromatic and dichromatic color spaces to determine whether several light sources were suitable illuminants for the Farnsworth-Munsell Panel D-15 (D-15) color vision test. Results for fluorescent lamps showed that lamps with a correlated color temperature (CCT) of 7200 degrees K and a general color rendering index (GCRI) of at least 90 are acceptable substitutes for illuminant C. Predictions for filtered tungsten light indicated that lights with a color temperature near 5000 degrees K are unsuitable because of nonuniformities in the glass daylight filter transmittance. Conclusions based on these analyses are conservative because, with exception of the GCRI, color adaptation effects were not taken into account.

Adaptation, Ocular↗
PubMed1998

Validity of clinical color vision tests for air traffic control.

BACKGROUND: An experiment on the relationship between aeromedical color vision screening test performance and performance on color-dependent tasks of Air Traffic Control Specialists (ATCS) was replicated to expand the database supporting the job-related validity of 13 FAA-accepted screening tests. METHODS: The original experiment (10) (n = 108), and the replication (n = 136) involved a total of 121 normal trichromats, 31 simple and 44 extreme anomalous trichromats, and 48 dichromats; both protans and deutans were included. The simulations of ATCS color tasks which served as validation criteria were flight progress strips (en route centers), aircraft lights and the Aviation Signal Light indicator (ATC terminal operations), and color weather radar (flight service station and en route center facilities). RESULTS: The validities (Kappa) of aeromedical screening tests ranged from 0.44 to 0.91 for prediction of error-free performance on all color-dependent tasks. CONCLUSIONS: The aeromedical screening tests were generally acceptable in terms of selecting individuals who did not make errors on ATCS color tests, but several tests had high false alarm rates. High job-related validity, in the vicinity of 0.90, was confirmed for several aeromedical color vision tests used for ATCS screening.

Adult↗
PubMed1992

Color vision testing for the U.S. Naval Academy.

Normal color vision is a prerequisite for admission to the United States Naval Academy. The Farnsworth Lantern (FALANT) is the Navy's definitive test for color vision. A FALANT is not available at many locations where candidates are examined, so satisfactory performance on pseudoisochromatic plates has been considered an acceptable alternative. Until recently, the Farnsworth Dichotomous Test Panel D-15 had also been used as an alternative test, but is now considered unacceptable. In the summer of 1991, a large number of candidates reported for induction who were unable to pass the FALANT. Since their screening physical examinations had been reported to show normal color vision, a shadow of doubt was cast upon the ability of the alternative tests to predict performance on the FALANT. Four hundred subjects were then tested on several color vision tests to determine if these tests could predict FALANT success. The results of this study and recommendations are presented.

Adolescent↗
PubMed2004

Repeatability of the Waterloo Four-Contrast LogMAR Visual Acuity chart and Near Vision Test card on a group of normal young adults.

PURPOSES: To investigate the repeatability of logMAR visual acuity (VA) with the Waterloo Four-Contrast LogMAR Visual Acuity (FCLVA) chart and the Near Vision Test (NVT) card. The differences and agreements between near logMAR VA using horizontally- and vertically-presented letters were also determined. METHODS: Visual acuity of one eye (55 subjects) was first assessed by using the FCLVA chart, comprising four charts of varying contrast, and then with the NVT card (comprising four charts of two contrasts and two presentations). Measurements were repeated after 3 or 4 weeks. RESULTS: No significant between-visit differences were observed for any of the charts used. The repeatability coefficient for the distance 90, 60, 30 and 10% charts were 0.07, 0.11, 0.15 and 0.16 log units, respectively. The repeatability coefficients of the near vision charts were 0.06, 0.04 (high contrast), 0.11 and 0.10 (low contrast) log units. The agreements between horizontally- and vertically-presented letters were good. The differences were similar to the repeatability coefficient of each chart. CONCLUSIONS: The repeatability coefficient of the high contrast distance and near chart was about half a line. Repeatability coefficients increase with decreasing contrasts for both distance and near charts, with coefficients of one line or more for low contrast charts. Variabilities in both distance and near VA increase with decrease in contrast. The presentation of the letters does not affect near VA and the agreement between horizontally- and vertically-presented letters (both high and low contrast) was within the repeatability coefficient of each chart.

Adult↗
PubMedDate not supplied

Testing vision on adults.

Visual acuity testing is the most important part of the diagnostic workup. Patients need to be "encouraged" to read the smallest possible symbols to achieve the level of best-corrected vision. The pinhole differentiates between decreased vision from refractive errors or pathology and will indicate which further tests are required for a diagnosis. Testing patients with low vision involves the use of special techniques. It is best to use the handheld 20/200 symbol instead of "counting fingers" to assess vision below the 5/200 level. Light perception should be further defined as with or without projection. Finally, no light perception, or NLP, should be determined only by the ophthalmologist. The ophthalmic medical assistant can indicate the possible presence of NLP, but should use the NLP notation only after it has been confirmed by the doctor to exist. Accuracy in determining visual potential is extremely important in screening patients. This assessment must be as careful and thorough as possible. Accuracy in documenting the best acuity level helps to create the correct visual baseline. This visual baseline is then used as the foundation for further diagnostic and therapeutic endeavors.

Adult↗
PubMedDate not supplied

Illuminant and observer metamerism and the Hardy-Rand-Rittler color vision test editions.

A previous study identified a significant metamerism in the several editions of the Hardy-Rand-Rittller pseudoisochromatic plates (HRR) but did not proceed to quantify the consequences of that metamerism (Dain, 2004). Metamerism arises from two sources and is almost inevitable when a printed color vision test is reproduced in several editions. Metamerism has two consequences; these are illuminant/source-based changes in performance and changes in performance with observer (less well known) when assessing anomalous trichromats. This study addresses the effects of illuminant/source and observer metamerism on the fourth editions of HRR. Groups of colors intended to lie on a dichromat confusion line generally remain on a confusion line when the source id changed. The plates appear to be resistant to each form of metamerism, perhaps because the features of the spectral reflectance are similar for figure color and background gray. As a consequence, the clinician needs to be less concerned about using a non-recommended source than was previously believed.

Color Perception↗
PubMed1998

Colour discrimination thresholds in Parkinson's disease: results obtained with a rapid computer-controlled colour vision test.

A dysfunction of dopaminergic retinal neurons is thought to occur in Parkinson's disease, manifesting itself in impaired performance on various visual discrimination tasks. We have investigated whether differences in colour discrimination could readily be detected between a normal group and a Parkinsonian group, using a computer-controlled test of colour vision. Although some individual Parkinsonian patients showed an abnormal elevation of colour discrimination thresholds, there was no significant difference between the normal group and the Parkinsonian group.

Age Factors↗
PubMedDate not supplied

Color vision testing to assist in diagnosis of digoxin toxicity.

This report describes an initial step in the process of determining whether color vision changes might form the basis for testing to assist in diagnosis of digoxin toxicity. The research questions concerned the types of color vision deficiencies found in people with elevated digoxin levels, the types of color vision tests that could help identify color vision changes in these people, and the relationship between serum digoxin level and subjects' responses to color vision tests. Three groups of subjects with a minimum of one week on maintenance digoxin therapy were tested. Two groups who were free of selected known causes of abnormal color vision participated in a single test session: clinic women (N = 19) and hospitalized women (N = 30). A third group (N = 10) was initially tested at a time of elevated serum digoxin levels (greater than or equal to 2.5 ng/ml) and retested at therapeutic levels. The Farnsworth-Munsell 100-Hue Test was performed on the clinic women. All subjects were tested with the Ishihara; the Hardy, Rand, and Rittler (HRR) plates; and the Farnsworth Panel D-15. The 49 women who had a single test session demonstrated a positive relationship between digoxin level and failing the Ishihara (p less than .05). On retest at therapeutic levels, the group with initial high digoxin levels had a significant reduction in the number of Ishihara (p .005) and HRR (p less than .005) errors. The Panel D-15 lacked sensitivity. Most subjects with high digoxin levels would not have been able to perform a reliable 100-Hue test. Red-green deficiency was the most common defect.

Adult↗