scholarly journals Assist device in color discrimination using Heilmeier type guest‐host liquid crystal for red‐green color vision defect

2019 ◽  
Vol 102 (8) ◽  
pp. 17-24
Author(s):  
Keizo Nakayama
Keyword(s):  
Liquid Crystal ◽  
Color Vision ◽  
Color Discrimination ◽  
Assist Device ◽  
Green Color ◽  
Color Vision Defect ◽  
Vision Defect

Repeatability indices for the Farnsworth D-15 test

2004 ◽  
Vol 21 (3) ◽  
pp. 449-453 ◽  
Author(s):  
JEFFERY K. HOVIS ◽  
SHANKARAN RAMASWAMY ◽  
MATTHEW ANDERSON
Keyword(s):  
Color Vision ◽  
Kappa Coefficient ◽  
Clinical Population ◽  
Perfect Agreement ◽  
Green Color ◽  
Color Vision Defect ◽  
Vision Defect ◽  
Subject Pool ◽  
Color Vision Test ◽  
Test Result

The repeatability of the D-15 color-vision test is considered to be excellent. However, this conclusion is based on a subject pool which contained a large percentage of color-normals. This type of sampling could bias the repeatability results because color-normals rarely fail the test. Furthermore, color-normals usually do not perform the D-15 in the clinical setting. To establish the repeatability of the D-15 for a relevant clinical population, we examined the D-15 results from two different sessions for 116 subjects who had a congenital red–green color-vision defect. The kappa coefficient for intersession agreement indicated that approximately 84% of the subjects obtained the same pass/fail results at both sessions. The type of defect was repeatable on approximately 80% of the subjects. Although the repeatability of the D-15 for color-defective subjects was good, it was lower than the near-perfect agreement reported previously. The coefficients of repeatability for the crossings show that if a person makes less than five crossings then the test should be administered again in order to ensure that the test result is repeatable.

Validity of the Worth 4 Dot Test in Patients with Red-Green Color Vision Defect

2017 ◽  
Vol 94 (5) ◽  
pp. 626-629 ◽  
Author(s):  
Eunoo Bak ◽  
Hee Kyung Yang ◽  
Jeong-Min Hwang
Keyword(s):  
Color Vision ◽  
Green Color ◽  
Color Vision Defect ◽  
Vision Defect

scholarly journals Color Vision Defects in School Going Children

2010 ◽  
Vol 50 (180) ◽  
Author(s):  
R K Shrestha ◽  
MR Joshi ◽  
S Shakya ◽  
R Ghising
Keyword(s):  
Color Vision ◽  
Male Students ◽  
Male Population ◽  
Cross Sectional ◽  
Green Color ◽  
Color Vision Defect ◽  
Vision Defect ◽  
Color Vision Defects ◽  
Vision Defects ◽  
Rule Out

Introduction: Color Vision defect can be observed in various diseases of optic nerve and retina and also a significant number of people suffer from the inherited condition of red and green color defect.  Methods: A cross-sectional descritptive study was designed with purposive sampling of students from various schools of Kathmandu Valley. All children were subjected to color vision evaluation using Ishihara Isochromatic color plates along with other examination to rule out any other causes of color deficiency.  Results: A total of 2001 students were examined, 1050 male students and 951 females with mean age of 10.35 (±2.75) and 10.54 (±2.72) respectively. Among the total students examined, 2.1% had some form of color vision defects. Of the male population , 3.9% had color vision defects while none of the female was found with the deficiency.  Conclusions: The prelevance of color vision defect in Nepal is significant and comparable with the prelevance quoted in the studies from different countries. Keywords:color vision; congenital red green color effect; Nepal; prevalence.

scholarly journals Computerized color-vision test based upon postreceptoral channel sensitivities

2004 ◽  
Vol 21 (3) ◽  
pp. 465-469 ◽  
Author(s):  
E. MIYAHARA ◽  
J. POKORNY ◽  
V.C. SMITH ◽  
E. SZEWCZYK ◽  
J. McCARTIN ◽  
...  
Keyword(s):  
Color Vision ◽  
Current Data ◽  
Parvocellular Pathway ◽  
Green Color ◽  
Color Vision Defect ◽  
Vision Defect ◽  
Administration Time ◽  
System Data ◽  
Color Vision Test ◽  
Vision Defects

An automated, computerized color-vision test was designed to diagnose congenital red–green color-vision defects. The observer viewed a yellow appearing CRT screen. The principle was to measure increment thresholds for three different chromaticities, the background yellow, a red, and a green chromaticity. Spatial and temporal parameters were chosen to favor parvocellular pathway mediation of thresholds. Thresholds for the three test stimuli were estimated by four-alternative forced-choice (4AFC), randomly interleaved staircases. Four 1.5-deg, 4.2 cd/m2square pedestals were arranged as a 2 × 2 matrix around the center of the display with 15-minute separations. A trial incremented all four squares by 1.0 cd/m2for 133 ms. One randomly chosen square included an extra increment of a test chromaticity. The observer identified the different appearing square using the cursor. Administration time was ∼5 minutes. Normal trichromats showed clear Sloan notch as defined by log (ΔY/ΔR), whereas red–green color defectives generally showed little or no Sloan notch, indicating that their thresholds were mediated by their luminance system, not by the chromatic system. Data from 107 normal trichromats showed a mean Sloan notch of 0.654 (SD = 0.123). Among 16 color-vision defectives tested (2 protanopes, 1 protanomal, 6 deuteranopes, & 7 deuteranomals), the Sloan notch was between −0.062 and 0.353 for deutans and was <−0.10 for protans. A sufficient number of color-defective observers have not yet been tested to determine whether the test can reliably discriminate between protans and deutans. Nevertheless, the current data show that the test can work as a quick diagnostic procedure (functional trichromatism or dichromatism) of red–green color-vision defect.

scholarly journals The burden of color vision defect in Nepal – an iceberg phenomenon

2019 ◽  
Vol 9 (4) ◽  
pp. 69-71
Author(s):  
Anadi Khatri ◽  
Bal Kumar K.C ◽  
Sudhir Gautam ◽  
Muna Kharel
Keyword(s):  
Color Vision ◽  
Early Stage ◽  
Descriptive Analysis ◽  
School Level ◽  
Color Vision Defect ◽  
Vision Defect ◽  
Color Vision Defects ◽  
Color Vision Test ◽  
Sequential Group ◽  
Vision Defects

Background: Color vision tests are routinely performed and are mandatory in most part of the world. However, in Nepal and many other developing countries, color vision may often be overlooked. We evaluated a possible burden of color vision in a group of patients who were specifically evaluated for a color vision defects. This study evalutes the awareness of color vision defect among the patients evaluated and highlights the importance of the color vision evaluation. Methods: A sequential group of 73 people from August to September 2017 specifically evalu­ated for color vision defect for recruitment of government employment were evaluated. Ishi­harapseudo-isochromatic plates and Farnsworth-Munsell Dichotomous D-15 test were used for screening. Mean and Standard deviation were used for descriptive analysis of the data. Results: Fifty-seven were male and sixteen were female. The mean age was 23 years (SD ± 3.7). On evaluation of the color vision defect, 9 (12.3%) were found to have total color vision defect (achromatopsia), 3 (4%)-red-green defect and 1(1%) with blue red defect. None of the patients had undergone color vision test at eye hospital previously. There were 4 patients who were registered drivers who had color vision defect. Conclusions: Color vision is an important part of the vision. It should not be ignored.All of the patients evaluated were found to be unware of their condition. Early detection of color vision defects in individuals, if possible, at school level can help them to determine their careers and future endeavors at early stage.

Unique haplotype in exon 3 of cone opsin mRNA affects splicing of its precursor, leading to congenital color vision defect

2012 ◽  
Vol 424 (1) ◽  
pp. 152-157 ◽  
Author(s):  
Hisao Ueyama ◽  
Sanae Muraki-Oda ◽  
Shinichi Yamade ◽  
Shoko Tanabe ◽  
Takahiro Yamashita ◽  
...  
Keyword(s):  
Color Vision ◽  
Unique Haplotype ◽  
Color Vision Defect ◽  
Cone Opsin ◽  
Vision Defect

Effect of digitally generated colored filters on Farnsworth-Munsell 100 hue test by red-green color vision-deficient observers

2021 ◽  
Vol 2021 (29) ◽  
pp. 148-153
Author(s):  
Shunnma Saito ◽  
Keiko Sato
Keyword(s):  
Color Vision ◽  
Discrimination Performance ◽  
Color Discrimination ◽  
Spectral Transmittance ◽  
Green Color ◽  
Colored Filter

In this study, the effects of four different digitally generated colored filters on the Farnsworth-Munsell 100 hue test (100-hue test) are analyzed by red-green color-vision deficient (CVD) observers. We digitally simulate the colored filters based on the spectral transmittance of four colored filters, which have been used previously. Five red-green CVD observers are subjected to the 100-hue test on a monitor under nine filter conditions, which comprise one condition without filter and eight conditions with filters. The results suggest that a colored filter that transmits long wavelengths and absorbs medium wavelengths may improve the color discrimination performance of protans and deutans.

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