ABSTRACT

BACKGROUND: Color vision is the ability to make discriminations based on wavelength composition of light, independent of its intensity (chroma or saturation), also referred to as the brightness or dullness of a color or the degree of purity of a color (DeValois and Webster, 2011).

Color vision defect (dyschromatopsia) is the inability to distinguish certain shades of color while total color blindness (achromatopsia) is the complete loss of color sensitivity, where the world is seen as either black, white or gray. Color vision deficiency is best detected and classified using sorting or arrangement tests, and also color matching tests. Ishihara pseudoisochromatic plates which is a screening tool, is the most commonly used and affordable color vision testing tool used in our society today, however it is not diagnostic. There are other tests tools/instruments that are very diagnostic, more accurate and more sensitive than the Ishihara, e.g. the color arrangement test (dichotomous-15) and the color matching test (Anomaloscope). Albeit these set of instruments are very scarce and expensive but are the most diagnostic, sensitive and accurate, compared to the conventional Ishihara color plates.

This scarcity of this diagnostic instruments has finally been addressed by the production of an indigenous Amadi d-15 color arrangement instrument. There exist also the online versions of these color vision screening and diagnostic tests, which are usually performed online.

PURPOSE: This study was aimed at producing an indigenously made Amadi d-15 (dichotomous-15) color vision arrangement and diagnostic instrument and was compared to the standard online version of analogous dichotomous-15.

MATERIALS AND METHOD: A digital color mixer and picker, an indigenously made Amadi d-15 was used, first to evaluate the color vision status of the subjects binocularly and thereafter, an online version of analogous dichotomous-15 displayed on a laptop was used to evaluate the color vision of the same subjects binocularly. The results obtained for each subject from the two different diagnostic test was recorded and compared in order to assess the validity of the indigenously made Amadi d-15 color vision diagnostic instrument. Pairs of hand gloves was used in handling the color caps. A standard score sheet/card was used in recording the test result of each subject performance.  The test was carried out in the optometry clinic, under a bright illumination and day light color temperature of 6500k. Testing time was 1min per test.

DATA ANALYSIS: The results obtained was analyzed using the statistical package for social science (SPSS) computer software version 22.0. The data was presented in tables using descriptive statistics (as mean standard deviation).Chi-square statistical tool was used to find out the result, agreement or disagreement between the two test.

RESULT AND CONCLUSION: An indigenous dichotomous-15 was made. When both instruments were compared, their end results were very parallel. The P-value was 0.000. The two instruments produced the same result. Ten (10) subjects tested for color defect on both the online and the indigenous instrument. 

CONTRIBUTION TO OPTOMETRY: This study, until proven otherwise has produced an accurate color vision diagnostic instrument, after the validation, and it will be readily available and affordable for Optometrists and Ophthalmologist in evaluating the color vision status of their subjects.

Keyword: Dyschromatopsia, Achromatopsia, Pseudoisochromatic Plate, Dichotomous-15.