Ishihara Colour Charts 47640

Description

The Ishihara colour charts are used for quick and reliable screening of congenital colour vision deficiencies, such as red-green deficiency and the less common blue-yellow deficiency. Patients that are affected by a red-green deficiency have a more difficult time differentiating between red and green than do those with normal vision. Approximately 10 % of men and 0.5 % of women in Europe are affected. The colour flecks on an Ishihara chart are printed in various colour tones and sizes to create numbers or letters. Patients with red-green deficiency can only distinguish colours with difficulty or not at all and have difficulty recognising the numbers or letters displayed. With the help of the colour charts, the optometrist can diagnose the presence and severity of red-green deficiencies.