Ishihara charts

Selection and training of appropriately qualified and motivated persons for participation in analytical panels is essential to effective performance. Individuals participating in panels in which colour judgements are involved should have been screened for colour vision deficiencies using Ishihara charts. However, other tests may be necessary for the optimal performance of certain... 

Approximately 8% of men and 0.4% of women perceive colors in significantly different ways from the remainder of the population. Most of this color-deficient vision is inherited, but some can be acquired as a result of pathology, illness, or old age. The most common inherited causes relate to deficiencies or absence of the p- or y-cones. The Ishihara charts may be used to detect the presence of such conditions. These charts consist of a number of plates made up of differently colored spots, which form numbers that may wrongly be described or not detected at all. This is a first screening for detection of a color vision deficiency. 

Ethambutol should not be given with antacids. The ethambutol dose should be reduced to three times per week in patients with renal failure. Retrobulbar neuritis is the major adverse effect. Patients may complain of a change in visual acuity, the inability to see the color green, or both. They should be monitored monthly while on the drug using Snellen wall charts for visual acuity and Ishihara red-green color discrimination cards. ... 

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