Optometry practices use the Ishihara test as the standard colour vision screen in a routine eye examination, especially for children at their first examination and for adults whose work depends on colour judgement. The 38-plate edition covers demonstration, screening, classification and winding-line plates in one book.
Occupational health services and recruitment medicals use colour vision screening for roles where colour recognition matters, such as electrical work, transport, the armed forces and some laboratory roles. Such standards often begin with a pseudoisochromatic plate test and specify what follows a fail, so the service should check the protocol it must meet.
School health teams and paediatric services can screen children who cannot yet read numerals with the winding-line plates. Early identification lets teachers and parents adapt colour-coded learning materials.
Hospital eye services and neuro-ophthalmology clinics use colour vision testing as part of assessing optic nerve and macular function. The Ishihara plates are designed for congenital red-green deficiency, so acquired and blue-yellow defects need other tests alongside them.
Teaching clinics and training programmes use the book to show students correct technique: daylight illumination, three seconds per plate, no touching of number plates and a varied order.
Two situations suit it less well: detecting tritan defects, and occupational certification that names a different protocol. Where a test's validity rests on its printed colours, provenance matters, and every service using the book should confirm it before the first screening session. The conformity documentation those procurement routes require is issued by the manufacturer and provided by the seller.