Colour Vision Instrumentation
The assessment of colour vision can be carried out with a range of devices, which fall under one of two categories: screening or diagnostic
 
Screening Devices
 
The screening devices are relatively rapid to use and are therefore incorporated in the routine examination as applicable. The tests have a suggestive diagnosis of the problem but they lack sensitivity to fully quantify the severity of the defect encountered
 
At MICHEL GUILLON three devices are available:
 
  • The Ishihara Test, it is the classical test of colour vision, but the least favourite, due to its lack of sensitivity.
  • The HRR Test, it is similar to the Ishihara Test, but here the patient needs to recognise patterns instead of numbers. The test is, however, more sensitive and the preferred screening test.
  • The City University Test requires identifying the odd colour out of four colour dots. It is the test often used with children. Like the HRR test it is superior to the Ishihara test and gives some indication of a likely diagnosis.
 Diagnostic Devices
 
The diagnostic devices are more time consuming to use than the screening tests but used in tandem with a specialised software produce a diagnostic of the condition and its severity.
 
At MICHEL GUILLON the two devices are used:
 
  • The Farnworth D15 Test, requires the patient to rank in  colour order 15 colour ships. Each colour has a number, these number are entered in the software programme which produces the patient colour vision map and suggests a diagnosis.
  • The Antony D15 Desaturated Test,is similar to the Farnworth Test but uses colour ships which are less brilliant. The test is more difficult and slower to perform but also more sensitive to detect early defects.
 A new computer based device has been tested and is being introduced making available in addition to the D25.
INSTRUMENTATION > Videoaberroscope & Videokeratoscope > Subjective Vision Instrumentation > Binocular Vision Instrumentation > Colour Vision Instrumentation > Sports Vision Specialist Instrumentation > Dry Eye Specialist Instrumentation > Slit-lamp Biomicroscope > Confocal Microscope > Perimeter > Non-contact Tonometer > Non-mydriatic Retinal Camera > Macular Pigment Densitometer