Apparatus and method for alleviation of symptoms by application of tinted light

A method for assessing a subject for at least one of a plurality of vision related physiological defects and pathological conditions comprising:

• arranging a plurality of light sources to emit different spectral components within the visible spectrum;
• assessing the subject's performance with a series of targets under different levels of each of a plurality of illuminants, including individual spectral components or pre-determined ratios thereof;
• recording the level of each of said illuminants corresponding to improved performance by the subject;
• and
• combining the levels of each respective illuminant as recorded in said recording step to provide a resultant additive mix of said illuminants.

A method for the simulation of the use of a filter under expected lighting conditions comprising:

• defining the tristimulus values of a tint which would be observed under the expected lighting conditions by a subject when said filter is used in transmission for viewing a surface,
• providing a colour controllable lamp including narrowband coloured light sources,
• selecting the level of illumination provided by each light source and
• controlling the colour controllable lamp to illuminate the surface for viewing by the subject so that, in use, the defined tristimulus values are observed by the subject

A method for alleviating the symptoms of any one of a plurality of vision related physiological defects and pathological conditions suffered by a subject which comprises:

• arranging a plurality of light sources to emit different spectral components within the visible spectrum,
• controlling the weight of each of said spectral components to provide illumination,
• arranging at least two of the light sources to additively illuminate a surface for viewing by the subject;
• varying the amount of illumination from each of said at least two light sources to impinge on said surface;
• and
• providing a combination of said spectral components to alleviate the symptoms of at least one of said visually induced physiological defects and pathological conditions.