Balanced cone excitation for controlling refractive error and ocular growth to inhibit development of myopia

An apparatus comprising:

• a computer;
• a light source that produces a therapeutic light in response to control signals from the computer;
• and
• a spectroradiometer that measures spectral characteristics of components of the therapeutic light and provides an indication of radiance of the spectral characteristics of the components of the therapeutic light to the computer;
• wherein the computer generates the control signals based on the radiance and spectral characteristics of the therapeutic light such that the therapeutic light comprises components of different wavelengths in a predetermined ratio of radiance calculated to create a balanced L-cone to S-cone excitation profile that slows ocular growth thereby mitigating development of myopia, and wherein the predetermined ratio of component radiances of the therapeutic light is calculated to create an L-cone to S-cone excitation ratio in a range between 0.74 and 1.38.