Multi-channel subjective refractor

A multi-channel subjective refractor, comprising:

• a first display to generate a first image;
• a second display to generate a second image;
• a first channel to refract the first image with a first channel refraction;
• a second channel to refract the second image with a second channel refraction;
• a beam combiner to receive and to combine the first image and the second image;
• and
• a shared channel,
• to receive the first image and the second image from the beam combiner;
• to refract, in combination with the first channel, the first image with a first refraction;
• to refract, in combination with the second channel, the second image with a second refraction;
• and
• to present the first image with the first refraction and the second image with the second refraction to an eye simultaneously, wherein:
• the first channel refraction comprises at least one of a first channel defocus and a first channel cylinder;
• the second channel refraction comprises at least one of a second channel defocus and a second channel cylinder;
• the first refraction comprises at least one of a first defocus and a first cylinder;
• and the second refraction comprises at least one of a second defocus and a second cylinder.