Optometric procedure

Jackson Cross Cylinder

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Introduction of JCC Jackson crossed cylinder is a combination of two cylinders of equal strength but of an opposite sign placed with their axis at 90 degrees to each other and mounted in a handle. Also known as the flip cross technique Principle of Jackson cross cylinder When light rays passed through an optical system … Read more

Duochrome test principle

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Duochorme Test Principle

Duochrome test is a manual procedure that is performed as part of the subjective refraction process. Duochrome test is performed using a distance visual acuity chart with black letters, and the chart is split equally into two identical halves. Left side of chart have letter on a red background and right side of chart have … Read more