L14

Question 1

What is the main purpose of the cross-cylinder (JCC) routine in subjective refraction?

Answer 1

To refine the objective refraction results by accurately determining the cylindrical axis and power for astigmatism correction.

Question 2

Why should you always double-check for small cylinders with the cross-cylinder?

Answer 2

Because small cylinders may not be detected objectively, but can still affect vision and should be confirmed subjectively.

Question 3

How do you know when the cylinder power has been found?

Answer 3

When the patient cannot tell the difference in clarity, roundness, or darkness between two positions.

Question 4

What should you do after finding the cylinder power?

Answer 4

Double-check the cylinder axis using the same procedure as before.

Question 5

What is the main advantage of the cross-cylinder technique over other methods?

Answer 5

It is more sensitive and precise for refining both the axis and power of cylindrical correction.