Cross cylinder examination (otherwise known as Jackson’s cross cylinder) is an examination used for the final fine-tuning of the axis and strength of astigmatism after its determination through retinoscopy, stellate cycle or automatic refractometry.
Why is JCC used?
The optical principles of an optometric device: the Jackson cross cylinder (JCC) is discussed. The vector representation of the dioptric power is used to visualize the action of the JCC in each step of the clinical procedure for the subjective determination of an astigmatic refractive error.
How do you use JCC refraction?
- Swing the Jackson cross-cylinder (JCC) in front of the patient’s eye to refine cylinder axis and power.
- As a general rule, if the patient’s refractive error is primarily cylindrical, or if by retinoscopy or autorefraction you found 1.00D of cylinder or more, start by checking the cylinder axis first.
