These lectures has prepared for postgraduate student (Ophthalmology) according to the curriculum of Bangladesh College of Physician and Surgeons (BCPS) and Bangabondhu Sheikh Mujib Medical University (BSMMU) Bangladesh

2. The Jackson cross cylinder is a
spherocylindrical lens used in clinical
refraction. It is the combination of a plus
cylinder and a minus cylinder having axes
90deg apart and equal power.

3. • So it may be ± 0.25 spherical and ± 0.50
cylinder
• or ± 0.50 spherical and ± 1.0 cylinder
• If VA is 6/9 or better use ± 0.25 and if it is
6/12/ or 6/18 use ± 0.50

4. Which of the following represents a Jackson
cross cylinder?
• a. -2.00 +4.00 x 180
• b. -1.00 +3.00 x 90
• c. +2.00 +3.00 x 180
• d. +1.00 -1.00 x 90

5. The Jackson cross cylinder is a lens made of on
cylinder and half of cylinder is spherical of
opposite magnitude placed at 90deg apart; the
spherical equivalent of the resulting lens is
zero High power Jackson cross cylinders are
especially useful in refining the refraction in
low vision patients.

6. Jackson cross-cylinder in primary orientation. The
handle is down to the right and at 45º to the
horizontal.

7. Red dot: Axis of
minus cylinder
White dot: Axis of
the plus cylinder
This is the USA notation,
UK notation is opposite

8.  Handle is attached between the two marked axes,
which enables the lens to be "twirled" before the eye
by rotation of the handle.
 In this manner, the positions of the minus and plus
axes are interchanged rapidly and alternately.
 The common term used for the rotating the handle is
known as flipping. Hence, the JCC is often termed as
flip-cross cylinder.

9. 1) Adjust sphere to the most plus or least minus
gives the best visual acuity
2)Use test figures that are 1 or 2 lines larger than
the patient’s best visual acuity
3)If cylindrical correction is not already present,
look for astigmatism by testing with the cross
cylinder at axes 90 deg. and 180 deg. If none is
found at there test at 45 and 135 deg.

10. 4) Refine axis first. Position the cross-cylinder
axes 45 deg. From the principal meridians of the
correcting cylinder. Determine the preferred flip
choice and rotate the cylinder axis toward the
corresponding axis of the cross cylinder. Repeat
until the 2 flip choice appear equal.

11. 5. Refine cylinder power:
Align the cross-cylinder axes with the
principal meridians of the correcting
cylinder. Determine the preferred flip
choice and add or subtract cylinder power
according to the preferred position of the
cross cylinder.

12. Compensate for the change in position of
the circle of least confusion by adding half
as much sphere in the opposite direction
each time the cylinder power is change

13. 6. Refine sphere, cylinder axis and
cylinder power until no further change is
necessary

14. • Always refine cylinder axis before
refining cylinder power. This sequence is
necessary because the correct axis may be
found in the presence of an incorrect
power, but the full cylinder power is
found only in the presence of the correct
axis.