Jackson’s Crossed Cylinder
Jackson’s crossed cylinder has been used by eye doctors to refine the axis and power of astigmatism for well over a century.
Stokes seems to have first described the cross cylinder in 1849.
It consists of two cylinders of opposite powers set at 90 degrees to each other. The lens is then put on a knurled handle to allow for easy rotation.
This model is +0.25/-0.25 diopters.
It is unsigned and appears to be from the last half of the 1900’s.
The metal is stainless steel and the powers and axes are etched into the glass and then colored with red and white for easy identification in the exam room.
