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View Full Version : Can you tell which eye has the antistigmatism by my prescription?


Wendie60
Oct 22, 2013, 05:31 PM
OD
Sphere +1.25
Cylinder -.75
Axis 038

OS
Sphere +.75
Cylinder -.25
Axis 115
+225

smearcase
Oct 22, 2013, 06:11 PM
From: How To Read Your Eyeglass Prescription - AllAboutVision.com (http://www.allaboutvision.com/eyeglasses/eyeglass-prescription.htm)

"Cylinder (CYL). This indicates the amount of lens power for astigmatism. If nothing appears in this column, either you have no astigmatism, or your astigmatism is so slight that it is not really necessary to correct it with your eyeglass lenses.

Meridians of the eye are determined by superimposing a protractor scale on the eye's front surface. The 90-degree meridian is the vertical meridian of the eye, and the 180-degree meridian is the horizontal meridian.

The term "cylinder" means that this lens power added to correct astigmatism is not spherical, but instead is shaped so one meridian has no added curvature, and the meridian perpendicular to this "no added power" meridian contains the maximum power and lens curvature to correct astigmatism.

The number in the cylinder column may be preceded with a minus sign (for the correction of nearsighted astigmatism) or a plus sign (for farsighted astigmatism). Cylinder power always follows sphere power in an eyeglass prescription.

Axis. This describes the lens meridian that contains no cylinder power to correct astigmatism. The axis is defined with a number from 1 to 180. The number 90 corresponds to the vertical meridian of the eye, and the number 180 corresponds to the horizontal meridian.

If an eyeglass prescription includes cylinder power, it also must include an axis value, which follows the cyl power and is preceded by an "x" when written freehand.

The axis is the lens meridian that is 90 degrees away from the meridian that contains the cylinder power. "