On your prescription slip you see SPH, CYL and AXIS in a row. Many people only understand the first one. Here is what the other two mean, in simple words.
SPH is the sphere power. It is the main power of your lens. A minus number is for short sight. A plus number is for long sight. If you need a refresher, see what DS and SPH mean.
CYL means cylinder. It is an extra power added to the lens for a condition called astigmatism.
A healthy eye is shaped a bit like a football. With astigmatism, the front of the eye is shaped a bit more like a rugby ball, curved more in one direction than the other. Light then does not focus in one clear point. Things can look blurry or stretched, near and far.
A cylinder lens has more power in one direction and none in the direction at a right angle to it. That is what fixes the blur.
The cylinder power only works in one direction, so the lens maker needs to know which way to turn it. AXIS is that direction. It is an angle from 1 to 180 degrees.
That is why they always come as a pair. If your CYL box has a number, your AXIS box has a number too. If CYL is empty or says DS, leave AXIS empty as well.
Say your right eye (OD) reads SPH -1.50, CYL -0.75, AXIS 90. In words: "A main power of minus 1.50, plus an extra minus 0.75 cylinder power, turned to 90 degrees."
A small CYL, like -0.25 or -0.50, is common. A bigger CYL means the lens needs to correct more, and the lens can end up thicker at the edges. A thinner, higher-index lens can help. Our guide to high cylindrical power and thick lenses explains the options. Our lens price list shows the standard prices and the power range they cover (-6.00 / -2.00 to +2.00 / +2.00 (SPH / CYL)).
You can see the whole slip explained in how to read your eye prescription.
This article is general information, not medical advice. For persistent symptoms or any sudden change in your vision, see an eye-care professional.
Send us a photo of your slip. One of our opticians will read it back to you in plain words and check it with you before any lens is cut.
Send your prescription to Deepak Optical.
CYL means cylinder. It is the extra lens power that corrects astigmatism. It is written in diopters, like SPH, and usually has a minus sign.
SPH is the main power of the lens and corrects short or long sight. CYL is an extra power for astigmatism. A lens can have both, only SPH, or only CYL.
AXIS tells the lens maker the direction of the cylinder power, as an angle from 1 to 180 degrees. Without the right axis, the cylinder power does not work properly.
Astigmatism is very common and is usually corrected with glasses. Only an eye test can tell you what you have. See an eye-care professional if your vision changes suddenly.
A higher CYL number needs more lens material, so the lens can get thicker. Thinner lens materials can help. See our guide to high cylindrical power and high-index lenses.
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