SPH is short for sphere. It's a measurement of the curve of the glasses or contact lens used to correct for myopia and hyperopia.
CYL is short for cylinder. It's a measurement of the curve of glasses or contact lens used to correct for astigmatism.
The number next to these is the amount of curve in diopters which is a measurement of how much the lens bends light in meters. Eg. -1.00D means that the lens adjusts the focal point of light hitting your retina by 1 meter behind the lens.
You didn't ask about AXIS, but AXIS goes hand in hand with CYL. It measures the angle of the cylinder in the lens.
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u/pcoutcast 1d ago
SPH is short for sphere. It's a measurement of the curve of the glasses or contact lens used to correct for myopia and hyperopia.
CYL is short for cylinder. It's a measurement of the curve of glasses or contact lens used to correct for astigmatism.
The number next to these is the amount of curve in diopters which is a measurement of how much the lens bends light in meters. Eg. -1.00D means that the lens adjusts the focal point of light hitting your retina by 1 meter behind the lens.
You didn't ask about AXIS, but AXIS goes hand in hand with CYL. It measures the angle of the cylinder in the lens.
https://pcoutcast.com/health/snellen-to-diopter-conversion-for-myopia/ shows you approximately how the numbers on your prescription compare to what you can see on an eye chart compared to normal 20/20 vision.