Read Your Glasses Prescription
What SPH, CYL, AXIS and ADD mean for your eyes.
The Terms
What Each Box Means
SPH, Sphere
The main lens power in dioptres. Minus corrects near-sight, plus corrects far-sight.
CYL, Cylinder
Extra power for astigmatism, when the eye is shaped more like a rugby ball than a football.
AXIS
The angle, from 0 to 180 degrees, at which the cylinder power sits.
ADD
Reading power added to the bottom of varifocals or bifocals, usually after forty.
PD
Pupillary distance: the space between your pupils, so lenses sit centred.
How Long It Lasts
Adults: two years. Children and anyone with diabetes: every year.
Frame Size Finder
Read The Numbers On Your Temple
Inside the arm of your glasses: three numbers like 52-18-140. Type them for your frame size.