Should I use distance PD or Near PD?

Distance PD is used for viewing objects at a distance (Single ...

What does OD and OS refer to?

OD: Oculus Decter - This is latin for Right Eye. OS: Oculus ...

What is a Base? What is Base Up/down & Base In/Out?

Base is a measurement used to indicate the direction of your p...

What is a Prism?

Prism is a measurement used to correct misaligment with your t...

What is an Add?

Add is used for reading additions. This is extra power used to...

What is Cylinder (Cyl)?

The Cylinder (Cyl) refers to the amount of lens power which is...

What is PD? Why do I have 2 PD's?

PD refers to your Pupillary Distance. This is the measured dis...

What is Sphere (SPH)?

The Sphere (SPH) refers to the amount of lens power which is n...

What is the axis?

The Axis refers to the direction of your astigmatism. This is ...

What is the difference between single vision distance and near?

Single Vision Distance lenses are used to correct your distanc...