Commentary by Dr. Jeremy Ciano
When it comes to seeing clearly at all distances and having the ability to scan your eyes from side to side without strain, there is a huge difference in progressive lens designs and manufacturing techniques. Let’s examine the two biggest variables that impact your vision.
Field of View: If you look through a keyhole, the closer you get, the more of a room you can see. When your eyes are closer to the hole, you have less restrictions in your peripheral vision. As you move back, you see less and less of the room. In modern, digitally manufactured, progressive lenses, the prescription is etched onto the back surface of the lens (closer to your eye) to give you a remarkably wider field of view. Older technologies that are hand ground onto the front surface of the lenses give a much narrower and restrictive peripheral field view.
Clarity: Another alarming difference between the quality of progressive lens designs is in the precision and accuracy of converting the prescription from the doctor’s office to the lens itself. The difference between manually grinding lenses at your local one-hour retailer or your typical insurance-grade/mass-produced lenses versus a custom, digitally etched prescription is amazingly more accurate. In fact, the hand-shaving processes of lens fabrication is measured in 0.25 of a diopter, whereas digitally enhanced lenses are accurately produced in 0.01 diopter increments. That is 25 times more accurate! That precision and accuracy accounts for the difference between you watching your favorite movie on VHS or Blu-Ray or a 1-megapixel camera versus a 25-megapixel camera.
Hopefully, this info will allow you to make a more informed decision on your next pair of glasses so you can continue to see life in hi-definition!