A machine used in an eye doctor’s office that can measure the prescription in an existing pair of glasses. Some are manual and others are automated machines. Knowing your current glasses prescription gives us a starting point when performing refraction (checking your vision on the eye chart).  This measurement also allows us to advise you whether it’s worth it to update your spectacles … after all, if your new prescription is the same as your existing glasses, you might not want to bother purchasing another pair.

Dr. Timothy Root is a practicing ophthalmologist and cataract surgeon in Daytona Beach, Florida. His books, video lectures, and training resources can be found at:


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