Every morning, before he left for work, my dad would ask my sister and me, “What color are my socks?” He was satisfied if we said they were brown. We thought he was either trying to get our brains primed for the school day, or he just hadn’t taken the time to check before he rushed out to catch the train. Like most kids in those days, we didn’t question our parents much.
In Part 1, we discussed Position of Wear measurements and how they affect compensated power. Now you’ll see why. Are all these measurements necessary? The answer is yes and no. To create compensated lenses, we must use values for one or more of the key POWs.
All over the United States, kids are returning to school. The beginning of school is also the beginning of sports seasons. With any sport, there can be injuries. Eye injuries during sports are common and can be devastating. There are over 40,000 sports related eye injuries each year in the United States. Thirty percent of them are among children under age 17. Ninety percent of these eye injuries are preventable.
In the beginning, corrective lenses were simple. They consisted of a spherical curve on the front and a spherical or toric curve on the back. If the front curve was a +6 and the back curve was a -5 the power of the lens was +1. Lens power was simple math, +6 + ( -5) = +1.