What are Bifocal Lenses?
Bifocal lenses are prescribed for patients who need two different distances power and near power powers. Most eye doctors recommend the Online or Progressive lens that provides intermediate vision as well. Lined bifocals continue to be popular as an alternate but there may be a jump in vision when focusing from distance to near.
What is Fashion Tint?
Fashion tint is a dye applied to the lenses. If you want, a light tint of gray, brown, blue, yellow, pink, green, lavender or rose can be added to your lenses.
What are Hi-Index Lenses?
Hi-index lenses are a special material that is thinner and lighter weight than regular plastic. Depending upon the prescription, the lenses are thinner by about 30% and lighter in weight by about 25%. This material somewhat, but the application of an anti-reflective coating takes care of this problem can lessen the sharpness of vision through your lenses. Most people seem to have little or no difficulty adapting to this material.
Can you give me information about Lenses that Darken in the Sun?
There are two types of lenses that darken automatically in the sun: Photogrey (or Photobrown) Glass lenses or Transitions lenses. Photogrey Lenses need some “curing in” time, that is they need repeated changes from dark in bright light to clearer in dim light before you can really see a benefit. It depends on how sunny it is where you live is, but the average is about eight hours. Also, glass is heavier and more prone to breakage. Transition Lenses are available in gray and brown as well, and are available in plastic, hi-index or polycarbonate materials. They do not require a breaking in period, but they do not get quite as dark and their ability to change lessens over time. For people who are light sensitive or spend a significant amount of time in the sun, prescription sunglasses are recommended.
What are Polarized Lenses?
Polarized lenses are highly recommended for reducing horizontal surface glare. This is the glare that fishermen, boaters, swimmers, and skiers see on the water or snow and a significant amount of glare from driving is from horizontal surfaces. Pilots may find LED indicators cannot be read with polarized lenses, but virtually everyone else can use them. Polarized lenses with a back surface anti-reflective coating are incredibly comfortable sunglasses.