Cr39

Basic lenses or CR39 are standard plastic lenses. These lenses are widely used and much lighter weight than glass. While most any prescription can be made out of CR39 many patients feel more comfortable wearing thinner Hi-index lenses.

Polycarbonate

Polycarbonate and Trivex are generally considered steps above plastic CR39. Polycarbonate is a shatter resistant material making it an ideal choice for children, adults with an active lifestyle, and safety glasses. Polycarbonate is roughly 20% to 25% thinner and 30% lighter than conventional plastic CR39.
Polycarbonate is also used for rimless, semi-rimless and drill mounted frames. These types of glasses can sometimes be prone to chipping or cracking under day-to- day stress. The use of polycarbonate in these glasses helps to ensure the structural integrity of the glasses and warranties them in these situations.

Hi index

Hi Index lenses are thin and light weight. They are available in several varieties and are classified by a number called the index of refraction. Some examples are Hi-index 1.60, 1.66, 1.67, 1.70 and 1.74. The higher the index of refraction the thinner and lighter then lenses are going to be. In some prescriptions the thinnest lenses available are not always needed. There are situations when a prescription simply is not strong enough to need the thinnest lenses available. Kristin, our optician, is excellent at helping patients select the right material for their prescription. High index lenses can be more reflective than other types of lenses, so we advise that an antireflective coating is placed on these types of lenses.

Aspheric lenses

Aspheric lenses or an aspheric lens design is one where the lens profile is flatter than that of a traditional design. This gives the lens a slimmer profile especially for plus-powered prescriptions. We recommend an aspheric lens in hyperopes (far sighted individuals) to reduce the magnification of the patients associated with these prescriptions.

Antireflective Coatings

Anti-reflective (AR) coatings are placed on nearly all precision optical devices. They are designed to reduce or eliminate light scattering within a lens. This reduction in reflection in turn increases the efficiency of a lens.
When placed on glasses lenses, AR coatings perform several functions:

• Glasses with an AR coating are cosmetically nicer looking than those without.
• An AR coating makes the lenses nearly invisible. This makes it possible for those we interact with to see our eyes without interference from distracting glare. Less reflection means an improvement in vision during activities where glare can affect the wearer. Driving at night and working at a computer monitor are two such activities. In addition, many contact lens wearers find that an AR coating makes it easier for patients to switch between contacts and glasses. This is because vision through lenses with AR is much closer to that of the completely glare free contacts
  

Transitions®

Transitions® or photochromic lenses are lenses that darken when exposed to ultraviolet light. These are great for individuals that spend a lot of time outdoors. An anti-reflective coating improves the efficiency of the Transitions product allowing greater transmission of light, which in turn causes the lens to darken faster. It is important to note that these lenses do not get as dark while driving as vehicle windshields have a UV blocker that prevents UV rays from activating the lenses.

Polarized lenses

For those who are light sensitive, polarized lenses provide relief from the brutal Texas sun. To understand how polarization works you have to know a bit about the properties of light. When sunlight reflects off a surface like water or the windshield of a car, it becomes intensified and is seen as glare. Tinted lenses only dim glare while polarized lenses counteract the intensified light allowing the wearer to see more comfortably. For those who spend time on the water, polarized lenses allow the wearer to see through the water’s surface to deeper waters below. For commuters or those who spend a lot of time driving, polarized lenses allow one to see clearer in misty conditions. Polarization is available in most prescriptions and many materials.