Understanding Your Prescription
Are You Farsighted or Nearsighted?
Your eyeglass prescription will include numbers that may be confusing to you. On your prescription, your eye doctor will list the vision correction necessary for your left and right eye. Generally, if there is a plus ("+") sign before your prescription, this means that you are farsighted - meaning you have trouble seeing things up close. If there is a minus ("-") sign before your prescription, this means you are nearsighted and have trouble seeing far away. The higher the number is after the "+" or "-" sign, the greater the vision correction you need.
Do You Need Single Vision or Multifocal Lenses?
The prescription you receive from your eye doctor will require either single vision, bifocal, or trifocal lenses. Single vision lenses correct either distance or close vision depending on if you're nearsighted or farsighted.
If you have a prescription for bifocal or trifocal lenses (called multifocal lenses), this will correct both distance and close vision and perhaps middle range vision as well. Progressive or no-line lenses are considered the ultimate multifocal lenses because they provide a smooth visual transition from near to far without jumps in focus. And since progressive lenses have no lines, no one can tell you're wearing bifocals or trifocals.
KNOWING YOUR CHOICES IN LENS MATERIALS
Polycarbonate Lenses - Polycarbonate lenses are the lightest and most durable eyeglass lenses available - they really are the ultimate lenses. While no lens is completely shatterproof, polycarbonate lenses offer the highest level of impact resistance available. They're also 10 times stronger than, and up to 30% lighter than, plastic lenses. Plus, they're up to 15% thinner than traditional plastic lenses and have built-in UV protection. Ask your Optician, Optometrist, or Opthalmologist if polycarbonate lenses are a good choice for you.
High Index Lenses - For those with a strong prescription, high index lenses provide a thinner lens alternative than ordinary plastic lenses.
Plastic Lenses - Plastic lenses offer greater durability and comfort than glass lenses. Lighter than conventional glass lenses, plastic lenses should be specially treated for scratch resistance, and can be UV protected or tinted as well.
Glass Lenses - Glass lenses are the original lenses first used in eyeglasses. These lenses are heavier than plastic and polycarbonate lenses and are rarely used today.
LENS OPTIONS TO PROTECT YOUR EYES AND YOUR GLASSES
UV Protection - If you are exposed to a large amount of UV light, whether from being outdoors in the bright sunlight or from spending a lot of time in offices with fluorescent lighting, you are at risk. UV light is harmful to your eyes and is believed to contribute to the formation of cataracts. Polycarbonate lenses offer built-in UV protection, but UV protection can also be added to plastic lenses.
Tinted Lenses - Sunglass tints are a popular choice on prescription lenses allowing you to see clearly in bright sunlight. Fashion tints or tints to protect light-sensitive eyes are also available in a wide range or colors.
Scratch Resistance - Scratch-resistant protection can be added to your lenses to protect them from abrasions and scratches. Blurring and blind spots caused by lens scratches are less likely to occur, providing you with better vision.
Anti-reflective - Anti-reflective lenses allow you to see better by reducing reflections caused by lights, TVs, and computer screens. By reducing annoying reflections, anti-reflective lenses offer clearer, sharper vision especially when driving at night.