Prescription Lenses - Dr. Jiwani & Associates

Prescription lenses are prescribed after we determine from your comprehensive eye exam if you require lenses to correct vision problems such as nearsightedness, farsightedness or astigmatism.

Sometimes lenses can be used to protect your eyes from excess blue light from being on a computer all day. You will require a lens that addresses your particular vision issues. For this reason lenses are offered in many types, materials and coatings. This can be confusing if you haven’t purchased them before which is why we’re here to help you determine the best options for your prescription and your lifestyle.

We’ve done our best to explain what to look for in a prescription lens below to get you started.

What are the different types of prescription lenses?

Lenses come in different types to meet your vision correction needs. They are:

Single vision lenses – designed for one, consistent focal power to correct a single vision condition such as nearsightedness, farsightedness and astigmatism.
Progressive lenses – correct more than one vision condition, with the focal power “progressing” from top to bottom without a visible line separating them. These are lenses that provide near, intermediate and distance vision. The latest technology in progressive lenses is the digital progressive lens customized to meet your unique vision correction needs.
Concave lenses – are used to treat near-sightedness, or myopia. The lens shape is concave (thicker at the edge, thinner in the middle) to bend rays outwards.
Plus lenses – used to treat farsightedness, or hyperopia. The lens shape is convex (thicker in the middle, thinner at the edge) to bend rays inwards.
Cylindrical lenses — designed for astigmatisms, or when the cornea of the eye is oval, rather than round. A cylindrical lens is the most common way to correct astigmatism.

These lenses are manufactured in different materials. They include plastic, glass and polycarbonate. Plastic is the most common type of material used but with ordinary plastic lenses, a strong prescription can result in a thicker lens. In those instances you may want to consider lenses made of:

Hi-index plastic – this material is lightweight and thinner than most plastic offering an appealing aesthetic for greater comfort.
Polycarbonate – these lenses have superior impact resistance and are lighter than regular plastic lenses. They may be 20% thinner and 30% lighter than standard plastic lenses, yet they are very resistant and durable.

What else do I need to know when choosing prescription lenses?

There are other benefits most lenses offer which are important for safety and durability. They are:

Anti-scratch coating

lightweight eyeglass lens materials are significantly softer and more prone to scratches and abrasions than glass lenses. Though all plastic and high-index plastic lenses require a factory-applied anti-scratch coating for adequate lens durability to make your lenses scratch resistant if you’re hard on your glasses or you’re buying eyeglasses for your kids, you may want to consider lenses that include a warranty against scratches.

Anti-reflective coating

An anti-reflective (AR) coating eliminates reflections in lenses that reduce contrast and clarity, especially at night. They also make your lenses nearly invisible, so others aren’t distracted by reflections in your lenses when talking to you. AR-coated lenses are less likely to show glare and this is important if you opt for high-index lenses, because these types of lenses can reflect up to 50 percent more light, causing significantly more glare.

UV-blocking treatment

Cumulative exposure to the sun’s harmful UV rays has been associated with age-related eye problems including cataracts and macular degeneration. Though polycarbonate and nearly all high-index plastic lenses have 100 percent UV protection built-in due to their materials, other types of plastic lenses need an added coating applied to provide equal UV protection. Make sure you’re protected.

Photochromic treatment

This lens treatment enables eyeglass lenses to darken automatically in response to the sun’s UV and high-energy visible light rays and then quickly return to clear (or nearly clear) when indoors so you don’t have to constantly change your prescription glasses to your sunglasses. Photochromic lenses are offered in virtually all lens materials and designs.