Even though having a recommendation makes shopping for the right lens easy, we want you to understand the different specifications for each lens type and lens material. Let’s take a look at the lenses we offer, the various prescription types, and the prescriptions within those types the lenses cover.
Single Vision vs Multifocal
Each optical lens we offer accommodates a specific prescription range. The two broad prescription categories are single vision and multifocal (which comprise bifocal and progressive lenses).
For single-vision, iframefit can cover prescriptions for nearsightedness that go up to -20.00 and farsightedness up to +12.00. Nearsightedness and farsightedness are corrected according to the numbers in the Sphere (SPH) section of a prescription. You can learn more about how to read your prescription here.
You may be interested in a multifocal lens if your prescription includes a near add (ADD) power. iframefit can cover progressive prescription ranges -10.00 / +8.00 and bifocal prescription ranges -9.00/ +6.00. For progressives, we recommend using lenses that have at least a depth of 30 mm to cover the various fields of vision that come with multifocal lenses.
Remember that these prescription ranges can be further limited depending on the lens material or index that you choose.
Lens Index Options
iframefit offers several different lens index options from thickest to thinnest. From 1.499 to 1.74 Index.
Factors That Affect Lens Thickness
When buying glasses, there are three primary factors that affect your overall lens thickness:
- Prescription – Your prescription is what will ultimately determine how thick your lenses will be. Simply put, the higher the prescription, the thicker the lens. In addition, prescriptions with moderate to high astigmatism correction often result in thicker lenses.
- Lens Material or Lens Index – The lens index refers to the “index of refraction,” or how much the lens bends the light that enters it. This ensures that the light is focused properly onto the retina, helping you to see clearly when wearing your glasses. In general, the higher the index, the thinner the lens. (For example, a 1.61 lens is thinner than a 1.56 lens.) During the checkout process at iframefit, choosing a higher lens index will be the most direct way to ensure you have the thinnest lenses possible.
- Lens Size – The overall width and height of your lenses can have a considerable impact on the thickness of the lenses themselves. The bigger the lens, the thicker it tends to be. When buying frames at iframefit, the lens width and height are predetermined based on the frame you choose. Aside from choosing frames based on factors like style and face shape, you should also shop based on size, as well as your eye doctor’s recommendations.
Now that you understand the best lens index options for your prescription, you can learn about the different lens options that iframefit offers, such as photochromic lenses and blue light blocking lenses.