The lens that is pre-selected as a recommended option in ② Your Lenses during the ordering process will be the best option for your Rx. If you have a strong Rx, a higher lens index number will give you a thinner lens. Read on below to learn what affects lens thickness. 

What Affects Lens Thickness?

When buying glasses, there are three primary factors that affect your overall lens thickness:

1. Prescription. This 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.

2. 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 1.50 lens.)

During the checkout process at Zenni, choosing a higher lens index will be the most direct way to ensure you have the thinnest lenses possible. Note: the lens index that is recommended for your prescription during checkout will be the most appropriate lens choice.

3. 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 Zenni, 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.