There are many different types of lenses. Your doctor and optician will work together to choose which option best meets your specific needs.
Single vision lenses are lenses designed to correct only one refractive error. Any lens that includes an add power for the correction of presbyopia will be a variation of a multi-focal lens.
This lens is used to correct distance refractive errors plus the condition of presbyopia. These lenses will have two (bi) distinct areas of clear vision. Bi-focal widths can be 28mm, 35mm 45mm. The power in the segment allows patients to read and view objects at approximately 16 inches or “at near”.
These lenses will have three (tri) distinct areas of clear vision. One for distance, one for intermediate at approximately 30 – 40 inches and one for the near vision. Trifocal sizes include, ST 7 X 28 , or ST 8 X 35, ST stands for Straight Top, the first number 7 or 8 indicates the height of the intermediate zone and the second number 28 or 35 indicates the width of the segment.
Progressive lenses are used to correct distance vision plus the condition of presbyopia. These lenses have a distinct distance area and a variable non-specific power corridor that provides a wide range of viewing areas from near or 16 inches to intermediate approximately 30-40 inches, to anything within 20 feet of the eye.
Digital Progressive Lenses
Digital lenses utilize a computer aided process of surfacing lenses. This allows for more accurate prescriptions and designs that allow for wider intermediate and reading areas. These designs reduce the amount of peripheral astigmatism blur that occurs in progressive lenses. Providing for easier adjusting and greater versatility than a standard surfaced lens.