A “near add” on an eye prescription indicates additional lens power for viewing objects up close. This adjustment helps individuals see clearly during tasks like reading, using a computer, or engaging in hobbies that require close focus, compensating for changes in the eye’s natural focusing ability.
The Condition Behind Near Vision Needs
The need for a “near add” stems from a common, age-related eye condition known as presbyopia. This condition typically begins to affect individuals around the age of 40 and progresses over time.
Presbyopia occurs as the eye’s natural lens, which is normally flexible, gradually hardens and loses its ability to change shape effectively. This hardening prevents the lens from focusing light precisely on the retina for close-up images.
As a result, objects at reading distance appear blurry, leading to common symptoms such as difficulty reading small print, eye strain, and headaches. Many people find themselves holding reading materials farther away to achieve clearer focus. While presbyopia is a natural part of aging, its progression often stabilizes around age 60.
What Your “ADD” Number Means
On an eye prescription, “ADD” stands for “addition” or “near addition,” and it quantifies the extra magnifying power required for near vision tasks. This value is measured in diopters (D), which is a unit indicating the optical power of a lens. The “ADD” number is always a positive value, typically ranging from +0.75 D to +3.00 D, and is usually the same for both eyes.
This diopter value is added to your distance prescription’s spherical power to create the total power needed for near vision. For instance, if your distance prescription has a spherical power of +1.00 D and your “ADD” is +2.00 D, the near portion of the lens will effectively be +3.00 D. A higher “ADD” number indicates a greater degree of presbyopia and thus a stronger need for magnification to see close objects clearly.
How Near Add is Incorporated into Lenses
The “near add” power is integrated into various types of multifocal lenses, allowing for clear vision at multiple distances within a single pair of glasses.
Bifocal Lenses
Bifocal lenses feature two distinct optical powers separated by a visible line. The upper part corrects distance vision, while a smaller, lower segment contains the “near add” power for close-up tasks. This design requires individuals to shift their gaze to look through the appropriate section.
Trifocal Lenses
Trifocal lenses expand upon bifocals by including three distinct viewing zones. A middle segment provides correction for intermediate distances, such as viewing a computer screen, in addition to distance and near vision. These lenses also have visible lines separating the different power zones.
Progressive Lenses
Progressive lenses, also known as no-line bifocals or varifocals, offer a seamless transition between distance, intermediate, and near vision without any visible lines. The “add” power gradually increases from the top (distance vision) to the bottom (near vision) through a corridor of progressive magnification. This design provides a more natural visual experience, allowing the eye to find the appropriate power for any distance simply by adjusting the gaze.
Adjusting to New Near Vision Lenses
Adapting to new lenses that incorporate a “near add,” especially progressive lenses, requires a period of adjustment. Initially, individuals may experience some blurriness, slight distortion, or the sensation of objects “swaying” in their peripheral vision. These effects are normal as the brain learns to interpret the new visual information from the different lens powers.
Consistent wear is important during this adaptation phase to help the eyes and brain become accustomed to the new visual experience. Practicing proper head and eye movements can also aid adjustment; for instance, tilting the head slightly to look through the correct part of the lens for different distances.
While some people may experience brief dizziness or nausea, these symptoms typically subside as the brain adapts to the lenses. Patience is key, as full adjustment can take anywhere from a few days to several weeks.