Wearing over-the-counter reading glasses, commonly called “readers,” directly over contact lenses is a widely accepted, effective, and safe solution for near vision difficulties. This approach allows individuals to maintain the convenience of contact lens wear for most activities while easily adding temporary magnification for close-up tasks like reading small print or viewing a smartphone screen. This dual-lens strategy provides a simple, non-prescription method to achieve clear vision at all distances.
How the Combination Corrects Vision
The eye’s natural lens, located behind the iris, is flexible when a person is young, allowing the surrounding muscle to change its shape and focus light clearly onto the retina for close-up tasks. Starting around age 40, this lens gradually hardens and loses elasticity, a condition known as presbyopia.
Contact lenses are specifically designed to correct baseline refractive errors, such as nearsightedness, farsightedness, or astigmatism. By correcting distance vision, the eye functions as if it required no correction for far viewing. However, the aging lens inside the eye still lacks the ability to change shape for near focusing.
The reading glasses then supply the necessary supplemental focusing power, known as the “add power,” to compensate for the stiffened lens. This power is measured in positive diopters, which are units of optical strength. The simple convex lens of the reading glasses bends the light rays before they enter the eye, effectively moving the near focal point back onto the retina, allowing for comfortable close-up reading. This combination is a practical way to restore near vision without changing the distance correction provided by the contacts.
Selecting the Right Reading Glass Strength
Reading glasses are labeled with their power in diopters. The strength required increases with age; early presbyopes in their 40s start in the +0.75 to +1.50 range, and those over 60 require +2.25 or higher. Since contact lenses correct distance vision, the power of the readers needed is independent of the contact lens prescription.
To determine the correct strength, hold reading material at your normal comfortable reading distance, typically about 14 to 16 inches away. Start with a lower power, such as +1.25, and try progressively stronger lenses until the text appears clear and comfortable without strain.
If between two lens strengths, choose the lower power option. Selecting a lens that is too strong can cause eye strain, leading to discomfort or headaches during extended reading periods. Also, consider the fit of the frame, ensuring it is comfortable and does not cause distortion, as a poor fit can affect the optical center of the lens and reduce clarity.
Professional Alternatives to Combining Lenses
Professional eye care providers offer alternative solutions that eliminate the need for a separate pair of glasses. One option is multifocal or bifocal contact lenses, which incorporate multiple corrective zones on a single lens. These lenses feature separate zones for distance and near vision, and sometimes an intermediate zone, allowing the wearer to see clearly at various ranges.
Multifocal lenses provide a more natural visual experience and maintain better depth perception. However, because the light entering the eye is split between the near and far prescriptions simultaneously, some individuals may experience reduced contrast sensitivity or notice visual disturbances like halos, particularly in low-light conditions.
Another alternative is monovision correction. The dominant eye is corrected for clear distance vision, while the non-dominant eye is corrected for clear near vision. The brain learns to automatically favor the image from the appropriate eye for the task at hand, whether reading or driving. While many patients adapt well to monovision, it can result in a measurable reduction in stereoacuity, the ability to perceive depth.