Stick-on bifocals are thin, flexible lens segments designed to adhere to existing eyewear, converting single-vision glasses, sunglasses, or safety glasses into bifocals. These ultra-thin lenses allow users to maintain distance vision while gaining near-vision magnification for reading or close work. They adhere using only water and surface tension, making them temporary, removable, and reusable, which is a practical and cost-effective alternative to purchasing separate prescription bifocals. This guide clarifies pre-purchase considerations and details the retail channels available for acquiring these specialized lenses.
Understanding Diopter Strength
Determining the correct diopter strength is the primary consideration before buying stick-on bifocals. Diopter strength is the unit of measure for lens optical power, indicating the magnification needed to bring close objects into clear focus. These bifocals are generally available in strengths increasing in increments of +0.25, typically ranging from +1.00 to +3.50 diopters.
The easiest way to find your required strength is to use your current reading glasses prescription or try on various strengths at a retail store. If you have a recent comprehensive eyeglass prescription, calculate the required reading strength by adding the “ADD” power to the Sphere (SPH) value listed for each eye. This total positive power corresponds to the diopter strength you should purchase. The stick-on lens only provides additional magnification for reading and does not alter the prescription of the glasses they are applied to.
Retail Channels for Purchase
Stick-on bifocals are available across multiple retail environments, each offering different benefits in terms of price, selection, and immediate access.
Online Specialty Retailers
Dedicated optical supply websites and brand-specific online stores are a reliable source for stick-on bifocals. These retailers carry recognized brands, such as Hydrotac or Sticktoit, and offer the full range of available diopter strengths. Purchasing directly from a specialty site ensures authenticity and provides access to detailed product information and customer support. Prices for a pair of lenses generally range from $15 to $20, and these sites frequently offer clear return policies if the selected diopter strength is incorrect.
Major E-commerce Platforms
Large online marketplaces, including sites like Amazon and Walmart, offer a wide variety of stick-on bifocal brands and generic alternatives. This channel provides convenience and competitive pricing, often through multi-pack deals that reduce the per-unit cost. When buying from these platforms, check the seller’s rating and read customer reviews to verify the quality and optical clarity of the lenses. The price range is similar to specialty sites, though bundled offers can provide a lower cost.
Physical Retail Locations
For immediate access, physical stores such as large pharmacy chains and drugstores carry stick-on bifocals, usually near over-the-counter reading glasses. The selection of brands and diopter strengths may be more limited compared to online channels, but the advantage is the ability to purchase and use the product immediately. Optical shops may also stock them, particularly for customers needing to modify safety glasses or diving masks. Prices in physical stores can be slightly higher than online marketplaces, but the instant availability is useful for urgent needs.
Application and Maintenance Considerations
Applying the lenses is straightforward, relying on the principle of adhesion via surface tension. To apply, first clean the inner surface of your primary glasses thoroughly. Place a small drop of clean water onto the lens where the bifocal segment should sit. The pliable, half-moon shaped lens is then pressed onto the water droplet, allowing it to be slid into the precise position—typically centered horizontally and near the bottom of the lens. Gently press out any air bubbles and excess water with a lint-free cloth.
The lenses should be allowed to dry and bond for several hours, with some instructions recommending up to twelve hours, to ensure a secure fit before use. If the lens shape is too large for your frames, it can be trimmed to size using scissors before application. For cleaning, use only warm water and a soft cloth; avoid harsh chemical cleaners or abrasive materials, as these can damage the lens material or compromise adhesion. Since the lenses are reusable and removable, they can be peeled off and reapplied to other glasses, offering flexibility, though they may eventually need replacement.