You can get bifocal sunglasses, which are a practical solution for the age-related vision change called presbyopia. This condition reduces the eye’s ability to focus on close objects, making tasks like reading a book or checking a phone difficult while wearing standard distance-only sunglasses. Bifocal sunglasses solve this by incorporating a reading correction into the lower portion of the lens. This allows you to see clearly far away and up close without constantly switching eyewear.
Lined Bifocal Versus Progressive Lens Designs
The term “bifocal” is often used broadly, but two main lens designs incorporate multiple focal powers into a single sunglass lens. The traditional lined bifocal features a distinct, visible line separating the larger distance-viewing area from the smaller, magnified reading segment at the bottom. When the eye shifts from the distance zone to the near zone, the image instantly “jumps” due to the abrupt change in optical power at the dividing line. This design provides maximum clarity within each segment but lacks correction for intermediate objects, such as a car’s dashboard.
A progressive lens, often called a “no-line bifocal,” offers a more seamless visual experience. It transitions gradually from the distance prescription at the top, through an intermediate viewing corridor, to the full reading power at the bottom. This design eliminates the distracting line and the image jump, offering a more natural field of vision across all distances. However, the blending of powers creates areas of soft, peripheral distortion on the sides of the lens corridor, requiring the wearer to point their nose directly at the object of focus.
The seamless appearance of a progressive lens is preferred for cosmetic reasons, as the lack of a visible line makes the sunglasses look like standard single-vision lenses. While lined bifocals provide a wider viewing area for both distance and reading, progressive lenses offer the advantage of clear vision for intermediate tasks. Choosing between the two depends on your daily activities and sensitivity to the visual distortions inherent in each design.
Ready-Made and Prescription Options
Consumers have several options for acquiring bifocal sunglasses, ranging from ready-made pairs to customized prescription lenses. The most accessible option is over-the-counter (OTC) reading sunglasses, which feature a non-prescription distance area with a small reading segment embedded near the bottom. These are suitable for individuals who only need magnification for reading and have no other refractive errors for distance vision. They come in fixed reading powers, such as +1.50 or +2.00 diopters, making them an inexpensive choice for occasional use.
Another simple, temporary solution involves using adhesive bifocal segments. These are small, semi-circular lenses made of soft plastic that stick to the inner surface of any existing sunglass lens. These segments can be positioned by the user to turn any pair of sunglasses into a bifocal pair, working well for activities like fishing or cycling where a temporary reading boost is needed. For the highest level of visual acuity and customization, full prescription bifocal or progressive sunglasses are the best choice, as they incorporate the wearer’s specific distance and astigmatism correction, ensuring all focal zones are precisely matched.
Ordering prescription bifocal sunglasses requires a current eye examination that includes the reading power, known as the ADD power. These custom lenses can be fitted into virtually any sunglass frame, including high-wrap sports styles, and often include features like polarization or specialized tints. While they represent the greatest investment, prescription options provide the clearest and most comfortable vision for continuous wear outdoors.
Essential Measurements for Custom Sunglasses
When opting for custom prescription bifocal or progressive sunglasses, two measurements are important for ensuring the lenses function correctly: Pupillary Distance (PD) and segment height. Pupillary Distance is the measurement, in millimeters, between the centers of the pupils, which dictates where the optical center of the lens should be placed horizontally. If the PD is measured inaccurately, the wearer may experience eye strain or prism effects, where images are shifted.
The segment height is the vertical measurement that determines the precise placement of the reading segment within the lens aperture of a specific frame. For lined bifocals, this dictates the height of the top of the reading segment relative to the pupil. In progressive lenses, the segment height determines the vertical position of the intermediate and near viewing corridors. Because this measurement is dependent on the specific frame, it must be taken while the wearer is wearing the chosen sunglasses to ensure the reading zone is positioned correctly for their natural gaze.