Traditional lens implants are “single focus” lenses, which are generally selected for distance vision. They may be made of a highly polished and very stable plastic material called PMMA (polymethyl methacrylate), or of silicone or flexible acrylic material that allows folding of the lens and placement through a smaller incision. They are made with a central optic (lens) and two opposing flexible spring-like haptics, which press against the sides of the lens capsule to keep the implant centered in the eye.
These lenses are largely covered by Medicare and private insurers. Some “new technology” traditional lenses such as the Tecnis Z9000s (Abbott, Inc.) have special aspheric designs, which may provide better focus under conditions such as fog, rain, or dim light. All of these lenses typically provide excellent distance vision, but most people who have these lenses need reading glasses for near vision. All of these lenses have a tried and proven design and are the type most commonly used for modern cataract surgery.
Presbyopia-Correcting Lens Implants
New lens implants that provide enhanced near vision, in addition to good distance vision, have recently been developed. These new lens implants may eliminate or greatly reduce dependence on reading glasses after cataract surgery. They correct near vision by either a multifocal design or by an accommodative design. One of our preferred multifocal lens implants is the Tecnis Multifocal by Abbott. This lens is based upon the aspheric design of the single-focus Tecnis lens mentioned above, but it has concentric rings of near focus built into the lens. As a result, this lens provides not only distance focus, but intermediate and reading vision as well. Approximately 9 out of 10 patients who have this lens implant don’t need glasses for any range of vision. The dual focus nature of this lens means that, immediately after surgery, some patients may notice a slight glare and halos (rings around lights) at night. However, as the eye adjusts to the lens over time, the visual impression of the rings tends to diminish and, as a result, over 94% of those who have this lens would choose it again. Learn more about Tecnis Multifocal.
The Crystalens® implant by Bausch & Lomb is the first lens implant approved by the FDA that provides near vision by accommodation, using the natural near focus system of the eye. This implant has a smooth, single-focus lens supported with hinges, which allow the lens to shift in position in response to focusing effort. This approach provides a seamless, full range of vision and avoids some of the issues associated with multifocal design, which may include reduced contrast vision and halos around light sources at night. In 2003, Dr. Lueth became the first practicing ophthalmologist to have the Crystalens® implants placed in his own eyes when he underwent lens surgery at age 49.
These new lenses are more expensive than a traditional lens and the added near function is considered a refractive benefit, which is not covered by Medicare and most private insurances. These additional charges are usually an out-of-pocket expense. Treatments for astigmatism and refinement of the distance vision by laser PRK are usually included with these lenses if needed.