Presbyopia Correcting Lenses
The major classes of presbyopia correcting lenses that are available in the United States are the Multifocal (MF),Extended Depth of Focus (EDOF), and accomodative lenses.
Standard intraocular lenses have a single focal point. The focal point is the distance at which the best focus occurs, like a camera focusing on a single object. For a little way inside and outside of that point, acceptable but not perfect focus occurs. This is the depth of focus of the lens. Even standard lenses have some depth of focus.
Multifocal presbyopia correcting lenses focus some light at near, and some at distance. Most manufacturers provide three different strengths of near vision add. The higher the near add power, the closer the near focus, but also the greater the side effects such as glare, halos, and loss of contrast. There is a tradeoff between how close you can hold things and how noticeable the side effects are.
The extended depth of focus (EDOF) lens lens acts like a low powered multifocal lens.
The accommodative lens is able to move back and forth inside the eye to adjust focus.
Your surgeon may recommend mixing the lenses; for example, EDOF lens in the dominant eye, and MF lens in the non dominant eye. This is a complex topic that is beyond the scope of this website. There is an art to choosing the correct lens or lens combination. Most surgeons settle on a particular approach that they feel works best in their hands. Enthusiasm for presbyopia correction varies widely among cataract surgeons. This makes it especially important that you have an idea of what you are getting, and not getting, when you opt for presbyopia correcting lenses.
Side Effects of Presbyopia Correcting Lenses
MF/EDOF lenses can cause glare, halos, and loss of contrast.
The presbyopia correcting lenses provide near vision for practical tasks including texting and reading menus, but are not optimal for prolonged reading. Many people who have presbyopia correcting lenses will still choose to use reading glasses occasionally for detailed work.
With MF/EDOF lenses, there is almost always some small amount of glare or halos under certain conditions. How happy you are with presbyopia correcting lenses may depend on your personality, health of your eye, and goals. Read up on the 4P's (Personality, Physique, Pathology, and Predispositions) here.
Consider also the alternative of monovision and custom refractive design.