On cataract and clear lens extraction the lens, cloudy or “transparent”, is replaced by an intraocular lens.
Previously, the selected intraocular lens, apart from providing the transparency lost due to the cataract, provided the patient with good far sight without needing glasses or contact lenses. Regarding the vision in other distances, the patient still needed reading glasses for a good near and intermediate sight.
Monofocal IOLs are the lens type that provide the visual outcome we have just described. These intraocular lenses have only one focus whose diopters are calculated for the patient to have a good far sight without glasses. Even if this type of lens appeared years ago, it is still the most implanted intraocular lens. Most insurance companies cover them (without additional cost) and they are used in public health care (with a few exceptions).
Are all multifocal lenses the same?
The technological development in the optical field as well as in the materials used, has allowed the existence of alternatives to this monofocal design and has boost the development of lenses with more than one focus area: multifocal lenses. The objective of the manufacturers of this type of lens is clear: give the patient that has undergone the surgery a better visual quality without glasses at all distances (near, intermediate and far) and in all light conditions.
Following this objective, manufacturers have developed very different types of lenses. The current multifocal lenses available on the market differ from the materials used, the optical purpose (diffraction, refraction), the number of focus (bifocal, trifocal), the filters…and, obviously, they provide a “different vision” to the patient. The question that arises in the patient is: what of these multifocal lenses on the market is the one I am going to get?
When are multifocal intraocular lenses implanted?
Multifocal intraocular lenses are implanted in patients suffering from cataracts as well as those that want to get rid of the glasses and are good candidates for this surgery.
- When the patient suffers from cataracts, he does not have a lot of options and, sooner or later, he will probably need to undergo surgery in order to replace his cloudy lens for an intraocular lens. Thanks to multifocal lenses, the patient has the option of not only “seeing right again” after surgery, but also be able to see well at all distances without needing glasses or contact lenses.
- In the case of the patient with a lens that is not clouded but does not accommodate well due to presbyopia (or apart from presbyopia he has any other visual impairements: myopia, hyperopia, astigmatism…) and depend on glasses or contact lenses that he wants to get rid of.
Nowadays, there are toric multifocal lenses that can also correct astigmatism during surgery.
What is the main characteristic of trifocal intraocular lenses?
As its name indicates, the existence of three focus areas (See optical principles to generate focus). These three focus areas correspond to far, intermediate and near vision.
Their objective is to provide a “focus area” for each “visual distance” that we use in our daily life. Apart from a near and far focus, these lenses provide a specific focus for intermediate distance, providing a good vision required more and more for the use of tablets and computers.
When dividing light in three focuses (instead of only one focus like in monofocal lenses) situations where better lighting is required may appear. Lenses designs are fundamental to reduce energy loss and the need for additional light.
As well as the rest of multifocal lenses, the design of this lens is important to minimize the presence of halos and optical phenomenon at night. The latest models have been greatly improved in this regard.
How much do they cost?
Trifocal lenses are premium intraocular lenses and are not usually covered by any insurance company. Thus, these lenses are mainly paid by the patient himself (in most countries the cost of the lens is included on the price of the surgery but this changes depending on the chosen lens). Due to its characteristics, this lens is normally one of the most expensive ones.
What can I expect from my surgery with trifocal lenses?
Once we decide to go for multifocal lenses, we must establish our visual expectations after surgery in order to choose what type of IOL. On this selecting process, it is clear that nowadays we must assess the option of trifocal lenses together with the rest of multifocal designs.
Because these lenses have three focus areas, they are designed to allow a correct sight at all distances without the need of glasses. Their good results have been already tested by experience and supported by many scientific studies that provide many excellent visual results.
What are the alternatives to trifocal intraocular lenses?
An alternative to achieve similar postoperatory visual outcomes at all distances is the application of a strategy called “Blended vision”. A non-trifocal multifocal lens is selected, having a lower addition on the dominant eye and higher addition on the non-dominant eye. This strategy can help achieve excellent binocular results. The Mplus iols, from the manufacturer Oculentis, allow the combination of different iol models providing advantages for far sight on the dominant eye with advantages for near sight for the non-dominant eye.
What models of trifocal lenses can I get?
Nowadays, there are a few iol manufacturers that provide a trifocal model. We have been contacted by patients with a high level of satisfaction that wear the FineVision lens from the manufacturer Physiol. There is also a model provided by the manufacturer Zeiss.
The surgeon, based on his experience, will recommend you the type and specific model of intraocular lens that best fits your expectations and ocular situation. That is why the patient needs to provide his surgeon with all the information related to his visual expectations (life style, character…). According to your needs, the surgeon will explain you everything related to the surgery as well as the visual expectations that you may have after surgery with the chosen lens (neuroadaptation process, possibility of experiencing halos, the need of better lighting, dependence on glasses…). Do not hesitate to discuss with your surgeon any doubt regarding the type of lens selected.