MULTIFOCAL INTRA-OCULAR LENS AND EDOF
Lens surgery has been around for millennia. The current technique, the lens phacoméulsification exists since 1967. It allows to remove the lens through a 2mm small incision which usually does not require suture.
This procedure can treat myopia, hyperopia, astigmatism and also presbyopia. It may be interesting when a candidate for refractive surgery presents a appearing cataract (which happens earlier in case of strong myopia). It can also be considered after the age of 50 (when the patient loses his focus capacity). Finally, this technique is since short proposed to patients wishing to solve their presbyopia problem (nearsightedness problems after the age of 45). This is the PRELEX technique: PREsbyopic Lens Exchange. The lens is replaced by a multifocal intra-ocular lens, diffractive (PhysiolFineVision, TecnisSymphony, AlconPanoptix, ...), refractive (Lentis Comfort MF15 / MF30, ...) or EDOF "with extended depth of field" (Lucidis, ...).
This is an intra-ocular surgical procedure (the same as the cataract procedure). It is performed under local anaesthesia by drops with lens removal and placement of an intra-ocular lens.
The different types of lenses
There are different types of multifocal lenses. The benefits of those different lenses depends on their design. Multifocal diffractive lenses allow far-, intermediate and near-sightedness without glasses, but can cause light hales. Refractive and EDOF lenses generally provide better visual quality and resolution, but near vision can be slightly less efficient. Your surgeon, specialist in this type of lens, can guide you in the choice of the lens that best suits you.
Visual recovery is fast (24 hours most of the time) and painless. The monofocal implant will give good far-sightedness (glasses are needed for reading) or near-sightedness (glasses are necessary for distant vision). Multifocal implants are detailed in the section above.
- Multifocal diffractive implants can induce a slight reduction in contrast and the perception of halos around light sources.
- To be effective, the multifocal implant must be chosen to perfectly correct far-sightedness. As accurate as the pre-operative measures are, a small error margin is always possible. In this case, either the implant will have to be removed and replaced by another one, or a laser treatment will be needed to correct the residual defect.
- Some complications may occur: retinal detachment, post-operative retinal edema, infection (0.1%), inflammation. These complications are rare.
This technique must be reserved for certain very specific indications (age, focus, ...) and will only rarely be proposed without the presence of a cataract.