Cataracts are a leading cause of poor vision. Cataract surgery represents an exciting opportunity to improve the quality of your vision. The type of intraocular lens implant (IOL) you can receive depends on your individual circumstances. These fall into three main categories: monofocal (can correct your sight for one distance, typically for distance or for near), multifocal (they split the light over a number of distances, normally three or four to provide you with distance, intermediate and near vision) and extended depth of focus (EDOF) IOLs.
Each of these lens implants can achieve different outcomes for your visual function and each come with benefits and compromises.
EDOFs are a particularly exciting option for surgeon and patient alike, for a number of reasons. Clear intermediate vision is now more important to people than ever, given our use of smart phones and tablets. With an EDOF implanted in each eye, patients can achieve adequate distance and intermediate vision, for most daily visual tasks including cooking, painting or computer work.1 To achieve such flexibility in visual function, patients previously had to opt for a multifocal IOL. Multifocal IOLs are still a safe and effective option when implanted in the correct type of patient. They split light into distance, intermediate and near distances but do come with compromises. There is a chance of you noticing glare and haloes around light sources (which in some cases can affect your ability to drive at night) and some patients notice a reduction in their ability to discern fine detail (caused by reduced contrast sensitivity).2
Studies have shown EDOFs are less likely to cause troublesome glare and halo symptoms, having a very similar side effect profile to a standard monofocal lens implant. It is widely accepted that they are not as effective as giving effective unaided (without glasses) near vision, when compared to a multifocal IOL. Patients often have to wear reading glasses for prolonged near visual activities.
There are many variables to consider and your consultant will assess your suitability for each type of lens implant, by taking a detailed history from you in order to assess whether these lenses are likely to benefit you. Your eye will also be examined and specific scans performed to identify the options available to you. It is really important to carefully weigh up the pros and cons of each lens implant carefully. A consultant with specific training in refractive cataract surgery will guide you through your journey.
Mr Steven Naylor MBChB (Hons), PG Cert (Dis) Surgical Science, FRCOphth, CertLRS
References
- Auffarth GU, Gerl M, TYsai L et al. Clinical evaluation of new monofocal IOL with enhanced intermediate function in patients with cataract. JCRS 2020; 47(2): 184-197
- Yoon SY, Song IS, Kim JY et al. Bilateral mix and match versus unilateral multifocal intraocular lens implantation: long term comparison. JCRS 2013;39:1682-1690