How to Choose your Intraocular Lens for Cataract Surgery

Leo Sheck

Minute read

Over the last 10 years, there has been a rapid advancement in the types of intraocular lenses (IOL) available for cataract surgery. When you have your cataract surgery with Dr Leo Sheck, you will have access to the latest lens technology to achieve the quality of vision you desire. Here is my guide to the commonly available IOL. This is not an exhaustive list, and if there is a specific IOL you would like to consider, please discuss this directly with Dr Sheck.

Monofocal IOL

Monofocal IOL is the first time of IOL available for cataract surgery. These IOLs have only a single focus, and like your glasses, the power of these IOLs are denoted by its dioptres (e.g. 21D would be a typical IOL used in an eye with average axial length and keratometry measurement). If you have your cataract surgery in the public system, you will likely received one of these IOLs.

These IOLs are great at providing a single, very sharp focus, at the chosen focal point. However, any other distances outside of this focal point will be blurry without glasses. Typically, patients will choose to have this focal point at infinity, i.e. good distance vision or emmetropia, and wear glasses for intermediate and close up work.

Some patients may choose to have one eye focused for distance, and the other focused more up close, in a set up called "blended vision" to lower their dependency on glasses. However, with a monofocal IOL, one will always have some degree of glasses dependency for their activity of daily living.

The price of a monofocal IOL is always included in the cost of a cataract surgery.

The intuition behind premium IOLs

There is a desire from both patients and ophthalmologists to achieve a better range of vision after cataract surgery. Patients want their eyes to be like when they were younger, with good distance, intermediate and near vision without glasses. However, unlike our natural lens, IOL are made of acrylic, and cannot change shape (accommodate) after implantation. So, the natural solution of having an IOL that can shift focus is not possible, and the current solution is to a range of focus simultaneously present in the IOL to give glasses free distance, intermediate and near vision.

Multifocal IOLs

Initially, IOL manufacturers produce bifocal IOLs (e.g. Alcon Restore, now discontinued) to give both distance and near vision. These IOLs employ diffractive technology for their near segment (see diagram below).

A multifocal IOL with the distinctive diffractive ring design

The current iteration of multifocal IOLs are typically trifocal IOLs, with distance, intermediate and near segments. As a result, patients are likely able to achieve good distance, intermediate and near vision, and it is possible (but not always) to be able to read without any reading glasses.

However, there is a trade-off with these IOLs. Because of the diffractive rings, patients will definitely get halos and glare, and these symptoms are noticeable especially when driving in the dark with the point source of light coming from cars and street lights. There is also a degradation of contrast and the diffractive design will lead to some loss of light. As a result, these IOLs cannot be implanted in patients with or at risk of macular diseases, and there is a risk of needing explantation due to suboptimal vision quality.

You can find further information of these IOLs here.

Alcon PanOptix
Teleon Lentis MF30 (only for non-dominant eye)
Raynor Galaxy

Extended depth of focus (EDOF) IOL

This is a newer type of premium IOL that use a non-diffractive design to achieve a range of focus. As there are no diffractive rings, there is no loss of light and much less halos and glare, as compared to the multifocal IOLs above. EDOF IOLs will provide good distance and intermediate vision, and "functional" near vision, i.e. able to read unaided with good lighting, but will need glasses when reading at low light setting.

A schematic from the Alcon Vivity EDOF IOL illustrating the possible refractive outcome

A good way to think of EDOF IOL is that it will provide you with more youthful vision. Imagine back to the time when you first needed reading glasses. You are still able to to almost everything without glasses, but you are only reaching out for your +1.5D when you are reading at night. So, yes, with an EDOF IOL, you are still needing reading glasses, but you will be much less dependent on them.

Furthermore, there is new research from a team in Sydney to show that, unlikely multifocal IOLs, EDOF IOLs can be safely implanted in patients with macular diseases with good vision outcome. So, if you have macular diseases or are at risk of developing maculopathy, you are be reassured that an EDOF IOL will be safe for you to use.

You can find further information on EDOF IOLs here:

Raynor Rayone EMV (strictly an enhanced monofocal IOL but with up to 1.5D of defocus) - patient information and surgical brochure
Teleon Lentis Comfort
Alcon Vivity

How about toric IOLs?

Any of these IOLs discussed will have a toric option to treat astigmatism on the corneal plane. The cornea is a clear membrane over the colour part of the eye, and it is responsible for 2/3 of the total refractive power of the eye. As the cornea is a biological membrane, it is not perfectly spherical resulting in astigmatism. The corneal astigmatism causes image degradation and blur, but can be corrected using a toric IOL.

Generally, one would correct any degree of corneal astigmatism for the best unaided vision. This is certainly the case when a premium IOL is used, as these IOLs are less tolerant of residual astigmatism. However, if you choose to have a monofocal IOL and have residual astigmatism, this can be corrected with glasses.

About Dr Leo Sheck

Book your appointment now to see Dr Sheck

Dr Sheck is a RANZCO-qualified, internationally trained ophthalmologist. He combined his initial training in New Zealand with a two-year advanced fellowship in Moorfield Eye Hospital, London. He also holds a Doctorate in Ocular Genetics from the University of Auckland and a Master of Business Administration from the University of Cambridge. He specialises in medical retina diseases (injection therapy), cataract surgery, ocular genetics, uveitis and electrodiagnostics.