Dr Simon ChenCataract & Retina SurgeonThe artificial lens placed during cataract surgery or refractive lens exchange, called an intraocular lens or IOL, comes in several designs. This page compares them in plain terms.
Turn the lens through 360° and explore its details. Choose an optic design and add toric markings.
Scroll to turn, drag the lens, or use the angle control.
A clear optic without the rings shown in the other examples.
Marks near the optic edge indicate an orientation axis.
The small central zone is emphasised to explain a non-diffractive design.
Concentric rings illustrate one diffractive design.
Original teaching illustration · not to scale. Haptics, markings and optical designs vary between lenses. The EDOF central zone is enlarged for explanation: non-diffractive surface changes can be microscopic. This shows lens structure, not how vision will look.
Compare three ways a lens can focus light. Astigmatism correction is a separate feature, explained below. This is educational information, not a simulation of vision.
| Compare by | The standard lensMonofocalOne point of focus, usually set for distance. | Extended depth of focusA continuous range from distance into the middle distance. | MultifocalIncluding trifocal. Light is split between distance, intermediate and near. |
|---|---|---|---|
| Typically in focus | NearIntermediateDistance | NearIntermediateDistance | NearIntermediateDistance |
| Astigmatism corrected? | Only in its toric version | Toric versions available | Toric versions available |
| Typical trade-offs | Glasses for reading and usually for computer work. The simplest optics, with the fewest night-time effects. | Reading glasses for small print for many people. Mild haloes or glare around lights at night for some. | Haloes and glare around lights at night for some people, and slightly less contrast in dim light. Depends on a healthy macula and cornea. |
The highlighted column is marked because a monofocal is the standard design, not because it is being recommended; suitability is discussed individually. Near is reading distance, intermediate is a computer screen or dashboard, distance is driving and television. The bands show what each design is intended to do in a typical eye; individual results vary, and the trade-offs are discussed before any lens is chosen. This diagram is educational and does not simulate vision.
The standard lens. It focuses at one distance, most often set for distance, so that driving, television and walking about are clear without glasses and reading glasses are worn for close work. Some people choose the reverse. Optically the simplest, with the fewest night-time effects, and suitable for almost every eye, including eyes with retinal disease.
A lens that stretches a single focus into a range, typically from distance into the middle distance of a screen or a dashboard. Small print often still needs reading glasses. Night-time haloes or glare are milder than with a multifocal for most people, though not absent. A product-specific educational example from Dr Chen’s channel, explaining how one extended-depth lens works, is linked at the foot of this page for the mechanism only, not as a recommendation.
A lens with rings that split incoming light between distance, intermediate and near, so that most tasks can be done without glasses. The trade-off is that the split reduces contrast a little, and rings or haloes around lights at night are noticed by some people, particularly early on. These designs depend on a healthy macula and a regular cornea, which is why the retina is examined before one is suggested.
There is no best lens. There is a lens that suits this eye and this person, and the same design can be right for one and wrong for the other.
The health of the macula, the shape and surface of the cornea, previous laser vision correction and the other eye all narrow the sensible options before preferences come into it. Then the conversation turns to what you do most, how you feel about glasses for some tasks, and how you would take to haloes at night. Dr Chen will say plainly when a premium design is not the right choice for an eye.
Lens choice is the same conversation whether the operation is for a cataract or a refractive lens exchange, and the trade-offs are discussed before any lens is booked.
How cataract surgery works →General information. Individual suitability is discussed at the consultation.
Bring these, and anything else on your mind. Write the answers down, or bring someone who can.
No. Each design suits some eyes and some lives better than others. The recommendation follows your eye, particularly the retina and cornea, and what you want your vision to do.
Often it is not the best choice: designs that split light between distances depend on a healthy macula. The trade-offs are explained candidly, and a monofocal or toric lens may be recommended instead.
One eye set for distance and the other for nearer vision, usually with monofocal lenses. It suits some people and not others, and can be trialled with contact lenses beforehand.
An intraocular lens can be exchanged in selected circumstances, although it is a more involved operation than the first. See the IOL exchange page.
Yes. Astigmatism, previous laser vision correction and the health of the corneal surface all affect which designs are sensible and how accurately the lens power can be predicted.
Appointments and enquiries through Vision Eye Institute, Chatswood.
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