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.
Drag the lens, choose a view or move 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.
For another non-diffractive option, read about RayOne EMV’s design, mini-monovision benefits and limitations.
For the four-point sulcus lens family, read 1stQ AddOn: prescription correction, trifocal options and their limitations.
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 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.
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A general guide to what each design is intended to do, not a prediction for an individual eye. Glasses are often still helpful beyond the shaded range. Reading depends on the lens, the focusing target chosen, lighting and the health of the eye.
Compare three ways a lens can focus light. Astigmatism correction is a separate feature, explained below.
Scroll sideways to compare all three lens designs.
| 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. |
Near: reading. Intermediate: screens and dashboards. Distance: driving and television. Monofocal is the standard lens design.
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
Hydrophobic and hydrophilic acrylic lens materials differ in their capsule-clouding and material-opacity risks, including after some further eye operations.
Dr Chen can offer any intraocular lens commercially available in Australia and is not tied to any single manufacturer.
That range runs from monofocal and toric lenses to extended depth of focus and multifocal designs. The freedom means the advice starts with your eyes, your measurements and the way you want to see, rather than with one company’s range.
For eyes that need something beyond a standard lens:
Lens power is calculated from several independent measurements with latest-generation formulas, and checked by an experienced team. That includes eyes after laser vision correction, radial keratotomy or keratoconus, eyes with very high myopia, and lens exchange.
How lens calculations are doneLens design and the intended focus are separate decisions. A monofocal lens, for example, can be chosen to favour distance or a nearer task.
A common aim with monofocal lenses. Reading glasses are usually needed, and glasses may still improve other tasks.
Some short-sighted people value reading without glasses. Tell Dr Chen before surgery; choosing distance focus changes that familiar pattern.
Monovision or mini-monovision uses the two eyes together to extend the useful range. It needs a discussion about comfort, depth perception and your priorities.
Monovision and blended vision →Measurements help predict the required lens power, but healing and individual eye anatomy introduce uncertainty. A small residual prescription can remain even after careful planning.
For one refractive full-range option, read about the RayOne Galaxy spiral lens. →
Dr Chen uses all three lens types. These guides explain their different strengths, compromises and suitability in more detail.
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.
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.
Longer articles by Dr Chen go into these questions in more detail, including what the research shows.
Eye doctors’ personal lens choices explores eye doctors’ personal preferences and the trade-offs of monofocal, monovision and EDOF choices.
EDOF and multifocal lens trade-offs explains how a wider range of focus can affect contrast, haloes and your expectations.
Why your friend’s cataract lens implant may not be right for you explains why eye health, personal priorities and the planned focus matter when comparing a friend’s result.
What is the best intraocular lens (IOL)? uses the car analogy to explain why the right implant depends on your eyes, lifestyle and priorities.
Appointments and enquiries are made through Vision Eye Institute Chatswood.
Level 3, 270 Victoria Avenue, Chatswood NSW 2067Optometrists, GPs and ophthalmologists can refer through Oculo or with the PDF referral form.
Vision Eye Institute confirms your appointment after you submit your request. The request form is not for emergencies. A referral is not strictly essential to request an appointment, but you need a valid one to claim a Medicare rebate for your consultation.