Background: A Few Key Terms
Refractive Error
When the eye doesn't focus light perfectly onto the retina, you need glasses or contact lenses. There are three main types: myopia (short-sightedness — clear up close, blurry far away), hyperopia (long-sightedness — blurry up close), and astigmatism (oval-shaped eye causing distortion or ghosting).
Presbyopia
From around age 50, the eye gradually loses its ability to shift focus between near and far. Most people find they need reading glasses — often joking "my arms aren't long enough!" Cataract surgery is an opportunity to address this, depending on your IOL choice.
Cataract
The natural lens inside your eye becomes cloudy with age, making vision blurry even with glasses. During surgery, the cloudy lens is removed and replaced with a clear artificial IOL. Certain things can bring cataracts on earlier — injury, diabetes, or some medications.
Refractive Lens Exchange (RLE)
Essentially cataract surgery performed before a significant cataract has formed. Ideal for patients under 60 wanting to reduce dependence on glasses. Because your natural lens is removed, you will never develop a cataract in that eye and are unlikely to need further eye surgery.
Your IOL Options at a Glance
There are four main categories of IOL. Each involves trade-offs between vision quality, glass dependence, and side effects. Dr Abell will guide you towards the best fit for your eyes and lifestyle.
The lens is set for the sharpest possible distance vision. Reading glasses will be needed for anything closer than arm's length — phone, computer, books. The most commonly chosen option, and the gold standard for overall vision quality.
Some patients choose to wear multifocal spectacles afterwards so they can keep them on all day without constantly searching for reading glasses.
A monofocal lens is used in each eye, but set to different distances — usually the dominant eye for far and the other eye for near or intermediate. Most people adapt well, especially those who have tried this in contact lenses before.
Glasses may still be needed for very fine print, prolonged reading, or night driving. Can be trialled in contact lenses beforehand to see how you tolerate it.
Extended Depth of Focus lenses stretch the single focus point into a continuous range — giving good distance and intermediate vision (TV, computer, dashboard) with fewer compromises than a multifocal. Reading glasses may still be needed for small print.
There are many EDOF designs available; Dr Abell will select the best one for your individual eye.
Multiple focal points allow distance, intermediate, and near vision — around 9 in 10 people with these lenses rarely need glasses. However, there are important trade-offs to consider:
Halos or glare around lights (headlights, streetlights) are common, particularly at night. Some people notice a "waxy" quality to vision during an adaptation period of 6–12 months. Not suitable if you have macular degeneration, glaucoma, significant dry eye, or other eye conditions.
Up to 10% of patients may benefit from a laser touch-up afterwards to fine-tune the result.
How Monovision Works
It sounds unusual, but your brain quickly learns to combine the two images — using whichever eye is best suited for the task at hand. The illustration below shows how each eye is focused differently.
Set for distance
Driving · Sport · TV · Faces
Set for near/intermediate
Phone · Reading · Computer
What You Are Aiming For
The goal of all IOL choices is clear, comfortable vision. The difference is where that clarity is focused.
Driving, sport, watching TV, seeing faces clearly across a room
Reading books, menus, phone screens, and fine print without squinting
Quick Comparison
| IOL Type | Distance | Intermediate | Reading | Night Driving | Glasses Needed? |
|---|---|---|---|---|---|
| Monofocal | Excellent | Poor | Poor | Excellent | Yes — for reading |
| Monovision | Very good | Good | Good | Good | Sometimes — fine print, night |
| EDOF | Very good | Excellent | Moderate | Good | Sometimes — small print |
| Multifocal | Good | Excellent | Excellent | Variable | Rarely — 9/10 glasses-free |
Before your biometry appointment: Please use lubricating eye drops regularly in the days leading up to your measurements. Do not use drops on the morning of the appointment itself.
Please ask Dr Abell as many questions as you like before deciding.
Patient Decision Form
After reading this guide and discussing with Dr Abell, please tick your preferred option below.
I have read and understood the above information about intraocular lens choices. After reading this guide and asking any questions I have, I would like to discuss or proceed with: