Your guide to the lens options before doing lens replacement surgery
An IOL (IntraOcular Lens) is implanted into your eye during lens replacement surgery. Your natural lens needs replacement when it becomes cloudy (cataract) but can be removed before it clouds to enhance the focus of the eye.
You and your surgeon should understand and agree on the planned outcome for your vision after surgery. What you want to see clearly without glasses will help to determine the IOL choice. A standard (monofocal) IOL is "single-focus", providing a clear image at a specified distance (e.g. television OR computer OR reading) whereas a premium IOL is "multi-focus", providing a clear image over a range of distances (e.g. television AND computer).
Standard (monofocal) IOLs provide the greatest transmission of light to a single focus and thus provide the highest visual quality for a single distance. They can be set up in 3 main configurations:
A monofocal IOL is implanted into both eyes and is chosen to provide clear distance vision for both eyes. This will allow you to have minimal or no need to wear glasses for distance activities such as driving, television or swimming. Reading glasses will be necessary for ALL near vision tasks including reading, writing and mobile phone use.
A monofocal IOL is implanted into both eyes and is chosen to provide clear near vision for both eyes. This will allow you to have minimal or no need to wear glasses for near activities such as reading and craft hobbies. Distance glasses will be necessary for ALL distance vision tasks, such as driving and television.
A monofocal IOL is implanted into one eye to provide clear distance vision and the other eye to provide clear intermediate/near vision. Your brain will subconsciously switch between the two eyes for distance and intermediate/near tasks. This often requires a period of adjustment, but it is rare that this imbalance of focus between the eyes is not tolerated. Depth perception is mildly reduced, but this is not generally noticeable. Glasses can be required to boost your vision for tasks that you might find easier with both eyes perfectly focused (e.g. extended near work or night-time driving). This option can be simulated with a pre-operative contact lens trial if your natural lenses are not too cloudy.
Premium IOLs split the light into multiple focus points to allow for clear vision over a range of distances. They can reduce, or even eliminate, the need for glasses for both distance and intermediate/near tasks. Some compromise is necessary to achieve this. Because they split the light, they theoretically do not provide as good quality of vision for a single distance as a monofocal IOL. Most premium IOLs also suffer from night-time disturbances, such as haloes/starbursts/glare. There are a multitude of available premium IOLs, though there are two main categories:
Johnson & Johnson PureSee, or Alcon Clareon Vivity IOLs are implanted into both eyes, which delivers clear distance and intermediate vision. This particular IOL is unique in that there are usually minimal night-time disturbances, such as haloes/starbursts/glare. Often low powered "readers" will still be required for extended near work, particularly under low light conditions. A small amount of blended vision, that does not reduce depth perception, can be used to enhance near vision without glasses.
Alcon PanOptix Pro, or Bausch & Lomb Envista Envy IOLs are implanted into both eyes, which delivers clear distance, intermediate and near vision. There are always night-time disturbances, such as haloes/starbursts/glare, but most will adapt and not be troubled by this. This option will give you the most freedom from glasses of all those discussed.
Astigmatism is a condition where the shape of the eye is more like a rugby ball than a soccer ball. This means that the focus is different between the two "axes" of the eye, which blurs your vision at all distances. Both standard (monofocal) and premium IOLs come in toric models to treat astigmatism that is significant.
An IOL is chosen with the aid of sophisticated measurements taken prior to surgery as well as a calculation with several predictive formulae. These measurements provide 90-95% accuracy for the strength of IOL chosen.
Whilst every attempt is made to achieve the perfect result for each patient, sometimes outcomes fall short of surgeon and patient expectations.
In those patients who require further correction to achieve clear vision, this may be corrected with glasses, contact lenses or further surgery. Laser vision correction (LASIK or PRK) or further IOL surgery may be considered. As always, benefits must be outweighed by risk and the ultimate decision on further treatment is a joint decision between patient and surgeon.
All eyes undergoing lens replacement surgery will develop cloudiness (opacification) of the capsule (your natural lens support) behind the IOL, which will result in decreased vision some weeks, months or even years later. It is unsafe to remove the capsule during your initial lens replacement but can be treated with a quick and painless laser capsulotomy procedure to restore your vision. This is performed sitting behind the laser machine in clinic, rather than lying in an operating theatre. The treatment cost is not included with your lens replacement surgery.
| Option 1,2(clear distance or near) | Option 3(blended vision) | Option 4(premium IOL, no haloes) | Option 5(premium IOL, with haloes) | |
|---|---|---|---|---|
| Visual quality | Excellent | Excellent | Good | Usually good |
| Spectacle reduction | Poor | Good | Good | Excellent |
| Haloes/glare | Minimal | Minimal | Minimal | Always (usually tolerable) |
| Depth perception | Excellent | Good | Excellent | Excellent |
| Pre-existing eye problems | Suitable | Often suitable | Often suitable | May not be suitable |