Cataract & Intraocular Lenses (IOLs)

What is a cataract?

A cataract is a condition in which the natural lens of the eye becomes clouded or opacified, causing vision to deteriorate progressively.

When should I undergo cataract surgery?

Cataract surgery is recommended when reduced vision begins to impair normal daily activities such as reading, driving, or recognising faces. The clouded lens is removed and replaced with a clear artificial lens called an intraocular lens (IOL). While glasses may provide temporary relief in early stages, surgery is the only definitive treatment.

Is cataract surgery safe? What can I expect?

Cataract surgery is one of the most commonly performed and safest surgical procedures in the world. It is typically performed under local anaesthesia as a day-care procedure, meaning no overnight hospital stay is required. Most patients notice a significant improvement in vision within a few days. Full recovery usually takes two to four weeks.

Will I still need glasses after cataract surgery?

This depends on the type of IOL chosen. Monofocal IOLs correct vision at one distance — usually far — so reading glasses may still be needed. Premium IOLs such as multifocal or EDOF lenses can reduce dependence on glasses for near and intermediate distances. Toric IOLs additionally correct astigmatism. Your surgeon will help you choose the most appropriate lens for your lifestyle and visual needs.

What are the different types of intraocular lenses (IOLs)?

The main categories are:

• Monofocal IOLs — correct vision at one focal distance (usually far). Most commonly implanted.
• Toric IOLs — correct astigmatism in addition to distance vision.
• Multifocal IOLs — provide focus at both distance and near, reducing dependence on glasses
• Extended Depth of Focus (EDOF) IOLs — create a single elongated focal point to provide a continuous range of vision.
• Presbyopia-correcting IOLs — a broader category that includes multifocal, EDOF, and accommodative IOLs.
• Phakic IOLs — implanted without removing the natural lens; used in select cases such as high refractive errors.

What is a monofocal IOL?

A monofocal IOL corrects vision at a single focal length — typically distance. It does not correct astigmatism. It is the most widely used IOL globally.

What is a multifocal IOL?

A multifocal IOL provides focus at both distance and near, allowing most patients to read and drive without glasses. Unlike monofocal lenses, it reduces overall dependence on spectacles.

What is an EDOF (Extended Depth of Focus) lens?

An EDOF IOL creates a single, elongated focal zone rather than multiple distinct focal points as in multifocal lenses. This provides a smooth, continuous range of vision — particularly useful for intermediate distances such as a computer screen — with fewer visual disturbances such as halos or glare.

What is a toric IOL?

A toric IOL has a special geometry designed to correct corneal astigmatism of 1 dioptre or more, in addition to restoring distance vision. It is the preferred choice for cataract patients with significant pre-existing astigmatism.

How long does it take to adjust to a toric IOL?

Adaptation varies from person to person. Some patients adjust within a few days, while others may take up to three to six months. This is normal and expected.

How long do intraocular lenses last?

IOLs are designed to remain in the eye permanently. They do not degrade or require replacement under normal circumstances. Meticulous surgical technique and adherence to post-operative care instructions are important for long-term outcomes.

Can an IOL become cloudy after surgery?

The IOL itself does not cloud. However, the thin membrane (posterior capsule) behind the IOL can sometimes become hazy — a condition called posterior capsule opacification (PCO). This is treated with a quick, painless laser procedure called YAG (Nd:YAG) laser posterior capsulotomy, which restores clear vision.

What is complex cataract surgery?

Complex cataract surgery is performed in patients who have additional eye conditions or anatomical challenges that make standard surgery more technically demanding. It requires more extensive pre-operative planning and a longer recovery period. Conditions that may necessitate a complex approach include:

• Previous eye injury or trauma
• Glaucoma (lens-induced or phacomorphic)
• High corneal astigmatism
• Floppy iris syndrome
• Lens subluxation or phacodonesis
• Pseudoexfoliation syndrome
• Corneal swelling or Fuchs' dystrophy
• Active uveitis
• Macular degeneration
• Severe ocular abnormalities

The need for complex surgery is determined by the surgeon following a thorough eye examination.