# What is an Intraocular (Multifocal) Lens? Who It Suits, Advantages and Side Effects

Source page: https://www.kudretgozistanbul.com/en/blog/intraocular-lens-treatments/what-is-an-intraocular-smart-lens

**Author:** Kudret Eye İstanbul | **Medical Approval:** Op. Dr. Mehmet Ali Özdil | **Date:** 2026-09-04

> **Summary:** Intraocular lens (multifocal lens) surgery removes the eye's natural lens and replaces it with a specially made artificial lens, offering a permanent solution for cataract and high prescriptions, especially when the eye is unsuitable for laser. Trifocal lenses give clear vision at distance, intermediate and near ranges, while monofocal lenses focus at one distance.

## Quick Facts
- **Operation duration:** About 15-20 minutes per eye
- **Incision:** 2.2 mm micro-incision, no stitches
- **Anaesthesia:** Local anaesthesia with eye drops
- **Discharge:** Same day
- **Recovery:** Stinging, burning or soreness for a few days
- **Durability:** Permanent; replacement rarely needed

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## What is an Intraocular Lens?
A lens placed surgically in the position of the natural lens; unlike contact lenses, removing it requires surgery. Types are single-focus (monofocal), bifocal and trifocal. A monofocal lens set for distance can leave difficulty at near and intermediate ranges; trifocal lenses allow reading, watching television, driving and distance vision without glasses or contact lenses.

## Who is it Suitable For?
- Cataract patients
- People over forty with presbyopia or vision problems at more than one distance
- People with myopia, hyperopia or astigmatism
- People whose cornea is thin or very irregular, or whose eye is otherwise unsuitable for laser
- People who want to be free of glasses entirely
- Younger people unsuitable for laser: a phakic lens (ICL) placed in front of the natural lens
- In diabetic retinal disease or advanced glaucoma, multifocal (trifocal) lenses may not be suitable and a monofocal lens is preferred; suitability is decided at examination.

## Monofocal Versus Trifocal

| Feature | Monofocal Lens | Trifocal (Multifocal) Lens |
| :--- | :--- | :--- |
| **Focal point** | Generally distance only | Distance, intermediate and near |
| **Need for glasses** | May be needed at near and intermediate | Vision without glasses possible in daily life |
| **Visual comfort** | Night vision and contrast generally better | Some patients may see haloes around lights |
| **Quality of vision** | Very clear at a single distance | Adapts to different distances |
| **Who it suits** | People prioritising distance vision and simplicity | Active people wanting life without glasses |
| **Cost** | More economical | Higher, but more versatile |
| **Adaptation** | Short, easy | The brain may take time to adjust |

Intraocular lens treatment costs somewhat more than laser, but the lenses do not deteriorate and remain in place for life.

## Lens Planning
The power of each lens is calculated before surgery with biometry measurements to match the myopia, hyperopia or astigmatism. The surgeon explains how each lens type will perform and recommends the most suitable option.

## Side Effects
- Some eyes may not adapt to the lenses.
- Multifocal lenses can cause light phenomena: difficulty in dim light and haloes around lights, usually becoming familiar over time.
- Reduced contrast sensitivity and a slight decline in image quality with multiple focal points.

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## The Treatment Journey

### 1. Before Treatment
- Examination and biometry measurements to choose and calculate the lens.

### 2. During Treatment
- In a fully sterile environment, local anaesthesia with drops; no pain, mild discomfort possible.
- The old lens is removed through a 2.2 mm micro-incision and the intraocular lens fitted; about 15-20 minutes per eye; no stitches.

### 3. After Treatment
- Discharged the same day.
- Stinging, burning, soreness or blurring for a few days is normal; vision may feel different until the eye adjusts.
- One or both eyes can be treated.

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## Frequently Asked Questions

**Q: Do intraocular lenses last for life?**
A: Yes, they are permanent; most patients never need a replacement. Rarely the lens may shift or the eye structure may require intervention.

**Q: Is the surgery painful?**
A: No. It is done under local anaesthesia with eye drops; mild discomfort may be felt, and mild stinging or blurring afterwards usually settles within a few days.

**Q: Will I need glasses after surgery?**
A: It depends on the lens. With a single-focus lens, glasses may be needed for near or intermediate distances; with a trifocal lens, most situations at all distances can be managed without glasses.

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## References
- Intraocular Lenses (IOL) for Cataract Surgery, American Academy of Ophthalmology
- What are phakic lenses?, FDA
- Trifocal Intraocular Lenses, EyeWiki (AAO)