Monofocal Lenses: Single-Focus Intraocular Lenses Used in Cataract Treatment

Monofocal lenses are single-focus intraocular lenses that have been used safely for many years in the surgical treatment of cataracts. The primary goal of cataract surgery is to remove the natural eye lens that has lost its transparency and replace it with an artificial lens. At this stage, the type of lens selected plays a significant role in post-operative visual quality and daily visual comfort.

One of the most important decisions during this process is determining which type of intraocular lens will be used. This article provides an overview of monofocal lenses—also known as single-focus lenses—which have long been considered a cornerstone of cataract surgery.

What Is a Monofocal Lens (Single-Focus Lens)?

A monofocal lens is an intraocular lens designed to focus light at a single focal point. It is typically planned to provide clear distance vision. This approach aims to support comfortable vision for everyday activities such as watching television, driving, and outdoor tasks.

Due to their single-focus design, monofocal lenses do not split incoming light, helping maintain image clarity. They are often preferred in situations where sharpness and contrast sensitivity are particularly important.

Visual Experience With Monofocal Lenses

Distance Vision

In most cataract surgeries, monofocal lenses are set to provide clear distance vision. This allows many daily activities—such as watching television, driving, or viewing a cinema screen—to be performed without glasses or with minimal optical correction.

Near and Intermediate Vision

When a monofocal lens is adjusted for distance vision, near tasks such as reading, using a smartphone, sewing, or detailed close work generally require reading glasses.

Advantages of Monofocal Lenses

Despite advances in lens technology, monofocal lenses remain one of the most reliable options for many individuals.

High Image Quality

By focusing light at a single point, monofocal lenses can provide very sharp and clear distance vision. Contrast sensitivity—the ability to distinguish objects from their background—is typically high with these lenses.

Reduced Light Disturbances

Visual phenomena such as halos, glare, or light scattering, which may be observed with multifocal lenses, tend to occur less frequently with monofocal lenses. This characteristic can be particularly beneficial for individuals who frequently drive at night.

Ease of Adaptation

Adaptation to monofocal lenses generally occurs relatively quickly. Visual perception often stabilizes within a short period following surgery.

Cost-Effective Option

Monofocal lenses are commonly considered standard intraocular lenses and are often covered by public health systems or private insurance plans. Their cost is usually lower compared to lenses that involve advanced optical technologies.

Limitations and Considerations of Monofocal Lenses

The main limitation of monofocal lenses is that they cannot replicate the natural focusing (accommodation) ability of the youthful natural eye lens.

Need for Reading Glasses

Even when distance vision is clear after surgery, reading newspapers, viewing menus, or working on a computer typically requires near-vision glasses.

Intermediate Vision Comfort

Tasks at intermediate distances—such as using a computer screen or working at a kitchen counter—may also require optical correction, as mild blurring can occur at these ranges.

What Is the Monovision Technique?

In some cases, monofocal lenses may be combined with a technique known as monovision to reduce dependence on glasses. With this approach, one eye is set for distance vision while the other is adjusted for near or intermediate vision.

The brain may gradually adapt by integrating the two different visual inputs, allowing functional vision across multiple distances. However, this method may not be suitable for everyone, and a careful pre-operative assessment is required.

Who May Be Suitable for Monofocal Lenses?

Monofocal lenses may be considered a suitable option for individuals who:

• Perform frequent night driving and prefer minimal light sensitivity
• Have additional retinal conditions that limit the use of multifocal lenses
• Do not mind using reading glasses for near tasks
• Seek a reliable and cost-effective solution

There is no single “best” lens in cataract surgery; instead, the most appropriate lens is the one that aligns with ocular structure and lifestyle needs. With their proven reliability and high visual quality, monofocal lenses remain one of the most widely used and successful options in cataract treatment.

When selecting an intraocular lens, discussing daily habits—such as reading frequency or night driving—with an ophthalmologist plays an important role in determining the most suitable approach.