Types of Lenses for Cataract Surgery

Types of Lenses for Cataract Surgery | Monofocal, Multifocal & More 

Understanding Cataract and Need for Lens

One of the most common age-related eye conditions which affects millions of people worldwide is cataract. The condition is characterised by opacification of the natural lens of the eyes. The cataract can occur in one or both eyes. 

This usually develops slowly throughout life and is commonly seen in older people. Most people start getting cataracts after 40 years of age, but symptoms are typically seen after 50 years. 

Treatment Options for Cataract

Various surgical and non-surgical treatment options are available for cataracts based on the severity of the condition. Non-surgical management of cataracts includes opting for visual aids such as polarised sunglasses, anti-glare glasses, or updated glasses or contact lens prescriptions. 

For individuals with extremely dense cataracts, extracapsular cataract extraction surgery is used, which involves an even larger incision to remove the lens in a single piece. During this surgery, the cloudy natural lens of the eye is replaced with an artificial intraocular lens (IOL). 

But here’s where an important decision lies: What type of lens is right for you? The intent of this content piece is to help you understand the different types of lens and their functions. 

Types of Lenses for Cataract Surgery

1. Monofocal Intraocular Lenses

The most commonly implanted lenses during cataract surgery are the monofocal intraocular lenses, which have a fixed focal length. They help provide clear vision for a particular distance. 

Monofocal lenses bend light to focus on a specific set distance, usually far, after implantation. They offer several advantages, including affordability and high clarity of image at the chosen focal point. 

As they are quite common, they are covered by insurance in most countries. However, people with monofocal lenses may require glasses for near or intermediate vision.

2. Multifocal Intraocular Lenses

Premium lenses that help patients achieve optimal vision at multiple distances are known as multifocal intraocular lenses. These lenses have multiple concentric rings with different focal points, which help direct incoming light to different distances simultaneously. 

This allows the brain to gradually learn to choose the correct focus depending on the task. With multifocal intraocular lenses, bifocals or progressive lenses are not needed, which is a significant advantage for patients. 

The lens is ideal for daily activities such as reading, driving, cooking, and working. However, visual disturbances such as halos and glare may be present. Additionally, a specific issue known as neuroadaptation can arise with multifocal lenses, meaning the brain may take time to adjust to how the lens works.

3. Extended depth of focus (EDOF) lenses

Extended depth of focus (EDOF) lenses are an evolution of multifocal lenses and are designed to offer a continuous range of vision. They extend the focus range by stretching the focal point and reducing the jump between distances. 

This helps improve visual clarity and reduce side effects such as glare or halos, which usually occur with multifocal lenses. However, for near vision, patients may still require reading glasses.

4. Toric Intraocular Lenses

Specialised lenses for patients with astigmatism are known as toric intraocular lenses. In astigmatism, the front surface of the eye or the lens inside the eye is curved differently in one direction than the other, affecting normal vision. 

Toric lenses help correct the irregularity of the corneal shape, which causes blurry vision. They can be used for patients struggling with cataract and astigmatism, helping sharpen the overall quality and clarity of the image. 

For mild astigmatism, low cylindrical toric lenses are available. For moderate to high astigmatism, high cylinder toric lenses are used. On the other hand, custom toric intraocular lenses may be used for personalised treatment in cases of irregular corneas.

5. Accommodating Intraocular Lenses

Accommodating intraocular lenses are special lenses designed to move within the eye to reduce the effort of eye muscles. They shift backward and forward inside the eye using the eye’s ciliary muscles to adjust focus at different distances. 

They help mimic the natural function of the eye and offer better immediate vision correction compared to monofocal lenses. Additionally, they have fewer side effects compared to multifocal lenses.

6. Light Adjustable Intraocular Lenses

The only intraocular lenses that can be adjusted after surgery are the light adjustable lenses. These lenses remain adjustable after implantation. 

Special light treatments help alter the lenses to optimize focus and achieve perfect vision. This is a wonderful option for patients with previous eye surgeries, such as LASIK. 

However, these lenses require regular follow-up visits with the ophthalmologist and necessitate wearing UV-protective glasses until treatment is finalised.

Factors that Determine the Type of Lens

There are several factors that govern the selection of lenses for cataract surgery. Some of the factors are listed below:

• The lifestyle of the patient primarily governs the selection of lenses. People whose work requires frequent use of computers or laptops, or those who drive at night, require specific kinds of lenses.
• The visual goals of the patient also help determine the best type of lens for cataract surgery. For people wanting to be free from glasses, specific lenses are available.
• Patients struggling with eye conditions, such as astigmatism or glaucoma, require specialised lenses.
• Patients with a previous history of eye surgery, such as LASIK, also need specific lenses for cataract surgery.
• Lastly, budget and insurance coverage also play a role in determining the lens a patient may choose.

Frequently Asked Questions