Types of IOL Lenses

Introduction

Cataract surgery is the most common eye surgery performed worldwide. Here the opaque lens from inside the eye is removed because it was causing blurred vision. These days every time we perform a cataract surgery we implant an intraocular lens inside the eye, also known as the IOL. 

Why do we implant an IOL in the eye?

The natural lens in the eye has a job. It is to bend the rays of light entering the eye and focus them on the retina. So that you can see things. If the rays are not in focus then we will see everything blurry. Once we remove the lens there is nothing inside the eye to bend these rays of light entering the eye.

In the olden days when cataract surgery was performed without placement of the lens, people undergoing surgery had to wear thick glasses after surgery. These thick glasses were doing the work that our natural lenses did.

These days because we implant an IOL in the eye there is no need to wear thick glasses after cataract surgery. In fact with modern techniques, we can calculate the power of the IOL in such a way that the patient may not have to wear glasses at all.

Types Of Intraocular Lenses

Watch the video on how to choose the best lens for your eyes

1. Aspheric IOLs

Usually, a lens is considered to be part of a sphere. This is known as a spherical lens. These lenses cause spherical aberrations. Spherical aberrations are visual distortions that happen because of the shape of the lens.  An aspheric lens has a slightly different shape as compared to a spherical lens. An aspheric lens would be no or very less distortions.

2. Toric IOLs

A cylindrical number is also known as astigmatism. It is a type of eye power. When we implant regular spherical lenses this cylindrical power does not go away. It remains after the surgery and the person has to wear glasses. If someone wishes for the eye power to go away or at least significantly reduce then your eye specialist would suggest you go for a toric lens.

Know more about Toric IOLs here.

3. Accommodating IOLs

A camera that you use on the phone or elsewhere autofocusses. This means if you take a picture of something far away or a close up the picture will be clear. The natural lens of the eye is also able to autofocus. This autofocus ability is lost as we age. Most of the IOLs that we implant in the eye are not able to autofocus. Accommodating IOL is made in such a way that they are also able to autofocus attempting to give you glass-free vision after surgery. These lenses however have not become very popular.

4. Multifocal IOLs

Multifocals and Trifocals IOLs as the name suggests are lenses that help you see glass-free for multiple distances. Many individuals are keen to be glass free after surgery and these lenses help with that. Trifocals also help you see the computer distance which is the intermediate distance whereas multifocal IOLs help with far and reading distance.

Know more about Multifocal IOLs here.

5. Monofocal IOL

A monofocal IOL will give you glass-free vision far but you will need glasses for near work. There a newer monofocals available which give you about 50% reading vision too. 

Know more about Monofocal IOLs here.

6. EDOF IOL – Extended depth of focus IOL

These lenses give you clear glass-free vision for far and the intermediate distance and you may have to wear glasses for reading. 

Know more about EDOF IOL here.

Choosing The Right IOL

Lifestyle Design

There is no best lens for all people. The best lens for you might not be the best for someone else. It depends on your lifestyle, personality, and habits. Here are some pointers to keep in mind

• Multifocal lenses cause halos around the oncoming headlights at night so if you enjoy or require to drive in the late evenings and at night multifocal and trifocal lenses are not for you
• Multifocal lenses are also known to reduce the quality of vision if you have a retina problem. So if in your OCT eye test we find you have a retinal problem we should not be using a multifocal lens.
• If you are very keen to be glass free after your cataract surgery then multifocal and trifocal lenses are your options.
• If you want a very clear vision and don’t mind wearing glasses then monofocal lenses might be your best option
• If you want to be glass free but are not comfortable spending more money then you may choose monofocal lenses with monovision.
• If you would like to be glass free but would not mind wearing glasses for reading small print near only then lenses like the Eyhance lens may be a good option.

Pre-Existing Conditions

As mentioned certain eye conditions don’t go well with certain lenses. If you have any retinal problems then multifocal and trifocals should not be your first choice. Here is a list of conditions that will limit your lens choices. In other words, you will then have to choose from certain lenses only

• ARMD
• Diabetic Retinopathy
• History of retinal detachment
• History of injury to the eye causing weak lens supports also known as zonular dialysis
• A dislocated lens in the eye – this could be due to trauma or from birth
• Preexisting rupture of the posterior capsule of the lens

Costs

Usually, cataract surgery is performed at hospitals as a package. This means you would know beforehand your entire cost for each eye. While many items are consumed during the surgery the IOL is top of that list. The costs of these IOL vary greatly. These lenses are made by various companies from various countries and the cost of these lenses varies greatly.

• Indian lenses are cheaper than European / American or Japanese lenses
• Trifocal lenses would be the most expensive lenses
• Next, come the multifocal and then the monofocal lenses
• Toric lenses are also more expensive than their counterparts – Toric monofocal lenses are more expensive than monofocal lenses and toric multifocal lenses are more expensive than multifocal lenses.

Conclusion- Sometimes patients ask us what if we just do the cataract surgery without the lens. You will know by now that that is almost not an option. IOLs have changed the cataract surgery experience for patients. It’s important to choose the right lens based on your personality and lifestyle. However, the right lens can do only so much. One has to visit a doctor that is known for their surgical expertise and a hospital that is known for these kinds of surgeries. 

You can read more about Cataract Surgery at Eye Solutions.