How to select the best IOL for your cataract surgery?

IOL means intraocular lens. We all know that cataract surgery means removed the natural lens of the eye that developed an opacification and replaces with a new artificial lens which is called IOL. When someone diagnosed as a cataract in the eye then the consulted doctor advice for cataract surgery. Before the surgery doctor and his/her, counselor explains about the packages of cataract surgery. But so many of us got confused regarding the selection of IOL which will be put inside of the eye. So before IOL surgery, you should know which lens is suitable for your eyes and lifestyle. Most of the hospitals or doctor clinic have a different package of cataract surgery. Prices are different for different packages. So which package we should select? Because the general thinkings are –

  • Low packages lenses may not provide 100% vision
  • Higher packages lenses are best
  iol-in-the-eye

Everybody cannot effort the higher package of cataract surgery. Remember every lens can provide 100% vision if the lens power is correct and the surgery is uncomplicated. Everything depends on cataract surgeon and the person who calculated the Intraocular lens (IOL) power. The IOL power is measured by a technique which called A-Scan biometry. A higher package doesn’t mean that after the surgery we can see everything without glasses. We may need glasses after surgery but the power should be minimal. intraocular lens types are

  1. Single vision or monofocal IOL
  2. Multifocal IOL

Single vision IOL:- Single-vision IOLs are known as monofocal lenses because they provide vision only for distance or near. Most of the monofocal IOLs are use for correcting distance vision. Patients need to wear reading glasses after the surgery because generally, these IOLs are for distant vision correction. As I said before for distance it may or may not required glasses. The designs of lenses are aspheric design. They provide a sharp and clear vision for distance. Very few patients suffering from glare at night from theses lenses due to higher-order aberrations (HOA) of the lenses. The premium single-vision IOLs are provided sharper vision than standard IOLs, especially at dim light. Those who have relatively larger pupil they are a suitable candidate for these lenses. The lenses shape and optical qualities are almost similar to the natural lenses.

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Toric IOL:- Toric intraocular lens means the lens have cylindrical power as well as spherical power. Those who have astigmatism more than 1.00 D they need toric lenses. It is especially recommended for high astigmatism patient. Astigmatism power means cylindrical power. If you want almost 100% vision for distance after cataract surgery then must select toric IOL. Toric IOL and Multifocal both are costlier than monofocal IOL. Toric Multifocal lenses are also available in the market. You must select the experienced surgeon for the surgery.

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Multifocal IOL:-  A person can see distance, intermediate like television, and near through multifocal lenses. That means almost no need to wear glasses after the surgery.  These premier lenses also known as presbyopic IOL. Multifocal lenses are costlier than monofocal lenses. A person must have a healthy eye for implantation of these lenses. The person with dry eye, macular degeneration or glaucoma is not a suitable candidate for these lenses. Young patients, those need only one eye cataract surgery due to some reason they are the good candidate for multifocal lenses. 

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Limitation of Multifocal lenses:- As I told before the dry eye, macular degeneration and glaucoma patients are not ideal for these lenses. The patient can feel glare with these lenses. Decrease sharpness of vision (Contrast sensitivity) may occur under dim light or night.  If some driving more at night then these lenses are not suitable because glare at night is one of the disadvantages of these lenses. Reading under dim light may be more difficult due to qualitative vision changes compare with a standard IOL.

Accommodative IOL:- These premium type IOLs are a type of multifocal IOL which provide sharper and clear distance vision than conventional multifocal lenses. But the near vision is better with multifocal IOL compared to accommodative IOL. These types of lenses have very minimal glare at night. Those who drive more at night and wants distance as well as near vision without glasses they are the perfect candidate for the accommodative IOL. Accommodation means when we focus any object then our eye adjusted and make it clear. The process is called accommodation. After 40 years of age, the accommodation power decreases and we need to wear the glasses for near vision. Possible accommodation produces by crystalline lens. That’s why after cataract surgery the standard IOL unable to provide the near vision. Accommodative IOL haptic (leg of IOL) is different from normal standard IOL which helps to move forward and backward of the lenses to adjust the power.  Mature cataract or advanced cataract patients are not suitable for these types of IOL implantation. The actual surgeon removes only cloudy part of the human crystalline lens through the incision of the anterior part of the lens.

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What is monovision correction?

Monovision technique was used before multifocal lens invention for presbyopic correction. One eye intraocular lens is implanted for distance vision and another eye for near. A person can see distance as well as near while open both eyes. So no need to wear glasses for distance and near. But these types of correction is not recommended for everyone. Also, it takes time for adjustment. Depth perception problem is one of the disadvantages of monovision correction.

What is the tinted IOL?

It has been hypothesized that the natural lens protects our eye from harmful blue light and the protection power increase with the age. So the blue-blocking IOL will be better for our eyes. Studies show that cataract surgery with implantation clear IOL increases the risk of AMD (Age-related Macular Degeneration). Yellow tinted IOL is beneficiary for retina health because it protects our eyes from the harmful blue light. These lenses are important who are exposed more to the blue light. Advantages of yellow-tinted IOLs are reducing glare, reduce cyaniposia, and reduce choroidal melanoma and protection of macula.iol

Scotopic vision loss, altered color perception, and sleeping disturbance is main complaints from some patients. Shorter length blue light helps us to see more clearly under dim light condition. Maybe 1 in 10 patients also finds issue with altered colour vision.

So before surgery discuss with your doctors about the IOL which will best option for your vision and lifestyle. Premium package lenses are for better comfort and more natural vision but the visual outcome is almost same for all IOL. Premium quality IOL cost is more than standard IOL. If you are insurance patient then check which package lenses are providing by your insurance company. Maybe with some extra money you can get the premium quality lens. 

Reference:-

  1. http://www.nature.com/eye/journal/v26/n11/full/eye2012178a.html
Krishnendu Mandal
Optometrist, Blogger, Blogging since Jan 2016

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