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Cataract

What is a Cataract

Inside our eyes, we have a natural lens. The lens bends light that come into the eye to help us see. The lens should be clear. If you have a cataract, your lens has become cloudy. It is like looking through a dirty window. Things look blurry, hazy and less colorful with a cataract.

With a clear lens light focuses properly on the back of the eye (retina).

In an eye with a cataract light scatters throughout the eye and does not focus properly on the retina.

What are the symptoms of a cataract?

Vision changes you may experience if you have a cataract:‍

  • Blurry vision
  • Seeing double (when you see two images instead of one)
  • Being extra sensitive to light
  • Having trouble seeing well at night, or needing more light when you read
  • Seeing bright colors as faded or yellow instead

Normal

Faded or yellow vision

Blurry Vision

Why do we get cataract?

Ageing causes cataracts. This is due to normal eye changes that happen after around age 40. Normal proteins in the lens start to break down. This causes the lens to get cloudy. People over age 60 usually start to have some visible clouding of their lenses. Vision problems may only start years later.

Other reasons you may get cataracts:

  • Having a family history of cataracts
  • Having certain medical problems like diabetes
  • Having had an eye injury or eye surgery
  • Having spent a lot of time in the sun, especially without sunglasses that protect your eyes from ultraviolet (UV) rays

You may be able to slow down your development of cataracts.

Protecting your eyes from sunlight is the best way to do this.Wear sunglasses that screen out the sun’s ultraviolet (UV) light rays. You may also wear regular eyeglasses that have a clear,anti-UV coating.

Cataracts can be removed only with surgery. If your cataract symptoms are not bothering you, you don’t have to remove a cataract.

What to expect with blade-less cataract surgery

Your eye surgeon will numb your eye with local anesthetic drops.

1. In laser cataract surgery, an advanced femto-second laser replaces the use of a blade for the 2-3 corneal incisions near the edge of the cornea and opening the bag of the lens. It also breaks up the lens with a cataract for easy removal. Use of a laser can improve the precision and accuracy, potentially reducing risks of cataract surgery.

2. Using special instruments, your ophthalmologist will break up the eye’s natural lens with ultrasound and gently vacuum out the pieces through one of the incisions. The “capsular bag” that holds your natural lens in place stays intact.

3 & 4 Intra ocular lens (IOL) is folded and inserted through the incision. It is placed in the “capsular bag,” where it unfolds. An IOL will refract light properly again, giving you clear vision at certain distances.

The tiny incisions in your eye are “self-sealing,” and you will not need stitches.

It could take 6-8 weeks after surgery to be able to focus fully. Basically, your eye has to heal and relearn how to focus at various distances to see clearly.‍

Choosing a Mono-focal lens and glasses

Mono-focal lenses have only one power. This means that they can be selected to correct for either distance or near vision but not both. Although it is possible with mono-focal lenses to reduce an individual’s dependence on glasses they will still require them for some situations. Typically for reading as in most patients the power of the Mono-focal lens is selected to correct for distance vision. Some Mono-focal lenses can be implanted through a slightly smaller incision. This promotes wound healing and reduces inflammation.

Choosing a Multi-focal lens and glasses

Bifocal, trifoical and extended depth IOLs offer different focusing powers within the same lens. These IOLs reduce your dependence on glasses. Based on the scientific literature 90% of individuals do not require spectacles either for distance, intermediate or near vision, you will however still need them for certain tasks like prolonged reading. There are numerous designs that can be considered. You and your ophthalmologist will discuss the best option for you to fit your individual lifestyle and needs. The lens has several rings or zones set at different powers. With this design, you are actually using both near and far vision at the same time. However, your brain learns to automatically select the right focus for what you want to see. As yet there are no Multi-focal lens implants that are as good as the natural healthy human lens in a young person. There is no perfect vision. With multi-focal IOL’s there is always a trade-off.

What is the difference between multifocal intra-ocular lenses and multifocal glasses?

Implantable multifocal lenses have several rings or zones set at different powers. With this design, you are actually using both near and far vision at the same time. Your brain learns to automatically select the right focus for what you want to see

Unlike implantable multifocal lens where your brain selects the correct focus multifocal glasses have different zones from top to bottom. Far vision is at the top, intermediate vision in the middle and near vision at the bottom. This means that you actually look through different focusing powers in the lens to focus at different distances.

Multifocal IOL vs Multifocal glasses

Multi-focal IOL compromises

There are some compromises and differences in the quality of vision that need to be understood.

  • It takes time to adapt to seeing through the new multi-focal lenses
  • A Multi-focal IOL can reduce the dependency on glasses but some people it might result in generally less sharp vision, which may become worse in dim light
  • Not all patients are completely free of spectacles. About 10% will still require glasses for either distance, intermediate or near vision or a combination of these
  • Reading vision is usually very good but does depend on lighting. Reading may not be as good in dim light
  • The reading distance is typically at a fairly fixed distance so you will need to get used to moving reading material to that position
  • The selection of the correct power of the lens implant is based on very sophisticated equipment and computer formulas but it is not an exact science. Occasionally the focal length of the lens can settle too far in the distance or too close. Usually this is correctable by changing the focal length of the implant used for the second eye, “top-up” LASIK surgery or implanting a second “piggy-back” IOL
  • Astigmatism (a difference in the curvature of the cornea in different meridians) can be corrected during surgery by using limbal relaxing incisions or Multi-focal lenses with a toric (astigmatic) “in-built” correction
  • Vision typically is far better with the lens implants in both eyes rather than in just one. The improvement in vision after the second eye surgery can be dramatic
  • Visual side effects such as circles or halos around lights particularly at night are common. In the vast majority of cases these phenomena are regarded as insignificant. If you do a lot of night driving Mono-focal lenses may be a better choice for you