What is a cataract?
The lens is the primary focusing mechanism of the eye. As we age, this crystal clear lens becomes cloudy and yellow and looses its elasticity, or ability to change focus. When this occurs, it is called a cataract.
Who is at risk of having a Cataract?
- Aging (age-related cataracts), generally over the age of 60.
- Overexposure to ultraviolet radiation, such as from sunlight, tanning booths, or sunlamps.
- Diabetes, especially when the blood sugar levels are above the safe range, causes changes in the eye that can result in cataracts.
- Secondary to eye diseases like glaucoma, chronic uveitis, retinitis pigmentosa, or retinal detachment.
- Long-term use of steroid medicines.
- Frequent X-rays or radiation treatments to the head.
- Family history (genetics). A person may inherit the tendency to develop cataracts.
- Vitrectomy. People older than age 50 who have had the vitreous gel removed from their eye (vitrectomy) have an increased risk of cataracts.
- Eye injury. This is a leading cause of cataracts in children.
- Congenital cataracts. Some children are born with cataracts
Symptoms of cataracts
- Clouded, blurred or dim vision
- Increasing difficulty with vision at night
- Sensitivity to light and glare
- Seeing “halos” around lights
- Frequent changes in eyeglass or contact lens prescription
- Fading or yellowing of colors
- Double vision in a single eye
When should I have the surgery?
Cataracts should be removed when they begin to affect your daily lifestyle. When glare and blur interfere with driving, or you give up your favourite hobby, it is time to consider having surgery.
A tunneled incision is made in the sclera one to three millimeters above the iris. Through this tiny incision, the surgeon will remove the cataract and implant a foldable lens. Due to the architecture of the incision, the surrounding tissues overlap to make the incision self sealing. Your surgeon may decide to use a stitch when needed.
The most modern method of removing a cataract is through the use of phacoemulsification. The phacoemulsifier is an ultrasonic probe which vibrates 40 000 times per second. It breaks a cataract up into tiny microscopic pieces which are emulsified and gently aspirated out of the eye. This method of cataract removal is considered the least traumatic to the eye.
Insertion of the lens
A specially designed injector, much like a syringe, is used to implant a foldable replacement for the human lens, needed to restore focus to the eye. This implant is called an intraocular lenses. The injector is inserted through the scleral tunnel incision, over the iris, into the centre of the pupil. There, the lens is slowly injected where it expands and unfolds into position.
What will my vision be like after the op?
Before surgery, you and your doctor will determine which intraocular lens is best suited for you.
The current choices are :
- Monofocal Implants
(a) Both eyes are corrected for distance and you need reading glasses after the surgery
(b) Some people prefer to see near after surgery and choose a “near” lens
(b) Monovision : a slight undercorrection for distance in the non-dominant eye to give some reading vision and distance vision in the dominant eye.
- Bifocal or multifocal implants are available but not routinely used.
These have elements for both far and near. However, many patients complain of glare when driving at night with these implants.
- Toric implants are available in both obove options to correct astigmatism.
- Accomodating IOL eg: Crystalens by Bausch & Lomb
Crystalens® has a hinge on either side of the implant that allows the lens to bend and it is said to actually mechanically shift focus between near and far.
What can I expect after the op?
Will I still need spectacles after the op?
Everyone is different and how your eyes respond to surgery will vary. While a lot of people will not need specs after surgery, most people will need specs for either distance or reading purposes, depending on your choice of the implant.
Temporary reading glasses maybe used while waiting for the final spectacles. You may start using these from the first post op day, as they will do NO harm.
At approximately three to four weeks after surgery you will need to be tested for final spectacles(if required) by your local optometrist.
Can a Cataract grow back?
Once a cataract is removed, it cannot grow back. The thin posterior capsule that is left behind to act as a platform for the implant can opacify over a period of 3 months to 10 years. When this happens you will notice your vision starting to blur or get misty as though you are looking through a dirty window. Many people call this an “after cataract”.
Please book an appointment when this happens and I will advise you if I need to “polish” the implant. This requires puncturing a small hole in the posterior capsule(through which you will see more clearly) using a.Yag laser.