Cataract Surgery

Cataract Surgery

What is a Cataract surgery?

When the natural lens in the eye turns cloudy and causes blurring of vision, the surgeon will recommend a cataract surgery. It is a 2-step process which takes about 15-20 minutes depending on the type of cataract surgery. The first step is to remove the cloudy lens using ultrasound and the second step is to insert an intraocular lens (artificial lens) to replace the natural lens.

Cataract removal is one of the safest and most effective surgical procedures. A cataract surgery is usually done as a day surgery and the patient may go home after 3-4 hours’ rest in the hospital. Most patients are back to their normal activities the very next day.

Currently, there are no alternative treatments that can cause a cataract to disappear once it has formed. It is important to note that neither diet nor lasers can make a cataract go away.

The older methods of cataract removal are extracapsular cataract extraction (ECCE) and intracapsular cataract extraction (ICCE). More recently, phacoemulsification with intraocular lens implantation has become a popular choice for surgeons due to faster healing and less incidences of complications. The corneal incision can be made as small as 2.2-1.8mm which will heal without any stitching.

Once the doctor confirms the diagnosis of a cataract and the patient decides to undergo a cataract surgery, there will be additional tests before scheduling the surgery. The nurses will measure the blood pressures and perform an electrocardiogram (ECG) to determine that the patient is in good health. Then the optometrists will carry out biometry measurements to enable the surgeon to calculate the lens implant power for the patient.

After going through a counseling session to ensure the patient fully understands the procedures involved in a cataract surgery, some eye drops will be dispensed and the patient need to start instilling them 2 days prior to surgery day.

The video above shows the cataract surgery

What are the types of intraocular lenses (IOLs) available?

A monofocal implant is a lens with a single focal point. It is commonly implanted in an eye without corneal astigmatism. An eye which has myopia or hyperopia before undergoing a cataract surgery can potentially be corrected to perfect vision with the correct choice of implant power.

After the surgery, the eye can see distant clearly but will require reading glasses for near.

Another method of correcting vision with monofocal implants is the monovision technique where one eye is corrected to see distant and the other to see near. The doctor will discuss on the suitability for this technique as some patients may not adapt well to monovision.

A toric monofocal implant is similar to a normal monofocal implant except that it also corrects corneal astigmatism. Therefore, it can be used to correct myopia, hyperopia as well as irregularities of the corneal surface (astigmatism) to give clear vision after a cataract surgery.

This lens does not correct the near reading problem but the monovision technique (one eye for distant, one eye for near) can be employed to give the patient independence from glasses.

A multifocal implant is a lens with multiple focal points. It is commonly implanted in an eye without corneal astigmatism. Unlike a monofocal implant, this lens corrects both distant and near vision. Therefore, the patient will unlikely to need glasses after the cataract surgery.

Due to the design of the multifocal lens, the eye may see some glare and halo effects especially at night. Some people are able to adapt to these visual effects and are able to perform day-to-day activities without much difficulties. There are also people who may be adversely affected by the glare and halo effects. As these visual effects are not correctable with optical aids, the surgeon will access the suitability for multifocal lens implantation and advise the patient accordingly.

Another IOL which is increasingly becoming a popular choice for surgeons and patients is the multifocal toric implant. This lens corrects the distance and near vision, plus the irregularities of the corneal surface (astigmatism). With such an advanced implant lens, the patient can look forward to having all the refractive errors of the eye corrected with one single IOL.

Due to the multiple focus point design of the multifocal toric implant, the eye potentially may see some glare and halo effects, as with most designs of multifcal IOLs.

A multifocal IOL

A monofocal IOL

Who are suitable for a Cataract surgery?

People with systemic health conditions such as diabetes, high blood pressure, high cholesterol and heart diseases are usually suitable to undergo a cataract surgery. It is important to inform the surgeon of the medications that the patient is taking as certain medications may affect the surgery.

For people who have undergone previous eye surgeries such as LASIK, retinal detachment, glaucoma treatments and eyelid surgeries are also usually suitable to undergo a cataract surgery. The patient should inform the doctor of all pre-existing eye conditions during the initial consultation session.

What are the Possible Side Effects and Complications of a Cataract Surgery?

Cataract surgeries can potentially be 95-99% uncomplicated under the hands of a competent and experienced surgeon.

Some rare occurrences of complications are cystoid macular oedema, bleeding at the back of the eye, posterior capsule rupture, endophthalmitis, retinal detachment and glaucoma.

For eyes with pre-existing diseases which have caused irreversible damage to the vision, a cataract surgery may remove the cloudy natural lens but will not restore vision to 6/6. Some examples of these eye problems are macular degeneration, retinal hole, glaucoma, corneal scarring and ambylopia.

About 30% of patients may develop a posterior capsular opacity (PCO) after a cataract surgery which may appear as soon as after 1 month or after many years. This is also sometimes called a secondary cataract. It is important to note that a cataract does not grow again after an initial cataract surgery.

PCO causes hazy vision with occasional glare effects. It occurs due to protein deposition on the posterior surface of the capsular bag which contains the intraocular lens. This deposition reduces clarity of vision and can be easily removed with a YAG-laser capsulotomy. This laser needs to be applied for only one session and is rather quick and painless.

Some cataract patients enjoy clear vision for many years without encountering a PCO.