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Cataract

Surgical treatment
Dr McKellar operating on a patient with cataract.

The only treatment for cataract is surgery.

Overview

This section deals with the more technical aspects of cataract surgery. More information on what it is like to go through the process of cataract surgery can be found in having cataract surgery

The decision to operate

Many issues must be considered before the decision to operate is made. These include:

  • The visual problems experienced
  • Determining that cataract is present
  • An assessment of whether other eye disease is present and how this will impact on the expected outcome
  • A review of the risks of surgery

Preparation for surgery

Preparing for surgery involves two important processes:

  • Measurements of the eye, known as biometry
  • Completion of all paperwork including hospital admission forms and consent documents

Biometry

Measurement of the eye is a critical part of cataract surgery. The curvature of the cornea and length of the eye are determined with instruments known as a keratometer and A-scan ultrasound respectively. The data is then entered in formulae that calculate the power of the intraocular lens required for each individual patient.

Admission forms and consent documents 

There are certain legal requirements that must be completed prior to surgery. These include the hospital medical questionnaire and the consent for surgery.

The surgical process

Cataract surgery involves five main steps:

  • Dilating the pupil
  • Anaesthetising the eye
  • Removing the cataract
  • Implanting the new intraocular lens
  • Recovery

Pupil dilation

Cataracts lie behind the pupil and so it must be dilated prior to surgery.

Eye anaesthesia

Anaesthesia for eye surgery has changed significantly over the last decade. It is very rare for people to require general anaesthesia. Most patients now have one of two types of anaesthesia:

  • Topical anaesthesia
  • Sub-tenons local anaesthesia

Topical anaesthesia

Dr McKellar prefers to use topical anaesthesia using special eyedrops to 'numb' the eye. This avoids needles and results in more rapid and comfortable recovery.

Sub-tenons anesthesia

Patients who are very sensitive to light or touch around their eye may require sub-tenons anaesthesia, in which a soft canula (or tube) distributes anaesthetic around the eye through a tiny opening in the conjunctiva.

Removing the cataract
The concept of cataract removal. Courtesy Alcon.

Cataract surgery involves removal of the cloudy natural lens of the eye and the placement of a new clear artificial intraocular lens inside the eye to restore vision.

The easiest way to understand cataract surgery is to compare it to the process of removing the contents of an egg from an eggshell. The diagram to the right shows the cloudy lens exiting the eye.

The analogy of shelling out an egg is helpful but now no longer entirely accurate. Most cataracts are removed by small incision surgery in which the lens is broken up inside the eye and then aspirated through a tiny opening. This process is known as phacoemulsification. 

Phacoemulsification
The reality of cataract surgery. Small incision phacoemulsification or AquaLase®. Courtesy Alcon.

Phacoemulsification is an ultrasound technology in which a vibrating hollow tube breaks up the cataract.

Phacoemulsification is the most common method used to remove cataracts and is the most effective method of removing hard cataracts. 

Ozil®

Dr McKellar uses Ozil®, an advanced form of phacoemulsification in which the ultrasound tube vibrates longitudinally and transversly. Ozil® is safer and more efficient than traditional ultrasound. 

Intraocular lens implantation

Following removal of the natural lens a new 'plastic' lens is inserted into the eye to restore vision. Some people refer to intraocular lenses as 'implants'. The power of the intraocular lens is calculated for each patient before surgery.

Click here for more information on intraocular lenses.

Success rates

In general the chances of successful surgery are approximately 98%. Other eye disease and complications can limit the outcome.

Risks of cataract surgery

Modern cataract surgery is very safe with approximately 98% of all patients having successful outcomes and no complications. Nevertheless no surgical procedure is risk free. The most serious risks of surgery include:

  • Infection
  • Bleeding
  • Retinal swelling
  • Retinal detachment

Most complications can be successfully treated but in rare cases vision loss and even blindness can occur. In very rare cases inflammation can damage the unoperated eye.

Further information

Dr McKellar gives all of his patients a brochure produced by The Royal Australian and New Zealand College of Ophthalmologists which further outlines the process, benefits and risks of surgery. Even this brochure does not contain all the information you may need before deciding to have cataract surgery. Please ask Dr McKellar if you have any other questions.