Cataracts

Cataracts

Cataract is one of the leading causes of impaired vision for Australians aged over 55.

Under the guidance of Dr Matthew Russell, a nationally recognised cataract surgeon, the OKKO team is highly experienced in diagnosing and treating cataract to ensure the best possible eye health and vision outcomes for each patient.

What is a cataract?

When the eye’s naturally clear lens becomes clouded or hazy, it is called a cataract. This clouding means that images on the back of the eye are out of focus and degraded, which leads to impaired or blurred vision.

Causes and symptoms

Cataracts are usually the result of a natural aging process. They develop slowly and will affect the majority of people at some point after the age of 55. However, sometimes cataracts may be present at birth. Others develop as a result of physical injury or are drug induced.

Symptoms may include:

  • Deterioration of far or near vision (or both)
  • Light sensitivity
  • Decreased night vision
  • Increased glare sensitivity (especially at night)
  • Colours appearing less vivid
  • Dull vision or a loss of contrast sensitivity
  • Double vision or halos around lights
  • Increased short-sightedness (myopia)

Treatment

The only way to treat a cataract is to surgically remove it and implant an artificial lens in its place. Cataract surgery is the most commonly performed surgery in Australia; the procedure typically takes less than an hour and does not require an overnight stay.

The implanted lens can be designed to give a range of vision, from distance to close. The lens power will be calculated using scans performed at your initial consult for surgery. At this consult, clinical staff will discuss the available options and work with you to decide what vision range will work best.

(Types of lens)

Lens implants are permanent and ordinarily do not need to be replaced – they are good for the life of the patient. While most patients experience improved vision as soon as one day after surgery, at times you may still need to wear reading or prescription glasses. Your clinical team will discuss this with you prior to the procedure.

What to expect during surgery

Cataract surgery is performed in the day hospital adjacent to our Auchenflower rooms, which means easy access and continuity of care on the day of your treatment.

Cataract surgery uses local anesthesia (in the form of eyedrops) and light (twilight) sedation. A tiny incision is made in the cornea, the clear membrane on the surface of the eye. A fine instrument inserted through the incision uses ultrasound vibrations to break up the lens into a fine pulp. This pulp is then carefully removed under microscopic guidance.

Once the cataract has been completely removed, your surgeon will implant the artificial lens (intraocular lens or IOL) using a special lens injector. In the majority of cases the IOL will sit within the natural ‘bag’ that held the original crystalline lens, and sutures are not usually required.

The surgery takes less than an hour, and generally the total time at the hospital is approximately three hours. Once the surgery is complete a clear shield will be placed over the eye, which stays on for four hours post-surgery. At this stage post-operative drops (which consist of an antibiotic drop and two anti-inflammatory drops) will be commenced.

Usually the dominant eye is operated on first. Then, a minimum of two weeks later, the second eye can be operated on.

Driving is not permitted for 24 hours following surgery, due to the sedation used.

What to expect after surgery

At OKKO, we pride ourselves on a personalised approach to pre- and post-surgical care, and on ensuring you feel comfortable and empowered during all stages of your treatment.

After cataract surgery you will typically attend several follow-up appointments. The first will be the day after your treatment, so your surgeon can assess progress and answer any questions you may have.

After cataract surgery it is normal to feel mild discomfort, irritation or a stingy sensation. If you experience these symptoms you can take paracetamol (such as Panadol, Panamax, Dymadon or Panadeine). Mild mucous, a small amount of bloody discharge and watering of the eye is also considered normal.

It is also quite normal to be sensitive to light after surgery. You will be given a pair of dark glasses to aid with this if necessary. It is important after cataract surgery to not rub the eye. For two weeks following surgery, it is also advised to avoid:

  • Engaging in strenuous activity/exercise, gardening or heavy lifting (greater than 10kg)
  • Wearing makeup directly on the eyelids
  • Swimming
  • Allowing water/shampoo to come into direct contact with the eye

Cataract surgery is one of the safest and most commonly performed surgeries in Australia. Generally your recovery will be short and uneventful, and the OKKO clinical team will keep you informed at every stage.

How soon does vision improve after cataract surgery?

Vision is usually improved the day after cataract surgery. Maximum improvement is usually achieved when new glasses are prescribed, about a month after cataract surgery. Be sure to use any medications as prescribed to ensure the best possible long-term results.

What are the long-term effects of cataract surgery?

Lens implants are permanent and ordinarily do not need to be replaced – they are good for the life of the patient.

The capsule, or outer lining wall of the cataract, is left in place during surgery to hold the replacement implant. Clouding of this lining may occur months or years after cataract surgery. In this case, an office procedure using a YAG laser can easily and painlessly open a small hole in order to restore normal vision.

Will insurance cover the cost of cataract surgery?

Medicare and health insurance usually cover cataract surgery.

Eye Examination
Your eyecare practitioner will measure your visual acuity on a letter chart. They will also use a slit lamp microscope to classify and grade the cataract. Dilating drops are sometime used to enlarge the pupil. This will allow thorough examination of the back of the eye and to exclude the possibility of other eye disease. These drops will blur your vision for 2-3 hours and it is recommended that you do not drive on the day of your eye exam.

Optical Coherence Tomography (OCT)
Optical coherence tomography (OCT) allows non-invasive imaging of the macula in cross-section. It will screen for any macular pathology which could also be reducing vision (eg. age-related macular degeneration).

We recommend that an OCT be performed on everyone prior to cataract surgery to ensure that the health of the eye is fully evaluated.

Some macular problems may not be able to be detected in an eye examination alone, particularly in the presence of a dense cataract.

The only way to treat a cataract is to surgically remove it. Currently, the most common type of cataract surgery is known as micro incision phacoemulsification cataract extraction. This procedure is performed with local anaesthetic (eyedrops) and copious sedation.

A small (2-2.5mm) self-sealing incision is made on the side of the cornea, the clear membrane on the surface of the eye. A fine ultrasound (phaco) handpiece is then inserted. Vibrations from the tip of the phaco probe will fragment and emulsify the cataract into a pulp. These fragments of cataract are then carefully removed under microscopic guidance.

Following this, a plastic intraocular lens (IOL) implant that has been specifically preselected for your eye is inserted to replace the crystalline lens. The implant is rolled up in a special lens injector and gently guided into place by your surgeon. In the majority of cases, the IOL will sit within the natural bag that originally held the crystalline lens (the capsule), and sutures are not usually required to position the IOL.

Because an IOL replaces the natural crystalline lens, it is possible in most cases to choose the prescription that you will be left with after cataract surgery. To do this, a series of scans are taken at your initial visit which give precise measurements of your eye. These include measurements of the length of the eye and the curvature of the front the eye. These values are then inserted into a regression mathematical formula and an IOL power is calculated according to your needs. There is a 85 - 90% chance of achieving the desired outcome.

It is important to understand that no artificial intraocular lens can completely replicate the vision that your may have experienced in early adult life and there is no lens that can guarantee the exact focus that you and your cataract surgery aim for. Your ophthalmologist will discuss intra-ocular lens options with you as well the target focus for your eye after surgery. By working through this process, the best implant and focus target that most suits your needs is likely to be achieved. Some possibilities include:

  1. Distance Vision for Both Eyes
    No spectacles will be required for distance but you will require correction for intermediate and near vision.
  2. Blended Monovision
    This describes a mix of distance and intermediate/near vision. The dominant eye is corrected for distance and the non-dominant eye is corrected for intermediate vision. The brain generally adapts naturally and quickly to this configuration. Spectacles may still be required for reading (especially in dim light, with small writing and for long periods) and night-driving.
  3. Full Monovision
    This describes a mix of distance and near vision. The dominant eye is corrected for distance and the non-dominant eye is corrected for near vision. There is a greater difference in the prescription between the two eyes as compared to Blended Monovision, and adapting to this Full Monovision can take longer. Spectacles may still be required for intermediate vision.
  4. Multifocal Intraocular Lenses
    These IOLs contain concentric ‘rings’ or separate segments that enable the lens to provide distance and near vision to increase spectacle independence following surgery. These lenses will give good postoperative distance and near vision, however spectacles may be required for long periods of intermediate vision (eg. computer). Multifocal IOLs can also cause significant haloes around lights at night time

Nuclear sclerotic cataract is the most common type of cataract and describes an overall clouding in the central part (the nucleus) of the crystalline lens. They are most commonly associated with increased short-sightedness, altered colour perception and blurry vision.

Cortical cataracts cause spoke-like opacities to form in the periphery of the crystalline lens. Symptoms frequently include increased glare sensitivity and difficulties with night driving.

Posterior Subcapsular cataracts cause a plaque-like opacity to grow on the back of the crystalline lens. They will cause increased glare sensitivity and blurry vision. This form of cataract is sometimes associated with previous steroid use.

Early cataracts may not affect the vision or only affect the vision minimally. In these instances, treatment is not generally required. Moderate and advanced cataracts can cause symptoms such as:

  • blurry or hazy vision (often likened to a dirty spectacle lens)
  • difficulty driving, reading and recognising faces
  • need for more light when reading (reduced light transmission)
  • double vision in one eye
  • increasing short-sightedness
  • increased glare sensitivity due to internal scatter of light
  • difficulties with night driving (haloes and glare)
  • reduced contrast sensitivity
  • altered colour perception
  • reduced brightness/intensity of colours

Cataract progression is generally very gradual but symptoms may become apparent quite quickly in some people. Spectacle correction may help improve vision in early cataract but not in moderate and advanced cases.

Cataract surgery is performed under local anaesthesia and intravenous sedation. Typically anaesthetic eye drops that are used during routine eye examinates are used in order for the procedure to be performed painlessly. Surgery is able to be performed with little or no awareness of your surrounds. The majority of the sedative effect wears off within 15 – 20 minutes of surgery, although you will not be able to drive for 24 hours following surgery.

There is a 98 - 99% likelihood of undergoing cataract surgery without complications that may permanently affect your best possible vision. There is little to no awareness of your surroundings during the surgery, and there is no pain involved at any time. You may experience mild grittiness and dry eye symptoms following surgery, and this can last for a few weeks and in some cases several months. Some people may experience fleeting sharp pain related to dryness of the eye. These symptoms are usually manageable with lubricating eyedrops. If you are noted to have dry eye at your preoperative assessment, your surgeon may recommend you commence use of artificial tears prior to surgery.

Vision is normally blurred to some degree on the day following surgery and it will improve over the next first few days. Upgrades in spectacles can generally be made a month after surgery.

Postoperatively, there are no significant restrictions on lifestyle. In the first week, it is advisable to defer any activities which could introduce foreign matter into the eye (this includes avoiding getting water into the eye when showering) or potentially cause cause significant blunt trauma. You will be given a clear shield (for use when sleeping) and dark safety glasses to protect the eye.

The majority of cataracts develop as a result of natural age-related changes in the eye. Oxygen-related damage to the proteins in the natural lens accumulates throughout life. From about 40 years of age, this causes proteins within the crystalline lens to discolour and gradually the lens loses it clarity.

Other factors that cause cataract or accelerate its growth include:

  • excessive exposure to UV and other types of radiation
  • use of certain medications (eg. corticosteroids)
  • previous blunt/penetrating ocular trauma, surgery or disease
  • systemic disease (eg. diabetes and other metabolic disorders)
  • smoking
  • genetics and congenital disorders

There is a degree of variability in achieving the desired prescription following cataract surgery, between both individuals and eyes. This is because the IOL implant selected for your eye is calculated using a regression equation that is based on results from 35,000 cataract surgeries. It is possible that your particular eye may not conform exactly to this mathematical model.

In the majority of cases, even if the focus is not exactly as predicted it is likely to be very close to the expected result and the quality of you vision should still be very good. Wearing glasses for certain activities may be necessary. In cases where the desired postoperative prescription is significantly different from the expected result, your surgeon may discuss with you the possibility of fine-tuning your vision. Treatment options include inserting a secondary (piggy-back) IOL or performing laser refractive surgery.

A cataract is a clouding or loss of clarity of the natural crystalline lens inside the eye. The crystalline lens is normally a clear structure that focusses light onto the back of the eye (retina), much like a camera. When the lens becomes cloudy, images on the back of the eye are out of focus and dull, leading to impaired vision.

In certain people, the growth of a cataract can make them prone to primary angle-closure glaucoma. This is where the drainage channel in the front of the eye (trabecular meshwork) is gradually narrowed by the increasing size of the crystalline lens.

Eventually, the drainage channel can become completely blocked, resulting in a rapid increase in the pressure within the eyeball and a painful red eye. Long-sighted patients are more likely to be at risk of angle-closure glaucoma. Your eye specialist will be able to assess if you are at risk of primary angle-closure glaucoma and whether you would benefit from cataract extraction or other treatments to prevent this serious condition.