Cataract incidence / prevalence
Age-related cataract is one of the leading causes of impaired vision for Australians aged over 55.
What is a cataract?
Cataracts occur, affecting most of us when the natural lens of our eye ages and loses its clarity. As a cataract progresses, the natural lens becomes hazy and discoloured. This causes your eyesight to worsen.
- Your vision becomes blurred, and you cannot correct it with glasses
- Reading small print becomes challenging
- Colours fade
- Your confidence driving at night begins to falter. This is because the cataract scatters light causing glare sensitivity.
Cataracts usually occur as a result of the natural ageing process. The cataract forms slowly and will affect most people at some point after the age of 55. However, sometimes cataracts can be present at birth. Others face risks of cataracts 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)
Cataract diagnosis and examination
We will perform several tests and scans to determine whether you have a cataract and how it may be impacting your day-to-day life. The tests will include:
Visual acuity: to understand how far down the eye chart you can read.
Refraction: to determine the refractive error in your eyes.
Pachymetry: to measure the thickness of your cornea.
Topography: to generate advanced maps of the cornea to provide a contour plan of the front surface of the cornea. (This aids in the diagnosis of astigmatism and the exclusion of certain diseases).
Biometry: to measure the axial length, curvature, and chamber depths of your eye.
Optical coherence tomography (OCT): to provide detailed images of the retina.
We may use dilating drops that will make your vision blurry for up to 3 hours.
You will have the opportunity to ask any questions you may have.
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 half an hour and does not require an overnight stay.
At OKKO, we offer three types of cataract surgery:
- Standard cataract surgery – An ideal treatment for someone who is happy to not be free from glasses after the treatment
- Lifestyle cataract surgery – Restore clarity of vision AND reduce your dependence on glasses to suit your active lifestyle
- Laser cataract surgery Restore clarity of vision AND correct your glasses prescription, so you no longer need glasses for reading and distance vision
The right choice for you depends on your aims and expectations.
Any surgical or invasive procedure carries risks. Before proceeding, you should seek a second opinion from an appropriately qualified health practitioner.
What is a cataract?
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 focuses 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 vision problems.
What are the symptoms of a cataract?
Early cataracts may not affect the vision or only affect the vision minimally. In these instances, you may not need treatment; however, cataracts will likely progress. 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 (halos 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.
What causes a cataract?
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 its clarity.
There are other factors that accelerate the growth of cataracts including:
- Excessive exposure to UV and other types of radiation
- Use of certain medications (e.g. corticosteroids)
- Previous blunt/penetrating ocular trauma, surgery or disease
- Systemic disease (e.g. diabetes and other metabolic disorders)
- Genetics and congenital disorders
What are the different types of cataract?
Nuclear sclerotic cataracts are the most common type of cataract. It describes an overall clouding in the central part (the nucleus) of the crystalline lens. Nuclear cataracts 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.
How are cataracts detected?
We will measure your visual acuity on a letter chart. We will also use a slit lamp microscope to classify and grade the cataract. Sometimes, we use dilating drops to enlarge the pupil allowing us to examine the back of the eye thoroughly and to exclude the possibility of other eye diseases. These drops will blur your vision for 2-3 hours, and so we recommend 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 a cross-sectional view. It will screen for any macular pathology which could also be responsible for reducing vision (e.g. age-related macular degeneration).
We recommend that everyone has an OCT before cataract surgery to ensure that we have evaluated the health of the eye thoroughly. We may not detect some macular problems in an eye examination alone, particularly in the presence of a dense cataract.
What other complications can arise from cataracts?
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 you to see if you are at risk of primary angle-closure glaucoma and whether you would benefit from cataract extraction or other treatment to prevent this serious condition.
How are cataracts treated?
The only way to treat a cataract is to remove it surgically.
Cataract treatment FAQs
How can you reduce my dependence on glasses after cataract surgery?
Once we have removed your cataract lens we replace it with an artificial lens called an IOL. It is possible in most cases to choose an IOL that can correct your remaining prescription. To do this, we perform a series of scans at your initial visit, which gives precise measurements of your eye. These include measurements of the length of the eye and the curvature of the front of the eye. We take these values and insert them into a mathematical regression formula that calculates the IOL power according to your needs. There is an 85 – 90% chance of achieving the desired outcome.
It is important to understand that no artificial intraocular lens can completely replicate the vision that you may have experienced in early adult life. We also cannot guarantee that the lens will achieve the exact focus you and your cataract surgeon aim for.
Your ophthalmologist will discuss your intraocular 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, but are not limited to:
- Distance vision for both eyes – this is where we plan for no or minimal distance prescription, however, correction is expected to be required for intermediate and near vision.
- Blended monovision – This describes a mix of distance and intermediate/near vision. We do this by correcting the dominant eye to improve distance vision and the non-dominant eye for intermediate vision. The brain generally adapts naturally and quickly to this configuration. You may still require spectacles for reading (especially in dim light, with small writing, and for long periods) and night driving.
- Full monovision – This describes a mix of distance and near vision. We correct the dominant eye to improve your distance vision and correct the non-dominant eye to improve near vision. There is a greater difference in the prescription between the two eyes compared to blended monovision. Adapting to full monovision can take longer. You may still require spectacles for intermediate vision and other activities.
- Multifocal intraocular lenses (IOLs) – These contain concentric ‘rings’ or separate segments that enable the lens to provide distance and near vision to reduce your dependency on glasses. These lenses will give you good postoperative distance, and near vision, however, you may require spectacles for long periods of intermediate vision tasks (e.g. computer). Multifocal IOLs can also cause significant halos around lights at night time.
What can I expect during cataract surgery?
We perform cataract surgery using intravenous sedation, and local anaesthetic eye drops to ensure the procedure is pain-free. You will have little or no awareness of your surroundings during the procedure. For the majority of patients, the sedative effect will wear off within 15 to 20 minutes following surgery. You will not be able to drive for 24 hours after your procedure due to the residual effects of sedation such as drowsiness and decreased reaction times. We, therefore, recommend you have a carer to escort you home and avoid public transport for the same reason.
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 discomfort related to dryness of the eye. These symptoms are usually manageable with lubricating eye drops. If we see you have dry eyes at your preoperative assessment, your surgeon may recommend you commence the use of artificial tears before surgery.
Your vision may be blurred to some degree on the day following surgery but will improve over the next first few days. Upgrades in spectacles can generally be made approximately one month to 6 weeks after surgery.
Postoperatively, there are no significant restrictions on lifestyle. In the first week, we advise you to defer any activities which could introduce foreign matter into the eye (this includes avoiding getting water in your eye when showering). We will give you a clear shield (for use when sleeping) and dark safety glasses to protect the eye.
What happens if the desired focus is not achieved?
There is a degree of variability in achieving the desired prescription following cataract surgery, between both individuals and eyes. This is because we calculate the IOL implant using a regression equation, and it is possible that your 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 your 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 with an additional procedure. Secondary treatment options include inserting a secondary (piggy-back) IOL or performing laser refractive surgery.
Will insurance cover the cost of cataract surgery?
Medicare and health insurance usually cover cataract surgery.