A cataract is a clouding of the normally clear lens of the eye. Many people don’t know that not all cataracts are the same! There are many different ways to classify cataracts.
The three primary types of cataracts are:
This is the most common type of cataract. It is when the centre of the lens (nucleus) starts to become yellow and harden. This cataract develops slowly and affects your distance vision more than your near vision.
A cortical cataract is when whitish, wedge-shaped spokes start to grow on the edge of the lens (cortex). As the cataract progresses, the spokes start to develop towards the centre of the lens. This type of cataract causes blurred vision and causes issues with glare, especially at night time.
Posterior subcapsular cataracts develop on the back (posterior) of the lens just underneath the lens capsule (subcapsular). This type of cataract develops relatively quickly and causes problems with glare, light sensitivity and reading vision.
The above cataracts are usually caused by normal age-related changes to your lens, occurring in around 70% of Australians aged over 80.
However, they may also develop in younger individuals, secondary to other eye diseases such as uveitis, glaucoma, retinitis pigmentosa and high myopia.
Sometimes, people may develop cataracts as a side effect of systemic diseases or trauma to the eye. These cause cataracts of different and unique presentations. Some of these diseases include diabetes mellitus, myotonic dystrophy, atopic dermatitis and neurofibromatosis type 2.
Some unique presentations of such cataracts include:
These cataracts can present in young individuals with diabetes mellitus due to high blood sugar (hyperglycemia). They appear as snowflake-shaped opacities in the outer layer (cortex) of the lens.
Christmas tree cataracts appear like a Christmas tree; they appear as fine iridescent opacities on the lens’s outer layer (cortex). This is often found in patients with myotonic dystrophy over 90% of patients with myotonic dystrophy.
A glassblower’s cataract occurs as a result of exposure to infrared radiation, normally occurring in individuals who work in glass blowing or with hot, molten metals,
Blunt trauma to the eye can also induce cataract formation, often in the shape of a star or flower.
Cataracts can also occur in newborns from the time of birth. These are caused by various reasons, including inherited metabolic disorders, genetic syndromes, or infection during a mother’s pregnancy. Such cataracts can present as:
Blue-dot cataracts appear as small, discrete bluish opacities throughout the cortex of the lens caused by mutations to certain genes.
Lamellar cataracts are discrete, round-shaped rings in the cortex of the lens. These are the most common types of cataracts in children.
Sutural cataracts are fairly uncommon and appear as a Y-shaped opacity in the very centre of the lens (fetal nucleus).
These cataracts appear as a distinct, disc-shaped opacity found on the back (posterior) surface of the lens
These cataracts appear as small, milky white ‘plaques’ on the lens’s front (anterior) surface.
These cataracts are often seen in individuals with galactosemia, an inherited metabolic disorder. It appears as a yellow-orange coloured opacity in the centre (nucleus) of the lens.
Different types of cataracts have different rates of progression and impacts on your visual function. Cataracts can cause symptoms of cloudy, blurred vision, sensitivity to lights and glare, halos around lights, difficulty seeing at night or fading of colours.
If you have any of these above symptoms, it may be time to book an appointment with a GP or optometrist to obtain a referral to see a cataract specialist.
The only effective means of treating cataracts is surgery. Cataract surgery involves removing the cloudy lens and replacing it with a new artificial lens.
Read our next blog for the different methods of performing cataract surgery
Our team of highly qualified eye specialists at George Street Eye Centre are cataract specialists who are able to help you diagnose and treat your cataract. If you would like more information, please call us on (02) 9230 0010.