What are cataracts?
Cataracts occur when the lens in the eye becomes cloudy, either completely or partially. Cataracts occur most commonly due to age, inflammation, or steroid use.
There are many types of cataracts:
- Congenital or infantile cataracts: These occur in children under a year old. The cause is usually unknown, but it is sometimes associated with metabolic diseases such as Down Syndrome and infectious diseases during pregnancy, among others.
- Nuclear cataracts: This is the most common type of cataract. It is produced by a progressive hardening and yellowing of the centre of the lens. It is usually accompanied by progressive nearsightedness.
- Cortical cataracts: These are the second most common type. Opacification of the cortex of the lens occurs (outer part of the lens), and the person will notice blurred vision, loss of contrast sensitivity, and glare.
- Posterior subcapsular cataracts: This is a type of cataract that appears in young people after taking corticosteroids for a long time, following an inflammatory process or if they have magnum myopia. It causes vision loss and significant glare within a few months.
- Traumatic cataract: Usually unilateral and associated with other eye disorders such as iris sphincter rupture, zonular weakness or even rupture of the posterior capsule.
Vision deterioration after cataract diagnosis is very variable. Some cataracts can progress rapidly, decreasing vision in the months following diagnosis, while with others there is very little change over time. Monitoring and assessing the evolution of the cataract can only be done through regular check-ups by an ophthalmologist.
Cataracts are the most common cause of reversible blindness in the world.
Cataracts cause decreased vision.
In the initial stages, you might notice more subtle symptoms such as:
- Discomfort with light
- Altered colour perception.
Medical tests for cataracts
The diagnosis of cataracts should always be made by an ophthalmologist, either during routine check-ups or when a person attends the clinic with suggestive symptoms.
The diagnosis and degree of cataract, if any, will be determined after a complete eye examination with the pupils dilated (dilated with eye drops). Each case must be assessed individually to establish the appropriate treatment.
The tests that are usually performed include:
- Slit lamp examination: The cornea of the eyes, the iris, the lens, and the space between the iris and the cornea are closely examined.
- Retinal exam: With the eye dilated, the pupils open, the ophthalmologist can see the back of the eye more clearly. Using a slit lamp and/or an instrument called an ophthalmoscope, the ophthalmologist looks for signs of cataracts. They will also look for signs of glaucoma or other problems with the retina and the optic nerve.
- Refraction and visual acuity test: The sharpness and clarity of the person’s vision are tested by assessing the ability of each eye to see letters of different sizes.
What causes cataracts?
In the eye is a structure called the crystalline lens, which focuses images onto the retina. Under normal conditions, this crystalline lens is transparent. However, over the years this structure becomes opaque and is what we call a cataract.
In addition to ageing, there are other factors that can lead to non-elderly people developing cataracts, including:
- Diabetes and other metabolic diseases, or myotonic dystrophy
- Long-term use of some drugs (especially oral and inhaled corticosteroids)
- Congenital cataracts
- Exposure to solar radiation
- High blood pressure
- Eye diseases, such as uveitis (intraocular inflammation)
- Previous eye surgery
- Eye trauma
- Radiation therapy treatment
Can they be prevented?
The following advice may help prevent cataracts:
- Wear appropriate sunglasses
- Control diabetes
- Eat healthily
- Have periodic check-ups
Treatment for cataracts
The only treatment to cure cataracts and restore proper vision is to have them surgically removed, although this is only recommended if the person’s discomfort prevents them from going about their normal daily life or if they cannot wear glasses.
Surgery to correct cataracts involves removing the damaged part of the lens and replacing it with an intraocular lens.