The eye is one of the most important sensory organs in humans. This makes it all the more frightening when vision becomes cloudy and the ability to see changes as a result. After all, those who no longer see clearly can no longer participate fully in life.

Cataracts: is a disease of the eyes in which the normally clear lens of the eye becomes increasingly cloudy. As a result, the affected person’s vision is continuously reduced. In most cases, cataracts occur due to age, but they can also be the result of metabolic diseases or malformations or injuries involving the eyes. The good news is that cataracts can be treated very well by surgery – provided they are detected in good time. However, if cataracts remain untreated, they can lead to blindness.


If you get the feeling that you are seeing everything around you through a sort of grey veil, or your vision becomes clouded more and more often, these symptoms may be signs of cataracts. The lens of the eye turns greyish in the case of advanced disease and becomes cloudy. Suffers may also develop a fixed stare after this disease has caused them to become (almost) completely blind.


Most cataracts are age-related. However, they may also have other causes such as metabolic diseases, other eye diseases or eye injuries.

Age-related cataracts

Normally, the lens of an eye is clear and can be deformed as required by the muscles of the eyes. This deformability, together with the fluid surrounding the lens, enables us humans to see both at a distance and nearby with equal clarity. The medical term is accommodation of the eye, i.e. the ability of the eye to adapt to objects at different distances. The older you get, the less flexible your lens will be, which can cause it to become cloudy. For this reason, the vast majority of cataracts are “age-related cataracts,” which can occur from around the age of 60. However, there are a lot of people who suffer from cataracts without being aware of it as there is often no visual disturbance at the beginning of the illness.

Metabolic disorders

If you are diabetic, the sugar content in the aqueous humour in your eyes (and of course also in your blood) is naturally higher. The excess sugar is deposited in the lens of the eye, which swells up as a result. This in turn causes the arrangement of the lens fibres to shift, making the lens cloudy. Doctors refer to this form of cataracts as “diabetic cataract”.

In addition, there are other metabolic disorders that can lead to cataracts. Specifically, these are calcium deficiency, hyperactivity of the parathyroid gland, excess ferritin (known as iron-storage protein) in the blood or galactosaemia, a congenital problem with utilising the sugar contained in breast milk (galactose).

Eye diseases and injuries

Cataracts can also be caused by other eye diseases. The technical term for these types of cataracts is “complicated cataract”. Inflammation of the eyes or extreme short-sightedness can be a trigger for this. Contusions of the eyeball or a deep injury to the eye can also cause cataracts (known as traumatic cataract).

Congenital eye malformation

Cataracts can also be congenital (congenital cataract), which are either due to a genetic defect or to infectious diseases of the mother during pregnancy. Genetic defects can lead to a malformation of the eye and thus to clouding the lens of the eye and cataracts; in addition, certain infections in pregnant women – such as herpes, rubella or toxoplasmosis – can lead to the birth of a baby with cataracts.

Other causes

In addition, heavy smoking, malnutrition, radioactive radiation, UV light or lens metabolism defects can cause cataracts. And in rare cases, even medication or poisoning can cause the lens of the eye to become cloudy and result in loss of vision.


Cataracts can only be diagnosed with a detailed examination by an ophthalmologist. For diagnostic purposes, the specialist first takes the patient’s medical history – here, any pre-existing conditions, symptoms, personal circumstances and habits are queried. This is followed by various eye examinations, in which the pupils are often dilated using special eye drops:

  1. A general eye test with the aid of eye charts is carried out.
  2. The specialist also shines a light into the eyes (Brückner test), which allows them to visualise the clouding of the lens in the form of dark spots as the retina reflects some of the light.
  3. In addition, an investigation is carried out using a slit lamp; this type of lamp is a microscope with a light source that can be pivoted on both sides. This ray of light penetrates the transparent areas of the eyes, making it possible to examine the retina at the back of the eye and thus identify the type of cataract and what might have caused it.
  4. The ophthalmologist can also measure the thickness of the cornea and map its surface at front and back with the aid of a computer-based procedure. It then becomes clear whether the cornea is evenly curved and whether the cell layer that supplies the cornea and also ensures its transparency is intact.

With the naked eye, cataracts can only be seen when the disease has already progressed a great deal and the clouding of the lens has become literally unmistakable.


Cataracts can only be treated by surgery. In the course of this procedure, the opaque lens is removed and an artificial lens is implanted, with the surgeon rarely removing the entire lens, but trying to leave the capsules at the side and rear in the eye. This artificial lens then remains in the eye for life. Cataract surgery is a form of microsurgery, which means it is performed with a surgical microscope.

The following factors would make cataract surgery the preferred option:

  • The severity of the visual impairment for the affected person. If, for example, they feel that they are no longer able to cope with their day-to-day life due to cataracts, there is every reason to opt for surgery.
  • Actual deterioration of the eyes, so the person affected is no longer able to drive safely, for example, due to poor eye test results, even though this is absolutely essential for their job.
  • Very good vision is essential for the person's occupation, such as a pilot.
  • Complete blindness is imminent.

Cataract surgery is usually performed on an outpatient basis under local anaesthesia. Usually cataracts occur in both eyes at the same time, but one eye is operated on first and the other one later. Cataract surgery usually lasts 30 minutes.

Lens transplantation methods

Depending on the severity of the disease and the individual patient's situation, the following lens transplantation methods are available:

  1. Phacoemulsification
    The cornea is opened with an incision about 3.5 millimetres wide. The specialist then dissolves the nucleus of the lens using ultrasound or a laser and removes it via suction. The artificial replacement lens is now inserted into the remaining shell of the lens.

    The advantage of this surgical method is that the tiny incision closes automatically after the procedure without scarring. For this reason, it is possible to have new glasses made quite soon with this type of surgery and to lead a normal life.
  2. Intracapsular cataract extraction
    The lens is removed from the eye, including the capsule. This requires a large incision of 8 to 10 millimetres through the cornea. The lens is then frozen with a special cold pen and removed. The surgeon then inserts the artificial lens into one of the two chambers of the eye and closes the incision with a fine suture.
    This surgical method is usually used when cataract disease is already at an advanced stage.
  3. Extracapsular cataract extraction
    The surgeon opens the anterior lens capsule with an incision of around 7 millimetres in length and removes the nucleus of the lens, without crushing it, before inserting the artificial lens into the capsule.
    Since this type of intervention is the most gentle on the cornea, it is mainly used when advanced cataracts have already damaged the thin, innermost layer of the cornea.

After the operation, an ointment dressing is applied to the eye. If no complications occur, patients are allowed to return home after just a few hours. However, please note: you are not allowed to drive immediately after a cataract operation. So it’s better to be picked up and taken home on the day of your operation.


It is important that you see your ophthalmologist for all the regular follow-ups required. After all, this is the only way to ensure good eye health in the long term.


What are the early signs of cataracts?

Cataracts involve a clouding of the natural lens of the eye, which may progress slowly or even quickly. This clouding does not cause any pain. Cataracts usually manifest themselves through a gradual loss of vision. In addition, the eye is more sensitive to bright light and may be more sensitive to glare, especially at night. The outside world is increasingly perceived through a kind of fog, contrasts become weaker and colours fade. If left untreated, cataracts can lead to total blindness.

What treatment options are there?

Cataracts can only be treated successfully by means of a surgical procedure. Alternative methods, spectacle lenses, eye drops or medication do not provide a remedy. Modern eye surgery uses gentle surgical methods and can usually remove cataracts without pain and permanently, thus increasing the patient’s quality of life many times over.

Do cataracts come back?

Once the clouded lens has been removed, the cataract is permanently removed. However, after surgery, a film of tissue behind the lens may become cloudy (known as posterior capsule opacification). As clouding increases, this posterior capsule opacification may weaken the newly acquired visual acuity, but fortunately it can also be removed painlessly on an outpatient basis with a short laser procedure.

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