How is cataract caused?

eyes with cataract

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The inevitable ride of ageing brings several problems which were unfaced in the past. Joint pains, fluctuations in weight, indigestion and greying of hair are the biologically signs of ageing. Nearly all parts of the body age and exhibit characteristics different from when the individual was younger. However, due to scientific advancements, a majority of these issues are treatable, and people can enjoy their retired life with vigour and energy.

One of the most common consequences of ageing is the development of CATARACT. A cataract is a formation of a layer on the eye lens which causes clouding of the vision. People with cataracts are unable to see a clear and precise image and complain of blurry vision until the cataract is diagnosed by a professional. Since most people will be new to the vision caused due to a cataract, they assume it is due to a change in the power of their eyes. This misdiagnosis brought by self can worsen the condition as there is a delay in diagnosis. Hence, it is advised that people over a certain age have their eyes checked by an eye specialist (OPHTHALMOLOGIST).

eye1

What are the causes of cataracts?

The simplest answer to the question posed above is that the development of cataracts is a consequence of ageing. However, just like everything has a mechanism in biology, the occurrence of cataracts is triggered by a set number of causes as well as an explanation behind it. The most common causes of cataracts are –

  1. A habit of smoking
  2. Chronic usage of steroids
  3. A history of DIABETES
  4. Overexposure to ULTRAVIOLET (UV) light
  5. A physical trauma
  6. Continuous and long-term radiation therapy
  7. Excessive production of OXIDANTS – chemically altered oxygen molecules, brought on by daily life.
  8. Past eye surgery
  9. Heredity

 

How is a cataract formed?

A cataract is a condition wherein the EYE LENS is unable to send a sharp and clear image to the RETINA. Since a clear image is not received by the retina, the brain perceives a blurry image as well. The eye lens – located behind the IRIS (the coloured part of the eye) – focuses the light which enters the eye and the subsequent image falls on the retina. The eye lens moderates the amount of light entering the eye and the sharpness of the same.

People with glasses are not necessarily at a higher risk of having a cataract since a cataract is directly caused due to a defect in the eye lens. A young person’s eye lens is best described as a film in a camera. However, as the age progresses, the eye lens undergoes wear and tear, resulting in loss of flexibility – to become thicker and translucent. The causes listed above cause the tissues making up the lens to break down. As the tissue breaks down, the subsequent cells produced CLUMP together.

The entire eye lens does not degrade at the same time. Clumps cover up certain parts of the lens and the individual starts complaining of cloudy vision. This condition is an early stage of cataract. Over time, the clumps invade a bigger portion of the eye lens and restrict light to enter. This is a progressed stage of cataract. If someone experiences this stage, they are advised to undergo corrective surgery at the earliest.

The progression of cataract is uneven in both eyes. Just like the corrective power in both eyes may not be the same, the development of cataract is different in both eyes depending on exposure to light. A later stage of cataract is visible as a grey translucent colour of the eye which reflects less light.

eye lens

What are the types of cataract?

Since the area affected by cataracts on the eye lens is uneven and can occur at any portion at an early stage, it has been divided into categories.

  1. CORTICAL CATARACTS

Cataracts that impact the edges of the eye lens are called cortical cataracts. The appearance of these cataracts resembles WEDGE-SHAPED STREAKS at the edges of the lens. These streaks are of a white hue and advance to the centre of the lens with time.

  1. NUCLEAR CATARACTS

Cataract which impact the centre of the eye lens is called nuclear cataracts. A common experience with nuclear cataracts is a near-sighted clarity, but this should be considered as a symptom rather than an advantage since it is temporary. Eventually, the eye lens adopts a yellow colouration and at a much serious stage, may turn brown. The change in hue can cause partial blindness in identifying different colours.

  1. POSTERIOR SUBCAPSULAR CATARACTS

Cataracts that impact the back of the eye lens are called posterior subcapsular cataracts. An opaque spot is formed on the back of the lens in this condition and affects the reading vision, reduces the amount of light entering the eye and causes glares. This condition aggravates quicker than the other types of cataracts.

  1. CONGENITAL CATARACTS

Congenital cataracts are present from birth – may be genetic or triggered due to an INTRAUTERINE trauma or infection. These are also associated with conditions such as RUBELLA, MYOTONIC DYSTROPHY or GALACTOSEMIA. Congenital cataracts do not usually affect vision but if it is the case, they are removed during childhood.

 

How is a cataract removed?

Surgery is currently the only way to get rid of cataracts. Cataracts can hinder the daily life of a person by restricting the entry of light and the formation of a clear image. Thus, it is considered extremely dangerous for the person to drive, work or rather, perform any task they are required to do. There are largely two types of surgeries undertaken to remove cataracts and one of them is most practised.

  1. EXTRACAPSULAR SURGERY

This surgery employs the usage of surgical tools to make a long INCISION on the cornea. Through the incision, the surgeon can remove the clumped area of the lens. The worn lens is replaced with an artificial lens which performs the same function as the eye lens. This is a common surgery and is considered safe. The pre-operation and post-operation formalities are minimal, and the patients are kept under observation for a few years and are discharged the same day.

eye surgery

2. PHACOEMULSIFICATION

Phacoemulsification is a relatively new surgical procedure to remove cataracts. Here, the thickened eye lens is ‘broken down’ (EMULSIFIED) ultrasonic waves produced from an ultrasonic handpiece made up of titanium or steel. An artificial lens, such as the one used in extracapsular surgery, is placed in the place of the natural lens.

eye condition

Unlike the older times, aged people no longer have to lose their energy and abilities, owing to all the kinds of medical practices available to them. Although the development of a cataract tends to make a person afraid (mostly due to the surgical aspect of it), it is a treatable condition with an extremely safe procedure. The safety of the surgery ensures us that the world is open for us to see at every age.

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