health May 22, 2021
Photo by Perchek Industrie / Unsplash

All individuals are able to assimilate the information from their surroundings by visual system. The cornea and lens play a key role in visual system.

The act of seeing starts when the cornea and the lens of the eye focuses light from its surroundings onto a light-sensitive membrane in the back of the eye, called the retina. The retina of visual system is actually a part of the brain that acts as a transducer and converts light into neuronal signals.

Based on feedback from the visual system, the lens of the eye adjusts its thickness to focus light on the photoreceptive cells rods and cones of the retina. They detect the photons of light and respond by producing neural impulses. Retina sends the signals to the optic nerve, which carries them to the brain. These signals are processed via complex feedforward and feedback processes by different parts of the brain.  

In a normal eye, the lens will be clear and light passes through the transparent lens to the retina and the retina receives a sharp image.

If the lens is cloudy, the image striking the retina will be blurry or distorted and the vision will be blurry. The major problem in visual perception is that, what people see is not the image found on the retina.

The painless clouding of the lens of the eye is most common among the elder people. Cloudy area that forms in the lens of the eye is the cataract which is believed to be the result of oxidation that occurs in the lens of the eye.

"Cataract" is derived from the Latin cataracta, meaning "waterfall"

In cataract, proteins in the eye form masses that prevent the lens from sending clear images to the retina. Vitamin C helps to protect against this type of damage.

It can occur in younger people because of a rare metabolic defect.

Common symptoms of cataracts include: blurry vision, trouble seeing at night, seeing colours as faded, increased sensitivity to glare, coronae surrounding lights, double vision in the affected eye, a need for frequent changes in prescription glasses, near-sightedness (in older people), reading becomes difficult and eventually impossible and vision may be affected by small spots or dots.

The cloudy lens can be replaced with a clear, artificial lens by surgery.

Risk factors associated with cataracts include: older age, heavy alcohol use, smoking, obesity, high blood pressure, previous eye injuries, a family history of cataracts, too much sun exposure, air pollution, diabetes, exposure to radiation from X-rays and cancer treatments.

Prevention of Cataracts: To reduce the risk of developing cataracts, eyes should be protected from UVB rays exposure by wearing sunglasses outside, adequate intake of fruits and vegetables that contain antioxidants (such as vitamins A, C, and E), healthy and balanced diet that contains Vitamin A  as it plays an important role in maintaining good eyesight, having regular eye exams, avoiding smoking, maintaining a healthy weight, keeping diabetes and other medical conditions in check, avoiding driving at night, looking away from the computer screen.

Post-operative care
After the surgery normal household activities can be carried out but strenuous activities such as lifting heavy objects, high power exercise should be avoided for one week. Visitors with conjunctivitis, cold etc. should be avoided for fear of contacting infection. Depending on the amount of postoperative inflammation, the drops are used for a few weeks to a month. If needed, oral pain relievers may be prescribed. Driving on the first day should be avoided. Swimming or using a hot tub, exposing eye to irritants such as grime, dust and wind during the first few weeks after surgery should be avoided.

The activities which can be performed within a few hours of surgery are

  • Computer work
  • Light TV watching
  • Showering or bathing


A. Sandhya

M.Sc Zoology

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