What is a Cataract?

A cataract is a clouding of the natural lens of the eye, which lies behind the iris and pupil. The lens is responsible for focusing light onto the retina to produce a clear image. When the lens becomes cloudy, the incoming light is scattered and blocked, resulting in blurred vision.

Cataracts vary in severity from minor cloudiness to complete obstruction of eyesight. They are a leading cause of blindness worldwide but can be easily treated with a brief operation.

Cataracts are a normal ageing change, tending to occur after age 60. However, cataract
formation is accelerated by several things. Common risk factors include:

• Age:  Cataracts are common in individuals over 60.
• UV Exposure: Prolonged exposure to sunlight without adequate protection.
• Smoking: Increases oxidative stress, accelerating cataract formation.
• Diabetes: High blood sugar levels can lead to early cataract development.
• Medications: Long-term use of corticosteroids.
• Eye Injuries: Trauma or previous eye surgeries (especially vitrectomy).
• Eye inflammation (iritis)
• Short sightedness (myopia)
• High alcohol consumption

Early detection of cataracts can be challenging because the change in vision is
often slow. Here are the symptoms to watch for:

1. Blurred or Cloudy Vision
One of the most common symptoms of cataracts is blurred or cloudy vision. The cloudiness slowly worsens over time, making everyday activities like reading and driving more difficult.

2. Difficulty with Night Vision
Cataracts can impair night vision, making it harder to see in low-light conditions. Many patients report glare from headlights while driving at night, which can be hazardous.

3. Sensitivity to Light and Glare
As the lens becomes clouded, light scatters instead of focusing properly. This leads to heightened sensitivity to bright lights, glare, and halos around light sources, such as street lamps.

4. Fading or Yellowing of Colours
Cataracts can cause colours to appear dull, faded, or yellowish. This symptom develops gradually and usually go unnoticed until it becomes severe.

5. Double Vision in One Eye
Monocular double vision (double images in one eye) is a less common symptom of cataracts. It occurs when the lens has uneven clouding and thereby begins acting like a chandelier.

6. Frequent Changes in Glasses Prescription
If you find yourself needing frequent changes to your glasses or contact lens prescription, it may be due to progressive cataracts. This is especially true if your updated glasses fail to improve your vision significantly.

While an official diagnosis requires an ophthalmologist, there are steps you can take at home to monitor your vision:

1.Perform a Vision Test

Cover one eye at a time and check for asymmetry in clarity or color perception.

2.Observe Your Night Vision

Pay attention to difficulties while driving or walking at night.

3.Compare Your Vision with Others

Check if others can see details that you cannot.

4.Check for Halos around Lights

Look at lights at night to see if you notice a circular glow or starburst around them.

Cataracts are classified into different subtypes according to their appearance, as well as the location of the clouding within the lens. Understanding the different types of cataracts can help you to recognise their symptoms. The most common types of cataract are described below.

Nuclear Cataracts:

• Affects the centre of the lens.
• Appear as a yellow discolouration of the lens.
• Caused by aging and long term UV light exposure
• May initially cause a temporary improvement in near vision, known as
  “second sight.”
• Symptoms include blurred vision, halos around lights, dullness of colours,
  and difficulty seeing clearly in dim lighting.

Cortical Cataracts:

• These cataracts are spoke-like opacities radiating from the edge of the lens
  towards the centre of the lens.
• The cause is uncertain. It is likely that they result from constant stretching of
  the lens that occurs every time we attempt to focus our eyesight from the
  distance to near.
• If you have cortical cataracts, you may notice blurred vision, as well as
  seeing halos and streaks around lights.

Posterior Subcapsular Cataracts:

• Looks like a plaque on the back surface of the lens.
• Progresses more rapidly than other types of cataract.
• Often occurs in younger patients (<50 years old). Risk factors include
  diabetes, short-sightedness, eye trauma, and corticosteroid medications.
• Causes glare when driving at night, difficulty reading, and can profoundly
  reduce vision. It is not uncommon for a posterior subcapsular cataract to
  cause complete loss of vision within just six months.

Congenital Cataracts:

• Present at birth but get worse during adulthood.
• Can be hereditary or caused by infections during pregnancy, such as rubella.

Traumatic Cataracts:

• Result from an injury to the eye.
• May appear immediately after the trauma or develop years later.