Cataract: Types, Development, Causes, Risk Factors, Symptoms, Treatment And Preventions

Cataract: Types, Development, Causes, Risk Factors, Symptoms, Treatment And Preventions.

What is Cataract?

Cataract is the opacity or clouding of the lens of eye that prevents clear vision.

Opacity: This is a state or quality of being opaque, not allowing light to pass through.

According to WHO (2010 estimation), Cataract is responsible for 51% of world blindness, which represents about 20 millions people. It is the most common cause of blindness both in developing and developed countries in people over the age of 40 years and above. In many remote parts of developing world, people remain blind from cataract, due to lack of access to eye care.

How a cataract developed?

The lens, where cataracts form, is positioned behind the colored part of your eye (iris). The lens focuses light that passes into your eye, producing clear, sharp images on the retina — the light-sensitive membrane in the eye that functions like the film in a camera.

As you age, the lenses in your eyes become less flexible, less transparent and thicker. Age-related and other medical conditions cause tissues within the lens to break down and clump together, clouding small areas within the lens.

As the cataract continues to develop, the clouding becomes denser and involves a bigger part of the lens. A cataract scatters and blocks the light as it passes through the lens, preventing a sharply defined image from reaching your retina. As a result, your vision becomes blurred.

Cataracts generally develop in both eyes, but not evenly. The cataract in one eye may be more advanced than the other, causing a difference in vision between eyes.

What are the types of Cataract?

1. Congenital cataract

Babies are sometimes born with it as a result of poor fetal development before birth, injection, or it may develop during childhood. Visit to the appropriate hospital for early removal of it is very important to prevent blindness.

2. Degenerative cataract

This is also called age related or senile cataract, it is the most common type of cataract that affects older people, very common with increasing age. The incidences of its occurrence are equally in both genders but one eye may be worse more than the other.

3. Secondary cataract

This results from medical condition like diabetes mellitus, nutritional deficiency; high intake of certain drugs like corticosteroids, diuretics or even exposure to toxic substances like ultraviolet light and or radiations.

4. Traumatic cataract

It could be from a blunt/penetrating injury or radiation.

  Classification of Cataract

Cataract is classified as either Aetiological or Morphological.

_Aetiological form of cataract are:

Age related/senile/degenerative

Traumatic

Secondary

Heredity

Toxic

Congenital.

_Morphological form are:

Cortical

Nuclear

Capsular

Subcapsular

Lamellar

Sutural.

What are the risk factors of Cataract?

Risk factors that trigger on a person to get cataract are:

Diabetes Mellitus

Cigarettes smoking

Family history or heredity

Exposure to ultraviolet light

High myopia

Excessive consumption of alcohol

Previous eye surgery

Trauma

Nutritional deficiency e.g vitamin C, E, carotene

Severe diarrhoea with dehydration

Ageing changes

Hypoparathyroidism

Statin medicine to reduce cholesterol

Hormonal replacement

Steroids drugs

Down's syndrome

Recreational drugs like nicotine.

How to identify signs and symptoms of Cataract?

The signs and symptoms of cataract are as follow:

Reduction in visual acquity

Blurring of vision and difficulty in recognizing faces

Blurring of vision associated with difficulty in driving at night because of dazzling or glare

Diminishing sight/gradual loss of vision in one or both eye

Pupil is grey or white, but round and reacts briskly to light - while conjunctiva and cornea are normal.

To determine whether you have a cataract, your doctor will review your medical history and symptoms, and perform an eye examination. Your doctor may conduct several tests, including:

  Visual acuity test. 

A visual acuity test uses an eye chart to measure how well you can read a series of letters. Your eyes are tested one at a time, while the other eye is covered. Using a chart or a viewing device with progressively smaller letters, your eye doctor determines if you have 20/20 vision or if your vision shows signs of impairment.

  Slit-lamp examination. 

A slit lamp allows your eye doctor to see the structures at the front of your eye under magnification. The microscope is called a slit lamp because it uses an intense line of light, a slit, to illuminate your cornea, iris, lens, and the space between your iris and cornea. The slit allows your doctor to view these structures in small sections, which makes it easier to detect any tiny abnormalities.

  Retinal exam. 

To prepare for a retinal exam, your eye doctor puts drops in your eyes to open your pupils wide (dilate). This makes it easier to examine the back of your eyes (retina). Using a slit lamp or a special device called an ophthalmoscope, your eye doctor can examine your lens for signs of a cataract.

Treatment of Cataracts

If you’re unable or uninterested in surgery, your doctor may be able to help you manage your symptoms. They may suggest stronger eyeglasses, magnifying lenses, or sunglasses with an anti-glare coating.

Surgery

Surgery is recommended when cataracts prevent you from going about your daily activities, such as reading or driving. It’s also performed when cataracts interfere with the treatment of other eye problems.

One surgical method, known as phacoemulsification, involves the use of ultrasound waves to break the lens apart and remove the pieces.

Extracapsular surgery involves removing the cloudy part of the lens through a long incision in the cornea. After surgery, an artificial intraocular lens is placed where the natural lens was.

Surgery to remove a cataract is generally very safe and has a high success rate. Most people can go home the same day as their surgery.

Outlook of a Cataract

Cataracts can interfere with daily activities and lead to blindness when left untreated. Although some stop growing, they don’t get smaller on their own. The surgical removal of cataracts is a very common procedure and is highly effective roughly 90 percent of the time, according to the National Eye Institute.

How to prevent and control Cataract?

Cataract is a significant increasing global problem. The challenges are to prevent or delay its formation, and cure that which does occur. 

The preventions and control of cataract are:

I. Adquate Ante-natal Care in the community

II. Adquate control of Diabetes Mellitus

III. Adquate nutritional supplementation with vitamin C, E; Omega-3 fatty acid, more vegetables especially green leaves, spinach etc

IV. Avoidance of exposure to ultraviolet light rays using sunglasses

V. Avoidance of cigarettes smoking

VI. Proper environmental sanitation

VII. Reduction or maintenance of normal Body Mass Index (BMI)

VIII. Control of diarrhoeal diseases

IX. Early detection of cases so as to preserve vision and avoid blindness

X. Change in government policies with regard to cigarettes smoking

XI. Government should employ adquate health personale in order to conduct effective outreach services so as to health educate people living in rural areas especially those who lives in far away from the hospitals.

Sources

Unpublished Community Health lecture notes

www.mayoclinic.org

www.healthline.com

www.who.int

Binapate Health