Blindness - All A Seeing Person Must Know

Blindness is a state of being sightless or say an inability to see. World Health Organization - WHO (1972) describes blindness as the inability to count fingers at the distance of 3 meters in day-light after best possible spectacle correction in the better eye OR visual field less than 10° around the centre of fixation.

Blindness is of three TYPES:

1. Loss of visual acuity.
2. Colour blindness: Inability to recognize colours, and
3. Night blindness: Night vision is damaged.

Blindness is CLASSIFIED into four types:

1. Economic blindness: Vision in the better eye is 6/60 to 3/60.*
2. Social blindness: Vision in the better eye is 3/60 to 1/60*
3. Legal blindness: Vision in the better eye is 1/60* to the perception of light.
4. Total blindness: No perception of light in an eye.

(* The number written first describes distance in meters at which a person can see and a number is written afterwards describes distance in meters at which a normal person can see on Snellen’s chart for vision.)

Causes of blindness:

1. Congenital anomalies like anophthalmos, micro-ophthalmic, buphthalmos etc.
2. Refractive errors: Axial length is either more or less in different meridians
3. Cataract: Opacity in lens causing loss transparency of crystalline lens (mostly senile)
4. Glaucoma: Rise in intraocular-pressure leading to loss of vision due to optic atrophy without any symptoms
5. Trauma: Injuries
6. Infections: Trachoma, Leprosy, Onchocerciasis, Herpes simplex
7. Complications of diabetes, malnutrition and senile macular degeneration

Prevention of Blindness:

All of us know, prevention is better than cure. But hardly anyone follows.

• Health education and awareness is the master key to prevent blindness and for that matter any disease.
• Regular eye-check-up at birth (congenital anomalies), every time before going to primary school (refractive error and squint), high school and college, before joining one’s profession and every year after 35 years of age (glaucoma) will help us in early detection of the problem and taking all precautionary measures at an early phase of the disease.
• Pre-marital counselling can save us from genetic disorders.
• Hygienic living and public health measures can protect one from eye-infections.
• Medical care and intensive control of diabetes is a must.
• Nutritional disorders like Vitamin A deficiency has to do with social upliftment or free/subsidized food.

Treatment of Blindness:

• Early medical treatment for glaucoma and infection.
• Prescription of glasses for the error of refraction.
• Cataract, glaucoma, squint, corneal and retinal diseases need appropriate surgery.
• Treatment is available everywhere and at reasonably low cost, even free at charitable/government hospitals. Spectacles are no unaffordable. Just a little alertness and/or guidance is all that is needed.

Management of Blindness:

Last and the most important matter is living with blindness and doing self-development.

• One needs not lose heart and think of blindness as the end of life. Helen Keller, John Milton and so many other blind persons have shown the way of life.
• Persons having untreatable blindness require re-organization of their habits and re-education to allow them to do everyday tasks in different ways. Just learn that and life is not that difficult then.
• For professional development, one needs the help of Braille books and visual aids. Having an education can make one independent and self-sufficient.

Where do we stand?

Article Reference: Article by Dr Swaraj Haldar,

Professor and Head, Forensic Medicine, Kolkata.