Blindness : Types, Causes, and Treatment

Overview

What is Blindness?

Blindness is the incapability of a person to visualize anything. People with partial blindness have minimal vision, such as the inability to differentiate the shapes of different objects and blurred vision.

Complete blindness is when the person, including light, cannot see anything. If someone can only see 20 feet away, they are considered to be legally blind.

A normal person can visualize objects from 200 feet away. Depending on the blindness cause, immediate treatment might increase the chance of vision restoration. Treatment may be medication or surgery ¹Overview| Researched based study from Nlm.nih.gov

Prevalence of blindness

• Blindness is a widespread problem throughout the world
• There were approximately 1.1 billion blind persons in the world in 2020.
• Approximately 3.4 million people above 40 are legally blind in the United States.
• Legal blindness is not a medical name but a term made by lawmakers in nations or states to limit driving activities or to provide monetary and educational benefits to such individuals ²Overview| Researched based study from Iapb.org

Types

Types of Blindness

The three main types of blindness are as follows:

Night blindness

• It is poor vision in dim light or at night.
• Most people with night blindness function well in daylight
• It is not a disorder but an indication of a primary eye problem
• It can be inherited or acquired.

Color blindness

• A person cannot distinguish different color shades, mainly red and green.
• It runs in families and affects 1% of women and 8% of men.
• People with color blindness have normal vision; hence it is not genuine blindness.

Snow blindness

• It is the transient loss of eyesight brought on by excessive UV radiation from the sun that reflects off snow or ice.
• It is a painful condition due to swelling of the corneal cells.
• Individuals with snow blindness can see movement and shapes even in severe cases.

Some other types of blindness include:

Nutritional blindness

• Nutritional blindness is the vision loss due to vitamin A deficiency.
• Continual vitamin A deficiency causes xeropthalmia and damages the frontal part of the eye. If neglected, the eye condition xeropthalmia can cause total blindness.
• Nutritional blindness makes it difficult to see in dim light or at night due to incorrect functioning of the retinal cells.

Congenital blindness

• Congenital blindness is the poor vision from birth.
• The causes include familial retinal conditions and non-familial congenital disabilities ³Types| Researched based study from Springer.com

Symptoms

Symptoms of Blindness

Symptoms in partially blind people include the following:

• Unclear vision
• Poor night vision
• Incapability to see shapes
• Little shapes floating in front of the eyes(floaters)
• Bright points of light in the field of vision(Flashes)
• Tunnel vision
• Seeing only shadows
• Eye pain
• Seeing black spots in the vision

Symptoms of Blindness in young children

• Persistent eye redness
• Continual eye rubbing
• Extremely sensitive to light
• Poor focusing
• Continual tearing from the eyes
• White pupil instead of black
• Abnormal eye movement after six months of age
• Trouble following objects with the eyes

Symptoms of complete blindness

• Unable to perceive light
• Vision cannot be corrected by contact lenses or glasses ⁴Symptoms| Researched based study from Sciencedirect.com

Causes

Causes of Blindness

The diseases that can cause blindness are as follows:

Age-Related Macular Degeneration

• It is an eye condition that blurs the central vision.
• It occurs when the macula, the area of the eye that regulates sharp vision, is harmed by increasing age.

Glaucoma

• It is an eye condition that damages a nerve at the back of the eye called the optic nerve.
• It causes vision loss and blindness.

Cataract

• The clouding of the eye’s natural lens results in decreased vision
• It is more common in aged people.

Optic neuritis

• Optic neuritis is the optic nerve swelling that carries light signals from the eyes to the brain.
• It causes vision loss and pain⁵Causes| Researched based study from Nlm.nih.gov

Lazy eye

• A lazy eye is the decreased vision in one eye due to incorrect visual development in early life.
• It might lead to vision loss

Retinitis pigmentosa

• Retinitis pigmentosa is a hereditary disease affecting the retina of our eyes.
• The retina is the light-receptive tissue at the posterior side of the eye. It can lead to gradual loss of vision⁵Causes| Researched based study from Nlm.nih.gov

Diabetic retinopathy

• Diabetic retinopathy is a condition for people with chronic diabetes (high sugar)
• It is an eye condition that impacts the blood vessels in the retina
• It might cause vision loss and blindness.⁵Causes| Researched based study from Nlm.nih.gov

Other causes include

• Eye injury from a chemical burn, fight, and exposure to a toxin
• Disorders present at birth
• Vitamin A deficiency
• Complications resulting from eye surgery⁵Causes| Researched based study from Nlm.nih.gov

Causes of Blindness in Infants

• Blocked tear ducts
• Infections viz, pink eye
• Cataracts ( cloudy area in the eye’s lens )
• Crossed eye
• Droopy eyelid
• Improper development of blood vessels that supply the retina (retinopathy of prematurity)
• Delayed development of child’s visual system ⁵Causes| Researched based study from Nlm.nih.gov

Diagnosis

Diagnosis of Blindness

In Adults

An optometrist will carry out a thorough eye examination to determine the cause of partial vision loss or blindness.

The ophthalmologist (eye doctor) will then carry out the following test, which includes:

• Vision clarity
• Pupil’s reaction to light
• Functioning of the eye muscles

A general check-up of the eyes will also be carried out using a slit lamp (low-power microscope)⁶Diagnosis| Researched based study from Nlm.nih.gov

In Infants

• A pediatric ophthalmologist will screen the baby’s eyes shortly after birth.
• At around six months, the doctor will check for visual acuity, eye alignment, and focus.
• The doctor will also look at the baby’s eyes if they follow a colorful object or light.
• A child not responding to visual stimuli at eight weeks is a concern and should be examined further.
• A child not reacting to bright light or colored objects in front of the eyes at around 2 to 3 months needs an urgent eye check-up ⁶Diagnosis| Researched based study from Nlm.nih.gov

Risk factors

What are the possible risk factors for blindness?

• People over the age of 50
• People on a high saturated fat diet
• High blood pressure
• High blood sugar(diabetes)
• One with eye diseases such as Glaucoma and macular degeneration
• Stroke(blood flow to the brain is disrupted or stopped)
• Who had an eye surgery
• An eye injury
• People who work in the toxic environment
• People who work with a sharp instrument
• Regular Smoking
• Pregnant women who are diabetic
• Babies born prematurely ⁷Risk factors| Researched based study from Nlm.nih.gov

Treatment

Treatment of Blindness

Treatment for some forms of blindness is as follows:

Medication

• The anti-infective drug treats some forms of blindness due to infections

Vitamin supplement

• People with xeropthalmia might regain their vision loss by consuming vitamin A
• Doctors might prescribe vitamin D and vitamin B supplements to treat vision loss in people with poor diets.⁸Treatment| Researched based study from Nlm.nih.gov

Surgery

Cataract surgery

• The clouded lens of the eye is changed with an artificial lens during the cataract procedure.

Retinal surgery

• The retina surgeon repairs damaged retinal tissue with laser or surgery

Corneal transplant

• It is an operation to remove part or the whole of the damaged cornea with healthy donor tissue.⁸Treatment| Researched based study from Nlm.nih.gov

Managing Limited vision

In some form of visual impairment, one can restore vision through glasses and contact lenses. However, there is no correction technique for partial blindness. An eye doctor can give management tips on how to work with limited vision, such as⁸Treatment| Researched based study from Nlm.nih.gov

• Use of magnifying glass to read
• Increasing the font size of the computer
• Using audio books and audio clocks

Managing Complete Blindness

Complete blindness management is challenging and requires learning new skills, such as

• Using guide dog
• Reading Braille
• Conveniently organizing the home to find things easily
• Using specialized smartphones ⁸Treatment| Researched based study from Nlm.nih.gov

Prevention

Prevention of Blindness

• Get regular eye check-ups to detect the disease and prevent vision loss.
• People with Glaucoma can prevent blindness through medication .
• One must regularly maintain blood sugar and blood pressure to prevent strokes that might lead to vision loss
• Wear protective gear while working or playing sports
• Practice the habit of regularly washing the hands before wearing contact lenses to avoid unexpected infections.
• According to American Optometric Association, young children must undergo eye check-ups at six months, three years, and every consecutive year from 6 to 17 years to prevent vision loss.
• Any noticeable symptoms of vision loss must be immediately intimated to an eye doctor for quick diagnosis and treatment ⁹Prevention| Researched based study from Nlm.nih.gov

Symptoms needing immediate eye check-ups

• Sudden loss of vision
• Pain in the eye
• Some injury or accident that affects the eye
• Have bright light points in the vision
• Have little shapes floating in the vision

Takeaway

Key takeaways

• Blindness is the most common problem worldwide
• Several disease conditions can lead to blindness
• Treatment for most of the causes of blindness restores the remaining sight but cannot bring back the lost vision.
• Early treatment is necessary in case of age-related macular degeneration and Glaucoma to slow the disease progression and prevent vision loss.