If you can read this, congratulations: you can see. It doesn’t matter whether you are reading through eyeglasses or not. What matters is that you're here, reading this.
That you're here now may also suggest you’re worried about your eyes. Perhaps your vision is getting blurry, and you wonder if you’re going blind. Your fears are understandable.
The World Health Organization (WHO) estimates that more than 250 million people worldwide are visually impaired. This figure is predicted to increase to 703 million by 2050. In Nigeria, experts estimate that 4.25 million people are blind. These statistics are enough to make anyone jittery.
But what does it mean to be blind? Is it when you can’t see at all and your vision is pitch black, or is it when you need glasses and other visual aids to read and do basic activities? Blindness can be that and more.
What is blindness?
Blindness is a condition in which a person cannot see anything or has extremely poor vision. Clinically, blindness is defined as visual acuity of less than 3/60 or a visual field of less than 10 degrees in your better eye, with the best correction.
Eye doctors, or ophthalmologists, define vision in terms of visual acuity and visual field. Visual acuity measures the eye’s ability to see things clearly and in detail, whether near or far away. The visual field is how much of a space your eyes can see with a steady gaze.
Vision acuity is expressed as a fraction. The top number is the distance that your vision is tested. This is usually 6 metres or 20 feet. The bottom number is the distance at which a person with normal vision is expected to see the image or text. It’s also 6 metres or 20 feet.
If your eyes are okay, you should be able to see an object clearly from six metres away, so you’ll score 6/6 or 20/20. The 6/6 records visual acuity in metres, while 20/20 is recorded in feet. We use 6/6 in Nigeria. A visual acuity lower than 6/6 often suggests a problem with your vision.
Glasses and contact lenses can correct mild and moderate vision problems. If, after correction, the vision is less than 3/60 (20/400) in the better eye, an individual will be considered blind.
Blindness can occur due to injury, infections, or genetic disorders. Whatever the cause, blindness can affect your ability to perform basic tasks.
What are the causes of blindness?
The most common cause of blindness worldwide is age-related macular degeneration. The macula is a thin layer behind the eyes that helps us to note the tiny details of an object and focus effectively. It deteriorates as we age, leading to vision loss.
However, in Nigeria and Africa, the leading causes are cataracts, glaucoma, and corneal opacity.
Other causes include:
- Injury from heavy blows, penetrating objects, toxic chemicals, or radiation exposure.
- Genetic disorders like retinitis pigmentosa and albinism
- Diabetes
- Hypertension
- Stroke
- Vitamin A deficiency
- Trachoma
- Onchocerciasis
Symptoms of blindness
Photo by Nathan Dumlao on Unsplash
One early symptom of deteriorating vision is blurry or hazy vision. Objects may appear fuzzy to you. You may struggle to identify figures and shapes at a distance or squint to read texts with regular font sizes and lighting conditions.
It could also be that you find it more challenging to move around at home, recognize faces, or function outdoors.
Other symptoms include:
- Difficulty seeing at night or in low-light conditions
- Increased sensitivity to light or glare
- Narrowed visual field
- Loss of peripheral vision, or the ability to see side objects
- Total loss of vision, or the ability to see light
Depending on the cause, you may experience frequent headaches, eye pain or discomfort, and light sensitivity. Pay attention to these symptoms and seek medical attention if you experience them.
Diagnosis of blindness
Photo by Photo By: Kaboompics.com
The diagnosis of blindness can only be done at a clinic. While you may be able to tell whether you can see or not, only an eye doctor can help you determine whether it is actually blindness and educate you on what you can do about it.
Your doctor will do a comprehensive eye examination, which may involve:
- Testing your visual acuity
- Measuring your eyes’ pressure or doing a tonometry
- Dilating your eyes with eye drops
You may need an MRI or a CT scan if the examination reveals any abnormalities.
Prevention of blindness
Unfortunately, some types of blindness cannot be prevented. Blindness due to macular degeneration or optic atrophy, for instance, is unavoidable and a natural consequence of old age. But most types are preventable.
The goals of prevention are to:
- Protect your eyes from any disease
- Prevent your vision from getting worse if you’re already having trouble with your vision
- Minimize the difficulties you may face as someone with visual impairment
So, how can you prevent blindness?
- Go for regular eye checks at least once a year
- Maintain proper eye hygiene
- Use protective eyewear such as glasses and safety goggles
- Manage underlying diseases like hypertension and diabetes
- Get treated against blindness-causing infections such as Trachoma
- Go for genetic counselling to know your risk for developing eye diseases
Treatment of blindness
The treatment of blindness depends on the underlying cause. Some causes may require drugs, others may require surgery or transplants.
- Drugs: Antibiotics and anti-worm medications can help treat blindness caused by bacteria and worms.
- Supplements: Vitamin A supplements may help restore vision loss in individuals with xerophthalmia.
- Surgery: Refractive errors, cataracts, glaucoma, and other eye structural eye diseases can be resolved through surgery.
- Corneal transplant: transplanting corneal tissues from a healthy donor helps improve vision loss or impairment caused by corneal damage.
Individuals with irreversible vision loss can use adaptive devices and technologies to help them navigate their environment and perform daily tasks. These may include braille devices, talking computers, and mobility aids like canes and guide dogs.
Note that treatment for blindness is best delivered by ophthalmologists who are readily available in most Nigerian hospitals. You may need to visit specialist centres, or contact your local clinics to access ophthalmologists who will treat you.
Conclusion
If you suspect your vision is getting poor, keep calm and visit a doctor. Your symptoms could be a sign of a mild eye disease or something more. Your doctor will tell you what they are.
Symptoms of blindness are often innocent. Except in cases of direct injury to your eyes, blindness often starts with blurry or hazy vision, then to partial or total vision loss if they are not treated.
Good eye care can protect you from common causes of blindness, while regular eye examination helps you detect eye diseases very early. Drugs, surgery, and transplants can resolve some of these causes; some other causes are irreversible.
