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  • Writer's pictureAtanas Bogoev M.D. and Maria Cholakova

Exploring The Leading Causes of Blindness

Blindness is a debilitating condition affecting millions of people across the world. The condition adversely impacts their quality of life and independence. We are here to provide an extensive overview of the leading causes of blindness, encompassing both preventable and non-preventable factors.

Understanding blindness at the core is crucial for implementing effective public health strategies, early detection, and timely intervention to prevent or manage visual impairment.

This Ophthalmology24 article aims to elucidate the various leading causes of blindness. As well as, to provide insights into their etiology, epidemiology, risk factors, and potential preventive measures.

Understanding Blindness

A medical definition of blindness is visual acuity of less than 20/400 in the better eye with the best possible correction or a visual field of 10 degrees or less.

Patient with Visual acuity = 20/20 or 1.0

Patient with Visual acuity = 20/400 or 0.05

The term "total blindness" denotes individuals who experience an absolute absence of light perception, formally known as "no light perception" (NLP). This specific type of blindness applies to roughly 15% of individuals with ocular disorders. The majority of individuals contending with visual impairment possess varying degrees of residual vision.

The term "low vision" designates individuals whose visual capacity is not fully recoverable through conventional means (corrective glasses, contact lenses, medical interventions, surgical procedures, magnification aids, or assistive technology).

"Visual impairment" serves as a functional descriptor for individuals whose low visual capacity hampers their capability to engage in daily life routine activities. The term encompasses both individuals with low vision and those who are blind.

*All term definitions are derived from the National Library of Medicine and WHO.

blind person with a cane and dog aid

Blindness represents a significant socioeconomic challenge, affecting people of all age groups and geographic locations.

There are various blindness causes, both acquired and congenital (from birth). We will explore them in the next few paragraphs.

Bear in mind, these conditions can affect individuals across different regions and demographics. The prevalence may vary depending on factors such as healthcare infrastructure, socioeconomic status, lifestyle, and genetic predisposition.

Blindness statistics for adults over 50 years of age:

Leading Causes of Blindness


The emergence of cataracts is one of the leading causes of blindness worldwide, predominantly among older adults in developing nations.

Clouding the eye lens, cataracts cast a shadow over clear vision, potentially culminating in irreversible blindness if neglected. Swift action is pivotal, as cataract-removal surgery, along with the installation of artificial lenses, offers a beacon of hope in the quest to restore sight.

The impact of cataracts extends beyond well-developed regions. In low and middle-income countries, cataract-induced blindness casts a disproportionate shadow, often due to inadequate access to medical resources and surgery options.

Age-Related Macular Degeneration (AMD)

AMD emerges as one of the leading causes of blindness in Caucasians among the aging population (over the age of 50), particularly in economically advanced countries.

Age-related macular degeneration is a progressive degenerative condition that affects the central part of the retina (macula) and triggers gradual loss of central vision. Consequently, this significantly impacts a person's ability to read, drive, and recognize faces.

In general, there are two types of age-related macular degeneration: dry form and wet form. For severe and rapidly progressing forms of the disease (wet-AMD or neovascular-AMD ), the treatment options may include anti-VEGF injections, photodynamic therapy (PDT), or laser therapy. For the milder form of AMD (dry AMD), eye doctors may recommend special eye supplements to slow down progression, low-vision aids like magnifiers, telescopic lenses, and adaptive technologies.


Glaucoma is an eye disease that damages the optic nerve, resulting in progressive peripheral vision loss due to the loss of special cells in the retina that compose the optic nerve fibers (retinal ganglion cells). The modifiable risk factor in glaucoma is the intraocular pressure. If left untreated it can lead to total blindness. Some people are more likely to get glaucoma than others. One of the important risk factors is having a family member who has glaucoma. Studies have shown that people who have a parent, sibling, or child with glaucoma are more likely to have glaucoma themselves than people who don’t have any relatives with glaucoma.

If you have a family member with glaucoma, don’t wait until you notice any problems with your eyesight. Go see your eye doctor regularly and get screened for glaucoma. It could make a big difference for your eye health and quality of life.

The objective of treatment in glaucoma is to reduce intraocular pressure under a certain threshold called the target intraocular pressure. By doing so, additional harm to the optic nerve is prevented, thus protecting the visual field and eyesight. The precise medical strategy is contingent upon the glaucoma type and/or severity. Some common treatment options include medications, laser therapy, surgical treatment, or combination therapies.

Glaucoma more often affects older adults and has a higher prevalence among certain ethnicities, including African, Asian, and Hispanic populations.

Diabetic Retinopathy

Schematic of eye with Diabetic retinopathy with aneurisms, hard exudates, vessels abnormalities and coton wool spots

As diabetes continues to rise globally, diabetic retinopathy has become a prominent cause of visual impairment among working-age adults (between 25 and 64) in both developed and developing countries. The condition is prevalent in regions with rising rates of obesity and unhealthy lifestyles.

At its core, diabetic retinopathy is an eye condition damaging the blood vessels in the retina, affecting people with diabetes. Without proper and timely treatment, a diabetic patient will experience vision problems, see things distorted, or even go blind.

Laser therapy (focal and panretinal photocoagulation) and anti-VEGF injections in the eye can alleviate certain forms of diabetic retinopathy. Some patients develop swelling of the center of the retina - the so-called diabetic macular edema (DME). Treatment for diabetic macular edema may involve eye drops, laser therapy or injections in the eye (anti-VEGF). In more severe cases with significant bleeding into the vitreous gel, an eye doctor may suggest vitrectomy surgery.

The main goal of treating the disease is to prevent or slow down its progression and manage any complications. In this context, we would like to emphasize the significance of diabetes management and routine diabetic eye exams!

Corneal Diseases

Corneal diseases are also a part of the leading causes of blindness in regions with limited access to eye care and medical resources. Particularly in low-income areas of developing countries. These diseases often result from infections and trauma due to poor living conditions and lack of proper sanitation.

These diseases cast a shadow over visual clarity, encompassing a range of eye conditions. From infections to degenerative disorders, these ailments compromise the cornea's integrity and may contribute to blurry vision, pain, and, in some cases, blindness.

In conditions such as keratoconus, where the cornea becomes progressively thin and bulges forward. Corneal dystrophies, consisting of abnormal deposits, undermine the eye's ability to focus light onto the retina. Corneal diseases not only diminish visual acuity but also impair the eye's capacity to transmit information to the brain, underscoring the vital role the cornea plays in visual perception.

Corneal transplantation is often the most effective treatment.

Retinal Detachment

retinal detachment infographic explanation by ophthalmology24

Retinal detachment can affect individuals of all ages and is one of the leading causes of blindness worldwide. Its occurrence is not peculiar to specific demographics, as it can result from various factors including trauma and eye conditions.

Retinal detachment occurs when the retina separates from the underlying tissue. If the patient delays treatment, this condition could lead to permanent vision loss and blindness.

The goal of treatment is to reattach the retina and prevent more damage to the light-sensitive cells, essential for vision. The specific approach depends on the type and severity of retinal detachment. Options include cryotherapy, pneumatic retinopexy, vitrectomy, or scleral buckling surgery.


Trachoma is primarily prevalent in economically deprived regions and densely populated communities. For example, rural areas of Africa, the Middle East, Asia, and Latin America. It disproportionately affects women and children due to its association with unhygienic living conditions and inaccessible healthcare. In developing countries, the incidence is decreasing due to public health action.

Trachoma is a chronic infectious disease of the eye stemming from the bacterial infection Chlamydia trachomatis. It highlights the complex interplay between health disparities and infectious diseases. The pivotal treatment strategy involves the SAFE initiative by the World Health Organization (Surgery, Antibiotics, Facial cleanliness, and Environmental improvement). Surgery addresses the late stage of trachoma where eyelashes turn inward, causing abrasions on the cornea. Antibiotics target the bacterial infection, reducing its spread. Promoting facial cleanliness and improving environmental conditions further inhibit transmission.

According to WHO, data from June 2022 states there are 125 million individuals residing in regions where trachoma is prevalent, placing them in danger of experiencing trachoma-related blindness.

Congenital Blindness

baby rubbing eyes

Some individuals are born blind or with severe visual impairment due to congenital conditions. The leading causes of blindness from birth are usually genetic factors, developmental abnormalities, or prenatal infections.

A few examples* of congenital blindness causes include:

  1. Congenital Cataracts

  2. Retinopathy of Prematurity (ROP)

  3. Optic Nerve Hypoplasia

  4. Aniridia

  5. Leber Congenital Amaurosis

*This list is not full, we will cover this topic more extensively in future publications.

Congenital cataracts develop in the womb or shortly after birth. They can lead to congenital blindness. Surgical removal of these cataracts early in life can often restore vision.

Premature infants are at risk of developing retinopathy of prematurity. A delay in the diagnosis of ROP can cause retinal detachment and blindness.

Optic nerve hypoplasia refers to the underdevelopment of the optic nerve, which may result in visual impairment or blindness from birth.

Aniridia is a rare genetic disorder where the iris is partially or completely absent. It can lead to significant or full sight loss.

Leber congenital amaurosis is a group of rare genetic disorders that cause severe vision loss or blindness from birth or early childhood.

Eye Injuries

eye injury bandage

Eye injuries stand as significant contributors to the incidence of blindness globally. Accidents, workplace mishaps, sports incidents, and environmental factors can lead to a wide spectrum of injuries to endanger vision. Beyond the immediate aftermath, eye injuries can have lasting repercussions.

Corneal abrasions and foreign bodies, while often treatable, underscore the fragility of the eye's surface.

Chemical burns, an alarming consequence of exposure to hazardous substances, can result in profound damage to ocular structures, potentially leading to irreversible blindness.

Penetrating injuries and blunt trauma pose grave threats, with the potential to damage internal structures and even compromise the optic nerve.

Orbital fractures can disrupt eye movement and affect visual alignment, contributing to functional impairment.

As an insidious consequence, mismanaging injuries or delaying treatment may escalate into complications such as retinal detachment, cataracts, or hyphema, amplifying the risk of vision loss over time.

The prevention and management of eye injuries demand:

  • High awareness

  • Personal protective measures

  • Swift access to medical care

In summary...

Modern advances in medical and surgical interventions, early diagnosis, and proper management have significantly improved the outlook for individuals with blindness or visual challenges.

Furthermore, assistive technologies, educational resources, and support networks are available to help people with visual disabilities lead fulfilling lives.

Despite the advancements and treatment options, the leading causes of blindness remain a global health challenge, affecting individuals of all ages and regions.

All resources are linked in the article.

Checked by Atanas Bogoev, MD.

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