Myopia: Causes, Symptoms, Diagnosis, and Management

~Introduction

Vision is one of the most essential senses for human life, allowing us to interact with and interpret the world around us. Among the many eye-related conditions that affect individuals worldwide, myopia, commonly known as nearsightedness, is one of the most prevalent. Myopia is a refractive error of the eye in which close objects are seen clearly, but distant objects appear blurred.

This condition has become a significant public health concern, with rising prevalence globally. According to the World Health Organization (WHO), it is estimated that by the year 2050, nearly half of the world’s population may suffer from myopia if current trends continue. Myopia not only affects vision but can also lead to complications such as glaucoma, cataracts, retinal detachment, and even blindness in severe cases.

This article explores myopia in detail, covering its definition, causes, risk factors, symptoms, diagnosis, management, prevention, and future directions in treatment.

~Understanding Myopia

Myopia is categorized as a refractive error, meaning that the eye does not bend light correctly to focus images on the retina. Normally, light rays entering the eye are focused directly on the retina at the back of the eye, producing a clear image. In myopia, the eyeball is too long, or the cornea (the clear front covering of the eye) is too curved. This causes light to focus in front of the retina instead of directly on it, leading to blurry distance vision.

Types of Myopia

Simple Myopia
- The most common type.
- Usually appears in childhood and progresses until early adulthood.
- Typically ranges from mild to moderate severity.
High Myopia
- Severe form of myopia, usually more than -6.00 diopters.
- Increases the risk of complications like retinal detachment, glaucoma, and macular degeneration.
Pathological or Degenerative Myopia
- Rare but serious.
- Progressive and associated with structural changes in the eye.
- Can lead to permanent vision loss if untreated.

~Epidemiology and Prevalence

The prevalence of myopia varies across regions and populations.

In East Asian countries such as China, Japan, and South Korea, myopia has reached epidemic levels, affecting 80–90% of teenagers and young adults.
In the United States and Europe, prevalence is lower but still significant, affecting about 30–40% of adults.
The condition is becoming more common worldwide due to lifestyle changes, such as increased screen time, reduced outdoor activity, and intensive education systems.

~Causes of Myopia

The exact cause of myopia is multifactorial, involving both genetic and environmental factors.

1. Genetic Factors

Family history plays a strong role.
Children with one myopic parent are more likely to develop myopia; the risk increases if both parents are myopic.
Several genes associated with eye growth and development have been linked to myopia.

2. Environmental and Lifestyle Factors

Near work activities: Prolonged reading, writing, computer use, and smartphone use can strain the eyes and contribute to myopia.
Lack of outdoor exposure: Studies suggest that spending more time outdoors reduces the risk of developing myopia, possibly due to natural light exposure and focusing on distant objects.
Urbanization: Children in urban environments are more prone to myopia than those in rural areas.

3. Structural Factors

Elongation of the eyeball (axial length increase).
Abnormal curvature of the cornea or lens.

~Symptoms of Myopia

The symptoms of myopia can vary depending on severity but generally include:

Blurry vision when looking at distant objects (e.g., difficulty reading signs, seeing the board in class).
Clear near vision, especially in mild cases.
Eye strain or fatigue after prolonged visual tasks.
Headaches due to squinting or eye strain.
Difficulty driving, especially at night (night myopia).
Squinting to improve clarity.

In children, signs may include sitting too close to the television, holding books very close, or complaining about not seeing the board at school.

~Diagnosis of Myopia

Eye care professionals such as optometrists and ophthalmologists use several methods to diagnose myopia:

Visual Acuity Test
- Measures clarity of vision using an eye chart.
- Patients with myopia cannot see distant letters clearly.
Refraction Assessment
- Determines the exact lens prescription needed to correct vision.
- Conducted using a phoropter or an automated machine.
Retinoscopy
- A light is shone into the eye to observe how it reflects off the retina.
Slit-Lamp Examination
- Provides a detailed view of the structures of the eye.
Axial Length Measurement
- Used especially in high or progressive myopia.
- Helps assess risk for complications.

~Complications Associated with Myopia

While mild to moderate myopia usually does not cause serious health issues if corrected with glasses or contact lenses, high myopia and pathological myopia can lead to severe complications:

Retinal Detachment
- Elongation of the eyeball stretches and thins the retina.
- Risk increases with higher degrees of myopia.
Myopic Macular Degeneration (MMD)
- Damage to the central retina (macula), causing loss of detailed vision.
Glaucoma
- Increased risk due to structural changes in the eye.
Cataracts
- Earlier development of cataracts is common in myopic patients.
Vision Impairment and Blindness
- Severe untreated or pathological myopia can result in irreversible vision loss.

~Management of Myopia

Myopia cannot be permanently “cured” in most cases, but there are several effective management strategies to correct vision and slow its progression.

1. Corrective Lenses

Eyeglasses:
- Most common and safest method.
- Negative-powered lenses (concave lenses) help focus light correctly on the retina.
Contact Lenses:
- Provide a wider field of vision compared to glasses.
- Types include soft lenses, rigid gas permeable lenses, and daily disposables.

2. Orthokeratology (Ortho-K)

Special rigid contact lenses worn overnight to temporarily reshape the cornea.
Provides clear daytime vision without glasses.
Particularly useful for children to slow progression of myopia.

3. Pharmacological Treatment

Atropine eye drops (low dose):
- Shown to slow the progression of myopia in children.
- Requires medical supervision due to side effects like light sensitivity.

4. Refractive Surgery

LASIK (Laser-Assisted In Situ Keratomileusis):
- Laser reshapes the cornea for permanent correction.
PRK (Photorefractive Keratectomy):
- Removes corneal tissue to reshape curvature.
SMILE (Small Incision Lenticule Extraction):
- Newer minimally invasive laser surgery.

5. Lifestyle and Preventive Measures

Spending at least 2 hours outdoors daily can reduce risk in children.
Limiting screen time and encouraging breaks during near work (20-20-20 rule: every 20 minutes, look 20 feet away for 20 seconds).
Maintaining good posture and proper lighting when reading.

~Prevention of Myopia

Although genetic predisposition cannot be changed, several preventive measures can help reduce the risk or slow progression:

Encourage outdoor activities for children.
Avoid excessive digital screen exposure and promote regular eye breaks.
Regular eye check-ups, especially for children with family history of myopia.
Use proper lighting for reading and studying.
Control educational and environmental pressures contributing to prolonged near work.

~Myopia Control in Children

Since myopia typically begins in childhood, early detection and management are crucial.
Options include:

Atropine eye drops (low-dose).
Ortho-K lenses to reshape cornea.
Multifocal contact lenses or glasses to reduce progression.
Parental awareness and timely eye exams to detect early signs.

~Future Directions in Myopia Research

Research is ongoing to find better ways to control and treat myopia:

Gene therapy may eventually help address genetic predispositions.
Advanced optical lenses specifically designed to slow myopia progression are under development.
New pharmacological agents (beyond atropine) are being studied.
Artificial intelligence (AI) tools may help predict progression and personalize treatment.

~Conclusion

Myopia is no longer just a minor inconvenience corrected by glasses; it is a growing global health concern. With increasing digital device usage, reduced outdoor activity, and educational demands, the prevalence of myopia continues to rise. While mild myopia is easily manageable, high and pathological myopia can cause severe visual complications if left untreated.

The key to addressing myopia lies in early detection, effective management, and preventive strategies. Parents, educators, healthcare providers, and policymakers must work together to spread awareness, encourage regular eye exams, and promote lifestyle habits that support eye health.

As research progresses, new methods of prevention and treatment will hopefully reduce the burden of myopia in future generations, ensuring that the world remains clear and vibrant for all.

Health Lines

Tuesday, August 26, 2025