Myopia, also known as nearsightedness, is a common vision problem that affects millions of people worldwide. Mild myopia may not require immediate corrective eyewear, but if the eyes are not properly cared for, mild or moderate myopia may progress into high myopia.

What is Myopia?

Myopia occurs when the eyeball is too long, or the cornea (the transparent part at the front of the eye) is too curved, causing light entering the eye to focus in front of the retina instead of directly on it. This results in blurry vision for distant objects, while close-up vision remains clear.

Myopia often begins in childhood and may worsen as the eye continues to grow. Generally, myopia stabilizes around the age of 20, but in some cases, especially with high myopia, vision problems may continue to worsen.

What is High Myopia?

High myopia is a more severe form of nearsightedness, with a much higher refractive error compared to regular myopia. Typically, when the myopia reaches over -6.00 diopters (D), it is defined as high myopia. The diopter (D) is the unit used to measure the severity of vision problems, with negative values indicating myopia.

In high myopia, the eyeball is longer than in mild or moderate cases, causing light to focus in front of the retina, leading to blurry vision for distant objects. Even with corrective eyewear like glasses or contact lenses, vision may still be significantly impaired. If left untreated or unmanaged, high myopia can lead to various complications that impact eye health.

What Causes High Myopia?

The development of high myopia is the result of a combination of factors, including both genetic and environmental influences. A family history of myopia is a significant risk factor for high myopia. If one or both parents have myopia, the likelihood of their child developing myopia increases. In addition, prolonged near-work activities, such as extended periods of reading, using a smartphone, or staring at a computer screen, can contribute to the development and progression of myopia. High myopia typically begins in childhood, and as the child grows, the eyeball may continue to elongate, leading to worsening myopia. In most cases, high myopia stabilizes during adolescence or around the age of 20.

High Myopia Symptoms

The main symptom of high myopia is blurry vision at a distance. However, those with high myopia may also experience other symptoms and potential eye complications, including:

1. Blurry Distant Vision: Individuals with high myopia may still struggle to see distant objects clearly, even when wearing corrective glasses or contact lenses. This can affect daily activities such as driving, watching television, or reading distant signs.
2. Frequent Changes in Prescription: Those with high myopia often find that their prescription for glasses or contact lenses needs frequent adjustments. This could be a sign that the myopia is progressing.
3. Eye Fatigue and Headaches: Due to the constant effort to focus on distant objects, individuals with high myopia may experience eye strain or headaches. This discomfort can interfere with long periods of reading or using electronic devices.
4. Increased Risk of Eye Diseases: Those with high myopia are at a higher risk of developing severe eye conditions, such as retinal detachment, glaucoma, cataracts and macular degeneration.

High Myopia Range

Myopia severity is typically measured in diopters (D). The higher the diopter value, the more severe the myopia. High myopia is categorized into the following stages based on diopter values:

• Mild Myopia: 0.00 D to -3.00 D
• Moderate Myopia: -3.00 D to -6.00 D
• High Myopia: -6.00 D to -10.00 D, typically causing severe blurry distant vision.
• Extreme High Myopia: Greater than -10.00 D. At this stage, the myopia is often associated with serious vision impairment and an increased risk of eye complications such as retinal detachment and macular degeneration.

High Myopia Treatment

Although high myopia cannot be completely “cured,” several treatments can help manage the condition and reduce further vision loss:

• Glasses and Contact Lenses: The most common treatment is wearing glasses or contact lenses to correct refractive error. This allows those with high myopia to see distant objects more clearly. However, as myopia worsens, the prescription for glasses or contact lenses may need frequent adjustments.
• Refractive Surgery (LASIK, PRK): Laser eye surgery such as LASIK or PRK can be a treatment option for some high myopia patients. These surgeries reshape the cornea to improve vision and reduce dependency on glasses or contact lenses. However, refractive surgery may not be suitable for extreme high myopia, as it could increase the risk of complications.
• Orthokeratology (Ortho-K): This non-surgical treatment involves wearing specially designed contact lenses overnight to temporarily reshape the cornea. Ortho-K lenses help maintain clear vision during the day and may slow down the progression of myopia.
• Atropine Eye Drops: Low-dose atropine eye drops have been shown to slow the progression of myopia in children, and in some cases, they can be used to control the progression of high myopia, particularly in adolescents.
• Surgical Treatment for Retinal Problems: If complications such as retinal detachment occur, surgery may be necessary, such as scleral buckle surgery or vitrectomy, to repair the retina and prevent vision loss.

How to Reduce Myopia?

Although there is no cure for high myopia, several measures can effectively manage the condition and reduce the risk of further progression:

• Regular Eye Exams: Regular eye check-ups are essential for monitoring vision changes, detecting potential complications early, and ensuring appropriate treatment.
• Limit Near-Work Activities: Limiting prolonged near-work activities, such as reading or using electronic devices, can help slow down the progression of myopia.
• Increase Outdoor Activity: Encouraging children to spend more time outdoors, especially in natural light, has been shown to reduce the incidence of myopia, particularly in children.
• Proper Lighting and Posture: Ensuring adequate lighting while reading or working, as well as maintaining proper posture, can help reduce eye strain and prevent myopia from worsening.

High myopia is a severe form of nearsightedness that significantly impacts vision and increases the risk of various eye diseases. Although its causes are multifactorial, including genetic and environmental factors, understanding the symptoms and treatment options is crucial for effectively managing the condition. Glasses, contact lenses, refractive surgery, and orthokeratology are common treatments, and adopting a healthy lifestyle and regular eye exams can help slow myopia progression and maintain eye health.