Myopia: Causes, Symptoms, and Diagnosis

Understanding myopia begins with recognizing it as a common vision condition that affects the ability to see distant objects. It is prevalent worldwide, impacting a significant portion of the population. Knowing the causes and symptoms of myopia is vital for maintaining eye health and seeking appropriate treatment early.

What is Myopia?

Nearsightedness, or myopia, is when you can see things up close just fine, but things farther away are blurry. Let's talk about what myopia is, why it happens, how to handle it, and how it differs from other eyesight issues.

Causes of Myopia

Myopia happens when your eye is a bit too long from the front to the back, making light focus in front of the retina (the part at the back of your eye) instead of right on it. This makes faraway things look blurry. It's usually something you inherit from your parents, can happen if you do a lot of close-up activities like reading, and is more common in cities or places where kids don't spend much time outside.

Understanding Myopia in Children

Myopia is a growing problem in children, with estimates suggesting that nearly one in three children in the U.S. are affected. The condition typically worsens in childhood until the eye stops growing in early adulthood. Early detection and management are crucial to preventing complications and reducing sight-threatening conditions risk.

Differences from Other Vision Impairments

Myopia makes it hard to see faraway things clearly, which is different from another eye issue called astigmatism, which can affect your vision for things near and far. Sometimes, people can have both myopia and astigmatism at the same time.

Astigmatism is caused by the front part of your eye (cornea) or lens not being perfectly round, leading to blurry vision. On the other hand, myopia happens because the eye is too long. Knowing the difference between these can help in treating them correctly.
 

Symptoms of Myopia

The symptoms of myopia can vary in severity and may include both visual and non-visual signs.

Visual Symptoms

• Blurry Vision: The most common symptom of myopia is difficulty seeing distant objects. This can include:

  • Difficulty reading road signs or seeing objects far away

  • Trouble watching TV or movies from a distance

  • Struggling to see the whiteboard in school or while driving
     

• Eye Strain: Myopic individuals may experience eye fatigue or discomfort due to the constant strain of focusing on close objects:

  • Headaches

  • Squinting to see properly

  • Difficulty adjusting to changes in lighting
     

• Difficulty with Distance Vision: Myopia can make it challenging to perform tasks that require clear distance vision:

  • Trouble seeing objects or people in the distance

  • Difficulty reading words on a display at the front of the classroom
     

Non-Visual Symptoms

• Headaches: Myopic individuals may experience headaches due to the constant strain on their eyes:

  • Frequent headaches

  • Eye fatigue
     

• Squinting: People with myopia often squint to see distant objects more clearly:

  • Squinting to see properly

  • Partially closing the eyelids to focus
     

• Eye Fatigue: Myopic individuals may experience eye fatigue due to the constant strain of focusing on close objects:

  • Eye strain

  • Eye fatigue

Diagnosing Myopia

Diagnosing myopia involves several standard procedures during an eye examination. Here are the specific tests used to diagnose myopia:

• Visual Acuity Test: his test checks how clear your vision is. You'll be asked to read letters on a chart that's set up about 20 feet away. The purpose is to see how well you can see from a distance.

• The Refraction Test involves placing different lenses before the patient's eyes to determine the correct prescription. The patient is asked to look through each lens and indicate the clearest vision.

• Eye Health Examination: This part of the examination involves a physical examination of the eyes, including a check for a normal light reflex. The doctor may also use a lighted retinoscope to measure how the retina reflects light.

• Cycloplegic Refraction (Optional): This test relaxes the muscles in the eye, allowing for a more accurate measurement of the refractive error. It involves instilling drops of a cycloplegic agent, such as tropicamide or cyclopentolate, and performing a refraction test after a certain period.

Risk Factors for Myopia

Here are the key risk factors for myopia:

Age-Specific Considerations in Myopia Development

Understanding the age-specific factors that contribute to myopia development is crucial for prevention and treatment strategies.

1. Myopia tends to develop and progress fastest during childhood, with the age of stabilization reported to be 15–16.

2. Ocular growth and myopia progression are functions of age, with rapid progression during childhood and adolescence.

3. The prevalence of myopia increases within a given location or school system as children age and complete more schooling.

The Impact of Family History on Myopia Risk

Whether or not you might get nearsightedness (myopia) can depend a lot on your family history. The way myopia is passed down through families is pretty complicated since it involves a bunch of different genes and how these genes interact with your surroundings.

• If both of your parents are nearsighted, you're about 5 times more likely to be nearsighted too. If just one parent is nearsighted, your chances double.

• Where you come from, like your ethnicity, also matters but you can't change it. For instance, myopia is more common in East Asian people.

• Both your genes and the things you do in your environment matter for developing myopia.

Educational and Occupational Risks

What you do for school or work can also make a big difference. Spending a lot of time doing close-up work like reading and not enough time outside can make it more likely for you to become nearsighted.

• Higher education level and school performance intensity are strongly associated with increased myopia risk.

• Continuous reading for more than 30 minutes increases the odds of myopia by 1.5 times. Reading distances closer than 30 cm increase the odds by 2.5 times.

Complications Associated with Myopia

The complications associated with myopia include several serious eye health issues that can lead to irreversible visual impairment if left untreated. These complications include:

• Myopic Macular Degeneration (MMD):

  • Characterized by lacquer cracks, Fuchs spot, choroidal neovascularization (CNV), or chorioretinal atrophy.

  • High myopia is particularly associated with a higher risk of MMD, which can cause significant visual impairment.
     

• Retinal Detachment (RD):

  • This is caused by the elongation of the eye, which can lead to a thinner retina and an increased risk of retinal tears and detachment.

  • RD can result in permanent loss of vision if not treated promptly.
     

• Cataracts:

  • Myopia is associated with an increased risk of developing cataracts, particularly nuclear cataracts, which can cause a myopic shift and affect the determination of the original refractive error.

  • Cataracts can be removed through surgery if necessary.
     

• Open Angle Glaucoma (OAG):

  • Studies have found a higher incidence of OAG among myopic individuals, with the risk increasing with the severity of myopia.

  • Untreated glaucoma can lead to blindness.
     

1. Retinal Tears:

   • The thinner retina in myopic eyes is more prone to tearing, which can lead to vision loss if not treated.

2. Myopic Choroidal Neovascularization (CNV):

   • Abnormal new blood vessels grow beneath the retina, which can leak or bleed, causing sudden vision loss.

3. Myopic Tractional Maculopathy:

   • The inner layers of the retina attempt to pull away from the outer retina, causing it to thicken. This requires regular monitoring and may require surgery.

4. Macular Hole:

   • A condition can occur due to the mechanical stretching and thinning of the retina layers in high myopia.

Treatment and Management of Myopia

Effective management of myopia involves a combination of corrective lenses, refractive surgery options, and innovative treatments to slow down its progression.

• Eyeglasses are the most common choice for regaining clear-distance vision. Full-time wear is necessary for higher prescriptions, while lower prescriptions may only require glasses for specific activities like driving or watching TV.

• Single-Vision Lenses: Generally prescribed for clear vision at all distances.

• Bifocal or Multifocal Lenses: These may be required for patients over age 40 or for myopia caused by focusing difficulties. These lenses provide different optical powers throughout the lens for clear vision at near and distant distances.

• Contact Lenses: Provide clear vision at all distances with a wider field of view than eyeglasses. They are preferred for aesthetic or social reasons and ease of comfort during sports.

Refractive Surgery Options

Refractive surgery is a surgical procedure that reshapes the cornea to correct myopia. These procedures are generally considered for individuals unsatisfied with wearing corrective lenses and looking for a more permanent solution.

• LASIK (Laser In Situ Keratomileusis): A laser procedure that reshapes the cornea to correct myopia.

• PRK (Photorefractive Keratectomy): Another laser procedure that reshapes the cornea to correct myopia.

• Phakic Intraocular Lens Implant: An implant placed before the natural lens for vision correction.

• Clear Lens Extraction with Intraocular Lens Implantation: An implant placed in place of the natural lens for vision correction.

Orthokeratology (Ortho-K)

Ortho-K is a method where you wear special contact lenses overnight that gently reshape the front part of your eye (the cornea). When you take the lenses out in the morning, you can see clearly throughout the day without needing glasses or contacts. This method has also proven useful in slowing down the worsening of nearsightedness (myopia).

Innovative Treatments and Myopia Control Strategies

Innovative treatments and strategies are being developed to manage myopia and slow its progression. These include various types of contact lenses and lifestyle modifications.

• Atropine Eye Drops: Low concentrations of atropine eye drops have effectively slowed down myopia progression with minimal side effects.

• Multifocal Lenses for Myopia Management: Multifocal contact lenses correct higher levels of myopia and are very comfortable. They provide clear vision for both nearby and distant objects.

• MiSight Lenses: Daily disposable, soft contact lenses designed to control myopia progression in children ages 8 to 15.

• Environmental Lifestyle Modifications: Advocated as an intervention for preventing the onset of myopia, especially for individuals at risk of developing myopia in the future.

Preventative Measures for Myopia

Preventative measures for myopia include a combination of lifestyle modifications, regular eye examinations, and specific treatments. Here are some key points:

Lifestyle Modifications

Outdoor activities are a crucial component of myopia prevention. Natural light exposure stimulates the release of dopamine in the retina. It also inhibits excessive eye growth and promotes healthier eye development.
 

1. Outdoor Activities: Spending more time outdoors, especially in natural environments, has been linked to a reduced risk of myopia development. This is thought to be due to the intensity and quality of natural light, which stimulates dopamine release in the retina, inhibiting excessive eye growth.

2. Limit Screen Time: Reducing near-work and screen time can also help prevent myopia. This is because excessive near-work can lead to increased eye strain and contribute to myopia progression.

3. Healthy Lifestyle Habits: Encouraging a balanced diet rich in essential nutrients like vitamins C and E, omega-3 fatty acids, and lutein, as well as regular physical activity and sufficient sleep, can support optimal visual health and potentially mitigate myopia.
    

Regular Eye Examinations

Getting your eyes checked often is really important to catch and keep an eye on nearsightedness (myopia) early on. Eye doctors, like optometrists or ophthalmologists, can look at your eyes to see how healthy they are, see if myopia is starting, and watch if it's getting worse. Catching it early means you can do something about it so it doesn't get too bad.
 

• Corrective Eyewear: If the eye doctor says you need them, wearing glasses or contact lenses can make your eyes feel better, help you see more clearly, and stop you from squinting or struggling to see. This can keep your nearsightedness from getting worse.

• Myopia Control Techniques: There are special treatments to control how fast myopia gets worse. Things like low-strength atropine eye drops, special contact lenses worn at night (ortho-K), and glasses with special lenses can help. Atropine drops make the eye's focusing system relax, which can help slow down how fast the eye changes and the myopia gets worse.

• Pharmacological Interventions: Low-dose atropine eye drops (0.05%) slow myopia progression. The 0.05% atropine group had the greatest mean myopic refractive error progression reduction compared to lower concentrations.

Conclusion

Understanding myopia is essential for proactive eye health management. Recognizing its impact allows individuals to seek timely interventions. This approach helps prevent the condition from worsening.
 

Staying informed about myopia developments and treatments empowers people to make informed decisions about their eye health. Knowledge ensures that one can access the latest and most effective care options available.