--- title: Myopia slug: myopia url: /detay/myopia type: article language: English entity: primary: Myopia type: article disambiguation: Myopia: Understand nearsightedness, causes, prevalence, and its increasing global impact. categories: - name: Biology slug: biyoloji url: /kategori/biyoloji - name: Health And Medicine slug: saglik-ve-tip url: /kategori/saglik-ve-tip - name: Biomedical slug: biyomedikal url: /kategori/biyomedikal tags: - Myopia author: Ömer Said Aydın created_at: 2025-03-15T11:54:44.110750+03:00 updated_at: 2025-04-17T11:06:18.692415+03:00 --- # Myopia ## Article Content Myopia, medically known as nearsightedness, is a common refractive error that causes distant objects to appear blurry while allowing near objects to be seen clearly. This condition occurs when the optical system of the eye focuses light in front of the retina instead of directly on it. Myopia is one of the leading causes of vision impairment worldwide, and its prevalence [has](/en/detay/has-3/llms.txt) been rapidly increasing in recent years. ### **Causes of Myopia** Myopia occurs due to one of the following reasons: - **Axial Myopia**: The eyeball is longer than normal along its front-to-back axis. - **Refractive Myopia**: The cornea or lens has excessive refractive power, causing light to focus in front of the retina. In a normal eye (**emmetropia**), light is properly focused on the retina, forming a sharp image. However, in myopia, this focusing error causes distant objects to appear blurry. Myopia typically begins in childhood and [can](/en/detay/can-3/llms.txt) progress throughout adolescence, though it [may](/en/detay/may-748395/llms.txt) also develop in adulthood due to environmental factors or medical conditions. ### **Severity Classification of Myopia:** - **Mild Myopia**: 0 to -1.5 diopters (D) - **Moderate Myopia**: -1.5 to -6.0 D - **High Myopia**: -6.0 D and above (also known as pathological myopia) High myopia is associated with serious complications, including **retinal detachment, glaucoma, cataracts, and myopic macular degeneration**, all of which can lead to vision loss. ![Image](https://cdn.kureansiklopedi.com/media/uploads/2025/03/15/ZkxfF5XGwcpixwC42Fxjs6FgvblRyy5m.jpg) [Normal Eye vs. Myopic Eye](https://www.nvisioncenters.com/nearsightedness/degenerative-myopia/) ### **Prevalence of Myopia** Myopia is [an](/en/detay/an-2/llms.txt) increasing global public health issue. Current estimates suggest that approximately **30% of the world's population** is affected by myopia, and this figure is expected to rise to **50% (around 5 billion people) by 2050**. The prevalence of myopia is particularly high in **East and Southeast Asia**, where countries like **South Korea, Japan, China, and Singapore** have reported rates as high as **80-90%**. In the **United States**, the prevalence of myopia has increased from **25% to 42%** over the past 30 years. In **Europe**, myopia affects **30-40%** of the population, while in **Africa**, prevalence rates range between **10-20%**. This increase is linked to both **genetic predisposition** and **modern lifestyle changes**. ### **Causes of Myopia** The development of myopia is influenced by a complex interaction between genetic and environmental factors: - **Genetic Factors**: - Myopia tends to run in families. If one parent is myopic, a child’s risk increases **threefold**; if both parents are myopic, the risk increases **sixfold**. - Twin studies have shown that **monozygotic (identical) twins** have a higher likelihood of sharing myopia than **dizygotic (fraternal) twins**. - Specific genetic loci and polymorphisms associated with high myopia have been identified. - **Environmental Factors**: - **Prolonged near work** (e.g., reading, computer use, and extended screen exposure) significantly increases the risk of myopia. Studies suggest that excessive screen use can increase the risk by **30%**, while excessive computer use can elevate the risk by **up to 80%**. - **Lack of outdoor exposure** has been identified as a key factor in myopia development. Natural light exposure is believed to regulate eye growth and prevent excessive elongation. - **Developmental Processes**: - At birth, most infants are **hyperopic** (farsighted). During early childhood, the eye undergoes a process called **emmetropization**, adjusting its refractive state. In some cases, this process overshoots, leading to **myopia**. ### **Symptoms of Myopia** The primary symptom of myopia is **blurred vision when looking at distant objects**. Other common symptoms include: - Difficulty reading distant text (e.g., road signs, school blackboards) - Squinting to see more clearly - Eye strain - Headaches - In children, behaviors such as sitting close to screens, frequent eye rubbing, or difficulty recognizing distant objects may indicate myopia. Since children may not recognize that their vision is abnormal, **regular eye exams** are essential for early detection. ### **Diagnosis of Myopia** Myopia is diagnosed through a **comprehensive eye examination**, including the following tests: - **Visual Acuity Test**: The patient reads letters from an eye chart at **20 feet (6 meters)**. A result of **20/40 vision** means that a myopic person sees at 20 feet what a normal eye sees at 40 feet. - **Retinoscopy**: A light is shone into the eye to observe retinal reflexes. - **Phoropter Examination**: Different lenses are placed in front of the eye to determine the correct prescription for clear vision. - **Cycloplegic Refraction**: Eye drops that temporarily prevent focusing are used to detect hidden refractive errors, especially in children. Myopia is typically diagnosed between **ages 6-14**, but it can also develop in adulthood due to visual stress (e.g., excessive near-work) or medical conditions like **diabetes**. ### **Treatment of Myopia** Myopia can be managed through optical or surgical methods: - **Glasses and Contact Lenses**: - The most common and accessible solution for correcting myopia. - Prescriptions are expressed in **negative diopters (-D)**. - Mild myopia may require glasses only for specific activities (e.g., driving), while high myopia often requires **full-time use**. - **Refractive Surgery (for adults)**: - **LASIK**: A flap is created in the cornea, and underlying tissue is reshaped with a laser. - **PRK**: The corneal surface layer is removed and reshaped—ideal for those with thin corneas. - **SMILE**: A minimally invasive procedure that removes a small piece of corneal tissue. - **Phakic IOLs or Lens Implantation**: Artificial lenses are implanted inside the eye. - **Myopia Control Methods (for children)**: - **Orthokeratology (Ortho-K)**: Rigid contact lenses worn overnight temporarily reshape the cornea. - **Atropine Eye Drops**: Low-dose atropine can slow myopia progression by up to **80%**. - **Peripheral Defocus Contact Lenses**: Help control eye elongation. - **Bifocal/Multifocal Lenses**: Balance near and distant vision to slow myopia progression. ### **Prevention of Myopia** While myopia cannot be entirely prevented, certain strategies can reduce its [risk](/en/detay/risk-2/llms.txt) and slow its progression: - **Outdoor Time**: Spending at least **90 minutes per day** in natural daylight may **delay myopia onset**. - **Reducing Near Work Strain**: The **20-20-20 rule** (every 20 minutes, look 20 feet away for 20 seconds) helps relieve eye strain. - **Regular Eye Exams**: Early detection lowers the risk of complications. ### **Complications of Myopia** High myopia significantly increases the risk of severe eye conditions, including: - **Retinal Detachment**: The elongation of the eyeball stretches the retina, making it prone to detachment. - **Glaucoma**: Increased eye pressure can damage the optic nerve. - **Cataracts**: Myopia raises the risk of early cataract formation. - **Myopic Macular Degeneration**: Damage to the central retina can cause central vision loss. Myopia is a rapidly growing refractive error influenced by both **genetic** and **environmental** factors. With **early diagnosis** and proper management, individuals can maintain **good visual quality** and reduce complications. From simple solutions like **glasses and contact lenses** to advanced treatments like **laser surgery and myopia control strategies**, a variety of options exist to manage this condition. Ongoing **scientific research** continues to improve our understanding of myopia and enhance prevention strategies. Regular **eye exams** and **healthy visual habits** remain essential in minimizing the impact of myopia. ## Academic Sources and References 1. American Optometric Association. “Myopia (Nearsightedness).” Healthy Eyes. Erişim tarihi 14 Mart 2025. https://www.aoa.org/healthy-eyes/eye-and-vision-conditions/myopia?sso=y.Canadian Association of Optometrists. “Myopia (Nearsightedness).” Eye Health Library. Erişim tarihi 14 Mart 2025. https://opto.ca/eye-health-library/myopia-nearsightedness.Cleveland Clinic. “Myopia (Nearsightedness).” Cleveland Clinic Health Library. Erişim tarihi 14 Mart 2025. https://my.clevelandclinic.org/health/diseases/8579-myopia-nearsightedness.Dünyagöz Hospital Editorial Board. “What Is Myopia?” Dünyagöz Hospital Medical Units. Son güncelleme 2 Haziran 2023. Erişim tarihi 14 Mart 2025. https://www.dunyagoz.com/en/medical-units/laser-and-intraocular-lens/what-is-myopia.Fredrick, Douglas R. “Myopia.” BMJ 324, no. 7347 (May 18, 2002): 1195–99. https://pmc.ncbi.nlm.nih.gov/articles/PMC1123161/.International Myopia Institute. “Myopia.” Erişim tarihi 14 Mart 2025. https://myopiainstitute.org/myopia/.Mayo Clinic Staff. “Nearsightedness.” Mayo Clinic Diseases & Conditions. Erişim tarihi 14 Mart 2025. https://www.mayoclinic.org/diseases-conditions/nearsightedness/symptoms-causes/syc-20375556.McManes, Amber. “Myopia (Nearsightedness): Causes, Progression and Management.” All About Vision. Son güncelleme 16 Şubat 2022. Erişim tarihi 14 Mart 2025. https://www.allaboutvision.com/conditions/myopia/overview-of-nearsightedness/.National Eye Institute. “Nearsightedness (Myopia).” Learn About Eye Health. Son güncelleme 23 Ağustos 2023. Erişim tarihi 14 Mart 2025. https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/nearsightedness-myopia.National Health Service. “Short-Sightedness (Myopia).” NHS Conditions. Erişim tarihi 14 Mart 2025. https://www.nhs.uk/conditions/short-sightedness/.Turbert, David. “Nearsightedness: What Is Myopia?” American Academy of Ophthalmology Eye Health. Son güncelleme 7 Kasım 2024. Erişim tarihi 14 Mart 2025. https://www.aao.org/eye-health/diseases/myopia-nearsightedness.