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Astigmatism

Disease Details

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Description: Astigmatism is a common vision condition caused by an irregular curvature of the cornea or lens, leading to blurred or distorted vision.
Type: Astigmatism is a type of refractive error in the eye where the cornea or lens has an irregular shape, leading to blurred or distorted vision. The genetic transmission of astigmatism is commonly multifactorial, meaning it involves both genetic and environmental factors. There is no single gene responsible; instead, multiple genes contribute to the risk of developing the condition, often influenced by lifestyle and environmental factors.
Signs And Symptoms: Although astigmatism may be asymptomatic, higher degrees of astigmatism may cause symptoms such as blurred vision, double vision, squinting, eye strain, fatigue, or headaches. Some research has pointed to the link between astigmatism and higher prevalence of migraine headaches.
Prognosis: The prognosis for astigmatism is generally good, especially with proper management. Astigmatism can usually be corrected with prescription eyeglasses, contact lenses, or refractive surgery such as LASIK or PRK. Early detection and treatment are important to prevent any potential complications like amblyopia (lazy eye) in children. Most individuals with astigmatism can achieve clear, comfortable vision with the appropriate corrective measures.
Onset: Astigmatism is a common vision condition that usually presents from birth (congenital) and can be noticed in early childhood. It occurs when the cornea or lens of the eye has an irregular shape, causing blurred or distorted vision. Although it can be diagnosed at any age, its onset is typically in the early years of life.
Prevalence: Astigmatism is a common refractive error affecting the eye's ability to focus light on the retina. The prevalence of astigmatism varies by population and age group, but it commonly affects around 30-40% of the adult population in the United States.
Epidemiology: In 2019, the World Health Organization reported that 123.7 million people worldwide were affected by uncorrected refracting errors, including astigmatism. A compilation of many systematic reviews found that there was an 8-62% prevalence of astigmatism among adults, with an estimated prevalence of 40% worldwide. The country with the highest reported prevalence among the compilation of systematic reviews is China at 62%. The prevalence of astigmatism increases with age due to changes in refractive index gradients. According to an American study, nearly three in ten children (28.4%) between the ages of five and seventeen have astigmatism. A Brazilian study published in 2005 found that 34% of the students in one city were astigmatic.Studies have shown that infants in their first few months have a high prevalence of astigmatism due to a steep cornea. The steepest corneas are found in infants with low birth weights and post-conceptional age. By the age of four, the prevalence of astigmatism has reduced as the cornea flattens. The cornea remains mostly stable during adulthood, and then steepens again in older adulthood (40+ years).Mild astigmatism has a higher prevalence than moderate and significant astigmatisms and increased until the age of 70, while moderate and significant astigmatisms showed an increase in prevalence after the age of 70. Of the levels of astigmatism, mild astigmatism is most prevalent, making up about 82% of the total reported astigmatisms.With-the-rule astigmatism among the total population has a prevalence range of 4 to 98% globally. The prevalence range for against-the-rule astigmatism is from 1 to 58%. For oblique astigmatism, the prevalence range is from 2 to 61%. With-the-rule astigmatism is more prevalent in young adults, and over time, the prevalence shifts to be mostly against-the-rule astigmatism. A Polish study published in 2005 revealed "with-the-rule astigmatism" may lead to the onset of myopia.The main cause of astigmatism is changes in the curvature of the cornea. When left untreated, astigmatism causes people to have a lower vision-related quality of life. Some factors that lead to this are a decrease in vision quality and an increase in glare and haloes. People with astigmatism have more difficulty with night driving and can have a decreased productivity due to errors. However, there are many ways to help correct astigmatisms. The use of glasses, contacts, Toric intraocular lenses, Toric implantable Collamer lenses, corneal refractive surgery have been shown to correct astigmatisms.
Intractability: Astigmatism is not considered intractable. It is a common refractive error of the eye that can be effectively managed with corrective lenses, such as glasses or contact lenses, and can also be corrected through surgical procedures like LASIK or other types of refractive surgery.
Disease Severity: Astigmatism is not classified as a disease but rather a common refractive error caused by an irregular curvature of the cornea or lens. It results in blurred or distorted vision at all distances. The severity of astigmatism can vary from mild to severe, depending on the degree of curvature and the impact on vision. Mild astigmatism may not require correction or may need only minimal intervention, while moderate to severe cases often require corrective lenses or surgery for optimal vision.
Healthcare Professionals: Disease Ontology ID - DOID:11782
Pathophysiology: Astigmatism is a common refractive error in the eye resulting from an irregular curvature of the cornea or lens. Unlike a perfectly spherical cornea, an astigmatic cornea has an oval shape, causing light to focus on multiple points rather than on a single point on the retina. This leads to blurred or distorted vision at all distances. The exact biological mechanisms behind the development of this irregular curvature are not fully understood, but genetic and environmental factors are believed to play a role.
Carrier Status: Astigmatism is not a disease that involves a carrier status. It is a common refractive error of the eye caused by an irregular curvature of the cornea or lens, which leads to blurred or distorted vision. It can affect individuals of any age and is typically diagnosed through a comprehensive eye examination. Treatment options include corrective lenses such as glasses or contact lenses, and in some cases, refractive surgery.
Mechanism: Astigmatism Mechanism:
Astigmatism is a common refractive error caused by an imperfection in the curvature of the eye's cornea or lens. Instead of being perfectly spherical, the cornea or lens is more oval-shaped, leading to distorted or blurred vision. This irregular shape prevents light rays from focusing properly on the retina, the light-sensitive surface at the back of the eye, resulting in blurred or distorted images at all distances.

Molecular Mechanisms:
Astigmatism is largely influenced by genetic factors, though the exact molecular mechanisms are not fully understood. Studies suggest that variations in genes responsible for the development and maintenance of the cornea and lens might play a role. Additionally, environmental factors such as eye strain or trauma can contribute to its development. Research is ongoing to identify specific genes and molecular pathways involved in the formation and regulation of corneal and lenticular shape, which could eventually lead to better prevention and treatment strategies.
Treatment: Astigmatism may be corrected with eyeglasses, contact lenses, or refractive surgery. Glasses are the simplest and safest, although contact lenses can provide a wider field of vision. Refractive surgery can eliminate the need to wear corrective lenses altogether by permanently changing the shape of the eye but, like all elective surgery, comes with both greater risk and expense than the non-invasive options. Various considerations involving eye health, refractive status, and lifestyle determine whether one option may be better than another. In those with keratoconus, certain contact lenses often enable patients to achieve better visual acuity than eyeglasses. Once only available in a rigid, gas-permeable form, toric lenses are now also available as soft lenses.
In older people, astigmatism can also be corrected during cataract surgery. This can either be done by inserting a toric intraocular lens or by performing special incisions (limbal relaxing incisions). Toric intraocular lenses probably provide a better outcome with respect to astigmatism in these cases than limbal relaxing incisions.Toric intraocular lenses can additionally be used in patients with complex ophthalmic history, such as previous ophthalmic surgery. In such complex cases, toric intraocular lenses seem to be as effective as in non-complex cases for correction of concurrent corneal astigmatism.
Compassionate Use Treatment: For astigmatism:

**Compassionate Use Treatment:**
Astigmatism generally does not require compassionate use treatments, as it is commonly managed with standard interventions such as corrective lenses or refractive surgery.

**Off-label or Experimental Treatments:**
There are several emerging and experimental treatments for astigmatism, which may include:

1. **Orthokeratology (Ortho-K):** A non-surgical option involving specially designed gas-permeable contact lenses worn overnight to temporarily reshape the cornea.
2. **Topography-guided LASIK:** An advanced form of LASIK surgery that uses corneal topography maps to guide the laser, potentially offering better outcomes for some astigmatism patients.
3. **Small-Incision Lenticule Extraction (SMILE):** A minimally invasive laser procedure designed for the correction of myopia and astigmatism. Though widely approved, it is still considered relatively new and under long-term study.
4. **Toric Intraocular Lenses (IOLs):** Used in cataract surgery to correct astigmatism along with cataracts. They are already in use, but ongoing research aims to improve their design and efficacy.

These options are at various stages of clinical use and research; some are more widely available than others. Always consult a healthcare provider to determine the most appropriate treatment based on individual conditions and needs.
Lifestyle Recommendations: Lifestyle recommendations for managing astigmatism include:

1. **Regular Eye Exams**: Schedule routine eye check-ups to monitor vision changes and update prescriptions as needed.

2. **Corrective Lenses**: Use prescribed glasses or contact lenses to help correct vision issues caused by astigmatism.

3. **Proper Lighting**: Ensure good lighting while reading, working, or engaging in other activities that require visual focus.

4. **Breaks from Screens**: Follow the 20-20-20 rule—every 20 minutes, take a 20-second break and look at something 20 feet away to reduce eye strain.

5. **Eye Protection**: Wear protective eyewear during activities that pose a risk to the eyes, such as sports or working with hazardous materials.

6. **Healthy Diet**: Maintain a diet rich in essential nutrients like vitamins A, C, and E, as well as omega-3 fatty acids, to support overall eye health.

7. **Exercise Regularly**: Engage in physical activity to maintain overall health, which can benefit your eyes.

8. **Hydration**: Keep your eyes hydrated, particularly if you spend a lot of time in front of screens or in dry environments.

9. **Adequate Sleep**: Ensure you get enough rest to help your eyes recover from daily strain.

Adopting these lifestyle habits can help manage symptoms and support overall eye health.
Medication: Astigmatism is a common refractive error caused by an irregularly shaped cornea or lens that leads to blurred or distorted vision. There is no medication to treat astigmatism. Instead, it is typically corrected with glasses, contact lenses, or refractive surgery such as LASIK.
Repurposable Drugs: Astigmatism is primarily corrected using glasses, contact lenses, or refractive surgery rather than pharmaceutical approaches. No drugs are specifically approved or commonly used to treat astigmatism.
Metabolites: Astigmatism is a refractive error in the eye caused by an irregular curvature of the cornea or lens. It affects how light is focused on the retina, leading to blurred or distorted vision. Astigmatism is primarily a structural issue and not a metabolic one, so there aren't specific metabolites associated with it. Nonetheless, good eye health can be generally supported by metabolites like antioxidants (e.g., vitamins C and E, lutein) that protect eye tissues from oxidative stress, although these are not specific treatments for astigmatism itself. For correction, options include eyeglasses, contact lenses, or refractive surgery.
Nutraceuticals: Nutraceuticals are not known to treat or correct astigmatism. Astigmatism is primarily a refractive error caused by an irregular curvature of the cornea or lens. The most effective treatments involve corrective lenses (glasses or contact lenses) and refractive surgeries, such as LASIK. Nutraceuticals can support overall eye health but will not directly address the structural issues causing astigmatism.
Peptides: Astigmatism is not related to peptides or nanotechnology. It is a common refractive error in the eye caused by an irregular curvature of the cornea or lens. This irregular shape prevents light from focusing properly on the retina, leading to blurred or distorted vision. Treatment options include corrective lenses (glasses or contact lenses) and refractive surgery, such as LASIK.