Refractive Error
Disease Details
Family Health Simplified
- Description
- Refractive error is a common vision problem causing blurred vision due to the eye's improper focus of light on the retina, including conditions like myopia, hyperopia, astigmatism, and presbyopia.
- Type
- Refractive errors, such as myopia (nearsightedness), hyperopia (farsightedness), and astigmatism, are typically complex traits influenced by multiple genetic and environmental factors. The genetic transmission is usually polygenic, meaning it involves multiple genes, and does not follow a simple Mendelian inheritance pattern. However, some studies have identified specific genetic loci associated with increased risk.
- Signs And Symptoms
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Refractive errors are visual disorders that occur when the shape of the eye prevents light from focusing directly on the retina. The primary signs and symptoms of refractive errors include:
- Blurred or distorted vision
- Squinting
- Headaches
- Eye strain or discomfort
- Difficulty focusing on near or distant objects (depending on the type of refractive error)
- Double vision in some cases
If you experience any of these symptoms, it is advisable to consult an eye care professional for a thorough examination and appropriate corrective measures. - Prognosis
- Refractive errors, such as myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia, generally have a favorable prognosis with appropriate management. These conditions are typically correctable with eyeglasses, contact lenses, or refractive surgery. Early detection and proper correction can minimize potential complications like eye strain and headaches, allowing individuals to maintain a good quality of life and functional vision.
- Onset
- Refractive errors typically develop during childhood and adolescence, although they can occur at any age. They are often related to the eye's shape and how it focuses light.
- Prevalence
- The prevalence of refractive errors varies globally, but they are among the most common vision problems. It is estimated that around one-third of the world's population has a refractive error, which includes myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia. Prevalence can be higher in certain regions and populations due to genetic, environmental, and behavioral factors.
- Epidemiology
- It is estimated that at least 2 billion people in the world have refractive errors. The number of people globally with refractive errors that have not been corrected was estimated at 660 million (10 per 100 people) in 2013.Refractive Errors are the first common cause of Visual Impairment and second most common cause of visual loss . The assessment of Refractive Error is now done in DALY (Disability Adjusted Life Years) which showed an 8% increase from 1990 to 2019.The number of people globally with significant refractive errors has been estimated at one to two billion. Rates vary between regions of the world with about 25% of Europeans and 80% of Asians affected. Near-sightedness is one of the most prevalent disorders of the eye. Rates among adults are between 15 and 49% while rates among children are between 1.2 and 42%. Far-sightedness more commonly affects young children, whose eyes have yet to grow to their full length, and the elderly, who have lost the ability to compensate with their accommodation system. Presbyopia affects most people over the age of 35, and nearly 100% of people by the ages of 55–65. Uncorrected refractive error is responsible for visual impairment and disability for many people worldwide. It is one of the most common causes of vision loss along with cataracts, macular degeneration, and vitamin A deficiency.
- Intractability
- Refractive errors are generally not intractable. They can typically be corrected or managed effectively using glasses, contact lenses, or refractive surgery such as LASIK.
- Disease Severity
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Refractive Error refers to a group of eye disorders where the shape of the eye prevents light from focusing directly on the retina. The severity of refractive errors can vary widely:
1. **Mild**: Slight difficulty in seeing distant or close objects clearly.
2. **Moderate**: Increased difficulty in vision that often necessitates corrective lenses, such as glasses or contact lenses, for daily activities.
3. **Severe**: Significant impairment in vision requiring strong prescription lenses or potential surgical intervention.
4. **Profound**: Rare cases where vision correction might be challenging even with the strongest corrective measures, potentially impacting quality of life significantly.
Conditions under this category include myopia (nearsightedness), hyperopia (farsightedness), astigmatism (distorted vision), and presbyopia (age-related difficulty in seeing up close).
Monitoring and treatment, typically through lenses or surgery, are essential to manage the condition effectively. - Healthcare Professionals
- Disease Ontology ID - DOID:9835
- Pathophysiology
- Refractive error occurs when the eye does not focus light directly on the retina, resulting in blurred vision. This can be due to the length of the eyeball (either too long or too short), changes in the shape of the cornea, or aging of the lens. The main types of refractive error include myopia (nearsightedness), hyperopia (farsightedness), astigmatism (distorted vision), and presbyopia (age-related loss of near vision). These conditions are primarily due to anatomical differences and imperfections in the optical components of the eye, preventing light from being properly bent (refracted) and focused.
- Carrier Status
- Refractive errors, such as myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia, are not typically referred to in terms of "carrier status" as they are not inherited in a simple Mendelian fashion like some genetic disorders. Instead, these vision problems arise due to a combination of genetic and environmental factors. There is no carrier status for refractive errors because they do not follow the carrier-based inheritance pattern seen in some other genetic conditions.
- Mechanism
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Refractive errors occur when the eye does not focus light directly on the retina, leading to blurred vision. The main types include myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia.
### Mechanism
- **Myopia (Nearsightedness)**: Light is focused in front of the retina because the eyeball is too long or the cornea has too much curvature. This makes distant objects appear blurry.
- **Hyperopia (Farsightedness)**: Light is focused behind the retina because the eyeball is too short or the cornea has too little curvature. This makes close objects appear blurry.
- **Astigmatism**: Light is focused on multiple points either in front of or behind the retina due to an irregularly shaped cornea or lens, causing distorted or blurred vision at all distances.
- **Presbyopia**: The lens hardens with age, losing its ability to change shape to focus on close objects, leading to difficulty reading small print or seeing close objects.
### Molecular Mechanisms
The exact molecular mechanisms underlying refractive errors are still being researched, but several factors have been identified:
- **Genetic Factors**: Numerous genes have been associated with refractive errors, influencing eye growth, development, and the structural components of the eye.
- **Signaling Pathways**: Growth factors such as TGF-β (Transforming Growth Factor Beta) and signaling pathways involving retinoic acid have been implicated in regulating the growth of the eye.
- **Extracellular Matrix**: Changes in the extracellular matrix of the eye, which provides structural support to cells, can influence the shape and size of the eye, affecting refractive properties.
- **Neurotransmitters**: Dopamine and other neurotransmitters in the retina are thought to play a role in eye growth and refractive development.
Understanding these molecular mechanisms can help in developing therapeutic interventions to correct or prevent refractive errors. - Treatment
- The primary treatment for refractive errors involves corrective lenses, such as eyeglasses or contact lenses, which help to focus light correctly on the retina. For those seeking a more permanent solution, refractive surgery options such as LASIK (Laser-Assisted In Situ Keratomileusis) or PRK (Photorefractive Keratectomy) can reshape the cornea to correct the vision. Another option includes orthokeratology, which involves wearing specially designed rigid contact lenses to temporarily reshape the cornea.
- Compassionate Use Treatment
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Refractive error primarily refers to conditions like myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia which impair the eye’s ability to properly focus light on the retina.
Compassionate use treatments and off-label or experimental treatments are generally more relevant to severe or life-threatening conditions. For refractive errors, standard treatments including eyeglasses, contact lenses, and established surgical options like LASIK are typically sufficient and well-researched.
While not considered "compassionate use" or experimental in the traditional sense, ongoing research into newer laser technologies, advances in intraocular lens implants, and other novel approaches can be regarded as cutting-edge. For instance, there are adjustable intraocular lenses being studied that can be fine-tuned post-implantation to better correct vision.
Always consult with a healthcare provider specializing in ophthalmology to understand the most appropriate and up-to-date treatments for refractive errors. - Lifestyle Recommendations
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Lifestyle recommendations for managing refractive errors (such as myopia, hyperopia, and astigmatism) include:
1. **Regular Eye Exams:** Schedule annual check-ups to monitor vision changes and update prescriptions as needed.
2. **Balanced Diet:** Eat a diet rich in vitamins A, C, and E, zinc, and omega-3 fatty acids to support eye health.
3. **Adequate Lighting:** Ensure proper lighting while reading or working to reduce eye strain.
4. **Protective Eyewear:** Use sunglasses with UV protection and safety goggles when necessary to protect your eyes from harmful rays and potential injuries.
5. **Screen Breaks:** Follow the 20-20-20 rule—every 20 minutes, look at an object 20 feet away for 20 seconds to reduce digital eye strain.
6. **Ergonomic Workspaces:** Adjust your work area to ensure comfortable viewing distances and proper posture.
7. **Limit Screen Time:** Reduce the amount of time spent on digital devices to prevent eye fatigue.
These lifestyle adjustments can help manage symptoms and potentially slow the progression of refractive errors. - Medication
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Refractive error, such as myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia, generally cannot be corrected with medication. The standard treatments include:
1. **Eyeglasses**: Prescription lenses to correct vision.
2. **Contact Lenses**: Lenses that sit directly on the eye's surface.
3. **Refractive Surgery**: Procedures like LASIK, PRK, or LASEK to reshape the cornea.
4. **Orthokeratology (Ortho-K)**: Specially designed contact lenses that temporarily reshape the cornea.
No medications are currently available to correct the underlying refractive errors themselves. However, eye drops might be prescribed for related issues such as eye strain or to slow the progression of conditions like myopia in children. - Repurposable Drugs
- Currently, there are no widely recognized repurposable drugs specifically approved for the treatment of refractive errors such as myopia, hyperopia, astigmatism, or presbyopia. Treatment for refractive errors typically involves corrective lenses (glasses or contact lenses) and surgical options like LASIK or PRK. Research is ongoing, but no existing drugs have been definitively established as repurposable options for correcting these visual impairments.
- Metabolites
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Refractive error is not typically associated with specific metabolites, as it is primarily a result of the shape and focusing ability of the eye rather than a metabolic process. Refractive errors, such as myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia, occur when the eye does not bend (refract) light correctly, which results in blurred vision. These conditions are usually corrected with glasses, contact lenses, or refractive surgery.
For more detailed metabolic aspects or correlations, more specific conditions or broader systemic metabolic disturbances need to be examined rather than refractive error alone. - Nutraceuticals
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Nutraceuticals are products derived from food sources that offer additional health benefits beyond basic nutrition. For refractive errors, however, there is limited scientific evidence to suggest that nutraceuticals can directly correct or improve conditions like myopia (nearsightedness), hyperopia (farsightedness), astigmatism, or presbyopia. Refractive errors typically result from the shape of the eye, the curvature of the cornea, or the lens, factors that are not easily modified by nutritional supplements. Standard treatments include corrective lenses (glasses or contact lenses) and surgical options like LASIK. It's always best to consult an eye care professional for appropriate diagnosis and treatment.
"NAN" in your context is unclear. It could mean "not a number" in scientific terms or be a typographical error. If you meant a specific product, acronym, or context, please clarify for a more accurate response. - Peptides
- Refractive error is not directly related to peptides. Refractive errors, such as myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia, are vision problems caused by the eye's inability to focus light correctly on the retina. These errors are generally due to the shape of the cornea or the length of the eyeball. They are typically corrected with glasses, contact lenses, or refractive surgery. Peptides, short chains of amino acids, do not have a direct role in the treatment or correction of refractive errors.