Symptoms
Common symptoms include:
Blurred vision (near or far)
Double vision
Hazy vision
Eyestrain
Headaches
Squinting
Difficulty focusing
Glare or halos around lights
Causes
Refractive errors occur due to variations in the shape of the eyeball, cornea (the clear front surface of the eye), or lens. These variations prevent light from focusing correctly on the retina. Specific causes for each type:
Myopia: The eyeball is too long or the cornea is too curved.
Hyperopia: The eyeball is too short or the cornea is not curved enough.
Astigmatism: The cornea or lens is irregularly shaped.
Presbyopia: The lens loses its flexibility with age.
Medicine Used
Refractive errors are typically corrected with:
Corrective Lenses: Eyeglasses or contact lenses are the primary method. They compensate for the refractive error by bending light properly before it enters the eye.
Refractive Surgery: Procedures like LASIK, PRK, and SMILE reshape the cornea to correct the refractive error.
Eye Drops: In some cases, eye drops (e.g., atropine for myopia control in children) might be prescribed, but they don't cure the error.
Orthokeratology: Special contact lenses worn overnight to reshape the cornea temporarily.
Is Communicable
Refractive errors are not communicable or contagious. They are not caused by infections and cannot be spread from person to person.
Precautions
While you can't prevent refractive errors, certain precautions can help:
Regular Eye Exams: Essential for early detection and correction.
Proper Lighting: Use adequate lighting when reading or doing close work.
Eye Protection: Wear safety glasses during activities that could cause eye injury.
Manage Screen Time: Take breaks from screens to reduce eye strain.
Healthy Diet: A balanced diet supports overall eye health.
How long does an outbreak last?
Refractive error is not an outbreak or infection; therefore, this is not applicable. Refractive errors are ongoing conditions that need correction.
How is it diagnosed?
Diagnosis is made during a comprehensive eye exam, which typically includes:
Visual Acuity Test: Measures how well you see at different distances (using a Snellen chart).
Refraction: Determines the lens power needed to correct your vision. This can be done manually or with an automated instrument (autorefractor).
Keratometry/Corneal Topography: Measures the curvature of the cornea, especially important for astigmatism and contact lens fitting.
Slit-Lamp Examination: Examines the structures of the eye under magnification.
Retinal Examination: Checks the health of the retina.
Timeline of Symptoms
The timeline of symptoms depends on the type and severity of the refractive error:
Childhood Myopia: May develop gradually during school years.
Adult-Onset Myopia: Can occur at any age, often linked to increased near work.
Hyperopia: Symptoms may be present from childhood or may not become noticeable until later in life.
Astigmatism: Often present from birth and remains relatively stable.
Presbyopia: Typically begins around age 40, with a gradual decline in near vision.
Important Considerations
Early Detection in Children: Important to prevent amblyopia ("lazy eye").
Progressive Myopia: Monitor and manage to reduce the risk of complications.
Dry Eye: Corrective lenses and refractive surgery can sometimes exacerbate dry eye.
Choosing Correction Method: Discuss the pros and cons of different options (glasses, contacts, surgery) with your eye doctor.
Eye Health: Regular eye exams are essential, even with corrected vision, to monitor overall eye health.