Refractive Errors

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Refractive Errors

Summary

The cornea and lens of your eye helps you focus. Refractive errors are vision problems that happen when the shape of the eye keeps you from focusing well. The cause could be the length of the eyeball (longer or shorter), changes in the shape of the cornea, or aging of the lens.

Four common refractive errors are

Myopia, or nearsightedness - clear vision close up but blurry in the distance
Hyperopia, or farsightedness - clear vision in the distance but blurry close up
Presbyopia - inability to focus close up as a result of aging
Astigmatism - focus problems caused by the cornea

The most common symptom is blurred vision. Other symptoms may include double vision, haziness, glare or halos around bright lights, squinting, headaches, or eye strain.

Glasses or contact lenses can usually correct refractive errors. Laser eye surgery may also be a possibility.

NIH: National Eye Institute

Start Here

Facts about Astigmatism (National Eye Institute) Also in Spanish
Facts about Hyperopia (National Eye Institute) Also in Spanish
Facts about Myopia (National Eye Institute) Also in Spanish
Facts about Presbyopia (National Eye Institute) Also in Spanish
Facts about Refractive Errors (National Eye Institute) Also in Spanish
Refractive Errors (American Association for Pediatric Ophthalmology and Strabismus)

Diagnosis and Tests

Dilating Eye Drops (American Association for Pediatric Ophthalmology and Strabismus)
Near Vision Test for Adults (Prevent Blindness America)
Retinoscopy (American Association for Pediatric Ophthalmology and Strabismus)
Vision Screening (National Library of Medicine) Also in Spanish

Prevention and Risk Factors

What Is a Comprehensive Dilated Eye Exam? (National Eye Institute) Also in Spanish

Treatments and Therapies

Cornea Transplant (Mayo Foundation for Medical Education and Research)
Eye Wear: MedlinePlus Health Topic (National Library of Medicine) Also in Spanish
Laser Eye Surgery: MedlinePlus Health Topic (National Library of Medicine) Also in Spanish
Phakic Intraocular Lenses (Food and Drug Administration)
What Is Refractive Surgery? (American Academy of Ophthalmology) Also in Spanish

Related Issues

Abnormal Head Position (American Association for Pediatric Ophthalmology and Strabismus)
What Are the Risks and How Can I Find the Right Doctor for Me? (Refractive Surgery) (Food and Drug Administration)

Specifics

Astigmatism (Mayo Foundation for Medical Education and Research)
Facts about the Cornea and Corneal Disease (National Eye Institute)
Farsightedness (Hyperopia) (Mayo Foundation for Medical Education and Research)
Nearsightedness (Myopia) (Mayo Foundation for Medical Education and Research)
Presbyopia (Mayo Foundation for Medical Education and Research)

Genetics

Genetics Home Reference: deafness and myopia syndrome (National Library of Medicine)
Genetics Home Reference: farsightedness (National Library of Medicine)
Genetics Home Reference: nearsightedness (National Library of Medicine)

Images

Corneal transplant - slideshow (Medical Encyclopedia) Also in Spanish
Patient Eye Examinations - Adults (National Eye Institute)
Presbyopia (Logical Images)

Statistics and Research

Blurry Worldview: Understanding Myopia (National Institutes of Health) Also in Spanish
Hyperopia (National Eye Institute)
Myopia (National Eye Institute)
Myopia Increasing in the U.S. Population (National Eye Institute)
Nearsightedness Linked to Years in School (American Academy of Ophthalmology)

Clinical Trials

ClinicalTrials.gov: Astigmatism (National Institutes of Health)
ClinicalTrials.gov: Hyperopia (National Institutes of Health)
ClinicalTrials.gov: Lenses, Intraocular (National Institutes of Health)
ClinicalTrials.gov: Myopia (National Institutes of Health)
ClinicalTrials.gov: Presbyopia (National Institutes of Health)
ClinicalTrials.gov: Refractive Errors (National Institutes of Health)

Journal Articles References and abstracts from MEDLINE/PubMed (National Library of Medicine)

Reference Desk

Diagram of the Eye (National Eye Institute) Also in Spanish
Glossary of Terms (Foundation of the American Academy of Ophthalmology)

Find an Expert

American Optometric Association
Find a Doctor - American Optometric Association (American Optometric Association)
Find a Refractive (Eye) Surgeon (International Society of Refractive Surgery of the American Academy of Ophthalmology)
Finding an Eye Care Professional (National Eye Institute) Also in Spanish
National Eye Institute

Children

Glasses and Contact Lenses (Nemours Foundation) Also in Spanish
Your Child's Vision (Nemours Foundation) Also in Spanish

Patient Handouts

Astigmatism (Medical Encyclopedia) Also in Spanish
Facts about Presbyopia (National Eye Institute) Also in Spanish
Farsightedness (Medical Encyclopedia) Also in Spanish
Nearsightedness (Medical Encyclopedia) Also in Spanish
Presbyopia (Medical Encyclopedia) Also in Spanish
Refraction test (Medical Encyclopedia) Also in Spanish

Basics

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Research

Resources

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