
Contact lenses fit over the cornea and correct vision problems such as nearsightedness, farsightedness, or astigmatism. Contact lenses may be hard or soft. Bifocal contact lenses may be worn by those who have presbyopia. Toric contact lenses are for people who have astigmatism. Read more: Contact Lenses: Colored, Soft, Hard, Toric and Bifocal Article
Multimedia: Slideshows, Images & Quizzes
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Picture of Astigmatism
Astigmatism is a common form of visual impairment in which an image is blurred due to an irregularity in the curvature of the...
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Picture of Blepharitis
Blepharitis is an inflammation of the eyelids and occurs in two forms, anterior (outside of the eyelid) and posterior (inner...
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Picture of Corneal Ulcer
Most corneal ulcers are caused by infections and can be bacterial (common in people who wear contact lenses), viral herpes...
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Top 13 Ways to Tame Eye Allergies
Eye allergies, or allergic conjunctivitis, cause itchy eyes and other allergic symptoms. Avoiding allergens and using medicated...

QUESTION
The colored part of the eye that helps regulate the amount of light that enters is called the: See AnswerRelated Disease Conditions
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Sty (Definition, Causes, Pictures, and Treatment)
A sty is a bump that forms on the eyelid as a result of a blocked gland. Styes may be caused by infections, burns, or trauma to the eyelid. Most styes resolve on their own. The application of warm compresses can speed healing. In some cases, steroid injection or incision and drainage may be necessary. Keeping the area clean and consuming a diet high in omega-3-fatty acids may help prevent the formation of styes.
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Subconjunctival Hemorrhage
A subconjunctival hemorrhage is bleeding under the eye's conjunctiva. There is usually no obvious cause for a subconjunctival hemorrhage, but it may be caused by sneezing, vomiting, infections on the outside of the eye, coughing, and clotting disorders. Symptoms and signs include blood in the white of the eye and a sense of fullness under the lid. No treatment is needed.
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Corneal Ulcer
A corneal ulcer is an open sore on the cornea. Infection is a common cause of corneal ulcer. Symptoms and signs of corneal ulcer include redness, eye pain and discharge, blurred vision, photophobia, and a gray or white spot on the cornea. Treatment depends upon the cause of the corneal ulcer.
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Blepharitis
Blepharitis is inflammation of the eyelids. Acne rosacea, staphylococcal bacteria, allergies, sensitivities to makeup or contact lens solutions, head lice, or other conditions may cause blepharitis. Symptoms and signs include itchy eyelids, burning sensation in the eyes, crusting of the eyelids, light sensitivity, red, swollen eyelids, loss of eyelashes, and dandruff of the lashes and eyebrows. Proper eyelid hygiene and a regular cleaning routine controls blepharitis.
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Blindness
Blindness is the state of being sightless. Causes of blindness include macular degeneration, stroke, cataract, glaucoma, infection and trauma. Symptoms and signs may include eye pain, eye discharge, or the cornea or pupil turning white. Treatment of blindness depends upon the cause of the blindness.
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Eye Allergy
Eye allergy (or allergic eye disease) are typically associated with hay fever and atopic dermatitis. Medications and cosmetics may cause eye allergies. Allergic eye conditions include allergic conjunctivitis, conjunctivitis with atopic dermatitis, vernal keratoconjunctivitis, and giant papillary conjunctivitis. Dry eye, tear-duct obstruction, and conjunctivitis due to infection are frequently confused with eye allergies. Eye allergies may be treated with topical antihistamines, decongestants, topical mast-cell stabilizers, topical anti-inflammatory drugs, systemic medications, and allergy shots.
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Marfan Syndrome
Marfan syndrome is hereditary (genetic) condition affecting connective tissue. A person with Marfan syndrome may exhibit the following symptoms and characteristics: Dislocation of one or both lenses of the eye A protruding or indented breastbone Scoliosis Flat feet Aortic dilatation Dural ectasia (a problem with the sac surrounding the spinal cord) Stretch marks Hernia Collapsed lung Though there is no cure for Marfan syndrome, there are treatments that can minimize and sometimes prevent some complications.
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Eye Care and Eye Disorder
Many common eye disorders resolve without treatment and some may be managed with over-the-counter (OTC) products. It's important to visit a physician or ophthalmologist is the problem involves the eyeball itself or the condition hasn't improved after 72 hours of use of an eye-care OTC product.
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Acanthamoeba
Acanthamoeba is an amoeba that lives in dust, soil, and fresh, sea, and brackish water. Acanthamoeba keratitis causes eye pain, a sensation of something in the eye, and blurry vision. Acanthamoeba causes granulomatous encephalitis, leading to seizures, hallucinations, stiff neck, nausea, and vomiting. Diseeminated infection may also result from Acanthamoeba infection.
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Astigmatism
Astigmatism is an eye condition in which the cornea is abnormally curved and causes out-of-focus vision. Symptoms of astigmatism may include eye strain, squinting, eye fatigue, and headaches. Most astigmatism arises within the cornea although some forms occur in the lens. Astigmatism is diagnosed via a complete eye exam. Some cases of astigmatism can be treated with corrective eyewear. Astigmatism can also be treated with LASIK surgery.
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Myopia
Myopia, or nearsightedness, makes it difficult to focus on objects that are far away. The condition runs in families and occurs because light focuses in front of the retina, instead of directly on it. Headaches, eye strain, and fatigue are symptoms of myopia. The condition is diagnosed by having an eye exam and can be treated by wearing glasses or contact lenses or by having refractive surgery.
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Acanthamoeba Keratitis
Acanthamoeba infection of the eye can cause Acanthamoeba keratitis, a serious infection that may result in permanent vision loss or blindness. Signs and symptoms include a sensation of something in the eye, pain, redness, light sensitivity, and tearing. Prescription medications treat this infection.
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Presbyopia
Presbyopia is the age-related loss of the ability to focus on objects that are close up. The condition generally affects people over 45 years of age and causes blurred vision, headaches, and the need to hold reading material at arm's length. Presbyopia cannot be cured. Prescription contact lenses and glasses can help those who have presbyopia to see more clearly.
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Astigmatism and Your Eyes
Astigmatism is a common eye condition that's easily corrected by eyeglasses, contact lenses, or surgery. Symptoms of astigmatism are headaches, fatigue, eyestrain and blurred vision.
Treatment & Diagnosis
Prevention & Wellness
- Could Your Contact Lenses Track, Treat Your Diabetes?
- How Contact Lenses Affect Your Risk of COVID-19
- With Coronavirus a Threat, Stop Wearing Contact Lenses
- 'Smart' Contact Lenses Might Also Monitor Eye Health
- FDA Approves First Contact Lens That Slows Myopia Progression
- Health Tip: Contact Lens Safety
- Spring Break Is No Vacation From Contact Lens Care
- Health Tip: Treating Dry Eye
- Health Tip: Travel Suggestions For Your Eyes
- Wearing Contacts 24/7 Can Bring Infection, Blindness, Doctors Warn
- Decorative Contact Lenses a Danger at Halloween, Any Time
- Health Tip: Wearing Colored Contacts
- Contact Lenses May Harbor Serious, Blinding Infection
- Sleep in Your Contacts, Risk Serious Eye Damage: CDC
- First Auto-Darken Contact Lenses Approved
- Health Tip: Use Contact Lenses Safely
- Dozens of Contact Lenses Found in Woman's Eye
- Improper Use of Contact Lenses Can Trigger Serious Eye Damage, CDC Says
- Contact Lenses May Disrupt Eyes' Natural Bacteria, Study Suggests
- Don't Take Short Cuts With Contact Lens Care, FDA Warns
- Most Contact Lens Wearers Take Chances With Their Eyes: CDC
- Health Tip: Don't Use Costume Contact Lenses
- When Your Child Asks for Contact Lenses
- It's 'Buyer Beware' for Decorative Contact Lenses, FDA Says
- Bacteria May Survive Longer in Contact Lens Solution Than Thought
- Young Girl's Plea For Contact Lenses Pays Off
- Don't Take Shortcuts When Caring for Contact Lenses: Expert
- Most Contact Lens Users Don't Follow Safety Steps
- Health Highlights: Dec. 8, 2011
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