Age-related macular degeneration: Causes loss of central vision as you get older.
Amblyopia: Often called lazy eye, this condition starts in childhood. One eye sees better than the other, so your brain favors that eye. The weaker eye, which may or may not wander, is called the "lazy eye."
Astigmatism: A problem with the curve of your cornea. If you have it, your eye can’t focus light onto the retina the way it should. Glasses, contact lenses, or surgery can correct the blurry vision it causes.
Black eye: Swelling and discoloration (bruise) around your eye caused by an injury to the face.
Blepharitis: Inflammation of your eyelids near the eyelashes. It can make your eyes feel itchy or gritty.
Cataract: A clouding of your eye’s internal lens. It can cause blurred vision.
Conjunctivitis: Also known as pinkeye, it’s an infection or inflammation of the conjunctiva, the clear layer that covers the front of your eye. Allergies, viruses, or a bacterial infection can all cause it.
Corneal abrasion: A scratch on the clear part of the front of your eye. Pain, light sensitivity, or a feeling of grit in the eye are the usual symptoms.
Diabetic retinopathy: High blood sugar damages blood vessels in the eye. Eventually, they start to leak or overgrow in your retina, threatening your vision.
Dry eye: Either your eyes don’t produce enough tears, or the tears are of poor quality. Most commonly due to aging but medical problems like lupus, scleroderma, and Sjogren's syndrome can be to blame.
Glaucoma: This progressive loss of vision comes from increased pressure inside the eye. Your peripheral vision (side vision) will go first, then your central vision will follow. It can go undetected for years.
Hyperopia (farsightedness): You can’t see near objects clearly. It can happen when your eye is “too short” for the lens to focus light the way it should. Distance vision may or may not be blurred too.
Hyphema: Bleeding into the front of the eye, between the cornea and the iris. Hyphema is usually caused by trauma.
Keratitis: Inflammation or infection of the cornea. It typically occurs after germs get into a scratch on your cornea.
Myopia (nearsightedness): You can’t see clearly at a distance. Your eye is “too long” for the lens, so light won’t focus properly on your retina.
Optic neuritis: The optic nerve becomes inflamed, usually due to an overactive immune system. The result: Pain and vision loss, typically in one eye.
Pterygium: A thickened mass usually on the inner part of your eyeball. It can cover a part of the cornea and lead to vision problems.
Retinal detachment: The retina comes loose from the back of your eye. Trauma and diabetes are the most common causes of this problem, which often requires urgent surgical repair.
Retinitis: An inflammation or infection of the retina. It may be a long-term genetic condition (retinitis pigmentosa) or come from an infection.
Strabismus: When the eyes don’t point in the same direction. Your brain may favor one eye. If it happens to a kid, it can decrease vision in the other eye. This condition is called amblyopia.
Stye: A red, painful lump on the edge of your eyelid. Bacteria cause it.
Uveitis (iritis): The colored part of your eye gets inflamed or infected. An overactive immune system, bacteria, or viruses can cause it.