Amblyopia (lazy eye): One eye sees better than the other as a result of not using the other eye during childhood. The weaker eye may or may not “wander.” The weaker eye is called the "lazy eye."
Astigmatism: A defect that causes an inability to properly focus light onto the retina. Astigmatism causes blurry vision that can be corrected with glasses, contact lenses, or, in some cases, surgery.
Black eye: Swelling and discoloration (bruise) around the eye as a result of injury to the face.
Blepharitis: Inflammation of the eyelids near the eyelashes. Blepharitis is a common cause of itching or a feeling of grit in the eyes.
Cataract: A clouding of the natural internal lens of the eye, which can cause blurred vision.
Chalazion: An oil-making gland gets blocked and swells into a bump.
Conjunctivitis: Also known as "pinkeye,” conjunctivitis is an infection or inflammation of the conjunctiva, the clear layer that covers the front of the eye. It is usually caused by allergies, a virus, or a bacterial infection.
Corneal abrasion: A scratch on the clear part of the front of the 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, weakened blood vessels may start leaking or overgrow the retina, threatening vision.
Diplopia (double vision): Seeing double can be caused by many serious conditions. Diplopia requires immediate medical attention.
Dry eye: Either the eyes don’t produce enough tears, or the tears are of poor quality. Dry eye can be caused by medical problems such as lupus, scleroderma, and Sjogren's syndrome.
Glaucoma: Progressive loss of vision usually associated with increased pressure inside the eye. Peripheral vision is lost first, often going undetected for years.
Hyperopia (farsightedness): Inability to see near objects clearly. The eye is “too short” for the lens, or certain eye muscles have weakened with age.
Hyphema: Bleeding into the front of the eye, between the cornea and the pupil. Hyphema is usually caused by trauma.
Keratitis: Inflammation or infection of the cornea. Keratitis typically occurs after germs enter a corneal abrasion.
Myopia (nearsightedness): Inability to see clearly at a distance. The eye is “too long” for the lens, so light isn’t focused properly on the retina.
Optic neuritis: The optic nerve becomes inflamed, usually from an overactive immune system. Painful vision loss in one eye typically results.
Pterygium: A thickened conjunctival mass usually on the inner part of the eyeball. It may cover a part of the cornea, causing vision problems.
Retinal detachment: The retina comes loose from the back of the eye. Trauma and diabetes are common causes of this problem, which often requires urgent surgical repair.
Retinitis: Inflammation or infection of the retina. Retinitis may be a long-term genetic condition or result from an infection.
Scotoma: A blind or dark spot in the visual field.
Strabismus: The eyes do not point in the same direction. The brain may then favor one eye, causing decreased vision (amblyopia) in the other eye.
Stye: Bacteria infect the skin on the edge of the eyelid, creating a tender red bump.
Uveitis (iritis): The colored part of the eye becomes inflamed or infected. An overactive immune system, bacteria, or viruses can be responsible.