Conjunctivitis, also known as pink eye is inflammation of the conjunctiva (the outermost layer of the eye and the inner surface of the eyelids). It is commonly due to an infection (usually viral, but sometimes bacterial or parasitic), or an allergic reaction.
A chalazion, also known as a meibomian gland lipogranuloma, is a cyst in the eyelid that is caused by inflammation of a blocked meibomian gland, usually on the upper eyelid. Chalazia differ from styes (hordeola) in that they are subacute and usually painless nodules. They may become acutely inflamed, but unlike a stye, chalazia usually sit inside the lid rather than on the lid margin.
Dry eye is a condition in which there are insufficient tears to lubricate and nourish the eye. Tears are necessary for maintaining the health of the front surface of the eye and for providing clear vision. People with dry eyes either do not produce enough tears or have a poor quality of tears.
Glaucoma is a group of eye diseases which result in damage to the optic nerve and vision loss. A major risk factor is increased pressure in the eye.
A cataract is a clouding of the lens in the eye leading to a decrease in vision. It can affect one or both eyes. Often it develops slowly. Symptoms may include faded colors, blurry vision, halos around light, trouble with bright lights, and trouble seeing at night.
Retinal detachment (also known as amotio retinae) is a disorder of the eye in which the retina peels away from its underlying layer of support tissue. Initial detachment may be localized or broad, but without rapid treatment the entire retina may detach, leading to vision loss and blindness. It is almost always classified as a medical emergency. Permanent damage may occur if the detachment is not repaired within 24–72 hours
Diabetic retinopathy is the result of damage to the tiny blood vessels that nourish the retina. They leak blood and other fluids that cause swelling of retinal tissue and clouding of vision. The condition usually affects both eyes.
Pterygium (Surfer's Eye) most often refers to a benign growth of the conjunctiva. A pterygium commonly grows from the nasal side of the conjunctiva. It is usually present in the palpebral fissure. It is associated with and thought to be caused by ultraviolet-light exposure (e.g., sunlight), low humidity, and dust.
Ptosis is a drooping or falling of the upper eyelid. The drooping may be worse after being awake longer, when the individual's muscles are tired.