Cornea and external disease

Cornea and External Disease involves the diagnosis and treatment of red eye.
The human conjunctiva is shiny, transparent and the cornea is smooth and reflective. The conjunctiva, which covers most of the eye ball, responds to pathological circumstances with hyperemia: the human eye will turn red. The causes of red eye can be quite different. It can be from slight irritation or a severe inflammation which can spread to the deep tissue. The recognition of the cause is very important.
An irritant in the eye is a very common cause of red eye. Many different irritants and conditions can make the eyes red and can cause various symptoms, such as itching, burning, discomfort, foreign body sensation, heavy eyelids or short episodes of blurred vision.
Possible causes include fatigue, eyestrain, or the use of contact lenses. The eyes can become irritated by dust, wind, smoke or fumes, air condition or chlorine from a swimming pool. Staring at a computer monitor can cause eye discomfort as well.
The dry eye is one of the most common eye problems between the ages of 40 and 50. As a result of hormonal changes in menopause, women are far more frequently affected than men.
Eye lubricants can help ease the irritating effects. There are a variety of eye drops. Some are made of water and minerals and are basically just for lubricating dry, irritated eyes. Other drops contain a chemical that constricts the blood vessels in the eye to drive the redness away. Overuse or extended use could lead to rebound redness. Some people can develop allergic reactions to preservatives or chemicals contained in the eye drops with their prolonged use. Lubricants are available in the form of drops or ointments. Ointments stay in the eye longer than drops, but are more likely to cause blurred vision. It’s best to use eye ointments at bedtime, when clear vision isn’t needed.

Conjunctivitis is an inflammatory process involving the surface of the eye and characterized by vascular dilatation. Two forms are distinguished, the acute and the chronic conjunctivitis.
Typical symptoms include reddened eyes, sticky eyelids due to increased secretion, itching and burning. Any conjunctivitis also causes swelling of the eyelid, foreign body sensation or lacrimation. Causes of conjunctivitis may be infectious, such as bacterial, viral, mycotic or chlamydial, and noninfectious from persistent irritation, allergic or toxic.
Acute conjunctivitis should be distinguished from the group of allergic conjunctivitis. The typical symptoms of allergic conjunctivitis are the itching, lacrimation, serous or mucoid discharge. The eye is moderately red, the conjunctiva is edematous. Both sides are affected.

Subconjunctival hemorrhage: extensive bleeding under the conjunctiva frequently occurs with conjunctival injuries, but also often occur spontaneously in elderly patients as a result of compromised vascular structures in arteriosclerosis, or may occur after coughing, sneezing, pressing or lifting heavy objects.
They are usually harmless, and resolves spontaneously within two weeks.
Severe inflammation is the keratitis, which causes red eye. Pathogens causing corneal infections may include bacteria, viruses, acanthamoeba and fungi. Often associates with autoimmune diseases.
Usually very painful and associates with photophobia, lacrimation, and swelling of the eyelids. Vision depending on the location of the disorder.
Iridocyclitis is frequently attributable to immunologic causes, can also be a symptom of systemic disease such as ankylosing spondylitis, Reiter’s syndrome, sarcoidosis, or infections secondary to penetrating trauma or sepsis.
Patients report pain in the eye, impaired vision, photophobia and tearing. Complications include secondary open angle glaucoma anterior synechiae, which is adhesion between the iris and posterior surface of the cornea, or posterior synechiae, which means adhesion between the iris and the lens.
Angle closure glaucoma is characterized by an acute attack of increased intraocular pressure. The elevated intraocular pressure cause dull pain, which referred to the temples, back of head, and jaws via three branches of the trigeminal nerve. Nausea and vomiting occur due to irritation of the vagus nerve and can simulate abdominal disorders. Patients notice obscured vision and colored halos around lights in the affected eye. These symptoms are caused by the corneal edema.
Elevated intraocular pressure causes progressive destruction of optic nerve fibers, fibrous and vascular tissue, and leads to visual field defects.