Myopia or Nearsightedness

Myopia, or nearsightedness, is an error of refraction in the eye that causes objects more than a short distance away to appear blurred. It usually result from the cornea of the eye being too far from the retina, so that images are focused in front of the retina.

The error can be corrected for by concave Eye Diseases or by contact lenses, severe cases of myopia are sometimes treated by a controversial surgical distortion of the cornea known as radial keratotomy.

Many thousand people are suffer of this eye error, nearsightedness make people difficult to see something in distance such as highway sign, or object in a distance, but can see for close object and can work easily for close object like sewing.

To correct this error people can use a eye glasses or contact lens, but currently the technology have improved using eye laser surgery. The kind of this surgery as follows:
PRK is laser eye surgery that removes a layer of corneal tissue, which flattens the cornea and allows light rays to focus closer to or even on the retina.

LASIK is the most common refractive procedure a flap is cut through the top of the cornea, a laser removes some corneal tissue, and then the flap is dropped back into place.

Glaucoma

Glaucoma is an eye disease in which the optic nerve is damage as a result of an imbalance between the production and draining of the watery fluid produced by cells behind the lens of the eye. Glaucoma is a major cause of blindness.

The normal eye continually produces a fluid that flows into the anterior chamber of the eyeball and eventually drains through tiny channels between the cornea and iris. A number of different disease processes can cause these channels to become blocked. The fluid pressure then builds within the eyeball and over a period of months or years, can damage the optic nerve. This condition, called chronic open angle glaucoma, is the most common form of the disease, the risk of its onset increases from middle age onward. No paint is involved, and the loss of peripheral vision is so gradual that it may go unnoticed for a long time.

A less common condition, called acute narrow angle glaucoma, results from a sudden and complete blockage of the drainage channels due to abnormal eye structure, injury to the eye, certain drugs, or systemic disorders such as diabetes. The risk of its onset also increases after middle age. The onset, sometimes preceded by preliminary attacks, is marked by pain, eye redness, blurred vision, and haziness of the cornea. Only one eye is usually affected at a time, but the other is likely to be affected later. Predisposition to both forms of glaucoma tends to run in families.

The peripheral vision lost in undetected chronic glaucoma cannot be restored. For this reason, regular examinations by an ophthalmologist are recommended for its early detection, especially after the age of 40. Chronic glaucoma is treated by drugs that increase fluid outflow or decrease fluid production. If drugs do not check the condition, surgery may be recommended to open drainage channels. Such surgery is essential following an attack of acute glaucoma, in order to prevent visual impairment. Drug therapies and modern surgical techniques, including the use of laser beams, have shown a high rate of success in treating the disease.