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Myopia

 
General Info

Myopia or short sightedness is a vision problem experienced by almost one-third of the population. It is the inability of a person to see the distant objects clearly.
 
For proper eyesight, the cornea (the clear window in front of the eye) and the lens (behind the pupil) must properly focus or "refract" light onto the retina (at the back of the eye). If the length or shape of the eye is not ideal, the light may get focused too early or too late leaving a blurred image on the retina. This problem is often discovered in school children and becomes progressively worse through adolescence and stabilize in early adulthood.

 

Causes
Improper reading habits is possibly the commonest cause of short sight.
Sometimes it can be due to lack of vitamins.
Myopia can also be a heriditary condition.

 
Symptoms

Children complain of their inability to see the blackboard.

Shortsighted people often have headaches or suffer from eyestrain.

They have blurry distant vision and tend to squint for a better image.

 
Diagnosis

Myopia is diagnosed by a simple vision test.

Treatment

Eyeglasses: Myopia is best treated with eyeglasses or contact lenses which compensate for the elongated shape of the eye allowing the light to focus properly on the retina.

Surgical Operations: Refractive surgery is another option which can reduce or even eliminate your dependence on glasses or contact lenses. The most common procedures are performed using an excimer laser.

USES OF EXIMER LASER: 

A. Laser-assisted in situ keratomileusis (LASIK) this is the most commonly performed 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.
B. In photorefractive keratectomy, or PRK the laser removes a layer of the corneal tissue, which flattens the cornea and allows light rays to focus on the retina.
C. Orthokeratology in this procedure one has to wear special retainer contact lenses that slowly reshape the cornea to correct your myopia over a period of time. Depending on your eyes, these contact lenses may need to be worn only at night. Orthokeratology is controversial in the eye care community. Some doctors find that the effects don't last very long.
D. Implantation This is the latest procedure for correcting early or mild myopia. It is the implantation of plastic corneal rings, which also alter the shape of the cornea. An advantage of the rings is that they may be removed in case of a problem, adjusted or can be left in place permanently.
 
 
FAQ

Are contact lenses good for my eyes? Can they cause damage to the cornea?
Contact lenses have proven to be a healthy vision option for millions of people. But only your eye care professional can determine if they are healthy for you. If you follow all prescribed steps for inserting, removing, and caring for them, contact lenses will continue to be safe and effective. You also need to see your eye care professional regularly to insure long-term corneal health.

At what age can contact lens wear begin?
As soon as the need for vision correction is identified, contact lenses are a viable option. In fact, they have frequently been used in premature infants, who sometimes have vision problems. With proper care and lens maintenance, infants, young children, teens, and adults of all ages can wear contacts effectively.

Is it true that there are some contact lenses that can actually slow or even control myopia?
A Many contact lens specialists agree that the use of Oxygen Permeable, or RGP (Rigid Gas Permeable) contact lenses, that are rigid by construction, may slow or retard the progression of shortsightedness, whereas spectacles or soft contact lenses offer no benefit of this type.
 
What is laser vision correction?
Laser vision correction is a precise method of gently reshaping the cornea. A specially trained ophthalmologist uses a computerized excimer laser to remove a thin layer of tissue from the cornea. This flattens the cornea to the desired correction so the eye can focus properly. This can be an expensive surgery but has good long term results.
 
 

Glossary
Myopia (shortsightedness): The ability see near objects more clearly than those at a distance.
Contact lenses: Lenses which fit directly on the eyeball under the eyelids.
Cornea: The clear tissue in front of the eye resembling a crystal of a watch.
Diplopia: The seeing of one object as two.
Nystagmus: An involuntary, rhythmical movement of the eyeballs.
Opthalmoscope: Device for viewing the interior of the eye or the retina.
Optic nerve: The nerve which carries visual impulses from the retina to the brain.
Optician: A technician who designs, verifies and dispenses lenses, frames and other fabricated optical devices upon the prescription of an ophthalmologist or an optometrist.
Opthalmologist: A physician who is qualified and especially trained to diagnose and treat all eye and visual system problems, as well as diagnose general diseases of the body. 
Photophobia: Abnormal sensitivity to light.
Refractive error: A defect in the eye that prevents light from being brought to a single focus exact on the retina.
Pupil: Apature allowing light to enter into the eye regulated by the iris and ciliary muscles.
Retina: Light sensitive membrane at the back of the eye. Light is focused onto this membrane and the retina then transmits this information to the brain as impulses which the brain interprets as sight.
Sclera: The firm white fibrous membrane that forms the white part of the eye.
Visual Acuity: Clarity of vision, with corrective glasses.
 
HIGHLIGHTS
Myopia or short sightedness is a vision problem experienced by almost one-third of the population. It is the inability of a person to see the distant objects clearly.
Improper reading habits is possibly the commonest cause of short sight.
 

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