It is refractive defect of the eye in which collimated light produces image focus in front of the retina when accommodation is relaxed.

Those with myopia see near objects clearly but far away objects appear blur.

Classification:

Myopia has been classified in various manners.

By Cause:

•Axial myopia: an increase in the eye's axial length.

•Refractive myopia: condition of the refractive elements of the eye.

Curvature myopia: excessive, or increased, curvature of one or more of the refractive surfaces of the eye, especially the cornea.

Index myopia: variation in the index of refraction of one or more of the ocular media.

By Clinical Entity:

•Simple myopia: optically too powerful for its axial length.

•Degenerative myopia/ malignant/ pathological/progressive myopia: characterized by marked fundus changes, such as posterior staphyloma, and associated with a high refractive error.

•Nocturnal myopia /night myopia or twilight myopia: is a condition in which the eye has a greater difficulty seeing in low illumination areas.

•Pseudo myopia: blurring of distance vision brought about by spasm of the ciliary muscle.

•Induced myopia/acquired myopia: results from exposure to various pharmaceuticals, increases in glucose levels, nuclear sclerosis, or other anomalous conditions.

•Index myopia: variation in the index of refraction of one or more of the ocular media.

•Form deprivation myopia: eyesight is deprived by limited illumination and vision range, or the eye is modified with artificial lenses or deprived of clear form vision.

•Nearwork Induced Transient Myopia (NITM): defined as short-term myopia rsspect.org Far point shift immediately following a prolonged near visual task.

By Degree:

•Low myopia: −3.00 diopters or less (i.e ambafrance-kwt.org closer to 0.00).

•Medium myopia: Between −3.00 and −6.00 diopters.

•High myopia: −6.00 diopters or more.

By Age of onset:

•Congenital myopia/infantile myopia, is present at birth and persists through infancy.

•Youth onset myopia occurs prior to age 20.

•School myopia appears during childhood. Due to the use of the eyes for close work.

•Adult onset myopia

•Early adult onset myopia occurs between ages 20 and 40.

•Late adult onset myopia occurs after age.

Signs and Symptoms:

•Blurry distance vision

•Vision seems clearer when squinting

•Eyestrain

•Headaches

Contact a Medical Professional:

Call if your child shows these signs

•Having difficulty reading the blackboard in school or signs on a wall.

•Holding books very close when reading.

•Sitting close to the television.

•Flashing lights

•Floating spots

•Sudden loss of any part of the field of vision.

Detection and Diagnosis:

•Measurement of the pressure of fluid in the eyes.

•Refraction test, to determine the correct prescription for glasses.

•Retinal examination

•Slit-lamp exam of the structures at the front of the eyes

•Test of color vision, to look for possible color blindness

•Tests of the muscles that move the eyes

•Visual acuity, both at a distance (Snellen), and close up

Treatment:

The treatment for nearsightedness depends on several factors such as the patient’s age, activities, and occupation. Vision can corrected with glasses, contacts, or surgery. Refractive procedures such as LASIK can be considered for adults when the prescription has remained stable for at least one year.

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