Introduction:
- The refractive condition in which parallel light rays from an object at optical infinity are focused by the eye in front of the retina, with accommodation relaxed.
- Myopia is a highly significant problem, not only because of its high prevalence, but also because it can contribute to visual morbidity and increase the risk for vision-threatening conditions:
- Retinal breaks,
- Detachment,
- Glaucoma.
- It can be a limiting factor in occupational choices.
- The posterior segment changes in the myopic eye place it at risk for the development of other ocular conditions.
- It is also called nearsightedness
Etiology of Myopia:
a. Axial Myopia:
- It occurs due to increase antero-posterior (axial) length of eye And others parameters are normal
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| Fig: Axial Myopia |
b. Curvatural Myopia:
- It occurs due to increased curvature of the cornea, lens or both.
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| Fig: Curvature Myopia. |
c. Positional myopia:
- It occurs due to anterior placement of crystalline lens in the eye.
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| Fig: Position Myopia. |
d. Index myopia:
- Due to increase in the refractive index of crystalline lens associated with nuclear sclerosis.
e. Myopia due to excessive accommodation:
- It Occurs in patients with spasm of accommodation.
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| Fig: Accommodative Myopia. |
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