1. Eye is like a camera in which sharply focused image is formed by the lens of the eye on the retina. In normal eye, no extra effort is needed to form a sharp image.
2. If image formed is not clear and is correctable with spectacles, this condition is called the refractive error.
3. Inability to see clearly at distance is called myopia or short sightedness in which minus power spectacles are required.
4. Image in myopia is not formed on the retina but in front of it i.e. eyeball size is relatively bigger.
5. Myopia usually starts in young child or teenager (early onset myopia) and it continues to increase with body growth till 18- 20 years of age, while late onset myopia starts after `teen' age and continues to increase till 21-25 years of age.
6. Myopia may be simple ( glasses power of less than -4 to -6D) or pathological (glasses power of >-6).
7. In pathological myopia, certain degenerative changes develop in the retina that may result in tear or hole formation causing retinal detachment. Hence detailed retina examination by retina specialist is must in all myopes at least once in a year.
8. Other than spectacles, CONTACT LENSES are especially useful in myopia which are not only cosmetically useful but also have advantages of not minifying the image and not reducing the field of vision.
9. Radial keratotomy (R.K.) is a surgical technique to flatten the cornea to remove myopia by multiple radial incisions. It is done by diamond knife. This procedure is now almost totally given up.
10. These days for removal of minus power, `LASIK' (Laser surgery) is now usually done which has very much predictable & stable results unlike R.K. It is done only after the myopia is stable (power is not increasing with age) i.e., after 17-18 years of age.
11. There is usually no role of diet, drugs, exercises or any `surma' to control myopia, although good reading habits may have a role.
12. Family history of myopia is common especially among parents, brother or sister or cousins.