Nearsightedness, or myopia is a condition in which near objects are seen clearly, but distant objects are not clear. This occurs due to light rays focus in front of the retina due to either longer eye ball or increased corneal curvature.
Nearsightedness is a common vision condition affecting nearly 20% of the Indian population. Commonly it starts in school-age children. Because the eye continues to grow during childhood, nearsightedness may increase up to the age of 18 to 21, which generally stabilizes by then. Recent studies showed that the nearsightedness could be hereditary as well as could be caused by too much stress on the eyes in terms of very close vision work in growing children. However, larger studies are still going-on to prove these theories.
A sign of nearsightedness is difficulty in seeing distant objects like TV screen and the child may want to watch it from very near or difficulty in seeing blackboard in the school, for which the child may want to copy from the student sitting next instead of looking at the blackboard. These children may have poor class work or class notes in spite of being regular and good at home work. A comprehensive eye examination is required in such cases to rule out nearsightedness.
The ophthalmologist can prescribe eyeglasses or contact lenses to optically correct nearsightedness, which you may only need to wear for certain activities, like watching TV or a movie or driving a car, or they may need to be worn continuously. The laser refractive surgery like LASIK could be a good option in these cases and would give the most reliable results in this condition.
Farsightedness, or hyperopia is a condition in which distant objects are usually seen clearly, but close ones are not clear. Farsightedness occurs if your eyeball is shorter than the normal or the cornea is less curved than normal, so light entering your eye is focused behind the retina.
Common signs of farsightedness include difficulty in clearly seeing near objects, headaches, eye strain, and/or fatigue after close work. Although the hyperopia is not as common as myopia the common vision screenings, often done in schools, are generally ineffective in detecting this condition. A comprehensive ophthalmological examination is required in all those with above mention complaints.
In mild cases of hyperopia, patient may not need corrective glasses, as eyes may be able to compensate by working harder. In other cases, your ophthalmologist may prescribe eyeglasses or contact lenses to optically correct this condition. The option of LASIK could be offered to some selected patients for hyperopia.
High myopia usually describes myopia of -6.00 or more. High myopia could be progressive even after 20 years of age and may increase very severely, which is called pathological myopia. People with high myopia are more likely to have retinal detachments, macular problem and primary open angle glaucoma. They are also more likely to experience floaters (shadow-like or insect like shapes which appear in the field of vision). Roughly 30% of myopes have high myopia.
All the cases of high myopia need at least annual retinal examination to avoid any serious complications. LASIK can be offered to selected cases and in very high powers option of phakic intraocular lens (Implantable Contact Lens or ICL) or clear lens extraction could be explored.
Presbyopia is a condition in which the crystalline lens of the eye loses its flexibility thus making it difficult to focus on near objects. Presbyopia usually becomes noticeable in the early to mid-40s. Presbyopia is a natural part of the aging process and is not a disease, hence it cannot be prevented.
The signs of presbyopia include inability to read small prints at normal reading distance, the tendency to hold reading materials away from the eyes, inability to thread the needle, eye fatigue and headache after doing close work. A detailed eye examination and reading glass would be able to take care of the condition. As the effects of presbyopia continue to increase it requires periodic changes in the spectacles.
Astigmatism is a condition where the front surface of your eye, the cornea, is irregular in shape preventing the light to focus at one point on the back of your eye, the retina. As a result, the vision would be blurred at all distances.
Most of astigmatism can be corrected with properly prescribed and fitted eyeglasses and/or contact lenses. However, higher astigmatism may be better handle by surgical means like astigmatic keratotomy or LASIK.