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What are refractive errors?
In normal vision, light rays from an object focus on the retina (emmetropia). Alternatively, in the presence of a refractive error, the light rays get focused in front or behind the retina causing blurred vision. Under normal conditions, as the eye ball grows in size from infancy to adulthood, there will be a corresponding change in curvature of cornea and the lens enabling the eye to remain emmetropic, at all ages.
When one of these fails to happen, refractive error occurs:
- The eye ball being larger or smaller than the normal size
- The corneal curvature being flatter or steeper than usual
- Increase or decrease in the power of the lens
These refractive errors can be classified as myopia (near sightedness) and hyperopia (far sightedness)
What is hyperopia?
In hyperopia or far sightedness, the light rays from an object form an image behind the retina.
Children with hyperopia
- Find difficulty in reading, writing and looking at both near and distant objects.
- Eye strain while trying to read for long hours
- May have squint (crossed eyes)
What is myopia?
In myopia or near sightedness, the light rays from an object form an image in front of the retina.
Children with myopia
- Have defective vision for distance and clear vision for near
- Squeeze their eyes while trying to see distant objects
- Hold books close to their face while reading
Children with the above conditions may also have
- Pain, watering or burning sensation in the eyes, rub their eyes constantly or blink frequently, because of the eye strain which they experience all the time
- Headache in the forehead region intensified in the evening
- Recurrent swellings in the eye lids.
Treatment for the above conditions
- Corrective spectacle is the best option available. Though children may initially refuse to accept glasses, they will become fond of them once they realise they can see better with them on.
- The power of the glasses may change depending on the growth of the eye ball. An eye check-up and change of glasses if necessary, has to be done once in 6 months for children under 5 years of age and once a year thereafter. Making a child wear glasses regularly is the duty and responsibility of the parents.
- Failure to wear glasses in childhood when needed will retard the development of vision in that eye.
- Children older than 15 years can use contact lenses if they don’t want spectacles. Those over 18 to 20 years of age with stable power also have the option of LASIK, a laser refractive surgery apart from contact lenses.
Failure to correct the refractive errors and the eventual low vision may hamper the academic activities of the child. So an ophthalmic consultation is essential in children, especially with symptoms of refractive errors.
Finally, there is no relationship between nutritional deficiency and the occurrence of refractive error. So loading these children with Vitamin A will not help them. Sometime this may lead on to other complications.
LASIK - Refractive Surgery
LASIK ( Laser Insitu Keratomileusis ) is the high-tech out patient surgical technique for the treatment of myopia, astigmatism and hypermetropia.
Utilising the accuracy and precision of the computer controlled excimer laser, LASIK changes the shape of the cornea and corrects refractive errors.
The Chiron Technolas 217C from Bausch and Lomb surgicals (Germany) uses plano scan with advanced software technology to perform LASIK. The procedure is relatively simple, painless and comfortable.
What do LASIK aims at?
LASIK aims at restoring good working vision without glasses.
Who is an Ideal Candidate for LASIK?
- Age over 19 Years.
- Spectacles Power ( refractive error) stable for the past 1 Year
- Have healthy Cornea
- Have healthy Retina
Pre - operative assessment
A detailed ophthalmic examination is carried out for about 4-5 hours on any working days to ascertain that the individual is fit for LASIK.
Pre - operative Instruction
Patients using contact lens have to stop wearing it for 2-3 weeks before the surgery.
The Day of Treatment
LASIK is done on every Wednesday and Friday in Madurai, Coimbatore, Tirunelveli and Puducherry.
Surgery Cost
Lasik: Rs. 20,500/-
Zyoptix: Rs. 35,000/-
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