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My Child has just been told he/she is longsighted and needs glasses!
The Optician told me about it - but it was complicated!
What does it all mean and where do we go from here?
Longsightedness - or - HYPERMETROPIA - or - HYPEROPIA are all words describing a condition of the eye where the eye is out of focus and has to accommodate - or focus - in order to see clearly. Just like looking through a telescope - you have to turn the dial and focus the lenses in order to get a clear picture.
I always find it easiest to explain longsightedness - in terms of comparing it to the normal eye.
THE NORMAL EYE:
This eye can see clearly at a distance - it is perfectly in focus - and does not have to focus or do anything to see clearly. Then, when the normal eye has to see up close, the muscles in the eye contract and the eye focuses up close - the closer you look up close - the more you can feel your eyes focus focusing / straining. But, as you look closer note that your eyes are turning in to your nose to see the object coming closer. - So, no focusing for distance and increasing amounts for near viewing. A young healthy eye can focus almost up to their nose ! but this ability to focus decreaces throughout life. In terms of diopters - a young child can focus up to about 15 diopters in total - but will only use about 3 - 4 Diopters to read a book held at about 30cm.
THE LONGSIGHTED EYE:
This eye is physically too small - meaning that the image formed by the lenses of the eye is focused behind the retina - meaning that the image on the retina is out of focus, or blurred. The brain recognises this problem and fixes it by telling the eye muscles to contract and focusing the lens in the eye in order to create a clear image on the retina. In a child with a large range of focus this is quite easily done.
THE PROBLEM WITH LONGSIGHTED EYE'S:
As a child grows their visual needs change. We all know how their school work changes over time - the print get smaller, maths get more complicated, they start doing Irish or other languages. In playtime children use computers, playstations, play sports to fast increasing levels of skill. All of these changes mean that the child is less and less able to predict what they will see or should see next. If their eye is out of focus, even briefly, they will make a spelling error, miscalculate or even misskick!.
BOTH EYES LONGSIGHTED:
If both eyes are reasonably equally longsighted - both will tend to focus equally. BUT, if the child is tried or not concentrating (how often does that happen! ) they may loose focus and no longer see clearly. Depending on the amount of longsightedness, this will vary from Zero to +10.00 Dioptres. Even a child with +3.00 will have to focus their eyes twice as much as a child with normal eyes. This will tire out the eyes quite quickly and cause the child to loose concentration and interest in the text.
SIGNIFICANT R / L DIFFERENCE:
If one eye is signifanctly more longsighted than the other, the childs brain will see clearly with one eye and blurred with the other. It will no longer be able to fuse these two pictures together and create a 3D image. In order to fix this, the brain will decide to simply ignore the eye with the blurred image and so see clearly in one eye only. This will cause the child to develope the so called LAZY EYE. From Birth until age about 8 is an extreemly critical period in the childs visual development. Should a child have an undetected lazy eye after the age of 8 it is effectively impossible to reverse the damage and retrain the brain to use that eye. For this reason it is critical a child is corrected with spectacles and if needed the child may need to put a temporary patch on his/her good eye to force the brain to use the lazy eye. This patching needs to be monitored very carefully and in Ireland requires ophthalmological monitoring. (I will here note that in the UK it is routinely done by optometrists with appropriate training / experience.)
SQUINT / TURN IN ONE EYE:
This vision problem in children is first presented when a parent (usually Mom) notices a turn in the childs eye. Most commonly this happens from birth until age 4-5, but usually earlier rather than later. This turn in the eye is usually due to the child being longsighted and as the child focus's its eye, the eyes over focus and turn in towards the nose - (Just like the normal eye turns in when it is focusing on something up close). The child, with small out of focus eyes, needs to focus more all the time and the stimulus to turn in develops and presto - one eye turns in to the nose and the child is left using the other eye to look at the object of interest. This means that the brain is again only using one eye. The eye turning inwards is ignored by the brain as it is not looking in the correct direction. This eye will therefore be a LAZY EYE. Giving the child spectacles will mean that he/she nolonger needs to over focus, the eyes will both look in the same direction and so the child will see equally with both eyes at the same time.
SPECTACLES FOR LONGSIGHEDNESS:
These spectacles lenses are convex - thick in the middle and thin at the edge - like a magnifying glass. Childrens faces are small so they need to be fitted with small frames. Adut frames need larger lenses. Larger diameter lenses are in their nature thicker in the middle and in turn are also heavier. It is therefore important to supply a child with the best fitting frame and then decide on the best matching lens size, material and design to suite the frame. There are numerous options available - small diameter lenses, aspheric lenses with flatter curves, high index lenses made from denser thinner lighter materials and custom made lenses which can incorporate all of the above into the lens that best suites the frame shape size and usage needs of the child. These choices are best made by your optometrist / dispensing optician.
NOLKE OPTICIANS AND CHILDRENS EYE TESTING:
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SOUTH EAST HEALTHBOARD AND CHILDRENS EYE TESTING
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