Your Child’s Vision: Refractive Errors (The Need To Wear Glasses)
Here we have come to the last part of the series Your Child’s Vision. In this post, we’ll explain about Refractive Errors (the need to wear glasses).
In normal vision, light enters the eye and the image is focused clearly at a single point on the retina (the light sensitive area similar to the film of a camera) at the back of the eye. Refractive errors result from abnormality of either the length of the eyeball or curvature of the front of the eye called the cornea.
When a refractive error exists, the image is not in focus and 3 situations can arise.
1. Myopia (short-sightedness)
Image source: Coolwinks
The image is focused in front of the retina because either the eyeball is too long or the cornea too curved. The child can see near objects but distant objects appear blurred. This is the commonest refractive error is Asians and usually manifests between the ages of 6 to 16 years of age. There is a correlation between short-sightedness and high intelligence, excessive reading, excessive playing of computer or handheld games and not spending enough time outdoors to see distant objects.
2. Hyperopia (long-sightedness)
Image source: Coolwinks
The image is focused behind the retina because the eyeball is too short. Both far and near objects appear blurred although the distant vision is slightly less blurred.
Image source: Coavision
The image is focused at 2 points on the retina and objects at all distances appear blurred and distorted. Astigmatism is due to unevenness of the cornea.
A child who develops a refractive error will require spectacle correction to be able to see clearly. This is very important for the child visual development (especially if the child is below the age of 9 years) because not wearing spectacles can lead to amblyopia.
When and how often should a child have the eyes checked?
It is recommended that children should have their first eye examination at the age of 3 years and again just before the start of school (around 6-7 years old) by either the eye doctor, orthoptist or optomterist.
The eye test should include:
- Measurement of any refractive errors (shortsighted, longsighted or astigmatism)
- Eye movement assessment and detection of any squint
- 3D vision (depth perception) assessment
Risk-free children can have the eyes checked every 2 years while children who wear spectacles should have their eyes checked every year by the optometrist as the prescription may change within this period.
|Age||No Symptoms & risk-free||At risk children|
|Birth to age 6 years||
One check by the age of 6 years. An eye check at age 3 years is optional
One eye check by the age of 1 year & as recommended thereafter
|Ages 6 to 18 years||Every 2 years||Every year|
|Children who wear glasses||Every year||Every year|
Ms. Melanie Yeoh
Orthoptist (Lazy eye /Squint)
Dr. Tsiang Ung