Importance of Eye Screening In Children

Good eye sight is one of the fundamental elements in the development of a child. 80% of a child’s learning ability depends on the visual efficiency. From the day a baby was born, development of motor skill, language, cognitive, social and emotional skills requires, visual ability. At the school age, reading, spelling, writing and computer work needs visual ability to focus and understanding the meaning from the learning materials. If the visual skills are developed poorly from the beginning, the child may lose the interest in learning. It is only through early eye screening that an eye problem can be detected and in most, early treatment will result in good outcome.

When to Bring Your Child for an Eye Examination?

Once your baby is born, the Obstetrician or Paediatrician in charge will screen for any serious eye diseases, but some of the eye condition will develop as the child grows. The ideal time recommended by American Optometry Association (AOA) to check your children eyes is given as below:-

1st eye exam 6 months old
2nd eye exam 3-4 years old
3rd eye exam 6-7 years old (before entering primary school)
Subsequent eye exam Every 2 years

What Are The Eye Problems That We Are Looking For During Eye Examination?

Refractive Error

Refractive errors found in children are:-

Myopia (short-sightedness) – close objects look clear but distant objects appear blurred.
Hyperopia (long-sightedness) – close objects appear blurred, so it would be difficult to do close-up tasks. If the power of hyperopia is high, distant objects would appear blurred as well.
Astigmatism – both far and near objects appear distorted and blurred.
A child can have myopia or hyperopia with or without astigmatism or simply just astigmatism alone without myopia and hyperopia. Myopia and hyperopia can never exist together. When the degree of the refractive error is significant enough, a child needs a pair of glasses for them to see clearly. The importance of knowing and treating refractive error early is if lazy eye is detected, treatment can be started immediately and vision can be improved to normal. Lazy eye is frequently caused by large differences of refractive error between the two eyes, termed as anisometropia. In this case the brain will favour the eye with lower power and ignore the eye with higher power leading to lazy eye. Ideally, the correction of the refractive error and initiation of lazy eye treatment before nine years old will result in a favourable outcome. Lazy eye can also affect both eyes simultaneously if both eyes have high degree of refractive error.

Squint

Squint refers to misalignment of the eye, which could be inward, outward, upward or downward. Squint usually develops before a child is five years old, but can appear later. Babies below three months old can have occasional squint during their visual development. Squint can be due to congenital (born with it) or due to poor vision from whatever cause. Untreated squint can result in lazy eye. Often, their stereovision, the ability to perceive depth is also affected. A child may adopt an abnormal head position like face turn or tilt to compensate the misalignment. It is important to treat the underlying cause before deciding for corrective surgery.

Ptosis

Ptosis is drooping of upper eyelid. Depending on severity, the lids may drop slightly or may cover the pupil. Lazy eye may result due to mechanical blockage of vision by severe ptosis or due to induced astigmatism. In children the cause is usually congenital (born with it) due to poorly developed upper lid muscle. A child may adopt himself by tilting the head backward into chin up position. The presentation is usually apparent to the parents.

Lazy eye

Lazy eye is a condition when vision does not develop properly in one eye. The scientific term for lazy eye is called as amblyopia. During the development of the vision the brain receive images from both eyes. If one eye is seeing poorly due to any cause the brain will suppress its image. As a child brain matures, the brain will completely ignore the image from the poorly seeing eye leading to permanent vision impairment, hence called as lazy eye. The key time to treat lazy eye is before nine years old, the respond to treatment is poor after this age. The cause of lazy eye can be due to high refractive error, squint, congenital cataract, ptosis, corneal opacity or any insult to the eye that causes poor vision. Therefore, it is important to treat the root cause of the lazy eye first then only proceed to lazy eye treatment.

Figure 1: Mechanism of lazy eye

Other Eye Diseases

Other common eye diseases that can occur at any age are sty, eye allergies, conjunctivitis (infection of the eye) and preseptal or orbital cellulitis (infection and swelling of eyelids). Other serious and rare eye diseases that can occur in children are congenital cataract, congenital glaucoma, retinoblastoma (tumour of the retina) and uveitis (inflammation of the eye). All these condition will usually have obvious sign like red eyes, tearing, swelling and cloudy eyes which will make the parents to bring their child early.

What Are The Signs And Symptoms That A Parent Should Aware Of?

  • Blurring or double vision
  • Child squeezing and straining eyes
  • Hold a reading material very close
  • Turning or tilting head
  • Short attention span
  • Worsening academic performance
  • Headache
  • Eyes turning inward or outward
  • Rubbing eyes
  • White pupil
  • Cloudy cornea

What Are The Things To Expect When Scheduling Eye Examination for Your Child?

Make sure the appointment made is during the time your child is happy and alert. Avoid his/ her nap time. If happen on the day of appointment your child is sick, change to other time. During the appointment, these examinations will be done routinely:-

  • History taking
  • Checking vision  
  • Checking power
  • Checking eye alignment

Examination of eye for any disease

Often, the additional examination involving instilling of eyedrop to dilate and relax the eye muscle will be needed to get the accurate power of younger children. Children eyes may require 30-60 minutes to dilate and relax (cyclopegic eyedrops), so it is good if you have prepare to wait this long. You may bring along some snacks, milk and his/her favourite toys for distraction. After the pupils are dilated, the vision will be blurred till next day.

The purpose of eye screening in children is to detect the eye condition which does not have apparent signs and warning to the parents. As for children, they usually will not complain of vision problems simply because they do not know what normal vision looks like. It is only through a serial eye examination that the above mentioned condition can be detected.