Pre-School Vision Screening

(Content revised 02/2023)

Your child is four years old now. Please contact your MCHC for Pre-School Vision Screening.

The Family Health Service of the Department of Health provides vision screening for preschool children at 4 to 5 years of age by registered optometrist/orthoptist.

Why should my child receive vision screening?

The visual system continues to develop after birth and matures by about 8 years of age. Abnormal vision or related abnormalities* are harmful to the maturation process. If not corrected, the child's future vision may be reduced.

However, it is difficult to identify affected children just by observation in daily life. The most effective method to detect these abnormalities is by vision screening. With vision screening, children can receive earlier treatment to protect the vision development.

*Common causes of abnormal vision include:

  1. Amblyopia
  2. Squint
  3. Significant refractive errors, such as long-sightedness, short-sightedness and astigmatism

My child wears glasses, does he need a vision screening?

No, he should have regular check for vision and refractive errors by his optometrist or eye doctor.

Why vision screening is done at 4 years old?

  • Children at 4 or 5 years are more co-operative than younger ones. The examination result is more reliable.
  • Early detection and treatment of amblyopia can lead to better result.

What tests are included in vision screening?

Optometrist / orthoptist performs tests at vision screening:

Tests included

  • Visual acuity
  • Binocular function (for detection of squint)

For children with reduced vision:

  • Estimation of refractive errors
  • Examination of the back of eyes

Tests NOT included

  • Colour vision
  • Test for disease of eye such as glaucoma or disease of the retina
  • Detailed assessment of refractive errors

How parents can help in vision screening?

Parents can help in the following ways to make the vision screening process easier for their children:

  • Arrange an appointment at hours when your child is not sleepy
  • Explain to your child what the screening is like by using pictures on this leaflet
  • Have a familiar adult accompanying the child

What does it mean if my child passes the vision screening?

It means the chance of having amblyopia and significant refractive errors are relatively low.  However, some children may develop visual problems at later age. So, your child still needs to be re-examined in primary one by the Student Health Service of the Department of Health.

What does it mean if my child fails the vision screening?

This means your child needs further assessment. The usual arrangement is as below:

  • When mild refractive errors are likely → Advise to have detailed assessment by community optometrists
  • When amblyopia, or severe refractive errors are suspected → Refer to Ophthalmology Clinics (Eye Clinics)

Does a normal vision acuity exclude refractive errors?

No.  Children may still have refractive errors despite they have passed the visual acuity test.  Like any other screening test, vision screening cannot detect ALL visual problems.   If you have any concerns, your child would need a detailed assessment performed by the community optometrists

Bring your child to consult your doctor or optometrist if

  • you suspect him to have a visual problem.
  • your child develops abnormal visual behaviour such as blinking more than usual, tilting his head, squinting, covering up one eye when reading or watching television, or holding objects close to his eyes to see.

How to make an appointment for Pre-School Vision Screening?

If your child has registered with MCHC and reaches 4 years old, you can contact the MCHC, or access the Online Child Health Service Booking System at our website and follow the instructions on the “Online Booking System for Child Health Service-Points to Note” to book, change, cancel or check an appointment.

If your child has not registered with any MCHC, make an appointment for registration first. For details of the registration procedures and locations of MCHCs, you can visit the Family Health Service website, or call the 24-hour information hotline 2112 9900.

Eye Care Tips


  • Have a balanced diet and outdoor physical activities daily
  • Read or work under a sufficiently lighted environment
  • Keep a reading distance of at least 30cm for books
  • Limit the screen time to no more than 1 hours a day for 2-5 year olds. Screen time should be under parents' guidance.
  • Keep a viewing distance no less than 50 cm for computer screens, 40 cm for tablet personal computers and 30 cm for smartphones. Keep a long viewing distance from TV, the longer the better.
  • After every 20-30 minutes of reading and screen use, rest for 20-30 seconds. Look far away to relax the eye muscles.
  • Wear protective goggles when playing sports that involves high speed objects, such as squash.
  • Consult doctor or optometrist in case of eye problem


  • Look directly at glares or read under strong light
  • Stay under strong sunlight for a prolonged period without wearing sunglasses
  • Read on a moving car or in bed
  • Watch TV in a dim environment
  • Rub your eyes with hands.  If dust gets into the eyes, close eyes to allow the tear washing away the dust
  • Place sharp objects and detergents or corrosives within children's reach or without supervision
  • Apply eye drops without consulting medical and health professionals