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This Newsletter aims to promote communication between students and the Student Health Service of the Department of Health

May 2016 Issue No.70

Published by the Student Health Service, Department of Health

Editorial

“Good eyesight is valuable. Eye care! I care!”

The eye is an important sensory organ in our body. If we have any eye problems, our daily activities may be affected. Among different kinds of visual conditions, myopia is a common refractive problem in Hong Kong. In this issue, we have invited our optometrist to provide information on the prevention and control of myopia.

The prevention and control of myopia

Optometrist, Student Health Service, Department of health

Introduction

Myopia is a common visual problem (refractive error) in Hong Kong. Severe myopia may cause eye problems such as retinal degeneration, retinal detachment or glaucoma, so it is important to prevent and control the increase of myopia.

The causes of myopia

Causes

The causes of myopia can be congenital and acquired factors. Congenital factors include genetic heritage and race (the prevalence of myopia is higher in Chinese), while acquired factors include improper reading habit, poor lighting, insufficient nutrition and poor general health etc.

Symptoms

People with myopia cannot see distant views/objects clearly which worsens with myopia increasing. They can see more clearly when they move closer to the views/objects. The higher the myopia, the severity of blurred vision increases.

Formation

With myopia, the light rays from the distant object entering the eye are focused in front of the retina instead of on it, resulting in blurred images. This is usually because the eyeball is too long or sometimes the cornea and the lens do not bend the light rays properly.

Methods to correct myopia

Glasses

  • Suitable for those with myopia, hyperopia and astigmatism.

  • Suitable for young children or those cannot wear contact lens.

Contact lens

  • Suitable for those with myopia, hyperopia and astigmatism.

  • Suitable for those with great difference of refractive error between two eyes, or those who do not want to wear heavy glasses or regular sports players.

  • Advise to have comprehensive assessment before wearing contact lens and should be regularly followed up by eye care professionals. Contact lens is suitable for older children who have self-care ability for contact lens. Therefore, it is not suitable for young children.

Lasik (refractive surgery)

  • Suitable for adult with no other eye diseases.

  • A prior assessment should be done by an ophthalmologist before the operation.

Orthokeratology / Ortho-K (overnight)

  • This is a recent hot topic. The rationale is to change the shape of cornea by using oxygen permeable rigid contact lens. For individual suitability and potential risks, please consult relevant eye care professionals.

Important notes

  • Please consult relevant eye care professionals such as optometrists or ophthalmologists on your choice of correcting myopia.

Tips for the prevention and control of myopia

(1) Good reading habit

  • Keep a distance of at least 30cm between the eyes and the books.

  • Do not read while lying in bed as you may move the book closer and closer to the eyes without noticing it.

  • Do not read without adequate lighting.

  • Rest for 20-30 seconds after every 20-30 minutes of screen use.

  • Change position, blink eyes and do muscle relaxation exercise.

  • Keep reading distance no less than 50cm for a computer, 40 cm for a tablet personal computer or 30 cm for a smartphone.

  • 6-12 years old: limit recreational screen time to no more than two hours a day. 12-18 years old: avoid prolonged screen time.

(2) Keep your eyes and body healthy

  • Engage more outdoor activities as they can relieve eye strain.

  • Have a balanced diet: eat more cereal/grains, vegetables and fruits as well as moderate amount meat, fish, egg and alternatives, but eat less fat/oil.

  • Eat food rich in vitamin A (e.g. tomatoes and carrots) since it is good for your eyesight.

  • Have adequate sleep to rest your eyes.

(3) Optimal lighting

  • Use ceiling lights when reading. Lighting should be even and bright without excessive glare.

  • For right-handed children, light from a desk lamp should be shone from the left upper corner when they are writing, and from the right upper corner for left-handers. Do not shine light directly into the eyes.

  • Watch television with room light on.

(4) Choose appropriate printed material

  • Poor quality printed materials will cause eye strain. Words should be clearly printed: both the font size and the spacing should be appropriate.

  • Glossy paper will produce glare and cause eye strain after prolonged reading.

  • Dark-colored paper reduces clarity and makes reading difficult.

(5) Have regular eye check-up and wear glasses when necessary

  • Have vision test once a year. Wear glasses if myopia affect your academic performance or daily activities.

  • Wearing glasses make your vision clearer but it cannot help to cure or prevent myopia from worsening. On the contrary, not wearing properly prescribed glasses will further affect your ability to see and your academic performance will suffer.

Conclusion

We cannot change the congenital factors but we can prevent myopia or its worsening as far as environmental factors are concerned. Parents and children can protect the “window of the soul” together. Parents are advised to take their children to have the first vision test at the age of 3-4 years old. Primary to secondary students should regularly check eyes once a year.

Bridge Blog

The advantages of regular vision check-up:

Early detection of any vision problems.
I could know whether my shortsightedness is worsen or not.
I could have suitable glasses if they are no longer correct.
To know more about my eye condition.
It helps us to adopt healthy lifestyle once we know that our eyesight are getting worse.
It can increase our awareness in eye care and health.

This publication is produced by Student Health Service of the Department of Health.

Tel: 2349 4212 / 3163 4600     Fax: 2348 3968

If you have any comments, you may email to our Edition Board at shsbridge@dh.gov.hk

 
(Revised in May 2016)
 
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Last Revision Date : 1 May 2016
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