UNDERSTANDING MYOPIA
THE NORMAL EYE
When you are able to focus an object in the distance perfectly onto the retina (back of the eye) you will have perfectly clear vision. This is known in the optometry world as ‘Emmetropic’ and there is no need for distance glasses.
THE MYOPIC EYE
When you are unable to see an object in the distance clearly, but can see things up close easily, then you most probably have myopia. Myopia is also known as ‘Short Sightedness’ or ‘Near Sightedness’. The distance object that you are looking at will be focus in front of the retina, as shown in the diagram.
WHY SHOULD WE BE CONCERNED ABOUT MYOPIA
Evidence is mounting that myopia is growing around the world, with a recent study estimating that on average, 30% of the world is currently myopic and by 2050, almost 50% will be myopic, that’s a staggering 5 billion people.1
Out of the people that are myopic, about 1 in 5 are at risk of developing myopia related ocular disease such as Glaucoma2 , Cataracts3, Retinal detachments4 and Myopic Maculopathy. The risk is significantly increased with moderate (-3.00 to -6.00) and high (> -6.00) myopia.
WHAT ARE THE RISK FACTORS OF DEVELOPING MYOPIA
Genetics and Ethnicity
Having myopic parents will increase your risk of developing myopia. The data indicates that if one parent is myopic you are 3x more likely to developed myopia, which doubles when two parents are myopic. East Asain people are also more likely to become myopic.
Age
Children that develop myopia at a younger age (5-7) will progress at a much higher rate than those you develop later. A child’s eye will normally grow 0.1mm per year to the age of 12, but is significantly more in children with myopia.
Outdoor Time
Spending a lot of time inside can increase the progression of myopia. It is recommended that your go outdoors at least 90 minutes per day. Be active for at least 60 minutes a day and don’t forget to be sun smart.
Time spent looking up close
Doing more than 2 hours of screen time / near work per day (not including school hours) can increase the rate of progression of myopia. Remember to have regular breaks every 20 minutes or so and look up as much as you can. Be sure to be at least 25cm from your reading material at all times.
WHAT OPTIONS DO I HAVE IF I HAVE MYOPIA?
Single Vision Correction
We are able to correct myopia easily with single vision spectacles or contact lenses. This will enable clear vison for distance, however has proved to be an ineffective way to control myopia progression, especially in growing children.
Atropine
Atropine eye drops can be effective in control myopia, and with more research we will be able to find out the true efficacy of this treatment. The drops are used at night before bed and glasses are needed during the day to see distance objects clearly.
Dual Focus Lenses
Specifical designed spectacle lenses such as MiYo Smart (by Hoya) and contact lenses such as MiSight can have an effective myopia control in children. Bifocal and Multifocal lenses can also be benefical in myopia control especially children with binocular vision anomalies.
Orthokeratology
Orthokeratology is a therapy to uses contact lenses to gently change the shape of your eye while you sleep, so there is no need for glasses or contact lenses during the day. Along with Atropine and Dual Focus lenses, Orthokeratology is one of the best forms of myopia control available.
To find out more please call us on 9804 6965 or come in for an appointment to speak to our optometrists.
For more information about myopia and controlling myopia in our children, please use the following links to find out the latest information and research results.
References
1. Holden BA, Fricke TR, Wilson DA, Jong M, Naidoo KS, Sankaridurg P, Wong TY, Naduvilath TJ, Resnikoff S, Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050, Ophthalmology, May 2016 Volume 123, Issue 5, Pages 1036–1042.
2. Qiu M, Wang SY, Singh K, Lin SC. Association between myopia and glaucoma in the United States population. Investigative ophthalmology & visual science 2013;54:830-5.
3. Younan C, Mitchell P, Cumming RG, Rochtchina E, Wang JJ. Myopia and incident cataract and cataract surgery: the blue mountains eye study. Investigative ophthalmology & visual science 2002;43:3625-32.
4. Group TEDC-CS. Risk factors for idiopathic rhegmatogenous retinal detachment. The Eye Disease Case-Control Study Group. American journal of epidemiology 1993;137:749-57.