Myopia occurs if the cornea is curved too much or the eye is longer than normal. Generally if the prescription is increasing quickly it is because the length of the eye is increasing. In other words the eye is growing too big, too fast.
This accelerated growth changes the structure of the retina and optic nerves as they are stretched in the process. People who are highly myopic have a higher life long risk of blindness from all causes of ocular pathology.
The global incidence of myopia is increasing in both how many children develop myopia and how high their prescription is.
Low levels of short-sightedness are an inconvenience with people requiring glasses or contacts to see clearly. Higher levels of short sightedness increase a person’s risk of developing potentially blinding conditions. These including retinal detachments and myopic degeneration of the central vision.
Higher prescriptions also require thinner, more expensive lenses in glasses (which adds up over a lifetime). They are less likely to qualify for laser correction. Which makes people incredibly dependent on their glasses or contacts (especially when travelling or outdoors).
This is a complex question! The short answer is a lot of things. Genetics matter – if one or both parents are short-sighted then it is highly likely their children will be too. But the visual environment important too. In particular spending lots of time outside in natural lighting is better than sitting inside all day.
Over the years there has been a lot of research into the prevention and causes of myopia. There are four main tools that we have available to us. These have been shown to be most effective in slowing or stopping the eye growing.
- Orthokeratology (Ortho-K or CRT). contact lenses that is worn overnight to reshape the eye. During the day it allows people to see clearly without glasses. It works by remodeling the cornea to the myopia. Also creating ideal optics that slows the growth and lengthening of the eyeball which causes the myopia.
- Atropine is a drug that has been used as an eyedrop for centuries. Recent studies show that that when used daily at very low concentration it slows the rate of eye growth. We use a 0.01% formulation which has almost no side effects. This can be used in combination with glasses, Ortho-K and Soft Contact Lenses.
- Soft Contact Lenses are worn each day and taken out each night. These lenses have the ability to slow the progression of short-sightedness.This is dine by the virtue of their special optical design which is similar to that provided by Ortho-K. They are available as Daily Disposable or rewearable Monthly replacement options.
- Spectacle lenses can be fitted as normal. These lenses have a very special optical design to change the way the eye focusses at near distances. In contrast to the usual Progressive Lenses, they are designed to be worn by children and young adults rather than the over 40’s.
- Time spent outdoors. There is increasing evidence that spending time outside in natural light helps protect the eye from developing myopia. The exact mechanisms are unknown.
Your optometrist may recommend one or a combination of these treatments if the glasses prescription is changing rapidly, if the child is young and already has a moderate to high power in their glasses or the parents have moderate to high powered glasses.
YES. Does it work for everyone? No. Some children’s glasses strength will change more slowly, some will stop changing and others will keep changing – there are no guarantees. We can’t predict who will benefit the most, but the good news is it will help the majority of children.