Myopia (nearsight) occurs when light entering the eye is focused in front of the retina rather than directly on it such that distant objects appear blurred. This is caused by the eyeball being too long, or the cornea & lens being too curved (or a combination of both).
Environmental and genetic factors have been associated with myopia. Myopia often begins in childhood and continues to increase until the late teens or early twenties. Besides the inconvenience of being reliant on vision correction, myopia carries a higher risk of eye disease including cataracts, retinal detachment, glaucoma and myopic retinal degeneration. Research has been striving to understand what drives myopia development and determine what we can do to slow its progression. Since myopia progression is usually due to the elongation of the eyeball, it is important to study how we can slow the rate of eye growth.
One theory advocates that when light rays are focused behind the peripheral retina, it stimulates further elongation of the eye. This is the type of image that a nearsighted person can receive when not wearing glasses, but also when corrected with traditional glasses or contact lenses. There is growing evidence to show that if we shift the focusing of the peripheral light rays inwards, it appears to help slow the eye growth and reduce myopia progression.
- Studies have shown that the amount of time spent outdoors is important: myopia is more common in children who spend less time outdoors, and findings seem to indicate that increasing outdoor light exposure to 2 hours per day is likely to help prevent the onset of myopia, and possibly slow the condition.
- While the amount of time spent reading or doing other close work has not been proven to be directly related to the development of myopia, it is generally accepted that it is good practice to take visual breaks (20/20/20 rule), ensure that the working distance for near activities is not too close, and to try and limit near tasks to 2 hours daily.
- Other mechanisms implicated in the progression of myopia include accommodative lag (the image forms behind the retina due to inability to provide enough focus at near) and near esophoria (inward resting position of the eyes at near which leads to too much focusing for a given target and an image that lies in front of the retina).
The research on the management of myopia is continuously developing, and at Smith & Walker we are committed to remaining on-top of this research to help optimize your child’s vision. Our current options for Myopia Control are:
Option # 1 Soft Multifocal Contact lenses
- What is the treatment? Wearing multifocal soft contact lenses that have a centre distance section and a peripheral near section.
- What is the science? Clinical research has demonstrated that soft multifocals slow myopia progression by approximately 30-50%
- How much does it cost? Fitting cost is £39.50. Disposable lens costs range from £23.10 – 39.50/month on Direct Debit.
- How does it work? The light rays from the peripheral optic zone of the lens focus in front of the retina, reducing the stimulus for growth, unlike typical myopia compensating lenses which focus peripheral rays behind the retina.
- What are the adverse effects? There is a low risk of inflammation or infection with soft contact lenses, which is increased by not cleaning lenses properly or not replacing on time.
Option #2: Multifocal Lenses for Myopes with Convergence Excess & Accommodative Lag
- What is the treatment? Spectacle lenses that compensate for myopia on the top portion with a reduced power on the lower portion to decrease over converging of the eyes.
- What is the science? Research has indicated that bifocal correction is effective in children who are esophoric (eyes that turn inwards) and have a large lag of accommodation (the eye doesn’t focus as accurately as it should).
- How much does it cost? There is a wide range of pricing for lined bifocal lenses and progressive lenses depending on the material, coatings, and level of technology. Average pricing would range approximately £50–200.
- How does it work? Overconvergence is a sign that the visual system is incorrectly centred and driving myopia. By having a lower portion of the lens that is less minus, the eyes go to a normal posture. Accommodative lag causes an image to be focused behind the retina which can drive elongation of the eye – the power in the bottom of the lens allows a more accurate focus onto the retina.
- What are the adverse effects? Some patients notice some peripheral blur compared to their standard single vision lenses.