Myopia, or ‘short-sightedness’ is an eye condition that occurs when light focuses in front of, not on, the retina, resulting in blurred vision. Traditionally myopia became apparent in adolescent years, however the condition is becoming increasingly prevalent in children of a younger age, with more children affected by myopia than ever before. With myopia reaching epidemic levels worldwide, statistics from some countries show as many as 80 percent of children and adolescents have developed myopia. Research suggests the onset of myopia in increasingly younger children can been attributed to the widespread use of digital devices such as smart phones and tablets – and a reduction in time spent outdoors.
Myopia does require a lens prescription to achieve clear vision. However, withtraditional glasses and contact lenses, light is focused exactly on the retina(the tissue at the back of the eye that detects light) centrally, to enable clear vision. And yet peripherally, light is focused behind the retina, thought to encourage the eye to grow longer, therefore increasing the level of myopia. This means a prescription will increase over time, requiring stronger and stronger spectacles or contact lenses.
Myopia is more than just a lens prescription; it carries very real risks of developing potentially blinding ocular health complications including cataracts, glaucoma, retinal detachment and myopic retinal degeneration. The higher the level of myopia, the higher the chance of developing these conditions.
The field of myopia control is an area of clinical practice and pertains to the use of optical and medical methods to slow down the progression of myopia, keeping it at the lowest possible level. The fact that in most cases myopia progression cannot be stopped outright, only slowed, highlights the significance of utilising myopia control options as early as possible to ensure the level of myopia is kept as low as possible.
The clinical team at Mortimer Hirst has vast experience in the field of myopia control and utilise the latest innovative methods and evidence-based clinical research to produce a tailored myopia control management plan. The team continue to expand and adapt their knowledge in this area, with active involvement in research on myopia control methods such as OrthoK at the University of Auckland.
Any child or teenager experiencing blurry vision or noted to be holding objects very close or sitting close to the television should have a comprehensive eye examination to determine if they have myopia, so myopia control can be initiated. If a child has two myopic parents, they are three times more likely to develop myopia. Those of Asian descent also appear to be more susceptible.
Optical Methods of Myopia Control.
Orthokeratology or “OrthoK” involves the design and fitting of custom-manufactured rigid contact lenses that are worn while sleeping and removed upon waking. Throughout the night these specialised contact lenses gently reshape the cornea (the clear front tissue of the eye) in a controlled fashion. Once the OrthoK contact lens is removed; the result is improved vision without any optical correction required during the day.
In OrthoK, the central tissue of the cornea is pushed outward, flattening the central surface to focus light on the central retina and provide clear vision. The tissue that is pushed outward accumulates around the peripheral cornea, making it steeper, creating a “myopic ring”, so light rays are focused in front of the retina peripherally (the opposite of traditional spectacles and contact lenses). This “peripheral defocus” is thought to signal to the eye that it does not need to grow any longer, thereby slowing down the progression of myopia. OrthoK is an excellent option due to its efficacy in myopia control and enabling the wearer to be free from optical correction during the day.
Read more about OrthoK on our dedicated page here (www.orthok.co.nz). If you or your child would like to consider OrthoK, click here to make an appointment with one of our OrthoK experts at Mortimer Hirst.
Dual Focus/Multifocal Soft Contact Lenses
Certain individuals are not good candidates for OrthoK – this is for several reasons, including myopia that is too severe, and an incompatible corneal shape. However, these individuals may still benefit from using specialised soft contact lenses designed specifically for myopia control. These myopia control soft contact lenses are “dual focus” or “multifocal” soft daily wear contact lenses which like traditional soft contact lenses, provide clear vision centrally, but are modified to create “peripheral defocus” to create a myopia control effect, similar to OrthoK.
Medical Methods of Myopia Control.
Low Dose Atropine Eye Drops
Some patients may not be suitable for, or ready to wear any type of contact lenses, or may prefer to wear glasses. Low-dose atropine eye drops can be prescribed by the therapeutically qualified optometrists at Mortimer Hirst and when used once a day, have been shown to be effective at slowing the progression of myopia. The mechanism by which atropine slows down myopia progression is not completely understood, but it is thought it may act on receptors in the retina; signalling the eye to stop growing. Low-dose atropine eye drops are very safe.
Research has not definitively determined if low-dose atropine has a synergistic effect with OrthoK or dual focus soft contact lenses, but they work on different mechanisms (medical and optical) so theoretically should provide an additive effect producing a potent myopia control option. Many clients at Mortimer Hirst have successfully used these treatment combinations formyopia control.