Contact lenses for childhood myopia
: MiSight vs Orthokeratology
Similarities between MiSight and Orthokeratology
While Orthokeratology (also called Ortho K) and MiSight lenses are fundamentally very different, they can both achieve similar outcomes.
Studies show that both Ortho K and MiSight can slow the rate of myopia progression in children by an average of around 50%, compared to wearing single-vision lenses. As with any health treatment, there is individual variability in treatment outcomes — some patients may achieve better than expected results, and others less.
Ortho K and MiSight lenses reduce myopia progression by focusing peripheral light in front of the retina, rather than behind the retina as occurs with regular glasses that only produce a single plane of focus. This is believed to reduce the stimuli for the eye to grow longer. Reducing abnormal eye growth and elongation is the goal of myopia control treatment.
Recent 4 year study data of MiSight (myopia control) vs Proclear (single-vision) contact lenses demonstrating effectiveness of MiSight in slowing myopia prescription increase as well as eye elongation increase [Link to paper]
Why choose Ortho K?
Orthokeratology (Ortho K) has been prescribed by specialty contact lens practitioners around the world for over 25 years. As an optical treatment for myopia control, it is considered the ‘gold standard’.
Ortho K lens wear and treatment takes place at home, at night-time, under parental supervision. The lenses are removed in the morning and the child goes about their day and all their activities without anything on their eyes until the lenses are reinserted at bedtime.
Each Ortho K lens is tailored to each eye’s individual shape, curvature and treatment effect required.
With the latest fully-customised Ortho K fitting systems, it is possible to design lenses to optimise the myopia control effect for each child.
Ortho K can correct a wide range of prescriptions, generally between -1.00 and -6.00 of myopia, and up to -2.00 of astigmatism. In many cases, in the hands of experienced Ortho K practitioners, higher corrections are achievable through the use of special lens designs.
For moderate to high levels of myopia (-3.00 and over)Ortho K is more able to create a large myopia control effect in the peripheral retina.
The temporary corneal moulding effect that occurs with Ortho K can last more than a day. In the event that the lenses are not worn for one night most children can still have adequate vision the next day, and some myopia control effect remains, whereas soft lenses work only when the lens is worn.
Many children find Ortho K lenses easier to insert and remove than soft lenses. This is because Ortho K lenses are smaller and rigid, which means they cannot fold over. Lens removal is easy with the help of a lens suction plunger.
Ortho K lens suction plunger is helpful for easy removal of lenses.
Disadvantages of Ortho K
With overnight wear of contact lenses, such as Ortho K, there is a theoretically higher risk of adverse events such as corneal infection. However with good hygiene, lens care and regular reviews, the actual risk is still very low (estimated to be around 13 out of 10,000 wearers, per year).
Ortho K lenses are small and can be lost or broken if mishandled, requiring a replacement lens to be ordered in such mishaps.
For the first few days of Ortho K wear there may some eye sensitivity adapting to wearing rigid lenses. This usually improves after the first week and the lenses generally don’t cause any discomfort during sleep.
Initially, Ortho K treatment can take several days to 2 weeks to achieve stable, clear vision. Lower prescriptions are usually faster, and higher prescriptions take longer. Some patience is needed while the reshaping process is taking place.
The initial cost for parents is higher for Ortho K treatment as the process requires a number of professional consultations at the beginning to monitor and review treatment effect and eye health. However, beyond the first year the ongoing cost of Ortho K with yearly lens replacment is comparable or less than with soft lenses.
Orthokeratology is less widely available as not all optometrists have the necessary equipment, training and experience to fit Ortho K lenses.
Why choose MiSight?
MiSight are daily disposable lenses, which is the safest type of contact lens with the lowest incidence of adverse events and lowest infection risk (statistically around 2 in 10,000 wearers, per year).
For low levels of myopia (-1.00 or less), MiSight is arguably a better choice than Ortho K for vision correction and myopia control.
No cleaning or disinfection products are required as used lenses are discarded and replaced daily. While maintaining good hygiene practices is still important, it is less critical than with Ortho K.
Soft contact lenses are more comfortable to wear than rigid lenses. Children with sensitive eyes may prefer to start with soft lenses over Ortho K.
Clear vision is immediate after insertion, right from the first day.
Lost lenses are easily replaced by opening a new lens from the supply.
Soft lenses such as MiSight are relatively easy for optometrists to fit, requiring fewer consultations to get started and less frequent reviews. The professional consultation fees will be less than with Ortho K.
Disadvantages of MiSight
The range of prescriptions correctable with MiSight is more limited, up to a maximium of -6.00 of myopia. No correction for astigmatism is available, which can compromise clear vision for children with moderate astigmatism in their prescription.
As MiSight lenses are made with one standard size and shape, it’s a one-size-fits-all approach. If the lens does not fit correctly it can cause the vision zones to be misaligned on the eye; if this happens the quality of vision and treatment effect may be sub-optimal.
It’s harder to predict and control what happens during the course of the day while the child is wearing daytime contact lenses. They may go swimming, take a shower, or get dirt in their eyes during play, which can increase the risks of lens wear.
Younger children with smaller eye apertures and tight eyelids can sometimes have more difficulties inserting and removing soft lenses, particular in the beginning during the learning process. However, with time and practice, most children can master the technique quite well.
Size difference. Left: MiSight soft contact lens; Right: Ortho K contact lens.
Ortho K and multifocal soft contact lenses such as MiSight are both excellent optical treatments for children with myopia. Both are very effective at slowing the worsening of their eyesight, and certainly more beneficial than wearing regular, single-vision glasses.
Contact lenses aren’t just for older children. With a little help from parents, even younger kids are often good candidates for contact lenses.
Which option is best for your child will depend on a number of factors: Prescription (level of myopia and astigmatism), eye shape, pupil size, eye sensitivity, the child and the parents’ motivation, assessing risk, personal hygiene, compliance, lifestyle and sporting activities, ease of use, and cost.
Careful evaluation of these factors, in discussion with your child’s myopia control optometrist, is an important part of the decision-making process.