In the last article, we looked at communication and how facial characteristics of younger children differ from adults.
In this article, we will look at the topic of slowing down progressing myopia in children. Considering the amount of coverage of this topic, most optical assistants (OAs) will have heard of myopia management. The aim of this article is to improve confidence when talking about myopia to patients, parents and carers.
By 2050, it is expected that 50% of the world’s population will be myopic and in Western Europe, the rate is predicted to be 56%. This figure highlights that more children are becoming short-sighted; some people may think that is not a problem as we can provide spectacles and contact lenses to correct their vision.
However, every dioptre of myopia can present an increased risk of developing potentially sight-threatening ocular pathology such as glaucoma, retinal detachment and myopic maculopathy in later life. This becomes even more significant for patients with higher prescriptions for example -6.00D and above.
The very first thing is to discuss myopia and myopia management with your practice team, optometrists, contact lens opticians and dispensing opticians as it is essential that a consistent message regarding myopia is communicated to patients, parents and carers.
There may already be a variety of resources that have been developed in practice that can be given to patients, which can help counter any misinformation they may have either read or seen on social media. Take time to view all these resources as this will also help your myopia discussions.
It is crucial to have an understanding of the following:
- What is myopia?
- What causes myopia to progress?
- What measurements are important in myopia management?
- How do I start myopia discussions?
- What are the current methods of myopia correction and myopia management?
What causes myopia?
As can be seen from figure 2, when a myopic eye looks at a distant object light focuses in front of the retina, the higher the myopia the further in front of the retina the image will be. Myopia is not just a visual acuity problem; the refractive error can be corrected by minus (-) spectacle lenses, which cause the light rays to diverge and move the image onto the retina.
Figure 2: A myopic eye
Standard single vision lenses will correct the myopic refractive error and provide a clear sharp image on the central retina or fovea, which is a depression in the centre of the macular region of the retina. The peripheral retina still receives a blurred image, and it is this peripheral blur that can stimulate the eye to grow longer, becoming more myopic.
As mentioned earlier high myopia has been connected to vision conditions, such as premature cataract, glaucoma, retinal detachment and myopic maculopathy, and it is the elongation or ‘stretching’ of the eyeball that can lead to these pathologies.
Elongation of the eyeball leads to an increased axial length and stretching, which can eventually lead to a tear or detachment. Vitreous fluid seeps through the tear and causes the retina to detach from the choroid, the vascular layer of the eyeball between the retina and the sclera. High myopia is the most common cause of retinal detachment.
What causes myopia?
There may not be a single cause leading to myopic progression and it is often referred to as multifactorial. It is believed to be a combination of genetics, optical and environmental factors. There is no known cure for myopia (short-sightedness), but myopia management treatment options can correct the refractive error and help to slow progression.
Genetics – it is always important to ask parents if they are myopic as it may not be obvious, they could be wearing contact lenses or have undergone laser eye surgery. A child’s risk of myopia increases if they have one myopic parent and increases still further if both parents are myopic. The genetic pathways are still not completely understood and there is also a specific gene (APLP2) linked to myopia but also dependent on reading behaviour.
The Northern Ireland Childhood Errors of Refraction (NICER) study found almost one in five UK teenagers are myopic, showing prevalence has doubled since the 1960s. Asian populations have the highest incidence of myopia, with data showing 96% of Korean 19-year-olds are myopic and African Americans are the lowest.
Environmental and lifestyle behaviours
It is believed it is these factors that are currently responsible for the increasing prevalence. Education and reduced outdoor time are key risk factors for myopia. Spending more time outdoors promotes mental wellbeing and a healthy lifestyle and is cost-free.
Limiting time children spend on digital devices and smartphones should be considered as these have been identified as being associated with myopia.
Alarmingly, the American Academy of Paediatrics found that children spend an average of about seven hours per day on entertainment media including television, computers and video games.
Before a diagnosis can be made regarding myopia progression an up-to-date full eye examination, including binocular vision assessment, must be undertaken to ensure this advice is given at the start of any discussion.
Currently, myopia development linked to accommodation and binocular vision is not fully understood but blur from lag of accommodation and short working distances may be associated with myopic progression.
Accommodation in the eye is the process of changing the shape of the crystalline lens to focus on near objects. Insufficient accommodation for near vision is called accommodative lag. Accommodative lag can cause light to focus behind the retina, which may stimulate eyeball growth.
What measurements are important in myopia management?
Refraction is the most widely used method of monitoring myopic progression but in an ideal world we would all have optical biometers and be able to measure axial length of the eye. This is a measurement from the anterior (front) of the cornea and the retinal pigment epithelium of the retina (the first of retinal layers), see figure 3.
Figure 3: Axial length
While this axial length measurement is the ideal way to monitor eye growth it is not a compulsory requirement although it is a more sensitive method of monitoring progression.
How do I start myopia discussions?
The general consensus is to begin myopia discussions at the earliest opportunity, ‘planting the seed’ for future further discussions.
All eye care professionals should be able to hold a conversation around individual risk factors for children relating to myopia as well as the lifestyle changes that may delay or prevent myopia onset.
Beginning a conversation about hobbies, sports, what the child likes to watch on TV, and not forgetting what games they like to play on their digital devices – this will be a good indicator of their lifestyle.
An OA will have the time to undertake detailed lifestyle discussions and gather essential information prior to the eye examination providing the optometrist with useful information when assessing a child’s myopia risk.
Remember myopia management treatments are not guaranteed to work, we need to manage expectations of both the patient, parents or carers. I find myopia management one of the more difficult subjects to explain, especially as current treatment options can be expensive and can make parents feel guilty if they are unable to afford myopia management spectacle lenses or contact lenses.
In these circumstances, clearly setting out lifestyle choices like increasing time outdoors, limiting screen time, ensuring the patient is fully corrected and their spectacles are accurately fitted are of great importance. It must also be clear that we cannot stop myopia we can only slow its progression.
The message we deliver has to be given professionally and sensitively. This means careful consideration of what is said in any myopia discussion and if there is anything that is above your knowledge or competency level, refer to the optometrist or dispensing optician.
For a child wearing a myopia management treatment lens, does it mean the treatment has failed if the child’s myopia increases? The answer to this is: not necessarily.
As mentioned earlier, we cannot stop myopia, we can only slow its progression. The child may be undergoing a growth spurt, and it is normal growth, there may be compliance issues and treatment efficacy is dose-related. The frame may not be fitting correctly, so a thorough investigation should take place whether they are wearing spectacles or contact lenses. There is a lot to consider, so again referral to an optometrist or dispensing optician would be the appropriate course of action. Having this background knowledge will again help you maintain realistic patient expectations and not promise, what we may not be able to achieve with an existing myope.
What are the current methods of myopia correction and myopia management?
Myopia management spectacle lenses
Myopia management spectacle lenses are designed to slow myopic progression. Two examples are Hoya Miyosmart and Essilor Stellest; these lenses work by providing clear foveal vision and a peripheral retinal myopic defocus.
There is considerable manufacturer information available on fitting, prescription ranges and frame requirements, so it is good practice to familiarise yourself with a range of myopia management spectacle lens treatment options.
These manufacturers have also conducted considerable research on and around their products, this is something to talk through with your optometrist or dispensing optician.
Myopia management contact lenses
The treatment method of peripheral myopic retinal defocus remains the same and there are daily disposable contact lenses available, for example, CooperVision MiSight and NaturalVue Multifocal 1 day.
Rigid contact lenses are also an option using orthokeratology (ortho-k), which has been around since the 1960s. The patient sleeps in the lenses and usually takes them out in the morning as the design of the lens alters the shape of the cornea to eliminate the myopia.
These lenses use a reverse geometry design, for example, the EyeDream lens by No7 contact lenses or Bloom Night by Menicon. These contact lenses do require specialist fitting but mean that the patient does not need to wear their contact lenses during the day – which is often a good option for children.
Atropine eye drops
Currently this is not licensed in the UK although there is research being undertaken using atropine combined with ortho-k.
Red light therapy
Using Repeated Low-Level-Red-Light (RLRL) uses a specific wavelength of light to influence eye growth. Therapy involves looking into the device for three minutes of treatment, twice a day, five days per week, with a minimum of four hours between sessions. The device is controlled with a simple touchscreen discussions on red light therapy currently are best referred to the optometrist or dispensing optician.
Lasik (Laser-in situ keratomileusis)
The Lasik procedure is about correcting myopia and involves lifting a corneal flap then by laser ablation creating a flattened corneal profile similar to that created by the ortho-k lens design. It must be remembered that this is refractive surgery and permanently reshapes the cornea and carries risks of complications. It is only an option for adults who have stable vision.
Resources
A useful resource is the Brien Holden Vision Institute (BHVI) website who have an online myopia calculator in which you enter the patient’s age and refractive error, and it will predict the patient’s refractive error by age with and without myopia management. This will help explain what you are trying to achieve with myopia management.
Another excellent resource is the patient facing My Kids Vision, which has lots of information on all aspects of myopia. The practitioner version of this is Myopia Profile, which is a lot more technical and reviews current research on myopia.
Conclusion
As with many other physical conditions, early intervention has been found to be key in slowing myopia progression. Myopia begins in children and progresses through adolescence but at a slower rate.It is important to identify candidates for myopia and put preventative measures and treatments in place early. We have seen that there is not one specific cause for myopia, instead it is multifactorial, genetic and environmental.
There are many myopia management treatment options now available and hopefully this article will help you talk more confidently about the background to myopia management before handing over to your registered colleagues.
Employer perspectives
‘My learner attending this lesson has highlighted a general lack of understanding in the practice on why increasing myopia is a problem, and methods at our disposal that we can utilise to slow it down.’
‘I thought OAs do not need to know about myopia management, as that is something only DOs would dispense in my practice. But my apprentice is having more myopia discussions and supporting our DOs because of her increased understanding.’
Student perspectives
‘This lesson has given me more knowledge and confidence to mention our myopia management lenses to potential patients.’
‘Before taking this lesson I never appreciated how much more there was to know about myopia, I have learned so much and I now feel confident to start myopia conversations and know which questions to ask before handing over to our DO.’
- Tony Douglass currently works part-time at the University of Central Lancashire as a lecturer in ophthalmic dispensing and part-time as a tutor on Training 2000 level 3 optical assistant apprenticeship. Douglass designed, developed and managed the level 3 optical assistant apprenticeship course at Training 2000, he was also involved in the development and delivery of the benchmark Btec level 4 certificate in optical dispensing, which started hundreds of students’ careers in optics with around 70% of students going onto further study as a dispensing optician. He is also an experienced author and presenter of CPD lectures and discussion workshops with audiences of up to 500. He also previously worked as a part-time lecturer in ophthalmic dispensing at Anglia Ruskin University.
