Myopia Progression in ChildrenA Discussion on Best Possible CareWRITER Dr Dhiren Dhanji From left: Dr Trent Sandercoe, Dr Loren Rose, and Dr Shanel Sharma.The first Myopia Progression in Children (MPIC) conference delivered an insightful and interactive experience exploring the current research into myopia management and its clinical application. Held during September, the conference was presented by Dr Loren Rose, Dr Shanel Sharma and Dr Trent Sandercoe. In this article, Dr Dhiren Dhanji shares some of the highlights from MPIC 2022.

As host of the MPIC conference, Dr Loren Rose commenced the day by stressing the increasing epidemic of myopia around the world. Citing a study by Dr Holden et al 2016, the global prevalence of myopia is predicted to increase from 28.3% to 49.8% in 2050. In Australia this is set to increase from 36% to 55% in 2050. With this increase will be a rise in pathological myopia associated changes, including posterior staphylomas, myopic maculopathy, optic neuropathy, and retinal detachments. Amid the growing epidemic, Dr Rose highlighted to not lose focus on the importance of “treating the individual” by close monitoring of myopia progression and treatment effect, both through refraction and axial length measurement through interferometry.

CAUSAL FACTORS

Dr Shanel Sharma continued the morning, evaluating the current literature regarding causal factors of myopia diffusing myths regarding myopia and evaluating the current evidence for lifestyle-based intervention. Bright light was found to have a protective effect in the development of myopia in both animal models and humans. Dopamine release appears to inhibit increased axial length elongation.

In animal models, increasing lux of light was found to be positively correlated to reduction in progression and myopia. Additionally, family history of myopia has a positive association with 55–84% genetic hereditability in twin studies.

A recommendation of 14 hours of sunlight extra a week was able to reduce risk of myopia. It is unclear whether duration of near work has a role in myopia development.

Dr Sharma also addressed “the silent epidemic” of ultraviolet-related eye diseases with increasing exposure to sunlight. These ultraviolet-related eye diseases include skin cancer, squamous cell carcinoma, cataract, pterygium and macular degeneration. By the age of 11 years, 30% of children have ultraviolet-related eye disease, increasing to 80% by the age of 15 years.

Supported by the World Society of Paediatric Ophthalmology and Strabismus, Dr Sharma stressed the importance of blocking UV radiation in light during our attempts to increase children’s exposure to sunlight, suggesting they “slip, slop, slap, slide”. Ideal sunglasses protect from both ground and overhead reflection. Standard sunglasses were not found to filter enough lux in a Singapore study and therefore wraparound glasses were suggested. Additionally, in those undergoing atropine treatment who are already more susceptible to glare due to increased dilation and aberrations; the role of wraparound glasses was reinforced.

REFRACTIVE INTERVENTIONS

Dr Rose continued by evaluating the developing evidence base for refractive interventions in treating myopia. Initial interest in refractive treatment for myopia came from animal models, where less axial length elongation occurred in animals with different imposed refractive errors. Therefore, accommodation was thought to contribute to myopia prevention with retinal blur acting as the stimulus.

The COMET studies, an American clinical trial, demonstrated that progressive addition lenses did have a statistically significant effect on progression of myopia, but not clinically significant. Additionally, there was no advantage to under correcting prescriptions, with data demonstrating an increase in progression.

Orthokeratology demonstrated a reduction of myopia progression by 30–60% however this effect may be unstable and must be balanced against the sight-threatening detrimental effects of significant microbial keratitis with pseudomonas and acanthamoeba; particularly in children who may have higher risk contact lens wear behaviour.

Recent pivotal animal studies demonstrated that the peripheral retina holds the key to axial length elongation rather than retinal blur, demonstrating that growth likely occurs locally. Dr Rose discussed a wide range of new refractive products based on this theory including MiyoSmart lenses, Essilor Stellest (HALT Technology) and DOT spectacles. Of particular interest, long-term data over a three-to-six-year period examining MiyoSmart glasses demonstrated effect of reduction in progression of axial length is maintained with no rebound effect and benefit in crossover.

PHARMACOLOGICAL INTERVENTION

Dr Rose continued by evaluating the current literature regarding pharmacological intervention with atropine. Atropine is a nonselective muscarinic acetylcholine receptor antagonist that dilates the eye and paralyses accommodation. In ATOM 1, comparing control to atropine 1% and ATOM 2 comparing 0.5%, 0.1% and 0.01%, atropine at all doses was demonstrated to reduce myopia progression. Both treatment effect and side effect profiles are dose responsive. LAMP 1 tested 0.05%, 0.025% and 0.01% atropine, reinforcing the definite dose-response effect. LAMP 2 put the control group on 0.05%, confirming a definite dose-response side effect profile. LAMP 3 confirmed a definitive dose-response rebound effect. Atropine 0.01% is at the forefront of treatment being tolerable, reducing progression by 60% and having the lowest rebound after stopping treatment. It is now available in a TGA-approved commercially available formulation called Eikance 0.01%.

After evaluating evidence behind lifestyle, refractive and pharmacological intervention, Dr Rose acknowledged the complexity for patients and carers, including cost of treatment and potential side effects.

A stepwise approach to assessment of myopia and monitoring treatment response tailored to the individual patient was proposed.

The basis of monitoring myopia progression is axial length monitoring via interferometry rather than dioptric change. Growth generally occurs to the age of 16 with above average growth being greater than 0.1mm every six months. A thorough assessment of medical history, family history, exposure to natural light and near work is necessary. It is important to note that the age of a patient isn't a predictor for cessation of growth, therefore monitoring is necessary. Further, a full examination consisting of visual acuity, cycloplegic refraction, ocular motility, fundus examination and interferometry is necessary.

After baseline measurements and a good cycloplegic refraction; both treatment options and the importance of monitoring to determine speed of progression should be discussed. At first, lifestyle factors should be enforced, including at least two hours per day of sun exposure and reducing near activities for long periods.

The baseline severity of myopia is not a predictor of progression, therefore the patients should have further follow-up prior to starting morbidity inducing treatment. Follow-up should be performed six monthly with repeat refraction and axial length measurement. If the axial length grows greater than 0.1mm over six months despite lifestyle measures, atropine 0.01% can be initiated after counselling regarding potential side effects. Additionally, if not using dual focus glasses such as MiyoSmart glasses, then it can be added to the current treatment regime or utilised before initiating atropine.

At six-month follow-up, if further significant axial length progression occurs despite atropine 0.01%, the dose can be increased to 0.05% and dual focus glasses should be more strongly suggested. Dr Rose suggests that there is minimal utility in using atropine 0.025% as data shows little added effect but still increases side effects. Potential pitfalls, including adverse drug reactions and poor compliance, are important to assess at follow-ups.

PANEL DISCUSSION

The afternoon continued with difficult cases being examined by a panel of doctors including Dr Rose, Dr Sharma and Dr Sandercoe. Dr Sharma started by discussing roles for cessation of atropine, either in the context of no change in myopia progression or due to adverse drug reactions such as glare.

When initiating atropine, setting expectations for use with the patient and family is important to prevent potential compliance issues and avoid consequences of rebound. Pupil size can be assessed as an indirect means of assessing compliance. Dr Sandercoe discussed coincident pathology which may masquerade as standard myopia, including keratoconus and previous retinopathy of prematurity; and further highlighted the importance of not forgetting to treat amblyopia.

Of importance, Dr Rose noted red flags when approaching myopia. Firstly, it is important to assess whether the increase in axial length correlates to the change in dioptre on cycloplegic refraction. A 0.2mm change in axial length should correlate to a 0.5 dioptre change in refraction. If not concordant, or the vision is out of keeping with the degree of refractive error, then the patient should be referred to a paediatric ophthalmologist for work-up for inherited retinal disease or connective tissue disease. Particular care should be taken when prescribing atropine in these patients as it may preclude disorders of the aorta in patients with connective tissue disease. Prescribers should also be aware of other contraindications to low dose atropine including allergy, acute angle closure; and the potential behavioural issues for autism/ADHD patients.

CONCLUSION

The MPIC conference brought together eye care providers from around the world to share insights and best practises with the goal of delivering the best possible eye care for each person with myopia and reducing the increasing future epidemic of myopia worldwide.