High myopia in childhood - special considerations and safe management

When treating a young child with a high myopia (more than 5-6D), it is important to consider underlying syndromic associations that cause rampant eye growth. Careful consideration should be given to potential complications, both the ocular and systemic. The rate of these in highly myopic children are significant, with 38% having complications such as retinal dystrophy, coloboma or lens subluxation.¹ A study on children under 10 with over 6D of myopia reported a mere 8% of the children included in this study had 'simple myopia' with no other associated ocular or systemic conditions. Over half (54%) had an underlying systemic general health condition.² The majority (89%) also had high myopia bilaterally.

Asian males are overwhelmingly represented in high myopia, and developmental delay and extreme prematurity were associated with 10% of the myopia. Retinal detachment was the most significant sight-compromising complication.²

Retinal detachments in children make up 3-13% of all retinal detachments³ but present their own series of unique challenges as patients often are poor historians, les compliant with office examinations and difficult to manage postoperatively by the simple nature that they are children. The nature of the detachments themselves often also cause complications to be higher and prognosis to be lower as they often have a chronic condition association and macular involvement, with studies suggesting up to 97% of paediatric RRD are macula off.⁴ The challenges to diagnosing them also lead to late referral further complicating successful repair.¹ There is also significant risk of a following detachment in the other eye, with 90% of nontraumatic paediatric RRD having bilateral involvement or other ocular abnormalities limiting vision.¹

Retinopathy of prematurity can also cause a number of associated ocular complications, including -6.00D of myopia on average.⁷ Along with retinal breaks and pigmentary vascular and pigmentary changes tractional changes and retinal detachment are common, in up to at least 26%.¹ The eyes most at risk are those with avascular changes and peripheral lattice. Unfortunately even with repair, rate of failure is high and visual outcomes poor.⁸

Children with a history of intraocular surgery are also more likely to experience retinal detachment, including post congenital cataract surgery.¹ What separates these detachments is they tend to occur in their twenties. The risk is poorly studied but potentially up to 51%, with bilaterality a risk. Glaucoma is also a secondary complication of these eyes, often requiring further surgical intervention to control the glaucoma.

Stickler syndrome refers to a group of syndromes that also include a flatter facial appearance, joint problems and hearing loss.³ Predominant features of Stickler syndrome, a connective tissue disorder, include nose, jaw and mouth malformations and cleft palate.¹ The same type II collagen tissue disorder causes anomalies in the vitreous gel, causing retinal detachment as the unusual vitreous fibrils can pull on the retina. These children are at particular risk of severe, macula off bilateral retinal detachment, that often occurs in the first decade of life.^1,3 There is often also early onset cataract with a wedge shaped lens, a lattice degeneration and optically empty vitreous cavity.

Marfan syndrome is also associated with high levels of myopia, with up to 20% of those with the condition having 7D of myopia or higher.⁵ Ectopia lentis (lens dislocation / subluxation) is more common, in up to 80%, and is often an initial presenting feature. Those with high myopia and ectopia lentis are also far more likely to have a retinal detachment, especially early in life (in their 20s). The surgical repairs can be particularly complicated due to poor pupil dilation and lens abnormalities, and the risk of bilateral disease is high.

Homocystinuria often has delayed diagnosis (mean age of 11.4 years) with high myopia and lens subluxation the first presenting symptoms.⁶ It is a genetic deficiency of an enzyme, which when not present leads to accumulation in tissue of the chemical homocysteine. When not managed, it causes thromboembolism, coronary artery disease and cerebrovascular disease. Treatment is possible with vitamins or dietary restrictions, but diagnosis is often delayed due to the rarity of the condition and the difficulty in getting samples. Unfortunately, even with treatment the ocular complications persist, with full lens subluxation, retinal detachment and poor vision features.⁶

The authors of the paper “Associations of high myopia in childhood” discuss the lack of a systemic approach to identifying syndromic associations in children with high myopia. They suggested referral to general paediatrics and/or paediatric ophthalmology to be appropriate for all children under 10, with 6D of myopia or higher due to the high proportion of associated conditions. Another potential rule of thumb is to be suspicious when the degree of myopia is more than a child’s age. This, along with careful inspection of all ocular elements is crucial to identifying complications. Retinal examination through dilated pupils, thorough history taking and communication with a child’s health professional team are all crucial to identifying children at risk. Challengingly, often there is no reliable clue, symptom or family history to identify the sinister causes, so consider 'simple myopia' a diagnosis of exclusion in children under 10 with high myopia.²

This is the most important first measure. Consider referral and/or co-management, depending on the scope of practice and appropriate clinical pathways in your country, for the following children:

• Where referral and/or co-management is prudent or required for strabismus, amblyopia or other eye health issues
• Children whose dioptres of myopia exceeds their age in years. These children could be at higher risk of systemic syndromes associated with myopia
• Children under age 10 with high myopia (more than 5-6D) who haven't yet seen an ophthalmologist. Remember that 'simple myopia' in this age group is uncommon, with the majority having some underlying systemic condition. Read more about these latter two types of children in this Clinical Case entitled How to manage the highly myopic toddler.

It's crucial to ensuring normal visual development in very young children, and the best optical correction for higher refractions in older children.

Spectacles are likely to be our first line solution for vision correction in younger children. Consider firstly giving them clear vision and perhaps monitoring myopia progression for 6-12 months while educating parents on myopia control interventions, including the lack of evidence on interventions for high myopia - see more detail on this below.

In her open access paper To prescribe or not to prescribe? Guidelines for spectacle prescribing in infants and children, Susan Leat wrote that when considering prescribing glasses for a child up to six years of age with high refractions, the key consideration for prescribing is if the correction will improve visual function. Key indications for correction are provided from Leat's paper in our related blog How to manage the very young myope.

Contact lens options are very important for high myopes, to ensure their best visual correction in the long term. Myopia controlling contact lenses - whether soft multifocal or OrthoK - provide an important opportunity to both provide the best refractive correction for such a high refraction, as well as offer the potential to slow myopia progression. Remember that children aged 8-12 appear to be safer soft contact lens wearers than teens and adults, and that contact lenses can have huge psychological benefits for kids too - read more on these topics in our blogs Contact lens safety in kids and Contact lenses for kids – paediatric, parent and practitioner psychology.

Most myopia control intervention studies enrol children from 1 to 5D of myopia. This means that for any child with high myopia, we have to extrapolate the evidence base.  This does not mean myopia management shouldn't be attempted - rather, it is important to be upfront with the patient’s parents about the lack of evidence for what results could be expected in their child's particular situation.

In high myopia, especially with axial lengths over 26mm, ongoing retinal health reviews will be required. It's also very important to educate parents that their child will have a lifelong journey of myopia management, both in terms of refractive changes and the higher risk of ocular disease across their child's lifetime. Myopia correction and myopia control should be discussed, along with education on the visual environment. While the results can't be predicted, implementing a myopia control strategy as soon as suitable for the child provides the best chance to manage this lifelong risk.

• Clinical case study: Thinking beyond myopia – managing the very high childhood myope

• Clinical case study: How to manage the highly myopic toddler

• How to manage the very young myope