Managing a teenager with very high myopia

How do you manage a very high myope? SD presented a case of extremely high myopia in a 13-year-old child, within the Myopia Profile Facebook group. Would myopia control necessary in this case? What else should be considered? Let's explore the case details and the advice from colleagues.

This is not an ordinary case of myopia. With such severe myopia, the patient may have associated systemic health concerns.1 Hence, it is important for her to evaluated by a paediatric ophthalmologist if this hasn't occurred already. The cause of the reduced acuity could be due to myopia-associated fundus changes - pathologic myopia - or it could be due to other reasons. Understanding this is important to setting expectations for optical outcomes of management (eg. fitting with contact lenses) and also for any ongoing co-management between optometry and ophthalmology.

While the axial length is not given, 26mm equates to around 5D of myopia so the axial length can be expected to exceed this value where the risk of ocular disease and vision impairment in the patient's lifetime is at least 25%. If axial length is over 30mm, this risk increases to 90%.2 Hence, this patient needs close ocular health monitoring now as well as across their lifetime - annual review with retinal health check through dilated pupils is recommended by the International Myopia Institute.3

It is also important for the patient to be counselled on the symptoms of retinal tears and detachment so they can recognise this ocular emergency and know how to respond, should it occur.

What is pathologic myopia?

The second volume from the International Myopia Institute, published in April 2021, include one report entitled IMI - Pathologic Myopia. It states that:

"Pathologic myopia is distinctly different from high myopia. High myopia is a high degree of myopic refractive error, whereas pathologic myopia is defined by a presence of typical complications in the fundus (posterior staphyloma or myopic maculopathy equal to or more serious than diffuse choroidal atrophy). Pathologic myopia often occurs in eyes with high myopia, however its complications especially posterior staphyloma can also occur in eyes without high myopia."

The benefits of prescribing contact lenses for a very high myope include:

• The magnification of the retinal image that comes with contact lens wear can improve acuity by 1-2 lines in very high myopia³
• Contact lenses are cosmetically more acceptable than very thick glasses³
• High myopes experience contrast sensitivity loss with spectacle correction whereas no contrast sensitivity loss occurs with contact lens⁴

The next discussion point… Rigid gas permeable (RGP) or soft contact lenses (SCLs)? Studies showed a patient preference for SCLs over RGPs after 6 weeks of experience with both - comfort and handling of SCLs being the winning factors.^6,7

Patients with moderate to high astigmatism, however, can prefer RGPs over SCLs, due to superior vision outcomes.8,9 When optical quality of RGPs, SCLs and spectacles were compared, RGPs achieved the best outcomes through reduction of the eye's aberrations.¹⁰ Therefore, to achieve the best acuity for this patient - and hopefully improve their reported spectacle acuity which currently meets the definition of vision impairment - RGPs are likely to be the superior option. The example of KW's personal experience as a very high myope and eye care practitioner reinforces this.

As this child falls outside the range of all myopia control studies, the prognosis of myopia control is very uncertain, so prioritizing good visual acuity is the primary clinical focus. Myopia control options can be communicated, though, as long as expectations of the parent and patient are appropriately managed. The best possible options could be adding low-concentration atropine to contact lens wear, and/or a multifocal RGP design although none of these have been studied in clinical trials. It would be important to not compromise acuity for the patient, especially considering the starting acuity which meets criteria for vision impairment. There would be a careful balance of risks and impacts to the potential benefits which would need to be made, to ensure the patient and their parents are fully informed.

A handful of commenting colleagues suggested surgery to help the patient. Scleral crosslinking aims to increase the stiffness of the sclera to prevent axial elongation. Animal trials have been promising,¹¹ but the IMI Pathologic Myopia report explains that scleral re-enforcement treatments in humans have yielded mixed results. Finally, one commenter suggested implantable contact lenses, however these should be considered only when a child is older and refractive error has stabilized.¹²

1. Rule out possible systemic associations causing the high myopia in this patient. Monitor the patient's ocular health annually.
2. Achieving good visual acuity is the first priority. Rigid contact lenses provide the best visual acuity in high myopes due to the reduction in aberrations.
3. Myopia control is not the first priority in this case - the outcomes are difficult to predict and there is no evidence base upon which to base a treatment selection. Adding atropine could be a consideration if parents and patient are well-informed on expectations and keen to proceed.

• How should we manage high myopia? 

• High myopia in childhood - special considerations and safe management

• Clinical case: Retinal detachment in children

• Science review: Scleral cross-linking using Rose Bengal green light