In a fascinating case, AJ is looking for treatment recommendations for her 7-year-old patient who has very high myopia and astigmatism that has progressed quickly in the last 3 months. Here's the link to the post.
What are the considerations?
1. This is not your normal myope - Consider possible ocular disease or syndromes
The possiblity of retinal or systemic health issues
- It is rare to see a child who is so young with such a high refractive error and axial length, so further investigation is warranted. Depending on your scope of practice in your country, this may include co-management with ophthalmology to rule out any ocular structural or general health syndromic issues before continuing on with your refractive and long term eye health management. Read more on this below.
- High axial length is associated with abnormal fundus changes which includes optic nerve crescent, retinal atrophy, Fuchs’s spot, lacquer cracks, retinal degenerations and posterior staphyloma.1 Therefore, fundus examination is important, especially when it involves a patient with an axial length of 27mm as in this case. An axial length over 26mm has been associated with increased risk of vision impairment across a lifetime.2
The possiblity of corneal ectasia
- Given the high degree of astigmatism, it is important to check for keratoconus, other corneal ectasia or irregularity
- The presence of corneal ectasia or lack thereof will influence your decision on myopia management, as DS discusses below in consideration of OrthoK.
2. To manage myopia or not?
With your very high myope, it is important to remember that myopia isn’t always the only condition that requires your attention. It is important to rule out any eye disease and even systemic syndromic conditions before making a decision on myopia management.
The community was split as to whether myopia management is necessary in this case. On one hand, the patient is young, and any myopia management is potentially better than none. On the other hand, current literature lacks information on myopia management in cases with very high myopia and since the typical myopia control results can't be expected, the benefit of managing myopia may not necessarily outweigh its risks and cost.
If it is decided to commence myopia management, the options include:
- Multifocal soft contact lenses
- Partial orthoK with top-up spectacles
- Low-dose atropine, plus best refractive correction
Achieving good acuity is the utmost priority for this patient. If myopia control is the parent’s option, make sure the patient is seeing well. Contact lens options provide an important opportunity here to achieve the best possible acuity for such a high refraction. Potential risks and outcome of any of these strategies should be properly discussed with the parents. If myopia management is not implemented, both soft CLs and RGPs are options for best correcting the patient’s vision.
What the research says:
- Patients with keratoconus have been shown to have a greater posterior segment length compared to emmetropes. There is significant relationship between keratoconus and axial myopia,3 which suggests there is a good chance this patient does have or will develop keratoconus.
- In a clinical ophthalmology study of 112 children under age 10 with myopia of more than 6D, only 8% had 'simple high myopia' with no other associated ocular or systemic associations. 54% had an underlying systemic condition (eg. developmental delays, Marfan, Stickler, Downs syndrome) and the remaining 38% had further ocular problems associated with high myopia such as lens subluxation, coloboma, retinal dystrophy).4
- There is currently no evidence on the efficacy of myopia management strategies in patients with myopia as high as this.
- There is also no information available on the natural course of myopia progression in patients with high myopia.
Take home messages:
- Monitor eye health - when you are presented with abnormally high myopia and axial length in younger children, remember to consider other possible drivers behind the high myopia - both ocular and systemic - and continuously monitor retinal health over time.
- Consider ophthalmology referral - in children under 10 with high myopia (over 6D), a single referral to paediatric ophthalmology at minimum is important to rule out underlying ocular pathology or systemic conditions; or consider co-management with ophthalmology dependent on your scope of practice. Remember though, that primary eye care / optometry is best placed to manage this patient's vision in the long term - whether you end up just managing the refraction for best acuity, or managing for myopia control as well.
- Remember ectasia - consider corneal ectasia in cases of high and especially progressive astigmatism. If ectasia is suspected but not confirmed, it is prudent to wait and watch before potentially fitting OrthoK to an undiagnosed ectactic cornea.
- Educate for informed consent - managing myopia at high degrees fall outside the range covered by current literature. This does not suggest that one should not attempt to manage myopia in these power ranges. It is important, however, to be upfront with the patient’s parents about the lack of literature in that regard - typical myopia control results can't be expected - and involve them in the discussion regarding management.
- Consider contact lenses - once other conditions are ruled out, and as long as risks and costs are acceptable to the parent, there is unlikely to be any harm in instigating a myopia management strategy in a case like this. Contact lens options 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.
- Flitcroft DI, He M, Jonas JB et al. IMI – Defining and Classifying Myopia: A Proposed Set of Standards for Clinical and Epidemiologic Studies. Invest Ophthalmol Vis Sci 2019;60:M20-30.
- Tideman JW, Snabel MC, Tedja MS et al. Association of Axial Length With Risk of Uncorrectable Visual Impairment for Europeans With Myopia. JAMA Ophthalmol 2016;134:1355-63.
- Scheer SE, Touzeau O, Morel C, Kopito R, Allouch C, Laroche L. Relationship Between Keratoconus and Axial Myopia. Investigative Ophthalmology & Visual Science. 2003;44(13):1310
- Marr JE, Halliwell-Ewen J, Fisher B, Soler L, Ainsworth JR. Associations of high myopia in childhood. Eye. 2001;15(1):70-4