worseningMyopia

We have completed an audit into the Myopia Control Clinic, which ran as a specialist clinic at The University of Auckland from 2010 to 2014. The results have been presented at the American Academy of Optometry conference in New Orleans, USA, and the full paper has been published in the peer-reviewed journal Optometry and Vision Science

Abstract

Below is our abstract that was accepted for the American Academy of Optometry 2015 conference in New Orleans, USA.  

Background

The prevalence of myopia continues to grow, and there are now a number of optical treatment options available to clinicians. However real world clinical data on their effectiveness is sparse. To promote anti-myopia treatments, a specialist Myopia Control Clinic (MCC) opened as a referral clinic at The University of Auckland, New Zealand in 2010, and this is the first comprehensive audit of the clinical outcomes. 

Case Series 

We present a retrospective case series of 110 patients (aged 4 – 33 years, mean: 12.13 ± 4.58 years, 57% female) who attended the MCC between 2010 and 2014. Of these, 56 underwent orthokeratology (OK), 32 wore dual focus soft contact lenses (DFCL), and 22 received advice only. Baseline myopia, vitreous and axial eye length, previous myopia progression, age, number of myopic parents, and gender were not different between OK and DFCL groups at baseline. However, the advice group were older (p = 0.037) and had less previous myopic progression (p = 0.001). Mean follow-up time was 1.30 ± 0.88 and 1.33 ± 0.80 years in OK and SCL groups respectively (p = 0.989). There was a significant reduction in the annualised myopia progression in both treatment groups (OK: -1.17 ± 0.55 to -0.09 ± 017D/yr, p < 0.001, DFCL: -1.15 ± 0.46 to -0.10 ± 0.23D/yr, p < 0.001). There was no difference between OK and DFCL treatment efficacy (p = 0.763), nor in axial or vitreous chamber length changes following treatment (p = 0.184). Only one adverse event was reported over the 4 year period.

Conclusions 

Contact lenses, whether OK or DFCL, are an effective strategy for targeting myopia progression in children. As there was no difference in the efficacy of the two methods, there are very few barriers in terms of upskilling, chair time, or capital expenditure, for any practitioner to be actively promoting myopia control treatments to at risk groups.

Figures

The "average" Myopia Clinic patient was a 12 year old East-Asian Female, however the clinic population was reasonably balanced. 51% of patients selected orthokeratology for their treatment, followed by 29% in MiSight soft contact lenses, while the rest recieved only advice. 

 

Change in Vitreal and Axial Length (mm)

Time in Clinic (hours)

There was no significant difference in the change in axial length (AXL) nor vitreous chamber depth (VCD) between orthokeratology and MiSight lens wearers. However, patients wearing orthokeratology required twice as much time in clinic to achieve these results. There was also a significant negative correlation between chair time and treatment efficacy for the orthokeratology group, suggesting that difficult to fit patients may not get the best results from orthokeratology. 

 

Myopia Progression (D/yr) Pre- and Post- Myopia Clinic Admission

Patients who opted for treatment, either with orthokeratology or MiSight lenses, had significantly higher myopia progression rates than the Advice group prior to admission into the Myopia Clinic. The mean progression rate was -1.16D per year, which is higher than other studies report, and suggest that our population may have been skewed toward higher progressing myopes. After treatment, both MiSight and orthokeratology groups had significant reductions in their progression (to -0.10D/yr and -0.09D/yr, respectively). There were too few followup appointments in the Advice group for meaningful comparison. There was no difference in the myopia progression between orthokeratology and MiSight groups after treatment, suggesting that MiSight is an equally effective treatment to orthokeratology, but requires half as much time in clinic to achieve this effect. 

 

Closing thoughts

The Myopia Control Clinic was far more successful that what was anticipated going into the endeavour. While our patient base may have been biased towards more severe myopes, this is the very group with the greatest need and the most to gain from anti-myopia interventions. 

Both orthokeratology and dual focus contact lenses were very effective in reducing the rate of myopia progression in a sub-adult population. While each has distinct advantages and disadvantages, the vast majority of practitioners will be comfortable with prescribing soft contact lenses, and our results suggest that this would be all that is required to make a significant reduction in the eventual refractive error of a young and progressing myope. 

We are pleased to have been able to serve myopes in New Zealand, and are excited watching the rapid adoption of anti-myopia therapies in mainstream optometry practice around New Zealand and the world.