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BLINK study results: comparing +1.50 vs +2.50 add multifocal contact lenses for myopia control

Posted on August 12th 2020 by Paul Gifford key paper.png

Authors: Jeffrey Walline(1), Maria Walker(2), Donald Mutti(1), Lisa Jones-Jordan(1), Loraine Sinnott(1), Amber Gaume Giannoni(2), Katherine Bickle(1), Krystal Schulle(2,3), Alex Nixon(1,4), Gilbert Pierce(1), David Berntsen(2), for the Blink Study Group

  1. The Ohio State University College of Optometry; Columbus
  2. University of Houston College of Optometry; Houston, Texas
  3. Private Practice, Houston, Texas
  4. Johnson & Johnson Vision Care, Inc, Jacksonville, Florida

Date: August 2020

Reference: JAMA. 2020;324:571-80


Summary

  • +1.50D centre distance design did not significantly slow myopia progression or axial eye elongation relative to the single vision control
  • The reported 43% slower myopia progression with +2.50D centre distance multifocal meets the following criteria for being considered clinically meaningful:
    • International Myopia Institute (>40% reduction)1
    • Workshop organised by the US Food and Drug Administration (FDA, >30%)2
  • The previously reported 3 year study on MiSight reported 59% less myopia and 52% reduction in axial eye growth relative to single vision controls3
  • Only 35 adverse responses were reported with none indicated as being serious or causing permanent discontinuation of CL wear

Clinical relevance

  • Centre distance CooperVision Biofinity multifocal lenses with a +2.50D slow progression of myopia (43%) and axial eye growth (36%) over three years relative to single vision CLs.
  • While the reported myopia control effect is less than previously reported for CooperVision MiSight, the outcomes of this study suggest that +2.50 centre distance Biofinity multifocal lenses offer a useful myopia control alternative:
    • for regions where MiSight is not available
    • MiSight is available but off label prescribing is a consideration (MiSight is FDA approved for myopia control in the USA, the centre distance Biofinity is not FDA approved in the USA)
  • The low level of adverse events provides evidence towards monthly soft contact lenses being a safe option for children to wear

Limitations and future research

  • Adjusted myopia progression of the SV (control) was slower than reported for other US based studies4-7
  • Only examined +1.50 and +2.50D adds - does not answer whether higher add powers than +2.50 create a better myopia control effect
  • The authors report that the control group in the MiSight study exhibited higher myopia progression (-1.24D) than the control group in the current centre distance multifocal study (-1.01D)
    • however, the same 0.62mm change to axial length was reported for the control group in both studies, which suggests that valid comparisons between the two studies can be made

Full story

Purpose

This paper only covers one aim of the Blink study, which is to compare differences in myopia progression between the lens types. Other aims, to be reported in future papers, are to assess the influence of peripheral defocus on myopia progression and change to eye shape.

Study design

3-year double masked study conducted across multiple sites in the USA. Children aged 7-11yrs with average refraction of -2.30D at baseline, were randomly assigned to wear CooperVision Biofinity soft contact lenses as either:

  • Single vision (n: start=98, end=97)
  • +1.50 centre distance multifocal (n: start=98, end=98)
  • +2.50 centre distance multifocal (n: start=98, end=97)

Follow-up measurements were conducted annually, lenses were found to have been worn on average of 11.0±4.4 hours per day.

Measurement procedure

  • Cycloplegic refraction (1 drop 0.5% proparacaine or tetracaine then 2 drops 1.0% tropicamide separated by 5 minutes)
  • Autorefractor (Average of 10 measures, Grand Seiko WAM-5500)
  • Axial eye length (Lenstar LS900, Haag-Streit) - taken immediately after cycloplegia auto refraction

Outcomes

Refraction change over 3 years

  • SV: -1.01D (51% progressed >-1.00D)
  • +1.50 MF: -0.85D (36.5% progressed >-1.00D)
  • +2.50 MF: -0.56D (16.8% progressed >-1.00D)

Axial length change over 3 years

  • SV: 0.62mm (80.2% with eye growth >0.36mm)
  • +1.50 MF: 0.55mm (61.5% with eye growth >0.36mm)
  • +2.50 MF: 0.39mm (47.4% with eye growth >0.36mm)

Adverse events
35 moderate adverse events with no significant difference between groups (i.e. related to soft CL wear and not lens type) were reported as definitely or probably being related to lens wear: Giant papillary conjunctivitis (9); Infiltrative keratitis (8); Ocular allergy (7); Corneal epithelial defect/erosion (3); Contact lens associated red eye (2); Sterile corneal ulcer (2); Toxicity (2); Superior epithelial arcuate lesion (1); probable microbial keratitis (1). None of the events were reported as being serious or causing permanent discontinuation of CL wear.

Observations
The authors reported that the high add did not clinically alter ability for participants to see. However it's not stated in the methodology what contact lens power was prescribed to the children and if any adjustments from their spectacle best-vision sphere were required to maintain good acuity. The same Study Group published a paper in 2018 which indicated that their +2.50D Add wearing children needed an extra -0.50 to -0.75D of correction, compared to their spectacle best-vision sphere, to achieve good acuity in these lenses.8

Comparisons
The most useful comparison to make is against the MiSight study that was also conducted over 3 years and is highlighted in the following table. When assessing this table it is important to keep in mind that the authors reported slower progression in the single vision control for the current study (-1.01D) than reported for the MiSight study (-1.24D), though change to axial eye length at 0.62mm in the control group was the same across both studies.

Blink-study-MiSight-comparison-table.png

Conclusions

  • The high add +2.50 centre distance CooperVision Biofinity multifocal slowed myopia progression by 43% and axial eye elongation by 36% relative to the single vision control over three years
  • A smaller, though not statistically significant effect was found from the same design with +1.50D add
  • There was a statistically significant greater difference in myopia control effect provided by the +2.50D add multifocal relative to the +1.50D add multifocal

Abstract

Importance Slowing myopia progression could decrease the risk of sight-threatening complications.

Objective To determine whether soft multifocal contact lenses slow myopia progression in children, and whether high add power (+2.50 D) slows myopia progression more than medium (+1.50 D) add power lenses.

Design, Setting, and Participants A double-masked randomized clinical trial that took place at 2 optometry schools located in Columbus, Ohio, and Houston, Texas. A total of 294 consecutive eligible children aged 7 to 11 years with −0.75 D to −5.00 D of spherical component myopia and less than 1.00 D astigmatism were enrolled between September 22, 2014, and June 20, 2016. Follow-up was completed June 24, 2019.

Interventions Participants were randomly assigned to wear high add power (n = 98), medium add power (n = 98), or single-vision (n = 98) contact lenses.

Main Outcomes and Measures  The primary outcome was the 3-year change in cycloplegic spherical equivalent autorefraction, as measured by the mean of 10 autorefraction readings. There were 11 secondary end points, 4 of which were analyzed for this study, including 3-year eye growth.

Results Among 294 randomized participants, 292 (99%) were included in the analyses (mean SD age, 10.3 1.2 years; 177 60.2% were female; mean SD spherical equivalent refractive error, −2.39 1.00 D). Adjusted 3-year myopia progression was −0.60 D for high add power, −0.89 D for medium add power, and −1.05 D for single-vision contact lenses. The difference in progression was 0.46 D (95% CI, 0.29-0.63) for high add power vs single vision, 0.30 D (95% CI, 0.13-0.47) for high add vs medium add power, and 0.16 D (95% CI, −0.01 to 0.33) for medium add power vs single vision. Of the 4 secondary end points, there were no statistically significant differences between the groups for 3 of the end points. Adjusted mean eye growth was 0.42 mm for high add power, 0.58 mm for medium add power, and 0.66 mm for single vision. The difference in eye growth was −0.23 mm (95% CI, −0.30 to −0.17) for high add power vs single vision, −0.16 mm (95% CI, −0.23 to −0.09) for high add vs medium add power, and −0.07 mm (95% CI, −0.14 to −0.01) for medium add power vs single vision.

Conclusions and Relevance  Among children with myopia, treatment with high add power multifocal contact lenses significantly reduced the rate of myopia progression over 3 years compared with medium add power multifocal and single-vision contact lenses. However, further research is needed to understand the clinical importance of the observed differences.

Abstract link is here


Meet the Authors:

About Paul Gifford

Dr Paul Gifford is a research scientist and industry innovator based in Brisbane, Australia, and co-founder of Myopia Profile.


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