MiSight 3-Year Data Analysis

Title: A 3-year Randomized Clinical Trial of MiSight Lenses for Myopia Control

Authors: Chamberlain, Paul (1), Peixoto-de-Matos, Sofia (2), Logan, Nicola (3), Ngo, Cheryl (4), Jones, Deborah (5), Young, Grame (6)

1. CooperVision Inc, Pleasanton, California
2. Clinical and Experimental Optometry Research Lab, Centre of Physics, School of Sciences, University of Minho, Braga, Portugal
3. Ophthalmic Research Group, School of Optometry, Aston University, Aston Triangle, Birmingham, UK
4. Department of Ophthalmology, National University Hospital, Singapore
5. Centre of Ocular Research and Education, School of Optometry and Vision Science, University of Waterloo, Waterloo, Ontario, Canada
6. Visioncare Research Ltd., Farnham, Surrey, UK

Date: August 2019

Reference: Optom Vis Sci. 2019;96;556-567 (Link to open access paper)

As the popularity and prescribing rates of the MiSight 1 Day contact lens continues to increase both in Australia and worldwide, it is imperative that robust studies continue to evaluate its long-term efficacy in reducing myopia progression. MiSight features a dual focus optical zone¹ designed with a sufficiently large central correction zone to provide good visual acuity, whilst simultaneously inducing peripheral myopic defocus. This 2019 study aimed to augment the existing body of research evaluating MiSight efficacy, by conducting a 3-year randomised clinical trial. The study was conducted across four different sites, in Singapore, Canada, Portugal and the UK. Subjects were randomised into either the treatment (MiSight), or control (single vision contact lens) group. In brief, the study yielded promising findings, with efficacy results comparable to previous studies, and overall high satisfaction reported by subjects. Eye Care Practitioners can utilise these results to confidently educate patients and their families on the efficacy of this treatment option.

MiSight 1-Day is effective in slowing the progression of juvenile onset myopia. 

• Change in spherical equivalent refraction at 3 years 
  • Control (SV): -1.240.61D
  • Test (MiSight): -0.51 0.64D
  • Statistically significant reduction (p<0.001) of -0.73D (59%)
• Change in axial length at 3 years
  • Control (SV): 0.620.30mm
  • Test (MiSight): 0.300.27mm
  • Statistically significant reduction (p<0.001) of 0.32mm (52%)
• These results can be utilised by Eye Care Practitioners to discuss the efficacy of MiSight contact lenses with patients

Visual acuity and "satisfaction" did not differ between groups

• Visual acuity
  • Follow up mean VA between groups did not differ by >2 letters at any visit 
  • With spherical over-refraction, BCVA with contact lenses remained similar for the two lens types (within one letter at each visit)
  • Only 1 child discontinued for vision quality reasons over the 3 year period
• Satisfaction
  • There was no statistically significant difference (p=1.00) between lens types in satisfaction
  • When asked "how much do you like wearing your contact lenses?", an average of 97% of children chose on of the top 2 responses across all visits 
  • Subjects demonstrated they were able to handle the lenses confidently, and had a positive response to contact lens wear
• These results indicate that the MiSight is well tolerated by children and does not compromise visual acuity in a meaningful way 

There were few adverse events reported during the 3 year period

• There were no serious (events that are vision threatening) or significant (events that are symptomatic but not vision threatening) adverse events in the 3 year study. There were no cases of microbial keratitis. 
• 4 asymptomatic corneal infiltrative (1 test, 3 control) events were observed at scheduled study visits
• These results are reassuring and can be utilised to reassure patients that MiSight is not only efficacious, but additionally relatively safe 
  • Read more about adverse events in paediatric soft contact lens wear

Strong correlation (p<0.01) was found between axial elongation and refractive error progression. This supports the notion that the lenses slow myopia progression by reducing the rate of axial growth

• It is widely reported that reduction in axial length is paramount to reducing the risk of developing pathological changes, such as myopic macular degeneration and retinal detachment.² 
  • Read further about the association between axial length and the risk of uncorrectable vision impairment
• Whilst the observed reduction in myopic progression of -0.73D across 3 years in this study may appear relatively modest, it has been reported that a reduction in myopia of merely 1D could reduce the risk of myopic macular degeneration by 40%, regardless of race or degree of myopia.³ 

Enrolment in the study was lower than target (150 vs 144)

• This was due to longer-than-expected recruitment period. However, subject retention was high, and the sample size was sufficiently large to show differences between the two lens types for the primary efficacy end point of 0.75D at 2 years.

Rebound effect was not evaluated in this study

• Subjects were not withdrawn from treatment to assess the extent to which the benefit is sustained. As recently discussed by Brennan et al (2019)⁴, rebound must be assumed to occur until proven otherwise. Further research is required to evaluate the rebound effect that may occur once MiSight is ceased.

Potential bias was introduced through sub-optimal randomisation procedure

• Investigators had access to the randomisation codes for the duration of the study. Although the codes were only identified as "lens A" and "lens B", theoretically an examiner could have identified whether a subject was in the experimental or control group. 

Compliance of lens wear in the study was very high (average 6.5 days/week, 13.7 hours/day on weekdays). It would be interesting to evaluate efficacy in groups with slightly reduced compliance.

The results of this study are only applicable to the specific study population. It is difficult to extrapolate the results of this study onto children of different populations (i.e. different age and level of myopia). Further research is required to investigate the efficacy of MiSight on different patient sub-groups.

This 3-year trial aimed to quantify the effectiveness of MiSight daily disposable SCL's in slowing the progression of juvenile-onset myopia.

Myopic children (SER -0.75 to -4.00D, astigmatism <1.00D) aged 8-12 years were enrolled in a 3 year, double-masked, randomised trial at 4 investigational sites in 4 countries. Subjects were randomised into 1 of 2 groups. 

• Test Group: MiSight 1-Day contact lens (n start=65, end=53)
• Control Group: Proclear 1-Day contact lens (n start=70, end=56)

Contact lenses were worn on a daily disposable basis. Change in cycloplegic spherical refraction (D) and axial length (mm) were measured at regular intervals. 144 subjects were enrolled, with 109 completing the trial. Subjects varied in age from 8-13 years.

All 4 test sites were provided with the same protocol and identical equipment calibration instructions were given to ensure standardised measurements across sites. Subjects were randomised, fit and dispensed contact lenses. The randomisation log was created centrally by the contract research organisation, and each clinical site was given a randomised log to assign the order in which subjects were dispensed the lens types. This log was stored in the study documentation, so all investigators could access it, but the study product was coded (lens A and B) and the randomisation log only had the lens codes listed on it. Participants and their parents were masked. 

Progress was monitored at follow-up visits at 1 week, 1 month, and 6, 18, 24, 30 and 36 months.

Both spherical equivalent refraction and axial length were measured at each follow-up visit. Cycloplegic spherical equivalent refraction was measured using the Grand Seiko Binocular Auto-refractor and axial length was measured using the IOLMaster. 

A change in lens power was provided at any study visit when subjective over-refraction was 0.50D or an improvement in visual acuity could be achieved (greater than ½ line). Lens fit and ocular health were assessed at each visit.

Both participants and parents completed questionnaires at each follow up visit. Questions were focussed on lens handling, comfort, vision and overall satisfaction. Wear time was also recorded. Safety was assessed using slit-lamp biomicroscopy findings and ocular adverse events were classified and reported.  

Compliance

Both lens types were worn for an average of 6.5 days per week. Mean weekday wear time for control group and MiSight group was 13.3 ± 1.5 and 13.7 ± 1.5 hours respectively. Mean weekend wear time for control group and MiSight group was 12.4 ± 0.9 and 12.1 ± 1.2 hours per day. There was no statistical difference in wear time between lens types.

Subjective Responses

Responses to various questions were obtained, regarding lens handling and overall satisfaction. Responses to the question "how easy is it to put the lenses on your eye" were obtained. At the 1 month visit, over 80% children in each group described insertion of lenses as "kind of easy" or "really easy". Over the remainder of the study period, more than 90% of subjects rated within the top 2 box category. There was no difference between study groups in response to this question. This information can reassure Eye care practitioners that children as young as 8 years old can be proficient at inserting and removing MiSight contact lenses.

A positive response to the general experience of wearing contact lenses was also observed, as explained above.  

BCVA

BVCA (with spherical over-refraction) remained similar for the two lens types and within 1 letter for the MiSight and control lens. Near VA remained within 1 letter for the MiSight and control lens at each visit. This indicates that MiSight does not compromise visual acuity.

Safety Evaluation

As discussed above, there were no serious or significant ocular adverse events in the 3 year study. There were 7 lens related events (6 subjects)  in MiSight, and 7 (5 subjects) in the control lens. These included corneal infiltrative events, superficial punctate corneal staining and bilateral allergic reaction. There were no reports of loss of BCVA associated with these adverse events.

Factors Impacting Progression

There was no significant interaction between lens type and site, suggesting that the myopia progression for both lens types was independent of investigative sites. Interestingly, the interaction of lens type with age, sex or baseline myopia was not significant. This suggests that the myopia control effect is independent of these factors in this study population.  

The findings of this 3-year RCT demonstrate that myopia progression is significantly slowed by the MiSight soft contact lens. No safety concerns were evident in this population of children. This study can provide Eye Care Practitioners with confidence when recommending MiSight contact lenses as a means of myopia control.

Title: A 3-year Randomized Clinical Trial of MiSight Lenses for Myopia Control

Authors: Paul Chamberlain, Sofia Peizoto-de-Matos, Nicola Logan, Cheryl Ngo, Deborah Jobes, Graeme Young

Significance: The purpose of this study was to quantify the effectiveness of MiSight daily disposable soft contact lens in slowing the progression of juvenile-onset myopia.

Purpose: Results of this randomized, double-masked clinical trial demonstrate the effectiveness of the MiSight soft contact lens in slowing myopia progression over multiple years.

Methods: Myopic children (spherical equivalent refraction, −0.75 to −4.00 D; astigmatism, <1.00 D) aged 8 to 12 years with no prior contact lens experience were enrolled in a 3-year, double-masked, randomized clinical trial at four investigational sites in four countries. Subjects in each group were matched for age, sex, and ethnicity and were randomized to either a MiSight 1-day contact lens (test) or Proclear 1-day (control; omafilcon A) and worn on a daily disposable basis. Primary outcome measures were the change in cycloplegic spherical equivalent refraction and axial length.

Results: Of the subjects enrolled, 75.5% (109/144) completed the clinical trial (53 test, 56 control). Unadjusted change in spherical equivalent refraction was −0.73 D (59%) less in the test group than in the control group (−0.51 ± 0.64 vs. -1.24 ± 0.61 D, P < .001). Mean change in axial length was 0.32 mm (52%) less in the test group than in the control group (0.30 ± 0.27 vs. 0.62 ± 0.30 mm, P < .001). Changes in spherical equivalent refraction and axial length were highly correlated (r = −0.90, P < .001). Over the course of the study, there were no cases of serious ocular adverse events reported. Four asymptomatic corneal infiltrative (one test, three control) events were observed at scheduled study visits.

Conclusion: Results of this clinical trial demonstrate the effectiveness of the MiSight daily disposable soft contact lens in slowing change in spherical equivalent refraction and axial length.

[Open access link is here]