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August 1, 2023
VANCOUVER — At THE Myopia Meeting held here June 11, 2023, Ying Zhao, OD, presented on behalf of CooperVision. Dr. Zhao discussed the company’s seven-year data on MiSight 1 day contact lenses, the longest continuous soft contact lens study for myopia management.
Breaking Down the MiSight Study
Kicking off the discussion, Dr. Zhao explained that the MiSight study took place over the course of seven years and was divided into three parts.
“In part one, we recruited 144 kids between the ages of 8 and 12, and we randomized them into two groups — half of them wore the MiSight 1 day, and the other half wore the ProClear 1 day,” Dr. Zhao said. “Due to the results in part one, we had to switch all of the kids in ProClear into MiSight, which became part two of the study. At this point, we had 108 kids enrolled, and 85 of them completed this phase of the study.
“Much of my discussion will focus on part three of the study, which enrolled 83 study participants. At this point in the trial, we moved all of the participants out of MiSight lenses and transitioned them into ProClear lenses; 78 kids completed this part of the trial. With part three, we were trying to answer the question: What happens when kids stop wearing MiSight?”
Valuable Insights into Long-Term Effects
Dr. Zhao then discussed the results of the final phase of the MiSight study, starting with the potential rebound effect of taking kids out of myopia treatment.
“When we decide to take the treatment out of the equation, we expect one out of three situations to happen,” she explained. “The first one is that the treatment effect is lost, which is also known as rebound. This is when we have an acceleration of progression to the point where previous gains are lost. In the second scenario, the treatment effect is retained, which means the eyes go back to age-normal myopic eye growth. In the last scenario, we have continued accumulation of treatment, which means we can still get the magical effect of myopia control even when the treatment isn’t being used.
“So, why is rebound a question? Based on various studies on different myopia treatments, we think there is evidence of rebound in low-dose atropine and orthokeratology, and we wanted to test this with MiSight. We learned that stopping MiSight wear for 12 months did not lead to any sort of rebound.”
Analyzing the Seven-Year Data
From there, Dr. Zhao discussed how researchers at the University of Waterloo CORE have analyzed the data from the MiSight study to better understand the long-term effects of the lenses.
“We took the annualized change in axial length in all three parts of the study and all of the groups and compared them against each other to answer our questions,” Dr. Zhao said. “Our first question is: do we have any signs of rebound? In order to get this answer, we compared the change between part three and part one, and the axial length growth is significantly slower in part three. From this, we conclude that there is no evidence of loss in treatment.
“Our second question is: Do the eyes go back to their age-normal eye growth? Since we no longer have a typical control group without any type of treatment, we had to get creative and pull control data from other studies with similar inclusion criteria. The data matched up quite nicely to our participants in part three, and we concluded that the eyes do go back to age-normal eye growth.
“Our third question is: Can we still have myopia control effect even when MiSight is not being worn? To do this, we compared the data between part two and part three. There was a slight increase in axial length growth after stopping MiSight, so unfortunately, when you stop wearing MiSight, you do not get any more myopia control effect.
“Our fourth question is: Since the two groups started on MiSight at different times, does the length of prior treatment affect the post-treatment effect? We compared the difference between the two groups in part three, and indeed, the length of prior treatment has not affected the post-treatment myopia control effect.
“This leads to two important points,” Dr. Zhao said. “One is that older kids will benefit from MiSight as well, and two is that it’s never too late to start myopia management on the right candidates.