New research published in JAMA Ophthalmology is reporting promising findings from a follow-up study to the three-year BLINK trial that demonstrate continued efficacy in multifocal (MF) contact lens wear for slowing the progression of myopia among pediatric patients.
Let’s start with some background on this.
With 5 billion people across the globe expected to develop myopia by 2050, do we really need to get into how prevalent of an issue this refractive disorder is?
- (We hope not, but if so: just check out our coverage from the last couple of years).
The demographic most affected by this: Pediatric patients
- Case in point: A trend of earlier onset of myopia has emerged among school-aged children.
Now to this initial BLINK trial: What was the setup?
Published in JAMA in 2020, the Bifocal Lenses in Nearsighted Kids (BLINK) multicenter, double-masked, randomized trial (NCT02255474) was conducted as follows:
- Participants: 294 patients (aged 7 to 11) diagnosed with myopia ( –0.75 D to –5.00D)
- The setup: Randomized to wear single-vision (SV) or MF contact lenses with either:
- High-add power (+2.50D)
- Medium-add power (+1.50D)
- The duration: 3 years, during which patients wore the lenses during the day (as often as comfortable)
The question to be answered: Could soft MF contact lenses with a high-add power slow myopia progression in children more than medium-add power or SV contact lenses?
So what did they find?
Patients in the high-add MF contact lens group presented with shorter eyes when compared to the medium-add power and SV groups—and most notably: they demonstrated the slowest rate of both myopia progression and eye growth.
Important to note: While these findings favored the use of the high-add MF lenses, the study authors stressed that additional research was needed to understand the differences between these three lenses.
Which brings us to … this follow-up study?
Indeed. Enter in: the BLINK2 study (NCT04080128).
Funded by the National Institutes of Health’s National Eye Institute and featuring researchers (aside from the University of Houston) from the Ohio State University of Optometry, this trial encompassed:
- Participants: 248 patients (aged 11 to 17) from the BLINK study
- The setup: All participants wore high-add (+2.50 D) MF contact lenses for 2 years followed by SV contact lenses for an additional year
- The measured outcomes: eye length (optical biometry) and refractive error (cycloplegic autorefraction) on an annual basis
- The duration: 3 years
And the study’s purpose?
Researchers sought to determine whether there was a loss of myopia treatment effect after discontinuing soft MF contact lens use in myopic pediatric patients.
Got it. Now to those findings.
Out of the 248 participants enrolled, 235 (95%; 80% of the original BLINK study participants) completed the trial, with a median age of 15 and 59% female.
Baseline data:
- Mean (SD) axial length (AL): 25.2 (0.9) mm
- (SD) spherical equivalent refractive (SER) error: −3.40 (1.40) D
- In other words: myopia progression
Data after switching from MF to SV lenses:
- (SD) AL: Increased by 0.03 mm per year (95% confidence interval [CI], 0.01 to 0.05), from a rate of 0.05 mm per year to 0.08 mm per year.
- This was regardless of patients’ original BLINK treatment assignments (p = .57)
How did myopia progression fare?
In general, younger participants’ progression was faster throughout the study’s duration—including when wearing both MF and SV lenses, according to the data.
However, when switching from MF to SV lenses in the study’s third (and final) year, investigators observed an increased rate of myopia progression for all participants.
- The increased rate: –0.17 D per year
- The progression: –0.05 D per year to –0.22 D per year (95% CI, –0.18 to –0.26)
Interestingly, the increased rate of myopia progression differed slightly by participants’ age, with younger patients seeing a smaller increase after switching to SV lenses than the increase noted among older patients.
And how did this compare to the original study’s myopia data?
Participants wearing the high-add MF lenses in that study “continued to have less myopia than in the [SV] group at the end of the BLINK2 study,” the investigators stated.
- The numbers: 0.71 D less myopia; 95% CI, 0.28 to 1.14
Importantly: No difference in myopia was observed at the end of the BLINK2 study between participants in the BLINK study medium-add and SV groups.
- The numbers: −0.08 D; 95%CI,−0.50 to 0.34
As noted by researchers: “Children who switched to high-add [MF] contact lenses for the first time during BLINK2 did not catch up to those who had worn high-add lenses since the start of the BLINK study when they were 7 to 11 years of age.”
Any limitations to take note of?
A few, including:
- Lack of a SV lens group for the study duration (as was included in the original study)
- Measurements of AL were not performed using cycloplegia
- No data to determine if results would apply to pediatric patients wearing MF lenses < 2 years
So what were the authors’ thoughts on all of this?
Among their discussion topics: Based on the results, “children return to a normal rate of eye growth for their age after discontinuing [MF] contact lenses”—as previous research has already reported.
Another key finding: The high-add MF treatment effect seen in the BLINK study continued by the end of the BLINK2 study, with the original high-add MF lens patients still presenting with shorter eyes and less myopia compared to the other original treatment groups (medium-add MF and SV lenses).
- Why this is crucial: “It differs from atropine studies that have reported faster than age-normal growth and loss of the treatment effect (rebound) after discontinuing treatment, with greater rebound as atropine concentration increases,” the author stated.
Lastly: the takeaways.
Ultimately, the authors concluded that this study supports the strategy of fitting pediatric patients with MF soft contact lenses for myopia management at a younger age and continuing that treatment through their late teenage years.
Even further: Discontinuing MF lens wear in the later teenage eyes led to a return of age-expected AL—with no evidence of a rebound (loss of treatment effect).