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Study confirms tolerability of spectacle lenses for myopia control
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VANCOUVER, British Columbia – Twenty-one children between 6 and 12 years old were able to tolerate three different designs of spectacle lenses intended for myopia control.
The children, whose myopia ranged from -1 D to -4 D, were randomized to one of three lens designs for 2 weeks and evaluated for distance visual acuity, contrast sensitivity and acceptability through a subjective questionnaire, according to a poster presented here at the Association for Research in Vision and Ophthalmology meeting. They were masked to lens design.
Joe Rappon, OD, MS, FAAO, chief medical officer of SightGlass Vision, maker of the spectacle lenses, and study co-author Jill Woods, BSc(Hons), MSc, MCOptom, FAAO, FBCLA, head of clinical research and senior clinical scientist at the Centre for Ocular Research and Education (CORE), spoke with Primary Care Optometry News about the study here at the meeting.
Before starting a pivotal trial of the technology in the U.S. and Canada, “we wanted to find out the proper dosages of our product that we should use in our large clinical study,” Rappon said, “and we contacted CORE to see if they could help us with this.”
“Everything was geared not so much towards any treatment,” Woods said, “but whether or not they could wear these, because it’s quite a different spectacle lens.”
The researchers explained in the abstract that the lenses had a clear central aperture and peripheral patterns intended to modulate peripheral contrast at three levels.
“We measured their acuity in high and low illumination to modulate the pupil size,” Woods said. No differences were seen in any of the measures except for some children reporting difficulties with the highest dose.
“We were quite happy that the lower two iterations really didn’t impact the children very much at all,” Woods said.
“And so that confirmed us using the two lower densities in the larger clinical trial, and we also used this study, which we called WALNUT, to develop the questionnaire for both the parents and the subjects,” Rappon said.
Woods noted that the researchers measured axial length with an IOLMaster (Carl Zeiss Meditec) pre-wear and 2 weeks later, “and we found some surprising results.”
“The axial length decreased,” Rappon said, “which is interesting and most likely due to a thickness increase of the choroid. This is consistent with findings we’ve had during the development of this particular product. It’s very interesting that in a short period of time you can see a measurable change in axial length.”
Rappon said the next step is to complete the ongoing 3-year clinical trial, called CYPRESS. Enrollment is completed with 265 children at 14 sites.
Woods noted that another study called CHERRY is evaluating only the study children at CORE using swept source OCT and visual fields.
“We’re hoping to learn more about how choroidal thickness changes over the long-term period of this study,” Rappon said.
“The choroid has historically been thought of as just a vascular structure to support the outer retina, but now it seems like there could be even a longer- or slower-acting accommodative function to the choroid,” he said. “And perhaps a thinning, or a thickening, is a sign that the eye is going to elongate or maybe stop elongating as well.”
He noted other variables that can affect choroidal thickness such as caffeine intake, time of day and time awake, “but it’s definitely an area of interest.” – by Nancy Hemphill, ELS, FAAO
Reference:
Rappon J, et al. Tolerability of novel myopia control spectacle designs. Presented at: Association for Research in Vision and Ophthalmology; Vancouver, British Columbia; April 28-May 2, 2019.
Disclosures: Rappon is employed by SightGlass Vision. Woods reports receiving financial support from SightGlass Vision. Please see abstract for other authors’ financial disclosures.