Smartphone 3-D Imaging Successful in Designing Glasses for Craniofacial Anomalies

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The 3-D technology was able to produce custom frames with a successful fit for patients with craniofacial anomalies at risk of vision loss.

The usage of smartphone-enabled 3-dimensional surface imaging (3DSI) for glasses design may benefit pediatric patients with craniofacial anomalies at risk for vision loss due to amblyopia, according to new findings.

The technology in combination with available 3D printing technology were able to produce custom frames with successful fit for this patient population and they remained well-tolerated, which may improve adherence in patients.

“The successful patient fit and overall similarities in fit measurements across [magnetic resonance imaging] MRI and 3DSI scans demonstrate that smartphone 3DSI provides sufficient resolution for the 3D design and subsequent 3D printing of custom glasses for these children who are unserved by the current market of individu-alized frame designs,” wrote study author Alejandra de Alba Campomanes, MD, MPH, University of California, San Francisco, Wayne and Gladys Valley Center for Vision.

Children with atypical facial development often experience challenges with glasses fit due to anatomical variation and subsequently, are at increased risk of amblyopia due to poor adherence in wearing glasses. Study investigators pointed out that their previously described custom 3-D printed glasses improved design and fit, there is a limit in access as a consequence of availability of computed tomography and MRI.

Based on these limitations, Campomanes and colleagues developed a new approach in which a child’s facial anatomy is captured in real time using smartphone 3DSI as the basis for the custom glasses design.

In the quality improvement study, the investigators analyzed data from a case series in a primary academic center with multiple referral centers throughout the United States. Comparisons were made between MRI and 3DSI scans, including key fit measurements.

The key anatomic parameters for glasses fit included face width, distance from ear bridge to nasal bridge, distance from center of pupil to center of nasal bridge, distance from lateral to email canthus, ear vertical offset, and nasal bridge width. They defined a 3DSI scan as successful if they met these key parameters and the difference in measurement was less than 5% between MRI and 3DSI.

Data show the key fit measurements across 3 patients aged 3 to 7 years were similar across MRI and 3DSI scans with a mean difference of 1.47 mm between parameters (range, 0.3 - 4.60 mm).

Investigators noted the distance from ear bridge to nasal bridge had the greatest variance between MRI and 3DSI scans (mean difference, 2.99 mm; range, 0.87 - 4.60 mm). They added that neither 3DSI or MRI measurements were consistently greater than or less than the other.

They additionally reported data for 20 patients aged 1 to 17 years who had poor adherence to ill-fitting glasses due to craniofacial abnormalities. All achieved successful fit, defined as daily glasses adherence without irritation, as judged by a patient and the parent or guardian. There were a mean of 1.7 revisions made from initial prototype to final frame production using the 3DSI technology.

The study, “Using a Smartphone 3-Dimensional Surface Imaging Technique to Manufacture Custom 3-Dimensional–Printed Eyeglasses,” was published in JAMA Ophthalmology.