The Noninvasive Measurement of Ocular Rigidity and the Pulsatile Choroidal Volume Change in Children and Young Adults.

PURPOSE: Measuring ocular rigidity (OR) and the pulsatile choroidal volume change (ΔV) from childhood to adulthood would provide essential insight into the role of the sclera and choroid in axial myopia. A validated measurement method based on Beaton et al (2015) is the only noninvasive, direct, and reliable method available, yet it has never been used in children. This study aims to assess the feasibility and repeatability of noninvasive OR and ΔV measurements in children and young adults using this method.

DESIGN

This is a cross-sectional study.

SUBJECTS: Children and young adults aged 6 to 26 years.

METHODS

OCT videos were acquired using enhanced depth imaging mode. A neural network (NN) approach was used to extract the choroid segmentation from OCT videos, which was then used to measure choroidal filling as described by Beaton et al. Ocular rigidity was computed from the ΔV and the ocular pulse amplitude using Friedenwald equation. Intrasession repeatability was assessed for subjects with 2 consecutive measurements of OR.

MAIN OUTCOME MEASURES: Ocular rigidity, pulsatile choroidal volume change, and the method's yield.

RESULTS

Sixty-seven subjects (67 eyes, 27 males) aged 13 ± 6 years were enrolled, and 62 subjects completed the study. ΔV and OR were computed. Out of the 62 videos, 98% (61) of the OCT videos were successfully segmented using the NN approach, with heart rate detectable in 79% (48) of the videos. Average OR and ΔV were 0.027 ± 0.022 μL-1 and 5.7 ± 2.8 μL, respectively (n = 48). The mean submacular choroidal thickness (CT) and pulsatile CT change were 283.6 ± 40.4 μm and 8.36 ± 4.4 μm, respectively. Intrasession repeatability for OR and ΔV was assessed in 31 eyes and was determined to be excellent based on a single measure intraclass correlation coefficient of 0.912, 95% confidence interval (CI) (0.825, 0.956) and 0.941, 95% CI (0.879, 0.972), respectively and a within-subject standard deviation of 0.0037 μL-1 and 1.14 μL, respectively.

CONCLUSIONS

Measures of OR and ΔV are achievable in children and young adults and have good repeatability. This noninvasive method can be used to establish structural biomechanical changes of the sclera and choroid with myopic axial elongation in childhood and beyond.

FINANCIAL DISCLOSURES: The author(s) have no proprietary or commercial interest in any materials discussed in this article.