Abstract
Purpose :
Studies have used choroidal vascularity index (CVI) to assess vascular status of the choroid in adults with high myopia. However, data in children with myopic eyes are lacking and, in this study, we examined the distribution and association of CVI and peripapillary retinal nerve fiber layer (RNFL) thickness in children with myopic refractive errors.
Methods :
Seventy seven myopic and nineteen emmetropic eyes with mean refractive error -4.29±2.30 D and 0.14±0.25 D, respectively, were recruited from the National University Hospital Eye Surgery outpatient clinic. All children underwent a detailed ocular examination, including refraction, and axial length (AL) measurement. Peripapillary choroid and RNFL were imaged using spectral-domain optical coherence tomography (SD-OCT). Choroidal scans were segmented by modified image binarization technique. Total peripapillary choroidal area (TCA) was segmented into luminal (LA) and stromal (SA) area, and peripapillary CVI was calculated as the proportion of LA to TCA. Peripapillary CVI and RNFL thickness was calculated in all children for the entire 360 degrees and four quadrants, respectively. Only scans with signal strength of >6/10 were included. Correlation between peripapillary CVI and RNFL thickness was calculated using the Pearson correlation coefficient.
Results :
Of the 96 included eyes (77 myopic), the mean age, mean spherical equivalent refraction and mean AL was 8.84±3.10 years, -4.15±2.23 D and 24.39±1.72 mm, respectively. The mean peripapillary CVI was 59.8±0.2% and 60.4±0.4% in myopic and emmetropic eyes, respectively, and the mean RNFL thickness was 98.44±1.39 µm and 99.42±2.34µm, respectively. The mean peripapillary CVI and RNFL thickness measurements showed regional differences in myopic eyes, peripapillary CVI was greatest (60.5±0.32%) at the superior and thinnest (59.3±0.34%) at the inferior quadrant, whereas RNFL was thickest (124±3.02 µm) at the superior and thinnest (73.71±2.04 µm) at the nasal quadrant. There was no correlation between peripapillary CVI and RNFL thickness in myopic children.
Conclusions :
Given both optic nerve head and peripapillary choroid shares the common source of blood supply, thinnest peripapillary CVI in inferior quadrant may explain the susceptibility of the inferior optic nerve region to glaucoma in myopes. Future studies with larger cohort is warranted to understand the role of peripapillary choroid in myopia.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.