Choroidal thickness varies depending on macular location in pediatric patients with myopia — it is thickest in the perifoveal superior region and thinnest in the nasal region, according to research published in Optometry and Vision Science. Thinner choroidal thickness is associated with longer axial length (AL) and higher myopic spherical equivalent refraction (SER), according to the report.
Researchers included 250 children with myopia (mean age, 11.3 years; 62% girls) from the Myopia Outcome Study of Atropine in Children clinical trial in the investigation. Patients underwent swept source-optical coherence tomography (SS-OCT) imaging for 9 macular Early Treatment of Diabetic Retinopathy Study (ETDRS) locations with diameters of 1, 3, and 6 mm, which corresponded with the central fovea, parafoveal, and perifoveal regions. The team examined choroidal thickness profiles and performed multiple linear regression analysis to determine associated factors.
“If the choroid is indeed involved in modulating myopia progression and the development of chorioretinal disease, it is worth exploring whether choroidal thickness measurements across the macular area could provide a useful biomarker for identifying children at risk,” according to the study authors.
The report shows variations in choroidal thickness according to macular location. Measurements were thickest in the perifoveal superior region (249.0 μm) and thinnest in the perifoveal nasal region (155.1 μm). Overall, the parafoveal region demonstrated greater choroidal thickness compared with the perifoveal region (231.8 vs 218.1 μm) except for the superior region.
Longer AL longer (≥26 mm) demonstrated more choroidal thinning compared with shorter (≤24 mm) or medium (>24 to<26 mm) AL (P <.001 for all).
Stratifying participants according to race revealed significant differences in choroidal thicknesses between individuals of different ethnicities. Participants who were Black exhibited the thickest subfoveal choroidal thickness (279.8 μm), followed by individuals with mixed race (239.1 μm), patients who were White (237.8 μm), and participants who were Asian (196.6 μm). Participants who were Asian had significantly thinner choroidal thickness in all regions compared with individuals who were White (P <.001 for all).
The investigators highlight that “[a]fter adjusting for axial length, race remained significantly associated with choroidal thickness in the superior regions, suggesting this relationship may be independent of axial length or myopia severity. These findings could be underpinned by genetic or behavioral factors such as near work activities [. . .].”
Study limitations include failure to account for diurnal variations in choroidal thickness measurements and a limited inclusion of participants with high myopia.
Kobia-Acquah E, Flitcroft DI, Lingham G, Paudel N, Loughman J. Choroidal thickness profiles and associated factors in myopic children. Optom Vis Sci. Published online December 6, 2022. doi:10.1097/OPX.0000000000001973.