Macular choroidal thickness in Chinese preschool children: decrease with axial length but no evident change with age.

AIM

To explore the distribution pattern of macular choroidal thickness (ChT) and its association with age as well as refractive status in Chinese preschoolers.

METHODS

School-based, cross-sectional study. A total of 550 healthy preschool children aged 3 to 6 years old from 6 kindergartens were enrolled. Comprehensive ocular examinations, including measurement of visual acuity, axial length, intraocular pressure and slit-lamp examination before cycloplegia, as well as refraction measurement and swept-source optical coherence tomography (SS-OCT) examination after cycloplegia, were performed. The macular ChT in each sector of the ETDRS grid was measured by the built-in software of SS-OCT.

RESULTS

The mean central ChT of the participants was 312±59 µm. The mean axial length and spherical equivalent refraction were 22.36±0.72 mm and 1.51±0.83 D, respectively. Axial length increased with age (<0.001), while the spherical equivalent refraction was similar among different age groups. Similarly, no significant difference was observed in ChT in all sectors among different age groups (all >0.05). The central ChT of 3-4, 5 and 6 years old children was 314±59 µm, 312±60 µm and 312±59 µm, respectively (=0.920). No difference was observed in ChT in most of the sectors between genders. No statistical significant difference was observed among different refractive groups (all >0.05), though the ChT of each sector seemed to be smaller in myopic children. Axial length and weight were the independent factors of central ChT. Children with longer axial length (=-21.184, <0.001) and smaller weight (=1.502, =0.041) tended to have thinner choroid.

CONCLUSION

In preschool children, the ChT remains relatively stable with age, while a negative association between ChT and axial length existed. This will be helpful to elucidate the characteristics of ChT during the early refractive development.