Axial Length Control Is Associated With a Choroidal Thickness Increase in Myopic Adolescents After Orthokeratology

Abstract

Objective: To investigate the changes in choroidal thickness and axial length after orthokeratology in adolescents with low-to-moderate myopia and to explore the relationship between choroidal thickness and axial length variation. Methods: Thirty eyes with low-to-moderate myopia were retrospectively studied, and optometric data were collected before and after 6 months of continuous orthokeratology. Axial length and choroidal and foveal thicknesses were measured using optical biometry and enhanced depth imaging–spectral domain optical coherence tomography, respectively. Results: Axial length in the low myopia group increased (P<0.001) after 6 months of orthokeratology, and the variation was greater than that in the moderate myopia group (P<0.05). The subfoveal choroidal thickness in low and moderate myopia groups increased (P<0.01), and the variation was greater in the moderate myopia group (P<0.05). Choroidal thickness in all seven measured spots increased, with the variation of subfovea, nasal 1 mm to fovea, and temporal 1 mm to fovea being statistically significant (P<0.001, P<0.05, and P<0.05). The change in axial length was negatively associated with subfoveal and average choroidal thicknesses (P<0.01). Conclusion: Adolescents with moderate myopia presented better axial length control after 6 months of orthokeratology. The choroidal thickness of low and moderate myopic eyes increased, and the variation was more significant in moderate myopic eyes. The axial length control effects can be associated with an increase in the subfoveal and average choroidal thickness.

Systematic Review of Myopia Progression after Cessation of Optical Interventions for Myopia Control

“…Recent studies have drawn connections between myopia and choroidal thinning [ 23 , 24 , 25 , 26 ]. Furthermore, the efficacy of optical interventions has been linked to an increased choroidal thickness [ 13 , 27 , 28 , 29 , 30 , 31 , 32 ]. With regard to orthokeratology treatment, several studies have shown that the initial increase in the luminal area or the thickness of the large choroidal vessel play a role in slowing eye elongation [ 28 , 31 ].…”

“…Choroidal thickening is identified as an outcome of effective therapy [ 13 , 27 , 28 , 29 , 30 , 31 , 32 ]. Additionally, certain orthokeratology studies have explored changes in the choroidal thickness after treatment cessation, suggesting a potential return to baseline levels [ 13 , 32 ].…”

“…Individuals with a higher baseline SE experience greater myopic defocus effects [ 43 ]. Notably, the choroidal thickness is greater in cases of high SEs [ 30 ]. After the discontinuation of wear, these two underlying mechanisms could potentially contribute to a more pronounced rebound effect.…”

Increase in choroidal thickness after blue light stimulation of the blind spot in young adults

“…There is compelling evidence for a relationship between choroidal thickness and vision-dependent processes that regulate the refractive state of the eye, with choroidal thinning associated with myopia and choroidal thickening associated with emmetropia or hyperopia (Nickla and Wallman 2010 ; Read et al 2019 ; Wildsoet and Wallman 1995 ). Studies involving the current treatments for childhood myopia, including orthokeratology (Li et al 2019 ; Wang et al 2023 ), defocus incorporated multiple segments (DIMS) lenses (Chun et al 2023 ), and atropine eye drops (Ye et al 2020 ), suggest that short-term thickening of the choroid in response to these treatments predicts long-term slowing of eye growth and myopia progression. Recent studies on the human eye have also shown an increase in choroidal thickness in response to exposure to increased light levels (Chakraborty et al 2022b ), with evidence from animals further suggesting that melanopsin signaling contributes to the light-mediated increase in choroidal thickness independent of the rod pathway (Berkowitz et al 2016 ).…”