Increased Choroidal Blood Perfusion Can Inhibit Form Deprivation Myopia in Guinea Pigs

Abstract

In guinea pigs, choroidal thickness (ChT) and choroidal blood perfusion (ChBP) simultaneously decrease in experimental myopia, and both increase during recovery. However, the causal relationship between ChBP and myopia requires further investigation. In this study, we examined the changes of ChBP with three different antimyopia treatments. We also actively increased ChBP to examine the direct effect on myopia development in guinea pigs. METHODS. Experiment 1: Guinea pigs wore occluders on the right eye for two weeks to induce form-deprivation myopia (FDM). Simultaneously they received daily antimyopia treatments: peribulbar injections of atropine or apomorphine or exposure to intense light. Experiment 2: The vasodilator prazosin was injected daily into the form-deprivation eyes to increase ChBP during the two-week induction of FDM. Other FDM animals received appropriate control treatments. Changes in refraction, axial length, ChBP, ChT, and hypoxia-labeled pimonidazole adducts in the sclera were measured. RESULTS. The antimyopia treatments atropine, apomorphine, and intense light all significantly inhibited myopia development and the decrease in ChBP. The treatments also reduced scleral hypoxia, as indicated by the decrease in hypoxic signals. Furthermore, actively increasing ChBP with prazosin inhibited the progression of myopia, as well as the increase in axial length and scleral hypoxia. CONCLUSIONS. Our data strongly indicate that increased ChBP attenuates scleral hypoxia, and thereby inhibits the development of myopia. Thus ChBP may be a promising target for myopia retardation. As such, it can serve as an immediate predictor of myopia development as well as a long-term marker of it.

Differences in Retinal and Choroidal Vasculature and Perfusion Related to Axial Length in Pediatric Anisomyopes

“…15,49 Of note, our recent study in guinea pigs found that actively increasing choroidal blood flow was accompanied by attenuation of scleral hypoxia and inhibition of excessive axial elongation during form-deprivation myopia. 17 In addition, treatment with atropine, apomorphine, or intense light, all of which attenuate myopia progression, simultaneously inhibit this decrease in choroidal blood flow. 17 Overall, these provocative findings suggest that the regulation of choroidal blood flow could be a target for myopia control.…”

“…[11][12][13][14][15][16] The role of hypoxia in the development of myopia is supported by results from studies in which choroidal blood flow was increased with the alpha adrenergic antagonist, prazosin. [17][18][19] Prazosin treatment inhibited the development of experimental myopia, as well as associated excessive axial elongation and scleral hypoxia. 17 This response suggests that choroidal blood flow could be predictive, prognostic, or even plays a causal role in myopia development.…”

“…[17][18][19] Prazosin treatment inhibited the development of experimental myopia, as well as associated excessive axial elongation and scleral hypoxia. 17 This response suggests that choroidal blood flow could be predictive, prognostic, or even plays a causal role in myopia development.…”

Investigation of Macular Choroidal Thickness and Blood Flow Change by Optical Coherence Tomography Angiography After Posterior Scleral Reinforcement

“…Wu et al ( 33 ) demonstrated that scleral hypoxia played an essential role in scleral remodeling during myopia progression. Zhou et al ( 34 ) found that increased choroidal blood perfusion inhibited eyeball elongation and myopia development via attenuating scleral hypoxia in guinea pigs. In this study, we also found that AL is especially associated with parafoveal subfields CT and CPA.…”

Assessment of Choroidal Vascularity and Choriocapillaris Blood Perfusion in Anisomyopic Adults by SS-OCT/OCTA

“…Of note, actively increasing ChBF with vasodilator prazosin inhibited myopia progression in guinea pigs, as well as axial elongation and scleral hypoxia. 57 We have argued that a decrease in ChBF may cause scleral hypoxia followed by axial elongation and myopia. 20,58 Because the choroidal thickness in humans could also respond rapidly and predictably to various visual stimuli (e.g., hyperopic defocus, myopic defocus, and accommodation), [25][26][27] it is plausible that decreased ChBF is a risk factor for the development of human myopia.…”