Abstract
Purpose: To characterize the choroidal morphologic and vascular features in different levels of myopes and patients with myopic choroidal neovascularization (mCNV).Methods: A total of 148 subjects were enrolled in this cross-sectional study, including 78 low-to-moderate myopes (LMM), 53 high myopes (HM), and 17 high myopic patients with mCNV. Ocular biometrics were measured using an optical low-coherence reflectometry device. Retinal and choroidal imaging was performed using enhanced depth imaging (EDI) spectral domain optical coherence tomography (OCT). Retinal parameters including retinal thickness and retinal volume were obtained from a built-in software. Binarization technique was adopted to investigate choroidal parameters including choroidal thickness (CT), vascular area, stromal area, and choroidal vascularity index (CVI). Choroidal parameters were measured at five locations to cover as much area of choroid as possible, and their patterns of distribution were further analyzed.Results: Patients with mCNV had an atrophic retina of comparable thickness to HM (273.65 ± 17.28 vs. 276.49 ± 13.29 μm, p = 0.47), but the choroid was thinner than that of HM (153.94 ± 15.12 vs. 236.09 ± 38.51 μm, p < 0.001). Subfoveal CVI was greatest in the mCNV eyes (0.651 ± 0.009), followed by HM (0.645 ± 0.012) and LMM eyes (0.636 ± 0.012). Similar to CT, CVI was also found significantly different among these three groups at all five locations (p for trend < 0.001 for all locations). Axial length (AL) was negatively correlated with retinal volume (r = −0.236, p = 0.009), which is the only significant finding in associations between ocular factors and retinal parameters. Strong, negative correlations were identified between AL and subfoveal choroidal thickness (SFCT, r = −0.820, p < 0.001). However, AL was positively correlated with subfoveal CVI (r = 0.668, p < 0.001). CVI was greater in myopic eyes with thinner choroid (r = −0.578, p < 0.001). BCVA exhibited no significant association with CVI (r = 0.139, p = 0.092), but was negatively correlated with SFCT (r = −0.386, p < 0.001) and positively correlated with AL (r = 0.351, p < 0.001).Conclusion: Choroid in patients with mCNV was thinner yet more vascularized than that in HM and LMM subjects. CVI increased with a longer AL which was associated with a smaller SFCT, choroidal vascular area (VA), and total choroidal area (TCA). Better BCVA was achieved in subjects with thicker SFCT and shorter AL.
Highlights
Myopia is one of the most common ocular disease globally, with a prevalence of 10–30% in the adult population and 80–90% in young adults in East and Southeast Asia [1]
In terms of reliability of choroidal thickness (CT) and choroidal vascular index (CVI) measurements, the intraobserver reliability for low-to-moderate myopes (LMM), high myopes (HM), and myopic choroidal neovascularization (mCNV) groups was excellent for all locations of choroidal parameters (Table 2)
Patients with mCNV had the highest CVI among three groups whereas both the numerator and denominator (TCA) of CVI decreased in mCNV eyes. These findings reveal that mCNV eyes suffered from a higher level of choroidal atrophy than HM eyes, with relatively greater reduction in the stromal component compared with vascular components, which was further supported by the strong correlation between CVI and axial length (AL)
Summary
Myopia is one of the most common ocular disease globally, with a prevalence of 10–30% in the adult population and 80–90% in young adults in East and Southeast Asia [1]. Recent development of enhanced depth imaging (EDI) optical coherence tomography (OCT) has enabled non-invasive, quantitative assessment of the choroid in myopia [11,12,13]. Reduction in choroidal circulation flow has been shown to occur in high myopia, which may be important in the pathogenesis of mCNV, and a reduction in CT in pathological myopic eyes with mCNV has been demonstrated using OCT imaging [18]. To the best of our knowledge, these studies mostly focused on the choroidal capillary plexus density as shown in OCTA [19,20,21], or only identified total choroidal vascular density (including choroidal capillary plexus, Haller’s and Sattler’s layer of choroid) in subfoveal areas [16, 22]. There is a lack of investigation on the variations of full-layer choroidal structure in different subretinal areas, and the role of choroidal vessel distributions in the pathogenesis of mCNV remains unclear
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
