## 4 Discussion
A recent study using SS-OCTA demonstrated that a sea-fan vascular network and type 2 neovascularization co-existed in the same eye, and that the tumor vasculature may have derived from one or both of these neovascular lesions [20]. Similarly, our study showed an interlacing pattern of CNV secondary to CO, presenting as numerous branching or radiating vessels connecting with feeder vessels in an en face image. In addition, cross-sectional B-scan images showed the corresponding hyperreflective lesion to contain hyporeflective tubular lamella that could detect blood flow signal, probably representing feeder vessels of the tumor, and hyperreflective lamellar lines representing unique features of the osteoma such as bone lamella or cement lines. To our knowledge, this detailed observation of the neovascular network in CO is revealed for the first time by SS-OCTA, indicating a distinct anatomical connection between CNV and the intrinsic vascularization of the tumor, which is quite different from CNV secondary to other common retinal and choroidal diseases. The composition of the newly developed vasculature network may include feeder vessels of the tumor, both growing intersected and stimulating interaction with one other, suggesting unique pathological features of CO.  
Another important finding of this study is that the hyperreflective lesion could be detected above [PERSON]'s membrane in the decalied region of osteoma lesions, accompanied by rupture of the overlying [PERSON]'s membrane in 73.9% of our patients. This result is inconsistent with previous SD-OCT and post-enucleation results that indicated all the tumor-related vasculature is located in the inner tumor, not outside the area between [PERSON]'s membrane and the RPE layer. [PERSON] et al. [31] were the first to report hyperreflective material above [PERSON]'s membrane, but since no disruption of the membrane was observed on SD-OCT, they speculated the material was extensive fibrous RPE metaplasia, as it was considered unlikely that the tumor tissue could grow over the intact Bruch's membrane. [PERSON] et al. [17] suggested that the hyperreflective area above [PERSON]'s membrane may be tumor-like tissue, as they observed a clear disruption of [PERSON]'s membrane in a case of osteoma by SS-OCT. Our previous study of 73 eyes with CO found that these hyperreflective tumor-like lesions presented as bone trabecular and bone appearance on SS-OCT in 18 eyes (24.7%), further supporting the hypothesis that osteoma tissue could break through [PERSON]'s membrane and grow along its surface [32]. The incidence of the hyperreflective area being located above the disrupted [PERSON]'s member in the present study was up to 73.9%, probably due to the higher resolution of this SS-OCT platform and the combined analyses of SS-OCTA. Of the 17 eyes showing this finding, the hyperreflective tumor-like tissues in four eyes showed blood flow on OCTA without subretinal hemorrhage or fluid and fluorescent leakage on FA. This does not indicate CNV but may be a precursor of active neovascularization, in view of the aforementioned relationship between the tumor's intrinsic feeder vessels and CNV. Thus, these hyperreflective lesions require close observation for early detection and timely treatment of severe complications. Similar to previous SD-OCT studies, our SS-OCT study showed unique features including horizontal lamellar lines, hyperreflective horizontal lines, horizontal tubular lamella with an optically empty center, vertical tubular lamella, and regions of speckled reflective dots within the CO. However, as reported by [PERSON] et al. [19], and [PERSON] et al. [20], the hyporeflective tubular lamellae that were presumed to be Haversian canals, Volkmanncanals, or vascular channels as described by [PERSON] et al. [13], did not show any flow signal in SS-OCTA. The blood flow inside these channel areas may be of quiescent neovascularization, meaning the slow velocity of the blood flow cannot be captured by OCTA.