Clinical Observation of Choroidal Osteoma Using Swept-Source Optical Coherence Tomography and Optical Coherence Tomography Angiography

Choroidal neovascularization (CNV) secondary to choroidal osteoma (CO) can cause profound visual loss, but detecting CNV and the tumor's feeder vessels using traditional fluorescent angiography imaging is challenging. Newly developed TowardPi swept-source optical coherence tomography (SS-OCT) and OCT angiography (SS-OCTA) enable ultra-high resolution, enhanced penetration with longer wavelength (1060 nm), a rapid scan rate (400 KHz), reduced loss of signal strength with increasing depth, and 120 degrees angular widefield of fundus view, enabling a nearly histological description of the retina and choroid. We therefore used this SS-OCT and SS-OCTA platform to observe the intrinsic features of osteoma in 23 eyes of 21 patients. It was found that the borders of CO were clearly demarcated from the adjacent choroidal Sattler's and Haller's layers, while on a corresponding B-scan the blood flow of the CO was detected mainly within the choriocapillaries and partly within Sattler's layer. The CNV was identified as numerous branching or radiating vessels connecting with intrinsic feeder vessels displaying various patterns including ginseng, instant noodle, growth ring, tangle, spider web, medusa, seafan, and irregular shape. Moreover, tumor-like tissues were found to grow above the disrupted Bruch's membrane. SS-OCTA can be used to detect the tumor vasculature in CO.