11 © Springer Nature Switzerland AG 2019 A. H. Algaeed, I. Kozak (eds.), Clinical Atlas of Ophthalmic Ultrasound, https://doi.org/10.1007/978-3-319-99870-1_3 Vitreous/Retina/Choroid Abdulrahman H. Algaeed, Maram A. Elsayed, and Igor Kozak This chapter covers perhaps the most frequent pathologies in which ophthalmic echography is used. The cases presented here include images of vitreous tractions and hemorrhages, images of retinal detachments due to causes such as prolif- erative diabetic retinopathy or proliferative vitreoretinopa- thy, images of silicone oil–flled eyes, and images of choroidal detachments (Figs. 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 3.10, 3.11, 3.12, 3.13, 3.14, 3.15, 3.16, 3.17, 3.18, 3.19, 3.20, 3.21, 3.22, 3.23, 3.24, 3.25, 3.26, 3.27, 3.28, 3.29, 3.30, 3.31, 3.32, 3.33, 3.34, 3.35, 3.36, 3.37, 3.38 and 3.39). The emphasis is placed on a presentation of clinically vari- able cases so that clinical correlations can be inferred. Ultrasound eye examination is not only an excellent diag- nostic modality but also can assist in surgical planning. The preoperative ultrasound evaluation of vitrectomy patients is of utmost value and involves the combination of an opti- mized and standardized A-scan and B-scan. The A-scan echography gives information about the quantitative and kinetic characteristics of the examined structures, and the B-scan echography demonstrates the shape and topographic relationship of the investigated structures [1, 2]. The usual scanning protocol starts with transverse views in all four quadrants, gradually extending from posterior to ante- rior. They are performed initially at high gain to assess the vitre- ous, and then at lower gain to assess the retina. The high-sensitivity high gain detects low refective echoes such as vitreous debris and posterior hyaloid face. The lower gain improves resolution of the retina. Longitudinal scans, usually at lower gain, assist detection and localization of pathologic fnd- ings found on transverse scans, but provide more detail [3–5]. 3 A. H. Algaeed Department of Diagnostic Imaging, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia e-mail: agaeed@kkesh.med.sa M. A. Elsayed Jeddah Eye Hospital, Jeddah, Saudi Arabia I. Kozak (*) Moorfelds Eye Hospitals, Abu Dhabi, UAE e-mail: igor.kozak@moorfelds.ae