OCT angiography is a recent evaluation of OCT technology which combines the structural assessment of ocular tissues obtained by OCT image with visualization of blood flow within the vessels in imaged area. So combined structural and function image can be obtained by OCT angiography.

Defferent type of uveitis often have specific OCT & OCT angiography findingwhich deffer according to the involved ocular tissue and according to the type of inflammatory / infectious process that characterize them.

The aim of study is to determine the role of OCT & OCT angiography in assessment of retinal and choroidal architectural and vascular changes in patients with posterior uveitis.

Uveitis is a challenging disease. It represents a major cause of ocular morbidity worldwide. More than half of all patients with uveitis develop sight threatening complications related to their disease, and up to 35% of patients suffer severe visual impairment.

Uveitis and its complications are responsible for 5% to 10% of all causes of legal blindness in developed countries .

The causes of uveitis are numerous, and include infectious conditions, autoimmune diseases, trauma and tumors (masquerade syndrome). To develop an accurate differential diagnosis, clinicians must consider all available information, including the patient history, anatomic location of the inflammation (anterior or posterior), character (granulomatous vs. non granulomatous), laterality, and chronicity of inflammation. Moreover, diagnostic tools, such as fluorescein angiography (FA), indocyanine green angiography (ICG), optical coherence tomography (OCT) and ultrasound, play an important role in the diagnosis and in the management of the uveitis.

OCT & OCT angiography are now proven to be an effective noninvasive method in detecting pathologic features in uveitis and are rapidly gaining popularity as an ancillary exam. It may be used to assist in the diagnosis of uveitis and may be repeated safely during follow-up to monitor response to any intervention.

OCT angiography is a recent evaluation of OCT technology which combines the structural assessment of ocular tissues obtained by OCT image with visualization of blood flow within the vessels in imaged area. So combined structural and function image can be obtained by OCT angiography.

Defferent type of uveitis often have specific OCT & OCT angiography findingwhich deffer according to the involved ocular tissue and according to the type of inflammatory / infectious process that characterize them.

Inclusion Criteria:

• - Patient age of greater than 18 years old.
• Patient can offer viable consent.
• Patient with posterior uveitis (infectious or non-infectious posterior uveitis).

Exclusion Criteria:

• - Patient unable to offer viable consent.
• Patient unwilling to participate.
• Any coexistence retinal pathology: diabetic retinopathy, other causes of retinal vascular occlusion, traumatic retinopathy, traumatic maculopathy, other peripheral ischemic retinopathy e.g. sickles cell retinopathy.
• Presence of media opacity hindering appropriate scan.

participants will be recruited from the ophthalmology outpatient clinic of Assiut University Hospitals.- Patient with posterior uveitis (infectious or non-infectious posterior uveitis).