Nonarteritic problems with flow could occur due to embolic or systemic disease or as part of the manifestation of severe hypertension. Emboli from the heart, corticosteroids or calcium hydroxyapatite injection, and intravascular coagulation all have the potential to occlude choroidal vessels. Vascular occlusion could also occur in patients with lupus anticoagulants. Thrombotic thrombocytopenic purpura causes a classic pentad of findings: (1) microangiopathic hemolytic anemia, (2) thrombocytopenia, (3) fever, (4) neurologic dysfunction, and (5) renal dysfunction. Patients with this condition may have multifocal yellow placoid areas and associated serous detachment of the retina. Similar fundus findings may occur in patients with disseminated intravascular coagulation, in which consumption of coagulation proteins, involvement of cellular elements, and release of fibrin degradation products lead to hemorrhage from multiple sites and ischemia from microthrombi.
Figure 9-8 Giant cell arteritis. ICG angiography image 1 day after this patient had severe vision loss secondary to arteritic anterior ischemic optic neuropathy revealed a wedge-shaped area of choroidal nonperfusion (curved arrow). The apex of the wedge of nonperfusion points toward the area of the occluded short PCA.
(Courtesy of Richard F. Spaide, MD.)
Figure 9-9 Granulomatosis with polyangiitis (formerly, Wegener granulomatosis). The early phase of wide-angle ICG angiography of the left eye reveals a widespread filling defect of the arterioles and choriocapillaris in the inferior fundus (curved arrow) and in a segmental area of the superior fundus (asterisk).
(Reprinted from Iida T, Spaide RF, Kantor J. Retinal and choroidal arterial occlusion in Wegener’s granulomatosis. Am J Ophthalmol. 2002;133:151–152. Copyright © 2002, with permission from Elsevier.)
Similar fundus findings occur in patients with acute hypertension, such as malignant hypertension or eclampsia (Fig 9-10). In addition to retinal and optic nerve head abnormalities, these disorders also commonly lead to serous detachment of the retina associated with areas of yellow placoid discoloration of the RPE (see Fig 9-10). The perfusion abnormalities may range from focal infarction of the choriocapillaris to fibrinoid necrosis of larger arterioles. Resolution of smaller infarcts, which initially appear tan in color, produces small patches of atrophy and pigmentary hyperplasia called Elschnig spots. Infarction of an arteriole can lead to Siegrist streaks, while sector-shaped abnormalities are called Amalric triangles.
Figure 9-10 Preeclampsia with HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome. A, Color fundus photograph reveals a serous detachment of the retina and multiple yellowish placoid areas at the level of the RPE and inner choroid. B, Early-phase fluorescein angiography image shows reticular patterns of decreased choroidal perfusion bordering areas of hyperfluorescence. Early leakage from the level of the RPE is evident and becomes more apparent in the later phases of the study (C). There is also staining of and leakage from the optic nerve. D, ICG angiography image shows profound choroidal vascular filling defects alternating with areas of abnormal vessel leakage and staining, a rare finding. E, In the late phase, numerous arterioles show staining of their walls, indicating severe vascular damage.
(Used with permission from Spaide RF, Goldbaum M, Wong DW, Tang KC, Iida T. Serous detachment of the retina. Retina. 2003;23:820–846.)
Older patients may have areas of slow blood flow in the choroid, causing choroidal filling defects. The flow problems may result from low inflow pressure. Histologic sections of eyes of older patients may reveal intimal hyperplasia and medial hypertrophy with a decrease in the lumen size. This change may also adversely affect blood flow. Decreased flow in the segmentally arranged choroid can cause areas of particularly decreased perfusion between areas of low perfusion; these are called watershed defects.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.