hemorrhages may resemble those associated with diabetes mellitus.

Severe ischemia causes anterior segment changes that may be confused with intraocular inflammation. The patient may have decreased visual acuity; a red, painful eye with episcleral vascular injection; and aqueous flare (ischemic uveitis). Even though neovascularization of the chamber angle and iris is common, intraocular pressure (IOP) may be low, normal, or high. Low or normal IOP in this setting is the result of impaired ciliary body perfusion. Fundus changes may include dilated retinal veins, narrowed retinal arteries with microaneurysm formation, midperipheral dot-and-blot hemorrhages, and macular edema (Fig 5-3). These changes have been termed venous stasis retinopathy (VSR) and may be caused by vascular occlusion anywhere between the heart and the eye.

Figure 5-3 Ocular ischemic syndrome. A, Fundus demonstrates retinal venous dilation, scattered hemorrhages, and mild

optic disc edema. B, Midperipheral dot-and-blot hemorrhages. (Reprinted with permission from John E. Carter, MD. From Carter JE. Panretinal photocoagulation for progressive ocular neovascularization secondary to occlusion of the common carotid artery. Ann Ophthalmol. 1984;16(6):572–576.)

Treatment of ocular ischemic syndrome includes CEA, IOP-lowering drugs, corticosteroids for pain, and panretinal photocoagulation. If the preoperative IOP is low, restoration of blood flow by CEA may precipitate dangerously high IOP. Once the patient incurs signs of chronic hypoperfusion, however, improvement is unlikely. In other patients, carotid occlusion may be too advanced for surgical correction. Early detection is crucial because neovascularization and progressive ocular ischemia occur with prolonged hypoperfusion (see also BCSC Section 12, Retina and Vitreous).

Mizener JB, Podhajsky P, Hayreh SS. Ocular ischemic syndrome. Ophthalmology. 1997;104(5):859–864.

Vasospasm, Hyperviscosity, and Hypercoagulability

TMVL can result from vasospasm of the retinal artery. Patients are generally younger than 50 years, have a strong personal or family history of migraine, and experience stereotypic episodes of painless TMVL that are often severe, even involving complete visual loss. The ocular examination findings are usually normal, but occasionally funduscopic examination reveals constriction of the retinal arteries. Diagnosis of vasospastic TMVL is one of exclusion. The workup should include complete blood count, cardiac evaluation, and carotid imaging. If the patient is older than 50 years, tests for