This chapter discusses retinal vascular diseases that are associated in some way with cardiovascular disease. When evaluating patients, it is important to consider the additional risk factors linked to many of these conditions.
Systemic Arterial Hypertension
Elevated blood pressure (BP) affects more than 72 million people in the United States. In a recent classification of BP for adults, normal BP is <120/80 mm Hg; elevated blood pressure is defined as 120–129 mm Hg systolic and <80 mm Hg diastolic BP; stage 1 hypertension is defined as 130–139 mm Hg systolic or 80–89 mm Hg diastolic BP; and stage 2 hypertension is systolic BP ≥140 mm Hg or diastolic BP ≥90 mm Hg.
Together with heart, kidneys, and brain, the eye is a major target organ of systemic hypertension. Ocular effects of hypertension can be observed in the retina, choroid, and optic nerve. Retinal changes can be described and classified using ophthalmoscopy and angiography. An ophthalmologist’s recognition of posterior segment vascular changes may even prompt the initial diagnosis of hypertension and alert the patient to the potential complications associated with this condition. BCSC Section 1, Update on General Medicine, discusses hypertension in more detail.
Kim SK, Mieler WF, Jakobiec F. Hypertension and its ocular manifestations. In: Albert DM, Miller JW, Azar DT, Blodi BA, eds. Albert & Jakobiec’s Principles and Practice of Ophthalmology. 3rd ed. Philadelphia: Saunders; 2008:4367–4384.
Hypertension affects arterioles and capillaries, the anatomic loci of both autoregulation and nonperfusion. An acute hypertensive episode may produce focal intraretinal periarteriolar transudates (FIPTs) at the precapillary level. The presence of cotton-wool spots (also referred to as soft exudates) indicates ischemia of the retinal nerve fiber layer (Fig 6-1). Uncontrolled systemic hypertension leads to nonperfusion at various retinal levels as well as neuronal loss and associated scotomas. Other, more chronic, hypertensive retinal lesions include microaneurysms, intraretinal microvascular abnormalities (IRMAs), blot hemorrhages, lipid exudates (also referred to as hard exudates or edema residues), venous beading, and neovascularization. The relationship between hypertensive vascular changes and arteriosclerotic vascular disease is complex, with wide variation related to the duration and severity of the hypertension, the presence of diabetic retinopathy, the severity of any dyslipidemia, patient age, and the patient’s history of smoking. Hence, it is difficult to classify which retinal vascular changes have been caused strictly by hypertension; the often-cited focal arteriolar narrowing and arterial venous nicking have been shown to have little predictive value for actual hypertension severity. Nonetheless, one historical classification of mostly arteriosclerotic retinopathy is the Modified Scheie Classification of Hypertensive Retinopathy:
Grade 0 No changes
Grade 1 Barely detectable arterial narrowing
Grade 2 Obvious arterial narrowing with focal irregularities
Grade 3 Grade 2 plus retinal hemorrhages and/or exudates
Grade 4 Grade 3 plus optic nerve head swelling
Hypertension may be complicated by branch retinal artery occlusion (BRAO), branch retinal vein occlusion (BRVO), central retinal vein occlusion (CRVO), or retinal arterial macroaneurysms (all discussed later in this chapter). In addition, the coexistence of hypertension and diabetes mellitus results in more severe retinopathy because precapillary and capillary insults act in combination.
Figure 6-1 Severe hypertensive retinopathy. A, Fundus photograph from a 25-year-old man with renal hypertension shows large superficial and white cotton-wool spots contrasting with small, tan, and deep focal intraretinal periarteriolar transudates (FIPTs). B, Angiography image shows areas of nonperfusion corresponding to the cotton-wool spots and punctuate hyperfluorescence corresponding to the FIPTs.
(Courtesy of Hermann D. Schubert, MD.)
Cheung CYL, Wong TY. Hypertension. In: Schachat AP, Wilkinson CP, Hinton DR, Sadda SR, Wiedemann P, eds. Ryan’s Retina. 6th ed. Philadelphia: Elsevier/Saunders; 2018: chap 52.
Wong TY, Mitchell P. The eye in hypertension. Lancet. 2007;369(9559):425–435.
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.