Browse the corpus

Hypertension remains one of the most significant global health concerns. In addition to its effects on the cardiovascular, renal, and cerebrovascular systems, this condition can also damage the retina, classifying it as a form of target-organ damage. The 3 primary types of ocular involvement include choroidopathy, retinopathy, and optic neuropathy. Hypertensive retinopathy develops as a result of sustained or abrupt elevations in blood pressure. Retinal findings include arteriolar narrowing, arteriovenous nicking, hemorrhages, hard exudates, and cotton wool spots. Specific changes observed on fundoscopic examination may indicate an increased risk of systemic complications, such as stroke. Malignant hypertension can lead to optic disc swelling (papilledema). Management strategies focus on achieving adequate systemic blood pressure control to prevent further retinal and systemic damage. Fundus photography and clinical examination play a critical role in monitoring disease progression and evaluating treatment efficacy. This activity is designed for healthcare professionals to enhance learners' competence in evaluating and managing hypertensive retinopathy. Participants will gain a deeper understanding of the condition's risk factors, pathophysiology, clinical features, and optimal diagnostic and therapeutic strategies. Greater proficiency will enable clinicians to collaborate more effectively within an interprofessional team caring for individuals with hypertension, thereby improving outcomes. Objectives: Identify the clinical and diagnostic features indicative of hypertensive retinopathy. Implement personalized, evidence-based strategies for managing hypertensive retinopathy and mitigating its potential complications. Improve communication approaches to educate patients about hypertensive retinopathy and promote treatment adherence effectively. Collaborate with the interprofessional team to educate, treat, and monitor individuals with hypertensive retinopathy to improve outcomes. Access free multiple choice questions on this topic.

Poorly controlled hypertension affects multiple organ systems, including the cardiovascular, renal, and cerebrovascular systems.[1] The retina also sustains damage, with changes in ocular structures such as vessels and nerves detectable through various imaging modalities. Damage to these organs is collectively referred to as "target-organ damage" (TOD).[2] Hypertension causes 3 types of ocular injury: choroidopathy, retinopathy, and optic neuropathy.[3] Hypertensive retinopathy results from damage to retinal vessels due to elevated blood pressure. Substantial evidence indicates that hypertensive retinopathy serves as a predictor of systemic morbidity and mortality related to TOD. A study by Erden et al demonstrated that the incidence of retinopathy correlates with both the severity and duration of hypertension.[4] Key features of hypertensive retinopathy include arteriovenous crossing changes, cotton wool spots, flame-shaped peripapillary hemorrhages, optic disc swelling (papilledema), and macular star formation.[5] Effective management of systemic hypertension and its associated morbidities is critical to limiting TOD.[6]

In 2017, the American College of Cardiology and American Heart Association Task Force on Clinical Practice Guidelines established blood pressure categories for adults, outlined in Table 1 below. Table Table. Blood Pressure Classification for Adults According to the 2017 American College of Cardiology and American Heart Association Guidelines. Systolic (SBP) and diastolic (DBP) blood pressure measurements require careful technique, with the average of at least 2 readings taken on 2 separate occasions used for classification. When SBP and DBP values fall into different categories, the higher category determines the individual’s classification.[7] Blood pressure thresholds for different categories vary slightly across guidelines.[8] For instance, SBP between 120 and 129 mm Hg or DBP between 80 and 84 mm Hg is classified as normal according to the European Society of Cardiology (ESC) and European Society of Hypertension (ESH) guidelines.[9] Definitions of malignant hypertension differ among guidelines.[10] The 2020 International Society of Hypertension (ISH) and 2018 ESC/ESH guidelines define this condition as a severe elevation of blood pressure, typically above 200/120 mm Hg, accompanied by advanced bilateral retinopathy characterized by retinal hemorrhages, cotton wool spots, and papilledema.[11] The ESC position document describes hypertensive emergency as the coexistence of markedly elevated blood pressure, often above 200/120 mm Hg, with advanced retinopathy, acute renal failure, or thrombotic microangiopathy.[12] The term "acute hypertensive microangiopathy" has been proposed for cases with acute microvascular damage to the brain and kidneys that may lack retinal lesions.[13] The National Institute for Health and Care Excellence (NICE, United Kingdom, 2019) defines accelerated hypertension as a severe increase in blood pressure to 180/120 mm Hg or higher, often exceeding 220/120 mm Hg, accompanied by signs of retinal hemorrhage or papilledema.[14]

The ESC position document describes hypertensive emergency as the coexistence of markedly elevated blood pressure, often above 200/120 mm Hg, with advanced retinopathy, acute renal failure, or thrombotic microangiopathy.[12] The term "acute hypertensive microangiopathy" has been proposed for cases with acute microvascular damage to the brain and kidneys that may lack retinal lesions.[13] The National Institute for Health and Care Excellence (NICE, United Kingdom, 2019) defines accelerated hypertension as a severe increase in blood pressure to 180/120 mm Hg or higher, often exceeding 220/120 mm Hg, accompanied by signs of retinal hemorrhage or papilledema.[14] Systemic hypertension is classified primarily into 2 main types: primary hypertension and secondary hypertension. Primary hypertension, also known as essential hypertension, represents the most common form. Risk factors for this type include advancing age, certain ethnic backgrounds, a sedentary lifestyle, smoking, excessive alcohol consumption, obesity, and an unhealthy diet characterized by high salt intake, diets rich in trans and saturated fats, and low vegetable consumption. Genetic predisposition and family history also play significant roles, alongside coexisting systemic conditions such as diabetes and kidney disease, and chronic stress.[15] Secondary hypertension arises from an identifiable underlying condition, such as kidney or heart disease, or the use of certain substances. Younger individuals may present with bilateral dimness of vision due to malignant hypertensive retinopathy. Investigation in these cases may uncover underlying causes, including kidney disease or pheochromocytoma.

Secondary hypertension arises from an identifiable underlying condition, such as kidney or heart disease, or the use of certain substances. Younger individuals may present with bilateral dimness of vision due to malignant hypertensive retinopathy. Investigation in these cases may uncover underlying causes, including kidney disease or pheochromocytoma. The most common cause of secondary hypertension is renal parenchymal disease, with diabetic nephropathy and glomerulonephritis frequently implicated. Other causes include renovascular diseases such as renal artery stenosis, endocrine disorders like primary hyperaldosteronism, Cushing syndrome, pheochromocytoma, hyperthyroidism, hyperparathyroidism, and acromegaly, as well as vascular disorders, including coarctation of the aorta and vasculitis affecting large and medium-sized vessels. Pregnancy-induced hypertension (PIH), particularly preeclampsia and eclampsia, also contributes, along with obstructive sleep apnea, polycystic ovarian syndrome, and certain medications such as nonsteroidal anti-inflammatory drugs and antidepressants.[16] Besides essential and secondary hypertension, several other factors influence the development of hypertensive retinopathy. The condition shows a higher prevalence among individuals of Afro-Caribbean descent compared to Europeans.[17] Genetic factors also contribute, with specific genotypes linked to increased risk. Pontremoli et al identified that deletion of the angiotensin-converting enzyme allele is associated with a greater likelihood of developing hypertensive retinopathy.[18] Additional genetic loci implicated in retinal venular caliber and potentially systemic hypertension include 5q14, 6q24, 12q24, and 19q13.[19] Smoking demonstrates a strong association with severe or malignant hypertensive retinopathy, as shown in the study by Poulter et al.[20] Renal dysfunction, evidenced by persistent microalbuminuria and reduced creatinine clearance, serves as a marker for various forms of TOD, including hypertensive retinopathy.[21] Uckaya et al observed elevated plasma leptin levels in patients with hypertensive retinopathy, suggesting a role for leptin in vascular endothelial injury.[22] The duration of systemic hypertension remains one of the most significant risk factors in the development of arteriosclerotic hypertensive retinopathy.[23]

An estimated 1.39 billion adults worldwide have systemic hypertension.[24] Data from the National Health and Nutrition Examination Survey in the U.S. from August 2021 to August 2023 indicate that approximately 47.7% of adults have systemic hypertension, with about 60% aware of their condition. Only around half of those diagnosed with hypertension are taking medications to control their blood pressure.[25] Hypertensive retinopathy is a common complication of systemic hypertension, with prevalence rates ranging from 28.5% to 77.1% among affected individuals.[26] Approximately 2% to 17% of adults without diabetes show signs of retinopathy, such as microaneurysms and retinal hemorrhages, likely due to hypertension.[27] Chronic hypertension leads to arteriosclerosis, which contributes to the arteriovenous changes observed in hypertensive retinopathy. The severity and duration of systemic hypertension directly correlate with the incidence of hypertensive retinopathy, as demonstrated by Erden et al, who reported a prevalence of 66.3%. Kabedi et al found an even higher prevalence (83.6%) among individuals with hypertension and identified chronic kidney disease as the strongest predictor of severe hypertensive retinopathy. In the study by Del Brutto et al, grade 1 hypertensive retinopathy was observed in 37% and grade 2 in 17% of hypertensive individuals.[28] Hypertensive retinopathy represents a common microvascular complication, affecting approximately 3% to 14% of the general population, with increased prevalence among individuals with poorly controlled or longstanding hypertension.[29] Incidence rises with advancing age and comorbidities such as diabetes and chronic kidney disease, and is more frequently observed in populations with limited access to healthcare or higher rates of undiagnosed hypertension. The incidence of hypertensive retinopathy increases with advancing age, male sex (up to midlife), and certain racial backgrounds. The prevalence of systemic hypertension rises with age, and hypertensive retinopathy is independently associated with older age.[30] The Framingham Heart Study reported a residual lifetime risk for developing hypertension of approximately 90% in individuals aged 55 and 65 years.[31]

The incidence of hypertensive retinopathy increases with advancing age, male sex (up to midlife), and certain racial backgrounds. The prevalence of systemic hypertension rises with age, and hypertensive retinopathy is independently associated with older age.[30] The Framingham Heart Study reported a residual lifetime risk for developing hypertension of approximately 90% in individuals aged 55 and 65 years.[31] Hypertension tends to be more prevalent in men than in women, particularly up to the age of 50, but this difference diminishes and can reverse in older age.[32][33][34] Studies from India indicate that men have a higher prevalence of hypertension until approximately age 50, after which the prevalence in women increases and surpasses that in men.[35][36] In terms of racial differences, individuals of Chinese or African American descent exhibit a higher prevalence of hypertensive retinopathy than Caucasians.[37]

Retinal blood vessels possess distinct characteristics that differentiate them from other vascular structures. These features include the absence of sympathetic nerve supply, the presence of autoregulation of blood flow, and the integrity of the blood-retinal barrier.[38] Consequently, an increase in blood pressure is transmitted directly to the retinal vessels, initially triggering vasoconstriction. However, when blood pressure continues to rise beyond this compensatory capacity, damage to the vascular smooth muscle and endothelium occurs. Systemic hypertension affects both the retinal arterioles and capillaries and may lead to retinal nonperfusion.[39][40] Focal intraretinal periarteriolar transudates (FIPTs) are specific indicators of malignant hypertension. These lesions result from the breakdown of the blood-retinal barrier at the level of the precapillary retinal arterioles, secondary to a sudden and severe rise in blood pressure that overwhelms autoregulatory mechanisms. The affected arterioles dilate, leading to the characteristic appearance of FIPTs as small, round or oval, dull white lesions, typically ranging from pinpoint to pinhead size. These transudates are located in the deeper retinal layers near the main retinal arteries and their primary branches. On fluorescein angiography, FIPTs exhibit multiple small areas of dye leakage originating from the dilated precapillary arterioles, without evidence of focal capillary obliteration. These lesions usually persist for 2 to 3 weeks and resolve without leaving any detectable changes on ophthalmoscopy, angiography, or microvascular imaging.[41] Additional retinal findings in hypertensive retinopathy include cotton wool spots (also referred to as "soft exudates"), hard exudates (lipid deposits), copper wiring of the retinal arterioles, and changes at arteriovenous crossings. Hemorrhages may be present in both the superficial and deep retinal layers, appearing as flame-shaped and blot hemorrhages, respectively.[42] Microaneurysms and optic disc edema can also occur. In rare cases, intraretinal microvascular abnormalities (IRMAs), venous beading, and retinal neovascularization may be observed.[43][44]

Additional retinal findings in hypertensive retinopathy include cotton wool spots (also referred to as "soft exudates"), hard exudates (lipid deposits), copper wiring of the retinal arterioles, and changes at arteriovenous crossings. Hemorrhages may be present in both the superficial and deep retinal layers, appearing as flame-shaped and blot hemorrhages, respectively.[42] Microaneurysms and optic disc edema can also occur. In rare cases, intraretinal microvascular abnormalities (IRMAs), venous beading, and retinal neovascularization may be observed.[43][44] However, distinguishing whether certain vascular changes, such as arteriovenous crossing alterations and focal arteriolar narrowing, are caused solely by systemic hypertension remains a challenge (see Image. Focal Arteriolar Narrowing). These changes may have limited predictive value in assessing the severity of hypertension. The development of hypertensive and arteriosclerotic retinal vascular changes is multifactorial and depends on several factors. These factors include the patient’s age, the duration and severity of systemic hypertension, the presence and severity of other systemic conditions such as diabetes mellitus, kidney disease, and dyslipidemia, the extent of coexisting diabetic retinopathy, and smoking history. Phases of Hypertensive Retinopathy Hypertensive retinopathy progresses through 3 distinct phases: vasoconstrictive, sclerotic, and exudative. In the vasoconstrictive phase, local autoregulatory mechanisms attempt to reduce blood flow in response to elevated blood pressure. This compensatory response leads to vasospasm, an increase in vasomotor tone, and generalized or diffuse narrowing of the retinal arterioles. Clinically, this vasoconstriction is observed as a decreased arteriole-to-venule diameter ratio (normal value is 2:3). In older individuals, the narrowing may be less apparent due to age-related arteriosclerosis, which renders the vessel walls more rigid and less responsive to vasomotor stimuli.

Hypertensive retinopathy progresses through 3 distinct phases: vasoconstrictive, sclerotic, and exudative. In the vasoconstrictive phase, local autoregulatory mechanisms attempt to reduce blood flow in response to elevated blood pressure. This compensatory response leads to vasospasm, an increase in vasomotor tone, and generalized or diffuse narrowing of the retinal arterioles. Clinically, this vasoconstriction is observed as a decreased arteriole-to-venule diameter ratio (normal value is 2:3). In older individuals, the narrowing may be less apparent due to age-related arteriosclerosis, which renders the vessel walls more rigid and less responsive to vasomotor stimuli. The sclerotic phase follows when elevated blood pressure persists, producing structural changes in the vessel walls. The intimal layer thickens, the medial layer undergoes hyperplasia, and the arteriolar wall shows signs of hyaline degeneration. These changes result in severe arteriolar narrowing, both diffuse and focal, along with arteriovenous crossing changes, commonly referred to as "arteriovenous nipping" or "nicking," and arteriolar wall opacification, seen as copper or silver wiring. Arteriovenous crossing changes occur when a thickened arteriole compresses a venule at a shared adventitial sheath. This compression leads to dilation and tortuosity of the vein distal to the crossing, often described as the Bonnet sign or retinal venous banking. In the exudative phase, a marked elevation in blood pressure disrupts the blood-retinal barrier, allowing leakage of blood, lipids, and fluid from the compromised vessel walls. Autoregulatory mechanisms fail at this stage, and visible retinal changes become evident. These changes include microaneurysms, flame-shaped and dot-blot retinal hemorrhages, hard exudates due to lipid accumulation, necrosis of smooth muscle and endothelial cells, subretinal fluid (SRF), and signs of retinal ischemia, such as cotton wool spots. Malignant Hypertension

In the exudative phase, a marked elevation in blood pressure disrupts the blood-retinal barrier, allowing leakage of blood, lipids, and fluid from the compromised vessel walls. Autoregulatory mechanisms fail at this stage, and visible retinal changes become evident. These changes include microaneurysms, flame-shaped and dot-blot retinal hemorrhages, hard exudates due to lipid accumulation, necrosis of smooth muscle and endothelial cells, subretinal fluid (SRF), and signs of retinal ischemia, such as cotton wool spots. Malignant Hypertension Severe systemic hypertension causes optic nerve ischemia and edema (papilledema), often indicating elevated intracranial pressure and potentially presenting as hypertensive encephalopathy. The progression of retinal findings does not always follow a strict sequence. Additional factors such as inflammation, ischemia, platelet activation, oxidative stress, dysregulated angiogenesis, renin-angiotensin-aldosterone system (RAAS) activity, and endothelial dysfunction also contribute to the pathogenesis of hypertensive retinal disease. Pathogenesis of Various Manifestations of Hypertensive Retinopathy Hypertensive retinopathy manifests through a variety of retinal changes resulting from chronically elevated blood pressure. The underlying pathogenesis involves vascular injury, ischemia, and breakdown of protective barriers within the retina, producing distinct clinical features. Retinal hemorrhages occur due to the breakdown of the blood-retinal barrier caused by endothelial damage and necrosis from prolonged or severe hypertension. This damage thickens the vessel walls and results in bleeding into the retina, producing flame-shaped or splinter hemorrhages in the nerve fiber layer, or dot-blot hemorrhages in the deeper retinal layers. Cotton wool spots in hypertensive retinopathy result from ischemia in the nerve fiber layer of the retina. This ischemia arises due to narrowing and occlusion of retinal arterioles, particularly the precapillary arterioles, causing a deficiency of oxygen and nutrients. The resulting hypoxia disrupts orthograde and retrograde axoplasmic transport within ganglion cell axons, leading to the accumulation of cytoplasmic debris and the formation of cotton wool spots.[45]

Cotton wool spots in hypertensive retinopathy result from ischemia in the nerve fiber layer of the retina. This ischemia arises due to narrowing and occlusion of retinal arterioles, particularly the precapillary arterioles, causing a deficiency of oxygen and nutrients. The resulting hypoxia disrupts orthograde and retrograde axoplasmic transport within ganglion cell axons, leading to the accumulation of cytoplasmic debris and the formation of cotton wool spots.[45] McLeod proposed renaming cotton wool spots as "cotton wool sentinels."[46] These spots often mark the boundary of ischemic areas, such as in branch retinal arterial occlusion. These structures also act as sentinels of ischemia affecting the entire retinal midperiphery in preproliferative diabetic retinopathy, represent an ischemic penumbra in acute panretinal ischemia, or indicate neuronal damage from transient venous hyperdistension that overwhelms the protection provided by peripapillary axonal decompartmentalization in Purtscher retinopathy.[47][48] Hypertensive Choroidopathy Hypertensive choroidopathy results from fibrinoid necrosis of choroidal arterioles, leading to segmental infarction of the choriocapillaris. This process gives rise to several characteristic findings, described below. Elschnig spots appear as areas where the overlying retinal pigment epithelium (RPE) looks yellow due to lobular nonperfusion of the choriocapillaris, which represents focal choroidal infarcts. Acute lesions are tan-colored and have a lobular or round shape, but over time, they become hyperpigmented with hypopigmented borders. Siegrist streaks develop from RPE hyperplasia overlying choroidal infarcts and appear as linear hyperpigmentation that follows the meridional course of the choroidal arteries. Angiographic studies reveal early focal choroidal hypoperfusion followed by late multiple subretinal pinpoint leakages. This pattern reflects fibrinoid necrosis of the choroid. Other manifestations of hypertensive choroidopathy include neurosensory RPE detachments and exudative retinal detachments (see Image. Exudative Retinal Detachment and Elschnig Spots in Hypertensive Choroidopathy).

Siegrist streaks develop from RPE hyperplasia overlying choroidal infarcts and appear as linear hyperpigmentation that follows the meridional course of the choroidal arteries. Angiographic studies reveal early focal choroidal hypoperfusion followed by late multiple subretinal pinpoint leakages. This pattern reflects fibrinoid necrosis of the choroid. Other manifestations of hypertensive choroidopathy include neurosensory RPE detachments and exudative retinal detachments (see Image. Exudative Retinal Detachment and Elschnig Spots in Hypertensive Choroidopathy). These signs typically occur in young patients who experience a sudden onset of severe systemic hypertension, often described as malignant hypertension, accelerated hypertension, or acute hypertensive crisis. This condition is commonly associated with underlying disorders such as kidney disease, PIH, or pheochromocytoma.

History Patients with malignant hypertension may present with headaches or bilateral visual decline. In some cases, the visual decline results from malignant hypertensive retinopathy accompanied by macular SRF, which can provide an important clue to an underlying diagnosis of hypertension. However, hypertensive retinopathy is more often discovered incidentally during routine ophthalmic examinations. A thorough history should include the duration of hypertension, current medications, adherence to treatment, and the presence of systemic comorbidities such as diabetes mellitus. Additionally, a history of hypertension-related complications, including cerebrovascular accidents and myocardial infarction, is important to assess. Physical Examination The physical examination should include vital signs and systemic examination, including cardiovascular, respiratory, and neurological systems. Careful assessment of blood pressure is essential, as hypertensive retinopathy often correlates with the severity and duration of systemic hypertension. Additionally, evaluation for signs of TOD, such as heart failure or stroke, can provide important clinical context. Ophthalmoscopic Features Hypertensive retinopathy is primarily diagnosed through characteristic findings observed during ophthalmoscopic examination. These retinal signs reflect the severity and duration of systemic hypertension and help guide clinical assessment and management. These funduscopic features are discussed in detail below. Arteriovenous crossing changes These features represent some of the earliest ophthalmoscopic signs of hypertensive retinopathy and indicate vascular remodeling due to chronic hypertension. Arteriovenous crossing changes occur where retinal arterioles and veins share a common adventitial sheath, leading to mechanical effects on the veins caused by thickened, sclerotic arterioles.

These features represent some of the earliest ophthalmoscopic signs of hypertensive retinopathy and indicate vascular remodeling due to chronic hypertension. Arteriovenous crossing changes occur where retinal arterioles and veins share a common adventitial sheath, leading to mechanical effects on the veins caused by thickened, sclerotic arterioles. The Salus sign is characterized by the deflection of the retinal vein as it crosses over or under the arteriole. When the retinal vein crosses obliquely over the arteriole, it shows a vertical hump or arch over the arteriole. More commonly, lateral deflections create an S-shaped appearance when the vein crosses the arteriole at right angles.[49] The Gunn sign denotes the tapering of the retinal vein on either side of the arteriovenous crossing, which reflects venous narrowing caused by arterial compression. The Bonnet sign describes the banking or dilatation of the retinal vein distal to the crossing (see Image. Arteriovenous Crossing Changes). This venous banking may precede branch retinal vein occlusion (RVO), a complication arising from the compression of the vein by the arteriole due to their shared adventitial sheath.[50] Arterial changes Arteriolar narrowing in hypertensive retinopathy is characterized by a decrease in the arteriovenous ratio, which can decrease to as low as 1:3 from the normal ratio of 2:3. This narrowing may be generalized, affecting large segments of the retinal arterioles, or focal, where irregular calibers result from localized spasm of the retinal arteriole. Chronic hypertension also leads to retinal arteriolar sclerosis, marked by thickening and stiffening of the arteriolar walls. Normally, retinal arterioles exhibit a central light reflex that is broader and brighter than that of retinal veins, caused by light reflecting off the convex cylindrical surfaces of the transparent blood column and vessel walls. With sclerosis, the vascular wall thickens and its refractive index increases, resulting in a widening and increased brightness of the light streak.

Chronic hypertension also leads to retinal arteriolar sclerosis, marked by thickening and stiffening of the arteriolar walls. Normally, retinal arterioles exhibit a central light reflex that is broader and brighter than that of retinal veins, caused by light reflecting off the convex cylindrical surfaces of the transparent blood column and vessel walls. With sclerosis, the vascular wall thickens and its refractive index increases, resulting in a widening and increased brightness of the light streak. Changes in the arteriolar light reflex appear as copper or silver wiring, which are hallmark signs of arteriolosclerosis. The earliest change is the widening and accentuation of the central light reflex, known as copper wiring, where the arteriolar light streak covers most of the vessel surface, giving it a burnished copper appearance. In more advanced cases, silver wiring occurs when the vessel wall becomes so opaque that it obscures the blood column, causing the arteriole to look like a white cord despite continued blood flow through it. Retinal changes Retinal changes in hypertensive retinopathy include various types of hemorrhages and exudates. Dot-blot hemorrhages occur due to bleeding in the deeper retinal layers, whereas flame-shaped hemorrhages result from bleeding in the superficial retinal layer, specifically the nerve fiber layer. Retinal exudates also manifest, with hard exudates representing lipid deposits within the retina. Soft exudates, also called cotton wool spots, arise due to ischemia affecting the nerve fibers. Macular Changes Macular star formation results from the deposition of hard exudates around the macula, specifically in the Henle layer. This star pattern becomes more prominent following the resolution of macular SRF. Optic Nerve Changes Hypertensive optic neuropathy is characterized by papilledema, which presents as blurring of the optic disc margins, radial peripapillary flame-shaped hemorrhages, severe disc swelling with retinal venous stasis, and the appearance of a macular fan or star caused by hard exudate deposition in the Henle layer. This finding indicates malignant or accelerated hypertension and defines malignant hypertensive retinopathy (see Image. Malignant Hypertensive Retinopathy).

Hypertensive optic neuropathy is characterized by papilledema, which presents as blurring of the optic disc margins, radial peripapillary flame-shaped hemorrhages, severe disc swelling with retinal venous stasis, and the appearance of a macular fan or star caused by hard exudate deposition in the Henle layer. This finding indicates malignant or accelerated hypertension and defines malignant hypertensive retinopathy (see Image. Malignant Hypertensive Retinopathy). In the acute phase, SRF accumulates at the fovea, predominantly on its nasal side, and is usually continuous with edema around the optic disc, as seen on optical coherence tomography (OCT). As the edema resolves over time, hard exudates organize in a radial pattern around the fovea, producing the characteristic macular fan or star. These patients require urgent but carefully controlled management of hypertension to prevent ischemic injury or hypoperfusion to vital organs such as the brain (ischemic stroke), heart (myocardial infarction), and kidneys.[51] Wong et al identified several retinal signs associated with an increased risk of stroke. These signs include arteriovenous nicking, focal arteriolar narrowing (linked to arteriosclerosis), microaneurysms, cotton wool spots, retinal hemorrhages (both dot-blot and flame-shaped), and a decreased arteriovenous ratio.[52] The presence of arteriovenous nicking may indicate longstanding hypertension even when current blood pressure readings are normal. However, mild arteriovenous changes may be nonspecific and may occur in the absence of hypertension. Wong and Mitchell proposed a classification system for hypertensive retinopathy based on population-level data, linking specific retinal findings to systemic vascular risks. This grading system, outlined in Table 2, helps stratify patients not only by ocular findings but also by their risk for cardiovascular and cerebrovascular complications. Table Table 2. Classification of Hypertensive Retinopathy by Wong and Mitchell Based on Population-Based Studies.

Classification The following classification systems are based on clinical fundus findings observed using indirect ophthalmoscopy or a +90 diopter lens. These systems help stratify the severity of hypertensive retinopathy and guide systemic risk assessment and management. The Keith-Wagener-Barker system categorizes hypertensive retinopathy into 4 groups, progressing from mild vascular changes to severe retinal and optic nerve involvement. This classification is commonly used to correlate retinal changes with the severity and chronicity of systemic hypertension. Group 1: Mild generalized narrowing or increased tone of the retinal arterioles Group 2: Moderate to marked arteriolar sclerosis, which may be chronic (exaggerated arteriolar light reflex and arteriovenous compression) or postangiospastic (generalized or focal irregular narrowing). RVO may be observed. Group 3: Retinal edema, flame-shaped hemorrhages, and cotton-wool spots superimposed on sclerotic and spastic arteriolar changes Group 4: All Group 3 findings plus papilledema [57] The Scheie system offers 2 separate grading schemes, one for hypertensive retinopathy and another for arteriolar sclerosis. This approach allows more precise documentation of both acute and chronic retinal vascular changes. Grading for hypertensive retinopathy focuses on acute retinal findings related to elevated blood pressure. None: No visible abnormalities Grade 1: Mild, diffuse narrowing of arterioles, especially in secondary branches Grade 2: Marked arteriolar narrowing with focal areas of vasospasm Grade 3: Grade 2 findings plus retinal hemorrhages or exudates Grade 4: Grade 3 findings accompanied by papilledema Grading for arteriolar sclerosis describes the extent of chronic arteriolar wall thickening and associated vascular changes. Grade 0: Normal retinal arterioles Grade 1: Slight widening of the central light reflex with minimal arteriovenous crossing changes Grade 2: More pronounced arteriovenous crossing changes with further widening of the arteriolar light reflex Grade 3: Copper wiring of the arterioles with marked arteriovenous changes Grade 4: Silver wiring of the arterioles, indicating the most severe form of arteriolosclerosis Systemic Evaluation

Grade 1: Slight widening of the central light reflex with minimal arteriovenous crossing changes Grade 2: More pronounced arteriovenous crossing changes with further widening of the arteriolar light reflex Grade 3: Copper wiring of the arterioles with marked arteriovenous changes Grade 4: Silver wiring of the arterioles, indicating the most severe form of arteriolosclerosis Systemic Evaluation Systemic evaluation includes repeated measurement of blood pressure. In younger individuals, secondary causes such as renal disease should be ruled out. These patients often present with associated cardiovascular, renal, and cerebrovascular conditions, requiring coordinated care among physicians, ophthalmologists, cardiologists, nephrologists, and neurologists. Coexisting anemia and diabetes mellitus can aggravate the retinal findings and should be investigated.[58] Ophthalmic Evaluation A comprehensive eye examination should be performed. Fundus photography, using either standard or wide-field imaging, is useful for documenting retinal findings and monitoring treatment response. In cases of malignant hypertensive retinopathy, OCT may reveal macular edema with SRF, with or without intraretinal fluid. This fluid accumulation is typically more prominent on the nasal side of the fovea and often connects with peripapillary SRF. A macular star may develop following the resolution of macular edema. Given the potential for severe renal involvement, nephrology consultation is essential. These patients may also require a fundus fluorescein angiogram (FFA), which can demonstrate microaneurysms, capillary nonperfusion, intraretinal microvascular abnormalities, venous beading, optic disc leakage, and occasionally neovascularization. In early FFA phases, a dendritic pattern of choroidal filling defects may be seen, followed by diffuse subretinal leakage in the late phase. Multiple FIPTs and acute Elschnig spots can cause multiple pinpoint leakages.[59] The relationship between Elschnig spots and FIPTs may require further investigation. Indocyanine green angiography may show a moth-eaten appearance of the choriocapillaris in malignant hypertension, which can appear as flow voids on OCT angiography.[60]

Given the potential for severe renal involvement, nephrology consultation is essential. These patients may also require a fundus fluorescein angiogram (FFA), which can demonstrate microaneurysms, capillary nonperfusion, intraretinal microvascular abnormalities, venous beading, optic disc leakage, and occasionally neovascularization. In early FFA phases, a dendritic pattern of choroidal filling defects may be seen, followed by diffuse subretinal leakage in the late phase. Multiple FIPTs and acute Elschnig spots can cause multiple pinpoint leakages.[59] The relationship between Elschnig spots and FIPTs may require further investigation. Indocyanine green angiography may show a moth-eaten appearance of the choriocapillaris in malignant hypertension, which can appear as flow voids on OCT angiography.[60] In 2014, Ahn and colleagues proposed a classification of hypertensive retinopathy based on ophthalmoscopic findings, which showed a significant correlation with final best-corrected visual acuity.[61] The classification includes the following categories: Mild to moderate retinopathy, with or without SRF Malignant retinopathy without SRF Malignant retinopathy with SRF

Retinal vessels are the only blood vessels that can be directly seen during a routine eye exam, making them important for screening hypertensive retinopathy. Retinal and choroidal changes reflect the systemic vascular damage from chronically elevated blood pressure. Ophthalmologists and general physicians should collaborate to ensure timely screening and appropriate management to reduce the risk of ocular and systemic complications.[62] Henderson et al noted that hypertensive retinopathy remains associated with an increased risk of stroke, even after control of blood pressure and other vascular risk factors. Management includes both systemic regulation and ocular evaluation. Systemic Control Hypertensive retinopathy, including papilledema and macular subfoveal fluid, often improves with adequate systemic control, particularly blood pressure regulation and management of renal dysfunction. Treatment depends on disease severity. In mild cases, management consists of blood pressure control with regular monitoring. In moderate cases, referral to a physician is essential to evaluate for coexisting conditions such as diabetes mellitus and cardiovascular abnormalities. Ongoing care requires strict blood pressure regulation and close follow-up. Severe cases demand urgent intervention and referral due to the strong association with mortality. Evaluation for TOD involving the kidneys, cardiovascular system, and brain is critical. Blood pressure should be lowered in a controlled manner in severe cases. Most guidelines recommend reducing the mean arterial pressure (MAP) by 10% to 15% in the first hour and no more than 25% of baseline within the first 24 hours during a hypertensive crisis.[63] MAP is calculated using the following formula: MAP = [(2 × DBP) + SBP] ÷ 3

Blood pressure should be lowered in a controlled manner in severe cases. Most guidelines recommend reducing the mean arterial pressure (MAP) by 10% to 15% in the first hour and no more than 25% of baseline within the first 24 hours during a hypertensive crisis.[63] MAP is calculated using the following formula: MAP = [(2 × DBP) + SBP] ÷ 3 Controlled reduction is essential to prevent ischemic injury to critical end organs such as the optic nerve, kidneys, and brain. Management typically begins with parenteral medications, followed by a gradual transition to oral agents. Common intravenous drugs used in hypertensive emergencies include labetalol, nicardipine, clevidipine, fenoldopam, esmolol, and sodium nitroprusside.[64] Primary drug classes for long-term blood pressure control include angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, thiazide diuretics, and calcium channel blockers. Additional options include β-blockers, α-blockers, and vasodilators.[65] Ophthalmic Management Most cases of malignant hypertensive retinopathy respond well to systemic blood pressure control. However, foveal SRF may persist on OCT despite adequate systemic management and a reasonable observation period. In a case series, intravitreal bevacizumab led to improvement in macular edema and fluorescein leakage in 4 eyes from 2 patients. Visual acuity improved in all but 1 eye, which showed no improvement due to foveal atrophy.[66] Other reports have documented similarly encouraging outcomes.[67][68][69] Systemic control should always be prioritized before considering intravitreal therapy, given the associated risks, including endophthalmitis and potential blood pressure dysregulation in individuals with hypertension.[70][71][72][73] The role of anti-vascular endothelial growth factor agents requires further investigation.

Other conditions that often present with optic disc swelling include the following: Idiopathic intracranial hypertension Anterior ischemic optic neuropathy Optic neuritis Central RVO Diabetic papillopathy Neuroretinitis Radiation papillopathy Retrobulbar tumor Conditions which mimic chronic hypertensive retinopathy include the following: Diabetic retinopathy Retinal venous obstruction Hyperviscosity syndrome Ocular ischemic syndrome Radiation retinopathy Anemia and other hematological disorders Differentiating hypertensive retinopathy from other conditions with similar retinal or optic nerve findings is critical for guiding appropriate treatment. These overlapping features highlight the importance of a detailed history, systemic evaluation, and ocular imaging.

Chronic hypertensive retinopathy rarely leads to significant visual loss. Retinal changes can stabilize with effective treatment of hypertension, although arteriolar narrowing and vessel crossing changes often remain. In untreated malignant cases, mortality reaches up to 50% within 2 months and nearly 90% within 1 year of diagnosis. Vision loss results from secondary optic atrophy following prolonged papilledema or from pigmentary changes after exudative retinal detachment. Malignant hypertensive retinopathy with papilledema shows a strong association with increased cardiovascular risk and mortality.[74][75] These patients are also more prone to retinal vascular occlusions and retinal arterial macroaneurysms.[76]

Systemic hypertension contributes to a broad spectrum of ocular pathologies. Retinal artery occlusion may occur as a direct consequence of elevated vascular resistance. RVO often results from chronic vascular stress and may be complicated by macular edema, epiretinal membrane, vitreomacular traction, vitreous hemorrhage, and tractional retinal detachment.[77][78][79][80] Retinal arteriole macroaneurysms may develop due to chronic arterial wall damage. When hypertensive retinopathy coexists with diabetic retinopathy, the condition is referred to as "mixed retinopathy." Hypertension plays a critical role in the progression and increased prevalence of diabetic retinopathy.[81] Anterior ischemic optic neuropathy may result from impaired optic nerve perfusion.[82] Age-related macular degeneration and glaucoma also show established associations with elevated systemic blood pressure.[83][84][85] Retinal arteriolar emboli may originate from systemic vascular pathology and reflect the burden of embolic disease.[86] Subconjunctival hemorrhage is another ocular finding linked with elevated vascular fragility in hypertensive states.[87] Suprachoroidal hemorrhage, a sight-threatening event during intraocular surgeries, has been strongly associated with hypertension.[88] This complication may also occur spontaneously in patients with severe hypertension, particularly in cases of PIH.[89] Additional risk factors include antiplatelet therapy, coagulopathies, hematologic disorders, and chronic renal failure in elderly patients with exudative macular degeneration.[90] Bilateral exudative retinal detachment may be seen in poorly controlled hypertension, especially among younger individuals.[91][92] These cases often exhibit signs of hypertensive choroidopathy in the attached retina.[93] Prolonged papilledema secondary to uncontrolled systemic hypertension may lead to optic atrophy, resulting in irreversible vision loss.[94] Persistent subfoveal fluid may cause long-term foveal thinning and RPE changes.[95]

Bilateral exudative retinal detachment may be seen in poorly controlled hypertension, especially among younger individuals.[91][92] These cases often exhibit signs of hypertensive choroidopathy in the attached retina.[93] Prolonged papilledema secondary to uncontrolled systemic hypertension may lead to optic atrophy, resulting in irreversible vision loss.[94] Persistent subfoveal fluid may cause long-term foveal thinning and RPE changes.[95] Proliferative hypertensive retinopathy is a rare but severe manifestation of uncontrolled hypertension. This condition mimics proliferative diabetic retinopathy, with features including retinal ischemia, neovascularization, vitreous hemorrhage, and tractional detachment.[96][97] A diagnosis requires the exclusion of other potential causes of retinal neovascularization, such as proliferative diabetic retinopathy, RVO, ocular ischemic syndrome, sickle cell retinopathy, hyperviscosity syndromes, sarcoidosis, and systemic lupus erythematosus.

Generalized retinal arteriolar attenuation correlates with elevated blood pressure and an increased risk of systemic hypertension.[98][99] In some cases, this vascular change may precede the clinical onset of hypertension.[100][101] Even in early childhood, between ages 4 and 8 years, generalized arteriolar narrowing may reflect the early vascular impact of elevated blood pressure.[102][103][104] Arteriolar narrowing and arteriovenous nicking typically indicate cumulative vascular stress from longstanding hypertension and serve as markers of chronic disease. In contrast, microaneurysms, retinal hemorrhages, and focal arteriolar attenuation tend to reflect short-term blood pressure fluctuations.[105] Dilated retinal veins also appear to be associated with elevated blood pressure levels.[106][107][108] Given the shared anatomy, physiology, and embryology between retinal and cerebral small vessels, hypertensive changes in the retina may predict the risk of subclinical or clinical cerebrovascular accidents.[109] Hypertensive retinopathy serves as a recognized indicator of TOD, including renal dysfunction, microalbuminuria, and left ventricular hypertrophy.[110] Associations have also been documented between hypertensive retinopathy and conditions such as congestive cardiac failure, clinical coronary artery disease, aortic stiffness, coronary artery calcification, and left ventricular hypertrophy.[111][112] Hypertensive retinopathy is linked to higher risks of cardiovascular disease mortality, coronary heart disease mortality, and stroke-related death.[113] Retinal vascular changes and hypertensive retinopathy may also be associated with cognitive impairment, dementia, and Alzheimer disease, though further research is needed in this area.[114][115]

Blood pressure measurement is recommended in patients presenting with diffusely reduced retinal arteriolar caliber in the absence of significant ocular disease. Most global hypertension management guidelines recognize hypertensive retinopathy, along with renal dysfunction and left ventricular hypertrophy, as evidence of TOD. These findings indicate the need for more intensive blood pressure control.

Hypertension involves multiple organ systems, requiring coordinated care among physicians, physician assistants, nurse practitioners, ophthalmologists, nephrologists, and cardiologists to support early detection and effective management. Patients must be advised to attend regular follow-up appointments with an ophthalmologist for comprehensive eye evaluations and receive clear education on the importance of adhering to antihypertensive therapy.[116] Vision is generally preserved in patients with hypertensive retinopathy if blood pressure is controlled. Uncontrolled hypertension, however, may result in irreversible vision loss within a short timeframe. The underlying causes include retinal pigmentary changes and secondary optic atrophy, both of which are permanent.[117]