What is the classification of hypertensive retinopathy?

Classification of Hypertensive Retinopathy

The most clinically relevant classification divides hypertensive retinopathy into two prognostic categories: mild (Grades I-II) with generalized arteriolar narrowing and arteriovenous nicking, and malignant/severe (Grades III-IV) with retinal hemorrhages, cotton wool spots, hard exudates, and papilledema—only the latter represents a hypertensive emergency requiring immediate intervention. 1, 2

Modern Two-Grade Classification System

The traditional Keith-Wagener-Barker classification has been simplified into a pathophysiology-based system that emphasizes clinical decision-making 3, 4:

Non-Malignant Hypertensive Retinopathy (Grades I-II)

• Grade I: Generalized arteriolar narrowing only 5
• Grade II: Arteriovenous crossing changes (arteriovenous nicking) 5, 4
• These findings indicate chronic hypertensive vascular changes but do not constitute acute target organ damage requiring emergency treatment 1, 6
• Grade II retinopathy correlates with left ventricular hypertrophy (OR 2.3) and coronary artery disease (OR 4.2), making it clinically significant for cardiovascular risk stratification 5

Malignant Hypertensive Retinopathy (Grades III-IV)

• Grade III: Presence of retinal hemorrhages (flame-shaped), cotton wool spots, and hard exudates 1, 2
• Grade IV: All Grade III findings plus papilledema 1, 2
• These findings define a hypertensive emergency, typically occurring with blood pressure >200/120 mmHg 1
• Requires immediate ICU admission and parenteral antihypertensive therapy with target mean arterial pressure reduction of 20-25% within the first hour 1, 2

Clinical Algorithm for Assessment

When evaluating hypertensive retinopathy:

1. Perform dilated fundoscopy to identify specific retinal changes 1
2. Assess bilaterality of findings—bilateral presentation is highly specific for chronic systemic hypertension 1
3. Stratify by severity:
   • Grades I-II: Outpatient management with oral antihypertensives, target BP <140/90 mmHg 1
   • Grades III-IV: Immediate emergency department referral, ICU admission, and IV nicardipine or labetalol 2

Important Clinical Context

The presence of retinopathy indicates chronic hypertension, not acute gestational hypertension, because retinal microvascular changes require sustained severe blood pressure elevation over time to develop 1. In pregnant patients, retinopathy suggests pre-existing chronic hypertension with superimposed preeclampsia 1.

Grades I and II are far more prevalent than advanced retinopathy in hypertensive populations (49.1% Grade I, 11.2% Grade II vs. rare Grades III-IV) 5. While European guidelines no longer classify Grades I-II as acute target organ damage, Grade II retinopathy remains clinically important for identifying patients at elevated cardiovascular risk 6.

Pitfalls to Avoid

• Do not dismiss Grade II findings as clinically insignificant—they predict coronary artery disease and warrant aggressive cardiovascular risk modification 5, 6
• Do not delay ophthalmologic referral for patients with moderate or severe nonproliferative changes identified on screening 7
• Avoid excessive rapid blood pressure lowering in patients with chronic hypertensive retinopathy, as altered autoregulation can precipitate cerebral, renal, or coronary ischemia 2