ABSTRACT
INTRODUCTION As far back as the nineteenth century, retinal changes were described in patients with arterial hypertension [1,2]. The traditional classification that grades hypertensive retinopathy into four grades with increasing severity goes back to the famous work by Keith et al. [3]. In 1939, Keith et al. demonstrated that the severity of hypertensive retinopathy as detected by direct ophthalmoscopy is of predictive value for mortality in patients with arterial hypertension: the 3-year survival rate was 70% among patients with mild retinal vascular alterations, that is, minimal arteriolar changes (grade 1 hypertensive retinopathy), versus 6% in patients with severe retinal abnormalities, that is, edema of the optic nerve head (grade 4 hypertensive retinopathy) [3]. In 1966, Breslin et al. found that direct ophthalmoscopy is also of prognostic significance in a cohort of patients with primary hypertension [4,5]. In addition, several other studies that had been conducted in the middle of the twentieth century or thereafter confirmed the prognostic value of more moderate or severe retinal abnormalities as detected by direct ophthalmoscopy for mortality in patients with arterial hypertension [6-11]. In 2004, Wong and Mitchell proposed a simplified classification system of hypertensive retinopathy based on the prognosis of different retinal changes and its relationship with cardiovascular disease outcomes from recent population-based data grading hypertensive retinopathy into mild (generalized arteriolar narrowing, focal arteriolar narrowing, arteriovenous nicking, and arteriolar wall opacification [silver or copper wiring]), moderate (microaneurysm, hemorrhage [blot, dot, or flame shaped], hard exudates, and cotton wool spot), and malignant (moderate retinopathy signs plus optic disc swelling) stages [12].
