Changing Perspectives in Classifications of Hypertensive Retinopathy.

Abstract

Hypertensive retinopathy represents the ophthalmic findings of end organ damage secondary to systemic arterial hypertension. The eye is a target organ as well as an established prognostic indicator of systemichypertension. Based on ophthalmoscopically visible alterations, several classifications, the majority of them grading hypertensive fundus changes into four stages have been suggested. The recognition of hypertensive retinopathy is important in cardiovascular risk stratification of hypertensive individuals. The review evaluates the changing perspectives in classification & prognostic significance of fundal lesions. consists of retinal vascular changes that are pathologically related to both transient & persistent microvascular damage from elevated blood pressure. Ocular changes can be the initial finding in an asymptomatic patient with hypertension necessitating primary referral. In other instances, asymptomatic patient may be referred to an ophthalmologist for visual problems caused by hypertensive changes. Elevation of systemic blood pressure causes both focal and generalized constriction of retinal arterioles mediated by autoregulation. These findings are relatively common in long standing hypertension. A prolonged duration of high blood pressure can be associated with a breakdown of inner blood retinal barrier with extravasation of plasma & RBCs . Retinal haemorrhages, cotton wool spots, intraretinal lipids & in severe cases , the development of macular star configuration of intraretinal lipid can be seen. Although its name implies only retinal involvement, changes in both choroid & optic nerve are observed. When choroidal vessels are severely affected by elevated blood pressure, as in acute hypertension, fibrinoid necrosis of choroidal arterioles can cause occlusion of areas of choriocapillaris, with a subsequent breakdown of outer blood retinal barrier. Ocular findings in accelerated hypertension are divided into three distinct categories: hypertensive retinopathy, hypertensive choroidopathy & hypertensive optic neuropathy. Ophthalmic findings in acute malignant hypertensive retinopathy include focal arterial narrowing, cotton wool spots, intraretinal transudates , macular edema and retinal haemorrhages. Cystoid macular edema, lipid deposits and arteriolar changes are signs of malignant hypertensive retinopathy (2) . Cotton wool spots are fluffy, elevated, tan white areas of retinal opacity occurring within a few disc diameters of optic nerve, caused by occlusion of terminal retinal arterioles. Cotton wool spots typically resolve in 3-6 weeks and are associated with permanent nerve fiber layer loss in the vicinity of the lesion (2) . Periarteriolar intraretinal transudates are tan white retinal lesions which resolve without residual retinal damage in 2-3 weeks (3) . Macular edema and subretinal fluid are retinal findings related to hypertensive choroidal changes affecting the retinal pigment epithelium, with alterations in the blood retinal barrier. Clinical changes from hypertensive choroidopathy are directly related to the release of endogenous vasoconstrictor agents (eg.,angiotensin II, epinephrine, vasopressin) during systemic hypertension. Angiographically, there is delayed, patchy choroida lfilling