High Blood Pressure and your Eyes – How Blood Pressure affects your Vision
HYPERTENSIVE RETINOPATHY
Basic Ophthalmology Review
Tittle: Hypertensive Retinopathy
Author: S. Hernández/MS4 UAG
Hypertensive retinopathy (HR) is a secondary manifestation of elevated systemic blood pressure.
The latter, is defined as healthy when the systolic pressure is not greater than 120mmHg and, the diastolic
is more than 60mmHg but less than 80mmHg. Alterations of a healthy systemic blood pressure, where it
exceeds the 140/90mmHg, causes vascular changes which in change decreases perfusion to organs causing
them damage. This retinopathy affects a variety of structures of the eye due to damage of the corresponding
circulation of such structures that include the choroid, retina and optic nerve. Damage to these structures
can be observed in both, chronic elevated blood pressure and acute rapid elevation of blood pressure 1
. In
the early stages of hypertension, no retinal changes may be observed and the first changes are generalized
constriction and irregular narrowing of the arterioles in the fundus 2
. The chronic changes include arteriolar
narrowing, arteriovenous nicking, and silver and copper wiring. Hard exudates, microaneurysms, retinal
blot and flame shaped hemorrhages are associated with exudative retinopathy phase. And acute changes
associated with rapidly elevated blood pressure include choroidal infarction and disc edema.
This retinopathy and hypertension are associated with the development of vision threatening
disorders such as retinal artery and vein occlusion, and aneurysms. In general terms, Hypertensive
retinopathy is the result of changes to the retinal vasculature. It can also be an independent risk factor for
strokes, cardiovascular mortality, renal disease and cognitive decline 1
. Due to the high prevalence of
hypertension in African Americans they are the group at highest risk for this retinopathy. Other groups like
Hispanics, that have high prevalence for diabetes are also at risk of developing hypertension, thus
retinopathy. Other related causes that are believed to be associated to retinopathy without diabetes but
increased association with hypertension are increasing age, dyslipidemia, hyperglycemia, autoimmune
disorders and a high mass index3
. In children, hypertensive retinal changes indicate that the child may have
an underlying renal disease, pheochromocytoma, collagen disease and cardiovascular disorders like
coarctations.
The pathophysiology of hypertensive retinopathy occurs in different phases. The first phase is the
vasoconstrictive phase in which autoregulatory mechanisms cause vasospasm in attempt to decrease blood
flow, and narrowing of the retinal arteriole 4
. The sclerotic phase is comprised of chronic and uncontrolled
increases in blood pressure which cause thickening of the intimal layer, hyperplasia of the media and
hyaline degeneration of the arteriolar wall. These, all result in severe narrowing, arteriovenous crossing
changes (when thickened arteriole crosses over a venule and subsequently compresses it, causing in turn dilation and torsion of the arteriovenous crossing/nicking), and accentuation of light reflex (silver and
copper wiring) 4
. A third phase, the exudative phase, is seen in patients with very poorly controlled or
severely increased blood pressure. It is characterized by disruption of the blood-brain barrier which causes
leakage of blood and plasma into the vessels walls disrupting physiologic mechanisms. It is in this phase
where signs such as hard exudative formations, retinal hemorrhages (flamed-shaped and dot blot), retinal
ischemia with cotton-wool spots and necrosis of smooth muscle cells. Based on these phases, classification
systems of vascular changes where implemented. There were two models of classification: Keith-WagnerBarker classification and the Mitchel Wong classification, though they haven’t been extensively utilized as
there has been differences between observers/physicians. Recent advances in digital retinal imaging are the
ones providing an opportunity to quantify and monitor hypertensive retinopathy, including such imaging
biomarkers as retinal vessel width6
.
There are some differential diagnosis or similar
pathologies that can overlap and present with similar findings to
hypertensive retinopathy. Diabetic retinopathy presents similarly
but usually lacks arteriovenous crossing and arteriole narrowing.
Another similar presenting pathology is retinal vein occlusion,
though this one is characterized by mostly being unilateral. When
hypertensive retinopathy is
suspected, the patient should
be evaluated systemically, most importantly for symptoms of
cardiovascular complications and end organ damage. Blood pressure
should be assessed and in addition, patient should get a funduscopic
evaluation 5
. If any signs of hypertensive crisis are seen, patient should
be treated immediately to lower the blood pressure and decrease end
target organ damage. It is important to note that malignant hypertension
(BP around or higher than 180/120mmHg) should be managed immediately as an emergency to reduce or
limit ischemia to the optic nerve and papilledema 5
. The management for hypertensive retinopathy is based
on treatment of the underlying cause of systemic hypertension or elevated blood pressure. This is achieved
with antihypertensive medications such as Angiotensin converting enzyme inhibitors (ACE), diuretics,
angiotensin II receptor blockers (ARB’s), calcium channel blockers or vasodilators. Finally, prevention of
Hypertensive retinopathy (HR) is very similar to the treatment. It is based or relies on the treatment of the underlying culprit causing increases in systemic blood pressure. Managing or controlling blood pressure
ensures or decreases fast deterioration of the structures that ultimately result in Hypertensive Retinopathy. Works Cited
1. Yanoff, M, et al: Hypertensive Retinopathy. Ophthalmology 2019, Fifth edition; 6.18, 516-519.e1
2. Olitsky S, Marsh J. Disorders of the Retina and Vitreous. Nelson Textbook of Pediatrics 2020; Chapter 648, 3377-
3385.e1
3. Ojaimi E, Nguyen TT, Klein R, et al: Retinopathy signs in people without diabetes: the multi-ethnic study of
atherosclerosis. Ophthalmology 2011; 118: pp. 656-662
4. Modi P, Arsiwalla T. Hypertensive Retinopathy. [Updated 2020 Jan 8]. In: StatPearls [Internet]. Treasure Island (FL):
StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK525980/
5. Bagheri Nika, Wajda Brynn N, Calvo Charles M, Durrani Alia K, Friedberg Mark A, Rapuano Christopher J. The Wills
Eye Manual: Office and Emergency Room Diagnosis and Treatment of Eye Disease. Seventh edition. Philadelphia:
LWW; 2016.
6. Wong TY: Fred hollows lecture: hypertensive retinopathy – a journey from fundoscopy to digital imaging. Clin Exp
Ophthalmol 2006; 34: pp. 397-40