AV nicking is a visible change in the blood vessels at the back of your eye where a small artery crosses over a small vein, causing the vein to appear pinched or narrowed at the crossing point. It is one of the hallmark signs your eye doctor looks for when checking whether high blood pressure has started to damage the tiny vessels throughout your body. Because the retina is the only place where doctors can directly observe blood vessels without surgery, AV nicking serves as a window into what prolonged hypertension may be doing to vessels in your brain, heart, and kidneys. The finding is common enough that it shows up in routine eye exams, yet significant enough that it has been linked to increased stroke risk in large population studies.
How AV Nicking Happens
Inside a healthy eye, small arteries (arterioles) and veins (venules) cross over each other in the retina and share a common outer sheath at the crossing point. When blood pressure stays elevated over months or years, the walls of the arterioles gradually thicken and stiffen. This process, sometimes called arteriolar sclerosis, means the artery wall physically presses on the vein beneath it at the crossing. The vein’s blood flow gets squeezed at that point, making it look tapered or nicked on both sides of the crossing when viewed through an ophthalmoscope or on a retinal photograph.
Prolonged hypertension drives this thickening of the arteriole walls, which in turn compresses the vein at the crossing point. This compression is sometimes called Gunn’s sign. A related finding, Salus’s sign, occurs when the vein is not just squeezed but actually deflected into an S-shaped curve as it passes under the stiffened artery.1PubMed. Automatic Gunn and Salus sign quantification in retinal images In mild cases, the vein simply looks a little narrower at the crossing. In more severe cases, the vein appears to vanish entirely on either side of the artery, a phenomenon sometimes called “banking” because blood pools up behind the obstruction.
The key detail that makes AV nicking clinically meaningful is that it reflects cumulative damage. Unlike a blood pressure reading that captures one moment in time, AV nicking appears to be a marker of long-term hypertension exposure. Studies have found that it correlates with blood pressure levels measured five to eight years before the retinal assessment, suggesting it reflects years of wear rather than a temporary spike.2PubMed Central. The use of retinal photography in non-ophthalmic settings and its potential for neurology
The Hypertension Connection
The relationship between high blood pressure and AV nicking has been documented in several large population studies. In the Beaver Dam Eye Study, which examined thousands of adults, hypertension was associated with a higher frequency of AV nicking even after adjusting for age. The relative risk was roughly 1.9 in men and 1.7 in women compared to those without hypertension.3PubMed. Hypertension and retinopathy, arteriolar narrowing, and arteriovenous nicking in a population The Blue Mountains Eye Study, conducted in an older Australian population, found a similar pattern. People with uncontrolled hypertension were about twice as likely to have AV nicking as those with normal blood pressure, even after accounting for age, sex, body weight, and smoking.4PubMed. Hypertensive retinal vessel wall signs in a general older population: the Blue Mountains Eye Study
These retinal changes can show up in a surprising portion of the general population. Epidemiological data suggest that retinal microvascular abnormalities, including AV nicking, are observed in roughly 2 to 15 percent of the non-diabetic general population and are strongly tied to elevated blood pressure.5Survey of Ophthalmology. Retinal Microvascular Abnormalities and their Relationship with Hypertension, Cardiovascular Disease, and Mortality That range is wide because prevalence depends heavily on the population studied, how strictly the grading is done, and how old the participants are. In communities with high rates of untreated hypertension, the numbers climb.
One detail worth flagging: AV nicking does not require active, uncontrolled blood pressure to persist. Because it represents structural remodeling of the artery wall, it tends to stick around even after blood pressure is brought under control with medication. This makes it distinct from some other retinal signs of hypertension, like generalized arteriolar narrowing, which can partially improve with treatment. AV nicking is considered a more permanent record of past damage.
What AV Nicking Means for Stroke and Heart Disease
Beyond simply confirming hypertension, AV nicking has drawn attention because of its link to stroke. The Atherosclerosis Risk in Communities (ARIC) Study, a large prospective study tracking thousands of middle-aged Americans, found that people with AV nicking had about a 60 percent higher risk of experiencing a stroke over the follow-up period, even after adjusting for blood pressure, diabetes, and other traditional risk factors.6PubMed. Retinal microvascular abnormalities and incident stroke: the Atherosclerosis Risk in Communities Study That is a meaningful increase, though it is worth noting it was a more modest predictor than some other retinal findings like microaneurysms or soft exudates, which carried higher relative risks in the same study.
A broader review of the evidence found that hypertensive retinopathy signs, including AV nicking and focal arteriolar narrowing, were associated with prevalent stroke, incident stroke, and stroke mortality independent of blood pressure and other cerebrovascular risk factors.7PubMed. Retinal signs and stroke: revisiting the link between the eye and brain The reasoning behind this connection is intuitive: the tiny blood vessels in your retina share structural and embryological similarities with the small vessels in your brain. If high blood pressure has visibly damaged the retinal vessels, the same process is likely underway in cerebral vessels, raising the odds of a small-vessel stroke.
The picture for heart disease is less clear. While some early studies suggested a link between retinal vessel changes and coronary artery disease, the evidence for AV nicking specifically has not consistently shown an independent association with ischemic heart disease or cardiovascular mortality after accounting for blood pressure and other risk factors.5Survey of Ophthalmology. Retinal Microvascular Abnormalities and their Relationship with Hypertension, Cardiovascular Disease, and Mortality This makes sense when you think about the underlying mechanism: AV nicking reflects small-vessel damage, and coronary artery disease primarily involves large arteries with a different kind of plaque buildup. The retinal vessels are better mirrors of what is happening in the brain’s small vessels than in the heart’s large coronary arteries.
How Doctors Detect and Grade It
AV nicking is typically spotted during a dilated eye exam, where drops widen your pupils so the doctor can see the retina clearly. Using an ophthalmoscope or a retinal camera, the examiner looks at the points where arteries and veins cross and judges whether the vein appears pinched. This sounds straightforward, but in practice it involves some subjectivity, and mild cases can be tricky to call.
Historically, doctors graded the severity of hypertensive retinopathy using the Keith-Wagener-Barker (KWB) system, a four-tier scale developed decades ago. AV nicking typically appears starting in grade 2 of that system, alongside more obvious arteriolar narrowing. More recently, a simplified three-grade classification proposed by Mitchell and Wong has gained traction. Studies comparing the two systems found that the simplified version was equally reliable in terms of agreement between different examiners, while having the advantage of correlating better with cardiovascular risk.8PubMed. Hypertensive retinopathy: comparing the Keith-Wagener-Barker to a simplified classification The simplified system essentially collapses the first two KWB grades into one, since research found no meaningful difference in organ damage between those early stages.9PubMed. The Keith-Wagener-Barker and Mitchell-Wong grading systems for hypertensive retinopathy: association with target organ damage in individuals below 55 years
The subjective nature of grading has pushed researchers to develop automated detection methods. One validated automated approach that measures the narrowing of veins at crossing points showed strong correlation with expert grading, achieving 77 percent sensitivity and 92 percent specificity.10PubMed. An automated method for retinal arteriovenous nicking quantification from color fundus images More recently, deep learning models trained specifically on retinal images have pushed accuracy higher, with one model achieving over 94 percent accuracy in classifying whether AV nicking is present or absent.11Advances in Intelligent Systems and Computing. Prediction of Arteriovenous Nicking for Hypertensive Retinopathy Using Deep Learning Other deep learning approaches have focused not just on detecting nicking but on grading its severity, a harder task that requires distinguishing mild from moderate from severe pinching.12Biomedical Signal Processing and Control. Domain-specific trained model to auto grade AV Nicking severity level These tools are not yet standard in your eye doctor’s office, but they are moving toward a future where retinal screening for hypertensive damage could be more consistent and less dependent on individual examiner skill.
AV Nicking in Children and Young Adults
Most of the research on AV nicking comes from middle-aged and older adults, but it can appear in much younger people with high blood pressure. A study of 97 children and adolescents aged 6 to 23 with essential hypertension found that about 8 percent had AV nicking on fundus photography, while 41 percent had arteriolar narrowing and 14 percent had vessel tortuosity. Overall, half of these young patients had at least one retinal vascular abnormality.13PubMed. The prevalence of retinal vascular abnormalities in children and adolescents with essential hypertension
That finding is worth sitting with: children as young as six already showing signs of vascular remodeling in their retinas. AV nicking was less common than simple narrowing in this age group, which makes sense given that it reflects more advanced structural change. But when it was present, it suggested that the hypertension had already been doing damage for some time. Detecting early signs of hypertensive retinopathy appears to be especially valuable in younger individuals. In people under 55, retinal findings have been associated with measurable stiffening of the aorta and thickening of the carotid artery walls, both markers of systemic vascular damage.9PubMed. The Keith-Wagener-Barker and Mitchell-Wong grading systems for hypertensive retinopathy: association with target organ damage in individuals below 55 years In older individuals, those associations weakened, likely because other age-related changes muddy the picture.
Can AV Nicking Be Reversed?
This is one of the most common questions people have after being told they have AV nicking, and the honest answer is that the evidence is mixed and depends partly on what you mean by reversal. Traditional clinical teaching holds that AV nicking, once established, is essentially permanent. It reflects physical thickening and stiffening of the arteriolar wall, not a temporary change in blood flow, so simply bringing blood pressure down does not undo the structural remodeling at the crossing point.
However, newer imaging technology called adaptive optics, which can visualize retinal vessels in far greater detail than standard photography, has shown that some microvascular changes from hypertension can partially reverse with blood pressure treatment. Studies using adaptive optics have observed increases in the inner diameter of arterioles and reductions in wall thickness after antihypertensive therapy, suggesting that at least some of the vascular remodeling is reversible.14Biomedical Signal Processing and Control. The New Era of Retinal Imaging in Hypertensive Patients Whether this translates to visible improvement in AV nicking specifically is less well established. The compression at the crossing involves not just wall thickness but also changes to the shared sheath between the artery and vein, and those changes may be harder to undo.
From a practical standpoint, even if AV nicking does not fully reverse, controlling blood pressure prevents it from worsening and reduces the risk of the more serious retinal complications that can develop if hypertension goes unchecked, including hemorrhages, cotton wool spots, and vision-threatening swelling of the optic nerve.
When Diabetes and Hypertension Overlap
Many people with high blood pressure also have diabetes, and the combination is particularly hard on retinal blood vessels. Diabetic retinopathy and hypertensive retinopathy can coexist in the same eye, and they tend to amplify each other’s damage. A case report illustrating this described a middle-aged patient with both conditions who presented with severe arteriolar narrowing, AV nicking, hemorrhages, cotton wool spots, and advanced proliferative diabetic retinopathy with new blood vessel growth, a combination that substantially increased the risk of irreversible vision loss.15International Journal of Science and Research Archive. Synergistic Effects of Diabetic and Hypertensive Retinopathy in a Middle-Aged Patient: Case Report
If you have both conditions, the retinal exam becomes even more important because the eye doctor needs to distinguish which changes are driven by which disease. Diabetic retinopathy tends to produce microaneurysms, dot-and-blot hemorrhages, and eventually new vessel growth, while hypertensive retinopathy produces the arteriolar narrowing and AV nicking described throughout this article. When both processes are active simultaneously, the retina takes a double hit, and the threshold for vision-threatening complications drops.
What AV Nicking Tells You About Branch Retinal Vein Occlusion
Beyond being a sign of systemic vascular health, AV nicking can have direct consequences for your vision through a condition called branch retinal vein occlusion (BRVO). This happens when the compressed vein at an AV crossing becomes so pinched that blood flow through it is blocked entirely or nearly so. The blockage causes blood to back up behind it, leading to hemorrhages and swelling in the portion of the retina served by that vein. Patients typically notice a sudden, painless blur or dark area in part of their visual field.
BRVO is one of the most common retinal vascular disorders, and the vast majority of cases occur at AV crossing points where nicking was already present. The thickened artery wall compresses the vein within their shared sheath, and if a blood clot forms at the narrowed point, the vein occludes. Research has identified AV nicking as a strong predictor of this eye-specific complication.10PubMed. An automated method for retinal arteriovenous nicking quantification from color fundus images Treatment for BRVO has improved substantially with intravitreal injections that reduce swelling, but preventing the underlying vascular damage through blood pressure control remains the frontline strategy.
What to Do if Your Eye Doctor Mentions AV Nicking
If you have just been told you have AV nicking, the first step is to make sure your blood pressure is being properly managed. For many people, this finding on a routine eye exam is the first clue that their blood pressure has been elevated long enough to cause vascular changes. It is not an emergency in the same way that retinal hemorrhages or optic disc swelling would be, but it is a meaningful signal that should not be dismissed.
Your eye doctor will likely recommend follow-up with your primary care physician or a cardiologist if you do not already have one. The retinal finding alone does not tell you exactly how high your blood pressure is right now, since it reflects cumulative past exposure, but it does tell you that your small vessels have been under enough pressure for long enough to physically change shape. If you are already on blood pressure medication, AV nicking can be a useful data point in conversations about whether your current treatment is adequate or needs adjustment.
Expect your eye doctor to want periodic retinal exams going forward, not just to track the AV nicking itself but to watch for progression to more advanced signs of hypertensive retinopathy, or for the development of complications like BRVO. The frequency of those exams will depend on the severity of your findings and how well your blood pressure is controlled. In most cases, annual dilated exams are sufficient, but your doctor may recommend more frequent visits if the retinal picture is concerning or if you have coexisting diabetes.