At this visit, best-corrected visual acuities were 20/20 OD and 20/25 OS. Pupils were reactive without APD. Color vision was 10/10 OD, OS on Ishihara plates. Amsler grid was normal in the right eye and revealed distortion on the temporal field of the left eye. Intraocular pressures were 18 and 18 mmHg. Blood pressure was 164/105 mmHg. Anterior segment exam was unremarkable. On dilated fundus exam, there were vascular crossing changes and mild venous tortuosity and retinopathy consisting of intraretinal hemorrhages, cotton wool spots and hard exudates (imaging in Figure 1, above). The macula in the left eye had star-patterned hard exudate with a neurosensory detachment. The optic nerves showed small cupping. In the left eye, the margins nasally were indistinct with grade 1 edema. In the mid-peripheral fundus in both eyes there were multiple chorioretinal lesions consistent with Elschnig spots. OCT imaging confirmed mild optic nerve edema with average retinal fiber layer values of 102 right eye and 121 left eye. The macular OCT in the right eye was normal with central subfield thickness (CST) of 254. The left eye showed a neurosensory detachment with CST of 309. Fundus autofluorescence (FAF) showed multiple focal areas of hyper-autofluorescence, some of which corresponding with the Elschnig spots.

Fig. 2. Comparison of KWB grading and the OCT-based modification which emphasizes the presence of subretinal fluid (SRF). Click image to enlarge.

The clinical picture and history were fitting with hypertensive retinopathy stage 3 right eye and stage 4 left eye, a result of acutely elevated and chronic hypertension. Target organ damage can be the result of hypertensive crisis. In the eye, that can take the form of retinopathy, choroidopathy and/or optic neuropathy. Hypertensive choroidopathy is often the result of acute elevations in blood pressure.¹ Necrosis of choroidal arterioles leads to non-perfusion of the choriocapillaris and results in focal ischemic damage. This can result in the formation of pigmented lesions with a halo, known as Elschnig spots, and linear hyperpigmented streaks over choroidal arteries, Siegrist streaks.¹ Retinopathy can manifest from chronic hypertension as well as an acute severe blood pressure elevation. The Keith-Wagener-Barker scale is a well-established grading scale for hypertensive retinopathy (see Figure 2).² Grade 1 and 2 stages are the retinal vasculature changes, typically the result of chronic hypertension. Grades 3 and 4 are the result of sustained or acute malignant hypertension, typically considered a blood pressure over 180/120 mmHg. The KWB scale emphasizes optic nerve edema development as the most severe stage which if persistent, can result in optic nerve atrophy and secondary vision loss. In 2014, Ahn et al. proposed an update to the KWB scale accounting for OCT findings.³ Their study found that the presence of macular subretinal fluid was associated with a poorer visual outcome in hypertensive retinopathy.³ Essentially, individuals with severely high blood pressure that developed subretinal fluid were at risk for subsequent development of irregularity or atrophy to the ellipsoid zone, as fluid resolved.³ The ellipsoid zone on OCT corresponds to the junction of the photoreceptor inner and outer segments and as such its integrity highly corresponds with visual acuity. In the KWB classification scale, grades 1-3 are combined into the category of mild to moderate retinopathy followed by malignant retinopathy either without or with subretinal fluid.³

Treatment and management of advanced-stage hypertensive retinopathy is focused on controlling blood pressure. A patient in hypertensive emergency requires immediate referral to the emergency department. The blood pressure should be gradually lowered with parenteral injection or infusion of anti-hypertensives before transitioning to oral anti-hypertensives.⁴ With blood pressure control, the fundus findings of optic nerve edema, hemorrhages, exudates and subretinal fluid will gradually resolve over weeks to months. Progression to proliferative disease has been reported, but is rare.⁵ In this case, the immediate crisis had already been managed in the ED. Therefore, retinopathy findings were communicated to her primary care provider. At one month follow-up, there was marked improvement in retinopathy and the optic nerve edema and subretinal fluid in the left eye had resolved.