In vivo imaging of Hypertensive Retinopathy using Fluorescence Adaptive Optics Scanning Light Ophthalmoscopy

Abstract

 

Purpose

 

While hypertension affects 1 in 3 adults and 2 in 3 adults over age 60, hypertensive retinopathy is often overlooked as an important indicator of systemic disease. Previous studies have explored the relationship between hypertensive retinopathy and diabetes, nephropathy, heart disease and cerebrovascular events. Reflectance adaptive optics scanning light ophthalmoscopy (RAOSLO) is a powerful tool in our exploration of the retina, providing access to retinal microstructure previously unavailable in vivo. However, the technology has not yet been optimized to study the microvasculature. Our group has combined AOSLO with fluorescein angiography (FAOSLO) to image patients with hypertensive retinopathy.

 

Methods

 

12 adult patients with vascular disease were recruited. Baseline RAOSLO images were collected using a 790 nm light source and 1° FOV. Patients then ingested 1g of fluorescein sodium mixed with juice. Starting at 15 minutes post ingestion, reflectance and fluorescence (488nm excitation emission; emission filter centered at 525nm; 45nm bandwidth) 1° FOV image sequences were recorded simultaneously. Conventional fundus photography with and without intravenous fluorescein was performed.

 

Results

 

FAOSLO revealed fine changes in the retinal microvasculature not seen with traditional imaging modalities and RAOSLO in all patients. We successfully imaged features of hypertensive retinopathy present in larger vessels on the microscopic scale, including microaneurysms, hemorrhages, intravascular lesions, focal arteriolar narrowing, and vessel tortuosity.

 

Conclusions

 

FAOSLO represents a promising new technology to image features of hypertensive retinopathy with resolution previously attainable only through biopsy. New quantitative classification schemas will need to be developed to describe and categorize these abnormalities. Following patients over time will capture the evolution of the disease, giving invaluable insight into the onset and progression of hypertensive changes, both in the eye and throughout the body.

 

 

Figure 2: Variable vessel tortuosity was seen in all levels in hypertensive retinopathy.

 

 

Figure 1: A tortuous tertiary artery imaged on both fundus photo (A) and IV fluorescein (B). While the artery was visible on RAOSLO (C), FAOSLO revealed a focal filling defect (D, E), suggesting local constriction or intravascular lesion.

 

Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • 688 retina