Monitoring Retinal Vasculopathic Changes Over Time Using In Vivo Offset Pinhole Adaptive Optics Scanning Light Ophthalmoscopy

Abstract

 

Purpose

 

Offset pinhole adaptive optics scanning light ophthalmoscopy (OP AOSLO) of the retinal microvasculature allows non-invasive imaging of the retinal microvascular wall, lumen, and blood flow, without the use of an exogenous contrast agent. In this study, we used OP AOSLO to detect and monitor subclinical microvascular change over time in various retinal vasculopathies.

 

Methods

 

: Longitudinal OP AOSLO imaging was performed on 6 patients: 2 with diabetic retinopathy (DR), 2 with central retinal vein occlusion (CRVO), 1 with branch retinal vein occlusion (BRVO) and 1 with hypertensive retinopathy (HR). OP AOSLO was implemented using a 790 nm light by displacing the confocal detection aperture laterally, according to the orientation of the retinal blood vessels. An additional 850nm light source was used as a wavefront-sensing beacon. Image sequences were acquired using a 1° or 1.5° field-of-view at a frame rate of 15 Hz. After sinusoidal distortion and eye motion were removed, registered averaged images were stitched together to create larger DF microvascular maps. Serial maps from the same eyes, taken 1 week to 5 months, were qualitatively assessed for vasculopathic change over time.

 

Results

 

All patients showed vasculopathic features including microaneurysms, lumen clots, vessel looping and sprouting, non-perfused vessels (endothelial sleeves), tortuous vessels, and irregular lumen diameters. In one patient, we were able to detect microvascular changes as early as 1 month after the first imaging session. Two of the patients imaged showed no changes in microvascular structure (1 CRVO and 1 BRVO; Fig. 1A and B). In 4 patients, microvascular remodeling was observed, including microaneurysm regression (1 HR) and progression (1 HR and 1 CRVO), angiogenesis and capillary regression over time (2 DR) (F ig. 1C and D).

 

Conclusions

 

OP AOSLO reveals subclinical microvascular changes cross-sectionally and longitudinally, offering a great opportunity for studying the natural progression of vasculopathy and the response to treatment.

 

 

A and B) Non-perfused capillary (black arrows) in a CRVO patient, taken 4 months apart. C and D) A new capillary (black arrows) and an engorged capillary (white arrows) in a DR patient, taken one month apart.

 

Keywords: 688 retina • 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • 749 vascular occlusion/vascular occlusive disease