Abstract
Optical coherence tomography angiography (OCT-A) is a non-invasive alternative to fluorescein angiography that allows for the study of the retinal and choroidal vasculatures. In this retrospective cohort study of 28 patients with retinitis pigmentosa (RP), we used OCT-A to quantify changes in perfusion density, foveal avascular zone (FAZ) area, and choriocapillaris blood flow over time and correlated these variables with ellipsoid zone (EZ) line width and best-corrected visual acuity (BCVA). Perfusion density decreased by 2.42 ± 0.62% per year at the superior capillary plexus (SCP) (P = 0.001) and 2.41 ± 0.76% per year at the deep capillary plexus (DCP) (P = 0.004). FAZ area increased by 0.078 ± 0.021 mm2 per year (P = 0.001) at the SCP and 0.152 ± 0.039 mm2 per year (P = 0.001) at the DCP. No changes were observed in the choriocapillaris blood flow. EZ line width had the strongest correlation to perfusion density at the SCP (r = 0.660 and 0.635, first and second visit, respectively, P = 0.001), while BCVA most strongly correlated with FAZ area at the SCP (r = 0.679 and 0.548, P = 0.001 and 0.003). Our results suggest that OCT-A is a useful tool for monitoring RP disease progression and may be used to measure retinal vascular parameters as outcomes in clinical trials.
Highlights
Retinitis pigmentosa (RP) refers to a heterogeneous group of inherited rod-cone retinal dystrophies characterized by progressive visual field constriction and nyctalopia[1,2,3]
Histopathologic studies have revealed that the migration of retinal pigment epithelium (RPE) cells around inner retinal blood vessels stimulates deposition of extracellular matrix (ECM) that resembles ectopic Bruch’s membrane, and this perivascular ECM progressively thickens and occludes the lumen of the vessels, leading to compromised blood flow[13,14]
In accordance with the changes observed by histopathology, hemodynamics studies by magnetic resonance imaging (MRI) on retinitis pigmentosa (RP) mouse models have shown reduction in the choroidal and retinal blood flow[15,16]
Summary
Retinitis pigmentosa (RP) refers to a heterogeneous group of inherited rod-cone retinal dystrophies characterized by progressive visual field constriction and nyctalopia[1,2,3]. OCT-A detects streaming blood flow and constructs an image of the retinal vasculature, allowing for the visualization of the superficial (SCP) and deep capillary plexus (DCP)[5]. The technology of OCT-A has been applied broadly to study vasculature changes in inherited retinal dystrophies, including RP, Stargardt disease, and choroideremia[7,8,9,10,11]. It has previously been reported that perfusion density, defined as the total area of perfused vasculature per unit area in a region of measurement ( referred to as vessel density in some studies12), is decreased while the area of the foveal avascular zone (FAZ) is increased in patients with RP compared to controls[8]. This work could have implications on the development of therapies for RP, but it could establish the use of perfusion density and FAZ area as outcome measures for clinical trials and disease progression
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
