Optical coherence tomography angiography in patients with retinitis pigmentosa who have normal visual acuity

Abstract

PurposeTo investigate flow area changes measured using optical coherence tomography angiography (OCTA; RTVue XR Avanti®) in patients with retinitis pigmentosa (RP) with preserved visual acuity (VA).MethodsThis was an age‐ and refraction‐matched case–control study. Consecutive patients with a best‐corrected visual acuity (BCVA) of ≥20/20 and normal subjects were recruited. Fifty eyes (32 patients) and 22 eyes (12 controls) were included. The flow area and foveal avascular zone (FAZ) were measured in both superficial and deep layers within a 3 × 3 mm central area of the fovea. Association between OCTA parameters and the length of the inner segment ellipsoid (ISe) and external limiting membrane (ELM), the area without abnormal fluorescence in fundus autofluorescence (normal FAF area ratio) and the area of I‐2e of the Goldmann perimeter were analysed using mixed‐effects regression analysis.ResultsFoveal avascular zones were significantly smaller in patients with RP than in controls in superficial (p = 0.004) but not in deep layers (p = 0.25). The flow area in superficial (p = 0.007) and deep layers (p = 0.004) was significantly smaller in patients with RP than in controls. In patients with RP, flow areas in the superficial layers, but not in the deep layers, were significantly associated with the lengths of ISe (p = 0.001) and ELM (p = 0.002) and the I‐2e area (p = 0.036), but not with the normal FAF area ratio (p = 0.399).ConclusionOptical coherence tomography angiography (OCTA)‐measured flow area in superficial layers gradually reduced with RP progression and may be a useful parameter of RP pathogenesis.

Optical Coherence Tomography Angiography Imaging in Inherited Retinal Diseases

“…Inooka and colleagues described decreased perfusion density and vessel length density in the superficial and deep capillary plexus and whole retina in RP eyes compared to controls [33]. Takagi et al examined flow area in both the superficial and deep capillary plexus and similarly showed that these parameters were lower in RP eyes vs. controls [34]. Wang and colleagues examined the foveal and parafoveal subfields and found that the vessel area densities in the superficial capillary plexus in all subfields in RP eyes were lower than in control eyes [35].…”

“…A qualitative study using wide angle swept source OCTA by Miyata and colleagues, with 43 RP eyes and 12 healthy eyes, demonstrated that concentric and vermicular choriocapillaris flow deficits were observed in 23% and 40% of RP eyes, respectively, and 0% of healthy eyes [38]. However, other studies showed no difference in choriocapillaris flow parameters between RP and control eyes [28,31,34]. Some authors have attributed this discrepancy to the size of OCTA images captured.…”

“…In addition, many groups have also examined foveal avascular zone (FAZ) size, and most agree that the FAZ area is larger in RP eyes when compared to controls [29,31,33,35]. Notably, Battaglia Parodi et al and Takagi et al examined the FAZ in the superficial and deep capillary plexuses separately, and while Battaglia Parodi and coauthors found that the deep FAZ but not the superficial FAZ is larger in RP eyes [28], Takagi et al found that the superficial but non-deep FAZ is larger in RP eyes [34]. In contrast, Koyanagi and colleagues found that neither the superficial nor deep FAZ was significantly different between RP and control eyes [32].…”

Projection-Resolved Optical Coherence Tomographic Angiography of Retinal Plexuses in Retinitis Pigmentosa

“…22,24,28 This limits the ability to accurately separate and quantify OCT angiograms into the three distinct macular vascular layers described in histologic studies: superficial vascular complex (SVC), intermediate capillary plexus (ICP), and deep capillary plexus (DCP). 29 Thus, previous investigations of OCTA in RP described microvascular changes in up to 2 vascular layers; the superficial and deep capillary plexuses, [30][31][32] dividing the ICP between the superficial and deep layers. Two layer segmentation could lead to inaccurate quantification of retinal perfusion.…”

Inherited retinal diseases

“…31,33,34,40,42,43 In this study we found the most frequent ABCA4 mutation p.G1961E in two unrelated STGD patients, it has been reported in patients from African American and European ancestry with the frequencies of 2% and 11% respectively. 44,45 Recently, the different stages of an 'optical gap' have been described on the SD-OCT in patients with p.G1961E mutations. 46…”