Evaluation of the Foveal Avascular Zone in Familial Exudative Vitreoretinopathy Using Optical Coherence Tomography Angiography

Abstract

Purpose To evaluate the foveal avascular zone (FAZ) and retinal structure in familial exudative vitreoretinopathy (FEVR). Patients and Methods Eighteen eyes with stage 1 or 2 FEVR and 20 control eyes were evaluated. The central retinal thickness (CRT), foveal inner retinal thickness (IRT), surface retinal vessel density (SRVD), and deep retinal vessel density (DRVD) were measured using optical coherence tomography. The FAZ area was calculated using ImageJ software. The equivalent spherical value (SE) and axial length (AL) were measured. Results The CRT (232.5±3.086 vs 211±12.6325 μm; p =0.003) and foveal IRT (15.83±13.95 vs 0.9±4.02 μm; p =0.002) were thicker in the FEVR group than in the control group. The surface FAZ area (0.265±0.08 vs 0.364±0.09 mm 2 ; p =0.004) and the deep FAZ area (0.364±0.1 vs 0.484±0.11 mm 2 ; p =0.03) were smaller in the FEVR group than in the control group. The SRVD values did not differ among the sectors, but the DRVD was higher in the FEVR group except for the inferior sector (superior, p =0.027; inferior, p =0.88; temporal, p =0.035; nasal, p =0.027). The SE and AL did not differ between the two groups. There were no correlations between the surface and deep layer FAZ area and age, CRT, SE, and AL. The surface, deep FAZ area, and foveal IRT were correlated negatively (surface, r = −0.47, p =0.033; deep layer FAZ area, r = −0.46, p =0.037). Conclusion Eyes with FEVR have a smaller FAZ because the vascular structure in the inner retina remained in the fovea.

Optical Coherence Tomography and Optical Coherence Tomography Angiography in Pediatric Retinal Diseases

“…Greater foveal thickness and central macular thickness; microstructural change, including posterior hyaloidal disorganization; vitreomacular traction; macular edema; and EZ disruption are correlated with poorer visual acuity in stage 1 and stage 2 FEVR [ 64 ]. A thicker central retinal thickness (CRT) can be attributed to a residual retinal inner layer and the absence of a foveal pit [ 71 , 72 ]. A recent publication by Zhang et al described using ultra-wide-field laser ophthalmoscopy and optical coherence tomography to identify a novel sign of temporal mid-peripheral vitreoretinal interface abnormality (TEMPVIA) in early-stage FEVR, which was characterized by retinal thickening at the posterior margin of avascularized retina, with mild or absent retinoschisis and leakage on the FA [ 73 ].…”

“…Conventional FA imaging of FEVR was able to show peripheral avascularized areas, abnormal venous–venous anastamosis, vascular branching and leakage in the peripheral retina [ 73 ]. In terms of OCTA of FEVR, central macular microvascular change was noted in several studies, which suggested that there may be more to FEVR than peripheral retinal avascularization [ 67 , 71 , 72 ]. Hsu et al reported a series of 11 eyes of 6 patients with FEVR imaged with OCTA, which showed dilation, disorganization, straightening, heterogeneous vessel density and curls formation in SCP [ 67 ].…”

“…Regarding the FAZ, some earlier studies showed smaller FAZs in FEVR patients in comparison to controls; Hasegawa et al found that in stage I or II FEVR, both the surface and deep FAZ areas (0.265 ± 0.08 and 0.364 ± 0.1 mm 2 , respectively) were smaller in the FEVR group than in the control group [ 71 ]. Chen et al also noted a smaller FAZ (0.27 ± 0.17 mm 2 ) in 31.70% of FEVR eyes (13 out of 41) but not in controls [ 72 ].…”