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

Tetsuya Hasegawa, Misaki Hirato, Chieko Kobashi, Aya Yamaguchi, Rina Takagi, Yoshiaki Tanaka, Toshikatsu Kaburaki, Akihiro Kakehashi Department of Ophthalmology, Saitama Medical Center Jichi Medical University, Saitama-shi, Saitama-ken, JapanCorrespondence: Akihiro KakehashiDepartment of Ophthalmology, Saitama Medical Center Jichi Medical University, Saitama-shi, Saitama-ken, JapanTel +81 48 647 2111Fax +81 48 648 5166Email kakeaki@omiya.jichi.ac.jpPurpose: 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 mm2; p=0.004) and the deep FAZ area (0.364± 0.1 vs 0.484± 0.11 mm2; 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.Keywords: familial exudative vitreoretinopathy, optical coherence tomography angiography, foveal avascular zone