Trc 50dx

The study procedures were the same for both the baseline visit and the 3-year follow-up and have been described in detail [9 (link),10 (link)]. Briefly, all included participants received a complete bilateral ophthalmologic examination and were imaged with 7-field, non-stereoscopic color fundus photographs (CFP) using either a Topcon TRC-50DX (Topcon Corporation, Tokyo, Japan) or a Zeiss FF-450Plus (Carl Zeiss Meditec, Dublin, CA, USA) camera. Additionally, complete medical history was obtained, which included self-reported data on smoking habits, and patients were invited to perform dark adaptation testing according to the protocol described below.
For all participants, fasting venous blood samples were collected into a sodium-heparin tube, which was centrifuged within 30 min (1500 rpm, 10 min, 20 °C) to obtain plasma for metabolomic analysis. Plasma aliquots of 1.5 mL were then transferred into sterile cryovials and stored at −80 °C. For the baseline visit, as patients were recruited during their regular ophthalmic appointments, an additional visit had to be frequently scheduled for blood collection in order to ensure overnight fasting. This was scheduled within a maximum of 1 month after study inclusion. For the 3-year follow-up visit, the patients were contacted in advance; thus, fasting blood collection usually took place on the same day of the remaining study procedures.

The clinical protocol was approved by the Second Xiangya Hospital Institutional Review Board, and the tenets of the Declaration of Helsinki were followed. Informed, written consent was obtained before blood sample acquisition. Eighteen members of the family were enrolled in the study. All the individuals underwent standard ophthalmic examinations including evaluation of best-corrected visual acuity (BCVA), non-contacted tonometry, slit-lamp biomicroscopic examination, computerized perimetry (Oculus Twinfield). After pupil dialation with tropicamide (1%) and phenylephrine hydrochloride (2.5%), patients were examined by indirect ophthalmoscopy, OCT (Zeiss Cirrus HD OCT –2000, Carl Zeiss meditec, Inc. Dublin, CA; Spectralis, Heidelberg, Germany), fundus photography (TOPCON TRC 50 DX). Some patients received intravenous fluorescein angiography (FA. Spectralis, Heidelberg, Germany) and Goldman applanation tonometry. ERG (Espion V5, Diagnosys LLC, MA, USA) was performed according to standard testing protocols recommended by the International Society for Clinical Electrophysiology of Vision (ISCEV). Diagnosis of XLRS was based upon history, clinical examination, and electroretinogram findings when available.

Spectral-domain optical coherence tomography (SD-OCT, HRA2 + OCT, Heidelberg Engineering, Heidelberg, Germany) was acquired with a minimum acquisition protocol of 20- × 15-degree pattern centered on the fovea constituting of 19 OCT B-scans. FAF and Multicolor^® were acquired simultaneously with the same instrumentation. Color fundus photograph (CFP) was obtained with either Clarus 500 (Carl Zeiss Meditec, Version 01 05/2017) or Topcon TRC-50DX (Topcon fundus camera, Tokyo, Japan). FA, ICGA, and/or OCTA were obtained to exclude the presence of any MNV subtypes. OCTA was achieved using either RTVue XR (RTVue XR Avanti, Optovue, Inc., Fremont, CA) equipped with the AngioVue software (version 2017.1.0.151; Optovue Inc) or Spectralis OCT (Heidelberg Engineering, Heidelberg, Germany). A 3- × 3-mm or 6- × 6-mm volumetric scan pattern was considered with projection artifact removal. The signal strength cut-off was set ≥ 45 signal strength index (SSI) for RTVue and > 15 Q score for Spectralis OCT.