Spectralis hra

FA was performed using a Spectralis HRA (Heidelberg Engineering, Heidelberg, Germany). Late-phase images obtained within 7 min after dye injection were used to assess the extent of vascular leakage.

Mice were given general anesthesia and placed on a platform. Color fundus photograph and fundus AF were acquired using a Micron III fundus camera (Phoenix Research Laboratories, Inc). The Micron III fundus camera has a filter for color fundus photography between 450 and 680 nm; and blue light excitation filter between 440 and 485 nm. For visualization of retinal structure, spectral domain optical coherence tomography imaging was performed using a Bioptigen Envisu (R2200; Bioptigen Inc.) coupled to a broadband LED light source (T870‐HP; Superlum Diodes, Ltd.). Confocal scanning laser ophthalmoscopy (cSLO) (Spectralis HRA; Heidelberg Engineering) was employed for visualization of fundus AF using BluePeak™ or simply blue autofluorescence (488 nm excitation) and near‐infrared AF (787 nm excitation) imaging modes. Images of the central and peripheral retina were obtained using the wide‐field (55°) lens and ultra‐wide field (102°) lens. Simultaneous fluorescein angiography and indocyanine green angiography were performed for the visualization of retinal vasculature. Fifty microliters of fluorescein and indocyanine green mixture were injected intravenously; then, fundus images were acquired with the 102° ultra‐wide field lens.

SD-OCT images were acquired using a Spectralis HRA (Heidelberg Engineering, Heidelberg, Germany), which provides 25 horizontal B-scans (20° x 20° OCT volume scan, 240 μm interscan distance) centred on the fovea with 9 automatic real-time tracking (ART) frames. Segmentation data for different layers within the volume-scan were automatically generated by the integrated software (Eye Explorer Viewing Module 1.0.15.0, Heidelberg Engineering) as described in detail by Invernizzi et al [7 (link)]. In brief, this software version provides eight measures: retinal nerve fibre layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), photoreceptors layer (PRC) and retinal pigment epithelium (RPE). Furthermore, the new software automatically provides thickness maps divided into nine subfields in an inner, intermediate, and outer ring with diameters of 1, 3, and 6 mm, respectively, centred on the proposed foveal pit (Fig 1). As visual pathway anomalies along the vertical midline (shifting/misrouting) are a key feature in albino patients, the GCLT areas along the horizontal meridian were of particular interest and used in the analysis. Each image was checked for proper segmentation and proper localisation of the retinal centre and, if necessary, corrected by an expert examiner (VB or JB).

Retinal angiography was performed using SPECTRALIS HRA (Heidelberg Engineering, Heidelberg, Germany) (105° field of view) or HRA2 Scanning Laser Ophthalmoscope (Heidelberg Engineering, Heidelberg) with the use of Staurenghi Scanning Laser Ophthalmoscope 230 contact lens (Ocular Instruments, Inc, Bellevue, WI) (150° field of view)^{7 (link)} or Optomap P200DTX (200° field of view) or P200MA (200° field of view) (Optos, Dunfermline, United Kingdom).^{16 (link)} Angiograms were centered on the posterior pole of the fundus.

We reviewed the medical records of patients with biallelic DRAM2 variants, which were detected by the genetic studies. The results of clinical examinations included visual acuity measurements, dilated ophthalmoscopy, fluorescein fundus angiography, visual field testing, OCT imaging (Cirrus HD-OCT; Carl Zeiss Meditec AG, Dublin, CA, USA), FAF imaging (Spectralis HRA; Heidelberg Engineering, Heidelberg, Germany, California; Optos, Inc, Marlborough, MA), and the recording of the full-field ERGs with the International Society for Clinical Electrophysiology of Vision (ISCEV) standards [34 (link)] were evaluated. Details of the ERG procedures and conditions have been reported [35 (link),36 (link),37 (link)].

SD-OCT examinations using Multiline OCT (based on a Spectralis HRA + OCT, Heidelberg Engineering)26 (link) were performed in Thy1-GFP rats at 0, 1, 7, 14, and 28 days after the retinal ischemic injury. Inner retinal thickness (inner retina [IR] = retinal nerve fiber layer + ganglion cell layer + inner plexiform layer + inner nuclear layer), ganglion cell complex thickness (GCC, ganglion cell complex = retinal nerve fiber layer + ganglion cell layer + inner plexiform layer), outer nuclear layer thickness, and outer plexiform layer thickness were measured using circle scan images within a circle 0.944 mm in diameter, the center of which was adjusted to the center of the optic nerve head.

Preoperative imaging included CFP, 45° infrared-reflectance (IR) and BR SLO images acquired with the Spectralis HRA (Heidelberg Engineering GmbH, Heidelberg, Germany) and OCT images acquired with the Cirrus HD-OCT 5000 (Carl Zeiss Meditec, Inc, Humphrey Division, Dublin, California, USA) with En Face analysis. OCT images included a macular cube of 512 (A-scans) × 128 (B-scans), (20 × 20°, 6 × 6 mm, spacing of 47 µm), 2 high-definition 5-line rasters (30° width horizontally and vertically, 9 mm, spacing of 75 µm). The En face analysis was performed using the Advanced Visualization ILM segmentation (20-µm thick slab) positioned on the retinal surface with contrast adjustment to obtain the best defined En Face image of the retinal folding and ERM limits.