To review the evidence for imaging modalities in assessing the vascular component of diabetic retinal disease (DRD), to inform updates to the DRD staging system.
Noncontact retinal blood flow measurements are performed with a Fourier domain optical coherence tomography (OCT) system using a circumpapillary double circular scan (CDCS) that scans around the optic nerve head at 3.40 mm and 3.75 mm diameters. The double concentric circles are performed 6 times consecutively over 2 sec. The CDCS scan is saved with Doppler shift information from which flow can be calculated. The standard clinical protocol calls for 3 CDCS scans made with the OCT beam passing through the superonasal edge of the pupil and 3 CDCS scan through the inferonal pupil. This double-angle protocol ensures that acceptable Doppler angle is obtained on each retinal branch vessel in at least 1 scan. The CDCS scan data, a 3-dimensional volumetric OCT scan of the optic disc scan, and a color photograph of the optic disc are used together to obtain retinal blood flow measurement on an eye. We have developed a blood flow measurement software called "Doppler optical coherence tomography of retinal circulation" (DOCTORC). This semi-automated software is used to measure total retinal blood flow, vessel cross section area, and average blood velocity. The flow of each vessel is calculated from the Doppler shift in the vessel cross-sectional area and the Doppler angle between the vessel and the OCT beam. Total retinal blood flow measurement is summed from the veins around the optic disc. The results obtained at our Doppler OCT reading center showed good reproducibility between graders and methods (<10%). Total retinal blood flow could be useful in the management of glaucoma, other retinal diseases, and retinal diseases. In glaucoma patients, OCT retinal blood flow measurement was highly correlated with visual field loss (R2>0.57 with visual field pattern deviation). Doppler OCT is a new method to perform rapid, noncontact, and repeatable measurement of total retinal blood flow using widely available Fourier-domain OCT instrumentation. This new technology may improve the practicality of making these measurements in clinical studies and routine clinical practice.
Importance Aflibercept biosimilars can expand available treatment options in retinal diseases and have the potential to improve patient access to safe and effective therapy. Objective To establish equivalence in efficacy and similarity in safety, pharmacokinetics, and immunogenicity of SB15 and reference aflibercept (AFL) in neovascular age-related macular degeneration (nAMD). Design, Setting, and Participants This was a randomized double-masked parallel group phase 3 trial conducted at 56 centers in 10 countries from June 2020 to March 2022, including follow-up through 56 weeks. Of 549 screened participants, 449 participants 50 years and older with treatment-naive nAMD were included and randomly assigned to SB15 (n = 224) or AFL (n = 225). Key exclusion criteria included considerable scarring, fibrosis, atrophy, and hemorrhage. This report includes results up to the end of the parallel group period at week 32. Of the 449 randomized participants, 438 (97.6%) completed week 32 follow-up. Intervention Participants were randomized 1:1 to receive 2 mg of SB15 or AFL every 4 weeks for the first 12 weeks (3 injections), followed by dosing every 8 weeks up to week 48, with final assessments at week 56. Main Outcomes and Measures The primary end point was the change in best-corrected visual acuity (BCVA) from baseline to week 8 with predefined equivalence margins of −3 letters to 3 letters. Other key end points were changes in BCVA and central subfield thickness up to week 32, safety, pharmacokinetics, and immunogenicity. Results The mean (SD) age among the 449 included participants was 74.0 (8.1) years, and 250 participants (55.7%) were female. Baseline demographic characteristics and most disease characteristics were comparable between treatment groups. The least squares mean change in BCVA from baseline to week 8 in the SB15 group was equivalent to that in the AFL group (6.7 letters vs 6.6 letters, respectively; difference, 0.1 letters; 95% CI, −1.3 to 1.4). Comparable efficacy between treatment groups was maintained up to week 32 (least squares mean change from baseline in BCVA: SB15, 7.6 letters vs AFL, 6.5 letters; least squares mean change from baseline in central subfield thickness: SB15, −110.4 μm vs AFL, −115.7 μm). No clinically relevant differences were observed in the incidence of treatment-emergent adverse events (TEAEs) (SB15, 107/224 [47.8%] vs AFL, 98/224 [43.8%]) and ocular TEAEs in the study eye (SB15, 41/224 [18.3%] vs AFL, 28/224 [12.5%]). The serum concentration profiles and cumulative incidences of overall antidrug antibody positive participants were comparable. Conclusions and Relevance In this phase 3 randomized clinical trial, SB15 and AFL showed equivalent efficacy and comparable safety, pharmacokinetics, and immunogenicity in participants with nAMD. Trial Registration ClinicalTrials.gov Identifier: NCT04450329
Purpose: To document a peculiar case of optic disk pit-associated maculopathy with extensive nasal retinoschisis with lamellar outer retinal hole. Methods: A 41-year-old woman presented to the eye clinic complaining of new photopsias and enlargement of the blind spot in the left eye. Uncorrected visual acuity was 20/20 in both eyes. Fundus examination of the left eye revealed an anomalous appearing optic nerve with a gray oval depression at the temporal margin of the disk consistent with an optic disk pit. Results: Optical coherence tomography confirmed the presence of the pit and demonstrated outer plexiform layer schisis superonasal to the fovea and extensive inner and outer retinal schisis nasal to the nerve extending to the equator. A large lamellar outer retinal hole was noted nasal to the disk without associated retinal detachment. The vitreous appeared to be attached over the nasal retina. Conclusion: Multimodal imaging revealed an unusual optic disk pit-associated retinopathy with dramatically more extensive retinoschisis and a lamellar outer retinal hole nasal to the nerve despite the temporal location of the pit. Although the precise pathophysiologic mechanisms are not fully understood, forces associated with the vitreo-retinal adhesion may have contributed to the distribution of the schisis in this case.
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