Evaluation of the Long-Term Clinical Results of 3 Patients Implanted with the Argus II Retinal Prosthesis.

This study presents the long-term clinical results of Argus II retinal prosthesis implantation in eyes with light perception and projection in 3 patients with end-stage retinitis pigmentosa. No conjunctival erosion, hypotony, or implant displacement was observed during postoperative follow-up. The electrical threshold values were lower in the macular region and higher close to the tack fixation region and peripherally. Optical coherence tomography scans showed fibrosis and retinoschisis formation at the retina-implant interface in two cases. This was attributed to mechanical and electrical effects on the tissue due to the active daily use of the system and the electrodes' proximity to the retina. The patients were able to integrate the system into their daily lives and perform activities that they could not do before. Studies on retinal prostheses for the rehabilitation of hereditary retinal diseases are ongoing, so both social and clinical observations and experiences related to the implant are valuable.

Evaluation of early and late COVID-19-induced vascular changes with OCTA.

OBJECTIVE: To evaluate vascular changes in the early period after coronavirus disease 2019 (COVID-19) infection and at 6-month follow-up. METHODS: This study included 50 eyes of 25 patients who had been hospitalized for polymerase chain reaction-positive COVID-19 infection and 50 eyes of 25 healthy individuals. All subjects underwent optical coherence tomography angiography using a 6 × 6 macular protocol in the early period after hospital discharge and 6 months later. Foveal vessel density (VD) and parafoveal VD values were measured from 4 quadrants (superior, inferior, nasal, and temporal) of the superficial capillary plexus (SCP) and the deep capillary plexus (DCP). The choriocapillaris (CC) flow area and the foveal avascular zone area also were measured. The OCTA measurements of the patient group were compared both between time points and with the control group at each time point. RESULTS: COVID-19 patients showed lower VD values than control subjects in all parafoveal quadrants of both the SCP (superior, p = 0.01; inferior, p = 0.048; nasal, p = 0.003; temporal, p = 0.048) and the DCP (superior, p = 0.001; inferior, p = 0.011; nasal, p = 0.012; temporal, p = 0.018) at the initial checkup and in all parafoveal quadrants of the SCP (superior, p = 0.0001; inferior, p = 0.007; nasal, p = 0.001; temporal, p = 0.017) and in 2 of the parafoveal quadrants of the DCP (superior, p = 0.003; inferior, p = 0.016) at 6-month follow-up. CC flow area values were significantly lower at the 6-month follow-up than at the initial examination (p = 0.044). CONCLUSION: It is important to perform appropriate follow-up for COVID-19 patients because retinal vascular flow changes may persist in the long term.

Optical coherence tomography angiography findings in patients with COVID-19.

OBJECTIVE: To examine the changes in choriocapillaris and retina caused by coronavirus disease 2019 (COVID-19) by comparing optical coherence tomography angiography (OCTA) findings of COVID-19 patients and healthy controls. METHODS: The study and control groups consisted of 54 eyes of 27 participants, each. Patients and controls underwent OCTA examination. Foveal zone vessel density and parafoveal zone vessel density (for 4 quadrants: nasal, temporal, superior, inferior) were calculated for both superficial and deep capillary plexuses. Additionally, choriocapillaris flow and foveal avascular zone areas were calculated. RESULTS: For the parafoveal area in the study group, vessel density was significantly lower in the superior and nasal quadrants of the superficial capillary plexus and in all quadrants of the deep capillary plexus compared with controls (p < 0.05 for all). The study group had significantly higher choriocapillaris flow area values compared with controls (p = 0.042). CONCLUSION: Reduced vessel density of the retinal capillary plexus was detected in COVID-19 patients who may be at risk for retinal vascular complications.

Evaluation of retinal neurovascular structures by optical coherence tomography and optical coherence tomography angiography in children and adolescents with type 1 diabetes mellitus without clinical sign of diabetic retinopathy.

BACKGROUND: The aim of the study was to investigate whether retinal neurovascular structural impairment in children and adolescents with type 1 diabetes mellitus (T1D) without clinical signs of diabetic retinopathy (DR) could be detected early via optical coherence tomography (OCT) and OCT angiography (OCTA). METHODS: In the current prospective, cross-sectional, observational clinical study children and adolescents with T1D without DR were evaluated between December 2018 and May 2019. Retinal neurovascular structures in the macular and optic disc regions were examined in detail and quantitatively assessed using OCT and OCTA. Data from subjects with T1D were compared with data from healthy controls. Whether retinal neurovascular structural changes were significantly associated with puberty stage, diabetes duration, and HbA1c level was also investigated. RESULTS: The T1D group included 110 eyes and the control group included 84 eyes. In the T1D group the mean inside disc vessel density (VD) was significantly lower than that of the control group (p < 0.001), as was the mean superior temporal disc VD (p < 0.043). Puberty stage was significantly associated with retinal thickness, parafoveal superficial capillary plexus VD, and peripapillary retinal nerve fiber layer thickness (p < 0.05). Diabetes duration and HbA1c level was significantly correlated with retinal layer thickness, foveal avascular zone diameter, and superficial and deep capillary plexus VDs. CONCLUSION: In children and adolescents with T1D without clinical signs of DR, the VD of the disc region is affected earlier than the macular region. In these patients, early neurovascular impairment can be detected non-invasively via OCT and OCTA.