Prospective, Single-Center, Six-Month Study of Intravitreal Ranibizumab for Macular Edema with Nonproliferative Diabetic Retinopathy: Effects on Microaneurysm Turnover and Non-Perfused Retinal Area.

PURPOSE: To analyze the effects on microaneurysm (MA) and perifoveal perfusion in nonproliferative diabetic retinopathy (NPDR) patients with macular edema (ME) after early intensive treatment using intravitreal ranibizumab (IVR) injections. PATIENTS AND METHODS: Prospectively, 25 eyes of 25 type 2 diabetes mellitus patients with ME were included between August 2016 and February 2019. For 6 months, patients were administered 0.5-mg IVR injections monthly. Ocular evaluation, including best-corrected visual acuity (BCVA; using the Early Treatment Diabetic Retinopathy Study chart), central retinal thickness (CRT; using optical coherence tomography), fundus photography, and fluorescein angiography, was performed for all participants. Results obtained at baseline were compared to those observed after 6 months. RESULTS: Mean BCVA increased significantly from 67.6±3.29 letters at baseline to 76.36±1.61 letters after 6 months (P=0.002) of IVR therapy. CRT decreased significantly from 479.12±16.66 µm at baseline to 369.12±13.02 µm at 6 months. Similarly, the total number of MAs decreased significantly from 5.68±3.41 to 1.60±1.73 (P<0.0001). MA turnover, calculated by adding the MA formation rate to the MA disappearance rate (both calculated as MA number/month) also decreased significantly from 6.88±3.83 to 1.92±1.75 after treatment (P<0.0001). Perifoveal non-perfused area decreased from 2.517±0.456 mm2 at baseline to 2.495±0.293 mm2 at 6 months, but the results were not statistically significant (P=0.954). CONCLUSION: Treatment with early intensive IVR therapy in NPDR patients with ME not only improved BCVA and CRT but also decreased MA turnover. However, in the study period of 6 months, IVR therapy did not show significant improvement in perifoveal non-perfused area.

Lateral geniculate body evoked potentials elicited by visual and electrical stimulation.

PURPOSE: Blind individuals who have photoreceptor loss are known to perceive phosphenes with electrical stimulation of their remaining retinal ganglion cells. We proposed that implantable lateral geniculate body (LGB) stimulus electrode arrays could be used to generate phosphene vision. We attempted to refine the basic reference of the electrical evoked potentials (EEPs) elicited by microelectrical stimulations of the optic nerve, optic tract and LGB of a domestic pig, and then compared it to visual evoked potentials (VEPs) elicited by short-flash stimuli. METHODS: For visual function measurement, VEPs in response to short-flash stimuli on the left eye of the domestic pig were assessed over the visual cortex at position Oz with the reference electrode at Fz. After anesthesia, linearly configured platinum wire electrodes were inserted into the optic nerve, optic track and LGB. To determine the optimal stimulus current, EEPs were recorded repeatedly with controlling the pulse and power. The threshold of current and charge density to elicit EEPs at 0.3 ms pulse duration was about ±10 µA. RESULTS: Our experimental results showed that visual cortex activity can be effectively evoked by stimulation of the optic nerve, optic tract and LGB using penetrating electrodes. The latency of P1 was more shortened as the electrical stimulation was closer to LGB. The EEPs of two-channel in the visual cortex demonstrated a similar pattern with stimulation of different spots of the stimulating electrodes. We found that the LGB-stimulated EEP pattern was very similar to the simultaneously generated VEP on the control side, although implicit time deferred. CONCLUSIONS: EEPs and VEPs derived from visual-system stimulation were compared. The LGB-stimulated EEP wave demonstrated a similar pattern to the VEP waveform except implicit time, indicating prosthetic-based electrical stimulation of the LGB could be utilized for the blind to perceive vision of phosphenes.

Outcome and significance of silicone oil tamponade in patients with chronic serous retinal detachment.

PURPOSE: To evaluate the effectiveness of silicone oil tamponade in patients with chronic serous retinal detachment (SRD) persisting for three months after the resolution of ocular inflammation. METHODS: A total of 17 eyes of 17 patients diagnosed with chronic SRD persisting for three months after the resolution of ocular inflammation and with high risk of phthisis bulbi by secondary ocular hypotony and macular detachment by subretinal fibrous membrane formation were subjected to surgical intervention. Subjects underwent silicone oil tamponade after surgical drainage of subretinal fluid. Retrospective analyses on anatomical and functional success rates were then performed. RESULTS: Anatomical success with retinal reattachment was observed in ten of the 17 eyes (58.82%), while functional success measured as difference in the best-corrected visual acuity before and after the surgery were logarithm of the minimum angle of resolution (logMAR) 1.95 ± 0.66 and logMAR 1.51 ± 0.66, respectively (p < 0.05). CONCLUSIONS: This study suggests that, in patients with chronic SRD despite prolonged medical treatment and resolution of inflammation, surgical drainage of subretinal fluid with silicone oil tamponade can achieve anatomical and functional success.