Localized intracellular potentials from pre- and postsynaptic components in the external plexiform layer of an insect retina

1971 ◽  
Vol 75 (4) ◽  
pp. 422-440 ◽  
Author(s):  
Matti J�rvilehto ◽  
Friedrich Zettler
Keyword(s):  
Plexiform Layer ◽  
Intracellular Potentials ◽  
Insect Retina

Inner Retinal Morphology and Visual Outcomes in Idiopathic Epiretinal Membrane Surgery: A Retrospective Optical Coherence Tomography Study

2021 ◽  
pp. 247412642198961
Author(s):  
Ioannis S. Dimopoulos ◽  
Michael Dollin
Keyword(s):  
Optical Coherence Tomography ◽  
Epiretinal Membrane ◽  
Strong Predictor ◽  
Plexiform Layer ◽  
Inner Plexiform Layer ◽  
Optical Coherence ◽  
Visual Outcomes ◽  
Retinal Pathology

Purpose: Epiretinal membrane (ERM) is a common retinal finding for patients older than 50 years. Disorganization of the retinal inner layers (DRIL) has emerged as a novel predictor of poor visual acuity (VA) in eyes with inner retinal pathology. The aim of our study is to correlate preoperative DRIL with visual outcomes after ERM surgery. Methods: Medical records and optical coherence tomography (OCT) images of 81 pseudophakic patients who underwent treatment of idiopathic ERM were reviewed. Preoperative DRIL on OCT was correlated with VA at baseline and at 3 and 6 months after ERM surgery. DRIL was defined as the loss of distinction between the ganglion cell–inner plexiform layer complex, inner nuclear layer, and outer plexiform layer. DRIL severity was based on its extent within the central 2-mm region of a transfoveal B-scan (absent/mild: <one-third, severe: >one-third horizontal width). Results: Review of preoperative OCT showed severe DRIL in 41% and absent/mild DRIL in 59%. Severe DRIL was associated with worse baseline VA ( P < .001). Preoperative VA and DRIL status at baseline were both predictors of postoperative VA at follow-up time points ( P < .001). Severe DRIL was associated with significantly less improvement in VA at 6 months (–0.23 logMAR for absent/mild vs –0.14 for severe DRIL). Conclusions: Presence of severe preoperative DRIL correlates with worse baseline VA in patients with ERM and reduced VA improvement at 6 months. DRIL can be a strong predictor of long-term poor visual outcomes in ERM surgery.

scholarly journals Retinal microvascular signs in COVID-19

2021 ◽  
pp. bjophthalmol-2020-318236
Author(s):  
Ralene Sim ◽  
Gemmy Cheung ◽  
Daniel Ting ◽  
Edmund Wong ◽  
Tien Yin Wong ◽  
...  
Keyword(s):  
Medical History ◽  
Vital Signs ◽  
Plexiform Layer ◽  
Nasopharyngeal Swab ◽  
Inner Plexiform Layer ◽  
Cross Sectional ◽  
Imaging Device ◽  
Asymptomatic Patients ◽  
Significant Difference ◽  
Retinal Microvascular Signs

Background/aimsTo explore if retinal findings are associated with COVID-19 infection.MethodsIn this prospective cross-sectional study, we recruited participants positive for COVID-19 by nasopharyngeal swab, with no medical history. Subjects underwent retinal imaging with an automated imaging device (3D OCT-1 Maestro, Topcon, Tokyo, Japan) to obtain colour fundus photographs (CFP) and optical coherence tomographic (OCT) scans of the macula. Data on personal biodata, medical history and vital signs were collected from electronic medical records.Results108 patients were recruited. Mean age was 36.0±5.4 years. 41 (38.0%) had symptoms of acute respiratory infection (ARI) at presentation. Of 216 eyes, 25 (11.6%) had retinal signs—eight (3.7%) with microhaemorrhages, six (2.8%) with retinal vascular tortuosity and two (0.93%) with cotton wool spots (CWS). 11 eyes (5.1%) had hyper-reflective plaques in the ganglion cell-inner plexiform layer layer on OCT, of which two also had retinal signs visible on CFP (CWS and microhaemorrhage, respectively). There was no significant difference in the prevalence of retinal signs in symptomatic versus asymptomatic patients (12 (15.0%) vs 13 (9.6%), p=0.227). Patients with retinal signs were significantly more likely to have transiently elevated blood pressure than those without (p=0.03).ConclusionOne in nine had retinal microvascular signs on ocular imaging. These signs were observed even in asymptomatic patients with normal vital signs. These retinal microvascular signs may be related to underlying cardiovascular and thrombotic alternations associated with COVID-19 infection.

scholarly journals En face image-based classification of diabetic macular edema using swept source optical coherence tomography

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Atsushi Fujiwara ◽  
Yuki Kanzaki ◽  
Shuhei Kimura ◽  
Mio Hosokawa ◽  
Yusuke Shiode ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Macular Edema ◽  
Diabetic Macular Edema ◽  
Outer Nuclear Layer ◽  
Subretinal Fluid ◽  
Plexiform Layer ◽  
Optical Coherence ◽  
Fiber Layer ◽  
Swept Source ◽  
En Face

AbstractThis retrospective study was performed to classify diabetic macular edema (DME) based on the localization and area of the fluid and to investigate the relationship of the classification with visual acuity (VA). The fluid was visualized using en face optical coherence tomography (OCT) images constructed using swept-source OCT. A total of 128 eyes with DME were included. The retina was segmented into: Segment 1, mainly comprising the inner nuclear layer and outer plexiform layer, including Henle’s fiber layer; and Segment 2, mainly comprising the outer nuclear layer. DME was classified as: foveal cystoid space at Segment 1 and no fluid at Segment 2 (n = 24), parafoveal cystoid space at Segment 1 and no fluid at Segment 2 (n = 25), parafoveal cystoid space at Segment 1 and diffuse fluid at Segment 2 (n = 16), diffuse fluid at both segments (n = 37), and diffuse fluid at both segments with subretinal fluid (n = 26). Eyes with diffuse fluid at Segment 2 showed significantly poorer VA, higher ellipsoid zone disruption rates, and greater central subfield thickness than did those without fluid at Segment 2 (P < 0.001 for all). These results indicate the importance of the localization and area of the fluid for VA in DME.

scholarly journals Blue light blind-spot stimulation upregulates b-wave and pattern ERG activity in myopes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ana Amorim-de-Sousa ◽  
Tim Schilling ◽  
Paulo Fernandes ◽  
Yeshwanth Seshadri ◽  
Hamed Bahmani ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Electrical Activity ◽  
Blue Light ◽  
Optic Nerve Head ◽  
Plexiform Layer ◽  
Pattern Electroretinogram ◽  
Blind Spot ◽  
Inner Plexiform Layer ◽  
Pattern Erg ◽  
Myopia Progression

AbstractUpregulation of retinal dopaminergic activity may be a target treatment for myopia progression. This study aimed to explore the viability of inducing changes in retinal electrical activity with short-wavelength light targeting melanopsin-expressing retinal ganglion cells (ipRGCs) passing through the optic nerve head. Fifteen healthy non-myopic or myopic young adults were recruited and underwent stimulation with blue light using a virtual reality headset device. Amplitudes and implicit times from photopic 3.0 b-wave and pattern electroretinogram (PERG) were measured at baseline and 10 and 20 min after stimulation. Relative changes were compared between non-myopes and myopes. The ERG b-wave amplitude was significantly larger 20 min after blind-spot stimulation compared to baseline (p < 0.001) and 10 min (p < 0.001) post-stimulation. PERG amplitude P50-N95 also showed a significant main effect for ‘Time after stimulation’ (p < 0.050). Implicit times showed no differences following blind-spot stimulation. PERG and b-wave changes after blind-spot stimulation were stronger in myopes than non-myopes. It is possible to induce significant changes in retinal electrical activity by stimulating ipRGCs axons at the optic nerve head with blue light. The results suggest that the changes in retinal electrical activity are located at the inner plexiform layer and are likely to involve the dopaminergic system.

scholarly journals Changes in each retinal layer and ellipsoid zone recovery after full-thickness macular hole surgery

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Min-Woo Lee ◽  
Tae-Yeon Kim ◽  
Yong-Yeon Song ◽  
Seung-Kook Baek ◽  
Young-Hoon Lee
Keyword(s):  
Macular Hole ◽  
Axial Length ◽  
Outer Nuclear Layer ◽  
Plexiform Layer ◽  
Retinal Layer ◽  
Inner Plexiform Layer ◽  
Full Thickness ◽  
Ellipsoid Zone ◽  
Full Thickness Macular Hole ◽  
Fellow Eyes

AbstractTo analyze the changes in each retinal layer and the recovery of the ellipsoid zone (EZ) after full-thickness macular hole (FTMH) surgery. Patients who underwent surgery for FTMH were included. Spectral-domain optical coherence tomography (SD-OCT) was performed preoperatively and postoperatively at 1, 3, 6, 9, and 12 months. A total of 32 eyes were enrolled. Ganglion cell layer, inner plexiform layer, and inner nuclear layer showed significant reductions over time after surgery (P = 0.020, P = 0.001, and P = 0.001, respectively), but were significantly thicker than those of fellow eyes at 12 months postoperatively. The average recovery duration of the external limiting membrane (ELM), outer nuclear layer (ONL), and EZ was 1.5, 2.1, and 6.1 months, respectively. Baseline best-corrected visual acuity (BCVA) (P = 0.003), minimum linear diameter (MLD) (P = 0.025), recovery of EZ (P = 0.008), and IRL thickness (P < 0.001) were significant factors associated with changes in the BCVA. Additionally, axial length (P < 0.001), MLD (P = 0.020), and IRL thickness (P = 0.001) showed significant results associated with EZ recovery. The IRL gradually became thinner after FTMH surgery but was still thicker than that of the fellow eye at 12 months postoperatively. The recovery of ELM and ONL may be a prerequisite for the EZ recovery. The BCVA change was affected by baseline BCVA, MLD, recovery of EZ, and IRL thickness. Additionally, axial length, MLD, and IRL thickness were significantly associated with EZ recovery.

Evaluation of retinal inflammatory biomarkers after intravitreal steroid implant and Ranibizumab injection in diabetic macular edema

2021 ◽  
pp. 112067212110294
Author(s):  
Ilkay Kilic Muftuoglu ◽  
Ecem Onder Tokuc ◽  
Fatma Sümer ◽  
V Levent Karabas
Keyword(s):  
Macular Edema ◽  
Diabetic Macular Edema ◽  
Outer Nuclear Layer ◽  
Plexiform Layer ◽  
Retinal Layer ◽  
Treatment Naïve ◽  
The Mean ◽  
The Individual ◽  
Inflammatory Component

Purpose: To compare the efficacy of intravitreal (IV) ranibizumab (IVR) injection with IV dexamethasone implant (IVDEX) in treatment naive diabetic macular edema (DME) patients with inflammatory component. Materials and methods: Treatment naive DME eyes with subfoveal neurosensorial detachment (SND) and hyperreflective spots (HRS) were treated either three loading doses of IVR (18 eyes) or one dose of IVDEX (19 eyes). Central macular thickness (CMT), height of SND, the number of HRSs scattered on the individual retinal layers and photoreceptor integrity were assessed using spectral domain- optical coherence tomography scans over 3-months follow-up. Results: The mean change in best-corrected visual acuity (BCVA) was −0.11 ± 0.08 logMAR in IVDEX group and −0.04 ± 0.06 logMAR in IVR group at 1-month ( p = 0.011). IVDEX group showed statistically significant more increase in BCVA compared to those receiving IVR injections at 2-months ( p = 0.004) and 3-months ( p = 0.017) visits. Compared to baseline, the number of total HRSs and the number of HRSs at each individual inner retinal layer significantly decreased in both groups at all follow-up visits. However, IVDEX group showed more decrease in the total number of HRSs at 2- and 3-months ( p < 0.001 at 2-months, and p = 0.006 at 3-months) and in the mean number of HRSs located at inner nuclear layer–outer plexiform layer level ( p = 0.016 at 1-month, p < 0.001 at 2-months, and p < 0.001 at 3-months). After treatment, the number of HRSs on the outer nuclear layer showed some non-significant increase in both groups. Conclusion: HRSs tended to migrate from inner retina to the outer retina in DME eyes by treatment. Dexamethasone seemed to be more effective option in such cases with inflammatory component.

scholarly journals Inner and outer retinal layer thickness alterations in pediatric and juvenile craniopharyngioma

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ga-In Lee ◽  
Kyung-Ah Park ◽  
Sei Yeul Oh ◽  
Doo-Sik Kong ◽  
Sang Duk Hong
Keyword(s):  
Layer Thickness ◽  
Outer Nuclear Layer ◽  
Plexiform Layer ◽  
Visual Field Defects ◽  
Retinal Layer ◽  
Inner Plexiform Layer ◽  
Healthy Controls ◽  
Fiber Layer ◽  
Photoreceptor Layer ◽  
Chiasmal Compression

AbstractWe evaluated postoperative retinal thickness in pediatric and juvenile craniopharyngioma (CP) patients with chiasmal compression using optical coherence tomography (OCT) auto-segmentation. We included 18 eyes of 18 pediatric or juvenile patients with CP and 20 healthy controls. Each thickness of the macular retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer, outer plexiform layer, outer nuclear layer, and photoreceptor layer was compared between the CP patients and healthy controls. There was significant thinning in the macular RNFL (estimates [μm], superior, − 10.68; inferior, − 7.24; nasal, − 14.22), all quadrants of GCL (superior, − 16.53; inferior, − 14.37; nasal, − 24.34; temporal, − 9.91) and IPL (superior, − 11.45; inferior, − 9.76; nasal, − 15.25; temporal, − 4.97) in pediatric and juvenile CP patients postoperatively compared to healthy control eyes after adjusting for age and refractive errors. Thickness reduction in the average and nasal quadrant of RNFL, GCL, and IPL was associated with peripapillary RNFL thickness, and reduced nasal quadrant GCL and IPL thicknesses were associated with postoperative visual field defects. In pediatric and juvenile patients with CP, decreased inner retinal layer thickness following chiasmal compression was observed. The changes in retinal structures were closely related to peripapillary RNFL thinning and functional outcomes.

scholarly journals An ethanolic phosphotungstic acid (EPTA) analysis of photoreceptor and synaptic ultrastructure in the guinea pig retina.

1980 ◽  
Vol 28 (2) ◽  
pp. 142-148 ◽  
Author(s):  
K R Fry ◽  
A W Spira
Keyword(s):  
Guinea Pig ◽  
Phosphotungstic Acid ◽  
Plexiform Layer ◽  
Synaptic Cleft ◽  
Basal Bodies ◽  
Inner Plexiform Layer ◽  
Synaptic Terminal ◽  
Presynaptic Membrane ◽  
Synaptic Ultrastructure ◽  
Plexiform Layers

Ethanolic phosphotungstic acid (EPTA) has been used to elucidate the structure of certain organelles contained within retinal cells not clearly discernible using conventional preparations. Both synaptic and nonsynaptic components of the guinea pig neural retina have been analyzed. Within the photoreceptor (PR) cell EPTA-stained components include the connecting cilia, their basal bodies, and the root filament system. Cross-striated fibrillar organelles, similar in appearance to the root filaments, are also observed in the nuclear region, the synaptic terminal and other parts of the PR cell. The possible structural continuity and significance of these structures are discussed. Within retinal synapses of both the inner and outer plexiform layers, ribbons and associated paramembranous specializations are stained. The photoreceptor ribbons have a trialaminar structure with filamentous, tufted borders. Synaptic cleft material and postsynaptic densities are also stained. Bipolar cell synapses in the inner plexiform layer contain stained short ribbons as well as closely associated peg-like densities extending towards the presynaptic membrane.

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