Electroretinograms Recorded with Skin Electrodes from Post-Vitrectomy Silicone Oil Filled Eyes with Proliferative Diabetic Retinopathy.

Purpose: To determine the physiological status of the retina by electroretinography (ERG) using skin electrodes and the RETevalTM system in eyes that had undergone pars plana vitrectomy (PPV) with silicone oil (SO) tamponade. The vitrectomy was performed for a retinal detachment and proliferative diabetic retinopathy (PDR). Design: Retrospective case series. Methods: ERGs were recorded with the RETevalTM system (LKC Technologies Inc. Gaithersburg, MD; Welch Allyn, Inc. Skaneateles Falls, NY) from eight eyes with PDR before and after the SO removal. The amplitudes and implicit times of the a- and b-waves of the ERGs before the SO removal were compared to that after the SO removal. Results: ERGs were recordable in four eyes before and after the SO removal and the a- and b-amplitudes improved in three eyes and worsened in one eye after the SO removal. In the remaining four eyes, ERGs were non-recordable both before and after the SO removal. Conclusion: These results indicate that ERGs picked up by skin electrodes can be used to assess the physiology of the retina in eyes with a SO tamponade. The flat ERGs in the SO-filled eye indicated the presence of diffuse retinal damage which was confirmed by the flat ERGs after the SO removal.

There has been an increasing number of reports on evaluating the retinal function using electroretinography (ERG) with skin electrodes. The main advantage of this system is the ability to record ERGs with a skin electrode that does not touch the cornea and ocular surface. This reduces the risk of infection especially in the postoperative period and in clinical situations where infection is suspected. In addition, there have been only a few reports evaluating the function of the retina by ERG in SO-filled eyes. We recorded ERGs with the RETeval (LKC Technologies Inc. Gaithersburg, MD; Welch Allyn Inc. Skaneateles Falls, NY) device, a relatively new ERG recording system that uses skin electrodes and is less invasive. We recorded ERGs from eight SO-filled eyes with proliferative diabetic retinopathy (PDR). In 4 SO filled eyes, the amplitudes increased in three eyes after the SO removal. In the other four eyes, ERGs were non-recordable before and after the SO removal. These results suggest that the RETeval system that uses skin electrodes can be used to assess the retinal function in PDR eyes with a SO tamponade. We suggest that the absence of ERGs in the SO filled eyes was not due to the electrical non-conductive effects of SO but may indicate the presence of diffuse retinal damage which was confirmed after the SO removal.

Electroretinographic and Optical Coherence Tomographic Evaluations of Eyes with Vitreoretinal Lymphoma.

Vitreoretinal lymphomas (VRLs) present with different clinical characteristics. However, only a few case reports have been published that evaluated the retinal function and the retinal morphology. The relationship between retinal morphology and function of eyes with a vitreoretinal lymphoma (VRL) was investigated via optical coherence tomography (OCT) and electroretinography (ERG). The ERG and OCT findings in 11 eyes of 11 patients (69.4 ± 11.5 years old) who were diagnosed with VRL at the Saitama Medical University Hospital between December 2016 to May 2022 were studied. The decimal best-corrected visual acuity ranged from hand movements to 1.2 (median 0.2). Histopathological studies of the vitreous specimens showed class II VRL in one eye, class III VRL in seven eyes, class IV VRL in two eyes, and class V VRL in one eye. The IgH gene rearrangement was positive in three of the six eyes tested. The OCT images showed morphological abnormalities in 10 of the 11 (90.9%) eyes. Severe attenuation was found for the amplitudes of the b-wave of the DA 0.01 ERG in 6 of 11 eyes (54.5%), the DA 3.0 a-wave in 5 of 11 eyes (45.5%), the DA 3.0 b-wave in 36.4%, the LA 3.0 a-wave in 36.4%, the LA 3.0 b-wave in 18.2%, and flicker responses in 36.4% of the eyes. None of the DA 3.0 ERGs had a negative shape (b/a < 1.0). In the five eyes in which the a-wave was severely attenuated, hyperreflective dots were observed subretinally. The ERG analysis in eyes with a VRL indicates a relatively severe dysfunction of the outer retinal layer and was helpful in determining the site of the morphological changes in eyes with VRL.

Early changes in photopic negative response in eyes with glaucoma with and without choroidal detachment after filtration surgery.

BACKGROUND/AIMS: To evaluate the electroretinographic (ERG) changes in the early postoperative period following glaucoma filtration surgery, and its relationship with choroidal detachment (CD). METHODS: This retrospective observational single-centre study included 57 consecutive patients with primary open-angle glaucoma who underwent unilateral glaucoma filtration surgery. The patients were divided into two groups according to the presence or absence of CD. ERG components, including the photopic negative response (PhNR), a-wave and b-wave were compared before and after surgery using skin electrodes. RESULTS: There were 46 patients in the non-CD group and 11 in the CD group. ERG was recorded within 5.1 (2.1 to 8.1) (mean (95% CI)) days after surgery. In the non-CD group, the PhNR amplitude, PhNR/b-wave amplitude ratio and PhNR implicit time improved significantly after surgery (p=0.008, 0.002 and 0.039, respectively). In the CD group, the amplitude of the PhNR, a-wave and b-wave were significantly deteriorated after surgery (p=0.002, 0.001 and 0.001, respectively). Postoperative intraocular pressure (IOP) (p=0.031) and postoperative CD (p<0.001) were significantly associated with change in the PhNR amplitude in the univariate models. In the multivariate analysis, severe CD (stage 3) cases tended to be deteriorated more. CONCLUSION: Even in the early postoperative period within several days, the PhNR amplitude increased with IOP lowering following filtration surgery in the absence of CD. The presence of CD may arrest the improvement of the retinal ganglion cell function. The present results enhance understanding the structural and functional recovery after glaucoma surgery and the role of postoperative CD.

Evaluations of microvascular density by optical coherence tomography, angiography, and function by multifocal electroretinography of the macular area in eyes with branch retinal artery occlusion.

Introduction: It is reported that eyes with a branch retinal artery occlusion (BRAO) had normal full-field electroretinography (ERG) but the response of the multifocal electroretinography (mfERG) was reduced in the area of the arterial occlusion. Optical coherence tomography angiography (OCTA) is a recently appeared modality that can evaluate microvascularizations in different retinal layers and in different regions of the retina. The purpose of this study was to determine the density of the microcirculation and the function of the macular area of eyes with BRAO, and to determine whether they are significantly correlated. Methods: The OCTA and mfERG findings of 7 eyes of 6 patients (3 men, 3 women) were studied. The mean age of the patients was 71.7±10.6 years. The OCTA examinations were made with volume scans of 3 × 3 and 6 × 6 mm squares centered on the fovea. The macular vessel densities (mVD) in the superficial retinal layer (SRL) and deep retinal layer (DRL) were measured for the superior and inferior halves of 3  × 3  and 6  × 6 mm diameter concentric circles. The mfERGs were recorded with targets set to stimulate the focal areas of the retina corresponding to the areas examined by OCTA. Results: The OCTA examinations showed that the mVD of the 3 mm concentric circle in the SRL was significantly lower on the affected side than on the unaffected side (P = 0.022). No such difference was observed in the DRL. The N1 amplitude of the 20.2° concentric circle and the N1-P1 amplitude of the 10.1° concentric circle of the mfERGs were significantly smaller on the affected side than on the unaffected side (P = 0.047 and 0.031). A significant positive correlation was found between the mVD of the 6 mm concentric circle in the DRL and the P1-N2 amplitude of the 20.2° concentric circle (ρ = -0.929 and p = 0.003). Discussion: These findings indicate that OCTA images may be able to show changes in the density of the retinal macular microcirculation, and the mfERGs may be able to show alterations in the function of the macular area of the eyes with BRAO. A layer-by-layer analysis of the local retinal microcirculation and function should help in determining the pathogenesis of BRAO.

Relationship Between Deep Retinal Macular Vessel Density and Bipolar Cell Function in Glaucomatous Eyes.

Purpose: To evaluate the correlation between macular retinal function and the changes in the macular retinal vascular structure in glaucomatous eyes. Methods: The study included patients with glaucoma who visited Saitama Medical University and underwent optical coherence tomography angiography, and multifocal electroretinographic examinations at the same time between February 2020 and April 2021. Correlations among the ocular parameters, macular vessel density, and multifocal electroretinographic parameters were evaluated using a mixed model. Results: Forty-one eyes (mean deviation, -12.4 ± 7.8 dB) of 24 subjects (mean age, 75.2 ± 8.3 years) were included in the analysis. There were no significant correlations for macular vessel density in the superficial retinal layer. However, macular vessel density in the deep retinal layer showed a significant positive correlation with P1-N1 amplitude (coefficient = 0.724; P = 0.001). There were no significant correlations between the optical coherence tomography parameters and any of the multifocal electroretinographic parameters. Conclusions: A decrease in N1-P1 amplitude was observed in glaucomatous eyes in relation to a reduction in macular vessel density in the deep retinal layer, which suggests that ischemia-induced bipolar cell dysfunction may be involved in the intermediate retinal dysfunction associated with glaucoma. Translational Relevance: Intermediate retinal dysfunction in glaucoma is related to the changes in deep retinal microvasculature.

Intraocular Temperature Distribution in Eyes Undergoing Different Types of Surgical Procedures during Vitreous Surgery.

Vitreous temperature has been reported to vary during intraocular surgery. We measured the temperature at three intraocular sites, just posterior to the crystalline lens (BL), mid-vitreous (MV), and just anterior to the optic disc (OD), and investigated temperature changes before and after different types of surgical procedures in 78 eyes. The mean temperature at the beginning was 30.1 ± 1.70 °C in the anterior chamber, 32.4 ± 1.41 °C at the BL, 33.8 ± 0.95 °C at the MV, and 34.7 ± 0.95 °C at the OD. It was lowest at the BL, and highest at the OD. The mean temperature after cataract surgery was slightly lower especially at an anterior location. Thus, the temperature gradient became slightly flatter. The mean temperature after core vitrectomy was even lower at all sites and a gradient of the temperature was not present. The mean temperature after membrane peeling was significantly higher than that after core vitrectomy, and there was no gradient. The mean temperature after fluid/air exchange was lower at the BL and higher at the MV and at the OD. Thus, a gradient of higher temperatures at the OD appeared. The intraocular temperature distribution is different depending on the surgical procedure which can then change the temperature gradient. The temperature changes at the different intraocular sites and the gradients should be further investigated because they may affect the physiology of the retina and the recovery process.