Prediction of glaucoma severity using parameters from the electroretinogram

The Use of the RETeval Portable Electroretinography Device for Low-Cost Screening: A Mini-Review

Electroretinography (ERG) provides crucial insights into retinal function and the integrity of the visual pathways. However, ERG assessments classically require a complicated technical background with costly equipment. In addition, the placement of corneal or conjunctival electrodes is not always tolerated by the patients, which restricts the measurement for pediatric evaluations. In this short review, we give an overview of the use of the RETeval portable ERG device (LKC Technologies, Inc., Gaithersburg, MD, USA), a modern portable ERG device that can facilitate screening for diseases involving the retina and the optic nerve. We also review its potential to provide ocular biomarkers in systemic pathologies, such as Alzheimer's disease and central nervous system alterations, within the framework of oculomics.

Assessing the length of hospital stay for patients with myasthenia gravis based on the data mining MARS approach

Predicting the length of hospital stay for myasthenia gravis (MG) patients is challenging due to the complex pathogenesis, high clinical variability, and non-linear relationships between variables. Considering the management of MG during hospitalization, it is important to conduct a risk assessment to predict the length of hospital stay. The present study aimed to successfully predict the length of hospital stay for MG based on an expandable data mining technique, multivariate adaptive regression splines (MARS). Data from 196 MG patients' hospitalization were analyzed, and the MARS model was compared with classical multiple linear regression (MLR) and three other machine learning (ML) algorithms. The average hospital stay duration was 12.3 days. The MARS model, leveraging its ability to capture non-linearity, identified four significant factors: disease duration, age at admission, MGFA clinical classification, and daily prednisolone dose. Cut-off points and correlation curves were determined for these risk factors. The MARS model outperformed the MLR and the other ML methods (including least absolute shrinkage and selection operator MLR, classification and regression tree, and random forest) in assessing hospital stay length. This is the first study to utilize data mining methods to explore factors influencing hospital stay in patients with MG. The results highlight the effectiveness of the MARS model in identifying the cut-off points and correlation for risk factors associated with MG hospitalization. Furthermore, a MARS-based formula was developed as a practical tool to assist in the measurement of hospital stay, which can be feasibly supported as an extension of clinical risk assessment.

The Role of Retinal Ganglion Cell Structure and Function in Glaucoma

Glaucoma, a leading cause of irreversible blindness globally, primarily affects retinal ganglion cells (RGCs). This review dives into the anatomy of RGC subtypes, covering the different underlying theoretical mechanisms that lead to RGC susceptibility in glaucoma, including mechanical, vascular, excitotoxicity, and neurotrophic factor deficiency, as well as oxidative stress and inflammation. Furthermore, we examined numerous imaging methods and functional assessments to gain insight into RGC health. Finally, we investigated the current possible neuroprotective targets for RGCs that could help with future glaucoma research and management.

CREG Protects Retinal Ganglion Cells loss and Retinal Function Impairment Against ischemia-reperfusion Injury in mice via Akt Signaling Pathway

PURPOSE

The irreversible death of retinal ganglion cells (RGCs) plays an important role in the pathogenesis of glaucoma. Cellular repressor of E1A-stimulated genes (CREG), a secreted glycoprotein involved in cellular proliferation and differentiation, has been shown to protect against myocardial and renal ischemia-reperfusion damage. However, the role of CREG in retinal ischemia-reperfusion injury (RIRI) remains unknown. In this study, we aimed to explore the effect of CREG on RGCs apoptosis after RIRI.

METHODS

We used male C57BL/6J mice to establish the RIRI model. Recombinant CREG was injected at 1 day before RIRI. The expression and distribution of CREG were examined by immunofluorescence staining and western blotting. RGCs survival was assessed by immunofluorescence staining of flat-mounted retinas. Retinal apoptosis was measured by the staining of TdT-mediated dUTP nick-end labeling and cleaved caspase-3. Electroretinogram (ERG) analysis and optomotor response were conducted to evaluate retinal function and visual acuity. The expressions of Akt, phospho-Akt (p-Akt), Bax, and Bcl-2 were analyzed by western blotting to determine the signaling pathways of CREG.

RESULTS

We found that CREG expression was decreased after RIRI, and intravitreal injection of CREG attenuated RGCs loss and retinal apoptosis. Besides, the amplitudes of a-wave, b-wave, and photopic negative response (PhNR) in ERG, as well as visual function, were significantly restored after treatment with CERG. Furthermore, intravitreal injection of CREG upregulated p-Akt and Bcl-2 expression and downregulated Bax expression.

CONCLUSION

Our results demonstrated that CREG protected RGCs from RIRI and alleviated retinal apoptosis by activating Akt signaling. In addition, CREG also improved retinal function and visual acuity.

Three-Dimensional Structural Phenotype of the Optic Nerve Head as a Function of Glaucoma Severity

Importance

The 3-dimensional (3-D) structural phenotype of glaucoma as a function of severity was thoroughly described and analyzed, enhancing understanding of its intricate pathology beyond current clinical knowledge.

Objective

To describe the 3-D structural differences in both connective and neural tissues of the optic nerve head (ONH) between different glaucoma stages using traditional and artificial intelligence-driven approaches.

Design, Setting, and Participants

This cross-sectional, clinic-based study recruited 541 Chinese individuals receiving standard clinical care at Singapore National Eye Centre, Singapore, and 112 White participants of a prospective observational study at Vilnius University Hospital Santaros Klinikos, Vilnius, Lithuania. The study was conducted from May 2022 to January 2023. All participants had their ONH imaged using spectral-domain optical coherence tomography and had their visual field assessed by standard automated perimetry.

Main Outcomes and Measures

(1) Clinician-defined 3-D structural parameters of the ONH and (2) 3-D structural landmarks identified by geometric deep learning that differentiated ONHs among 4 groups: no glaucoma, mild glaucoma (mean deviation [MD], ≥-6.00 dB), moderate glaucoma (MD, -6.01 to -12.00 dB), and advanced glaucoma (MD, <-12.00 dB).

Results

Study participants included 213 individuals without glaucoma (mean age, 63.4 years; 95% CI, 62.5-64.3 years; 126 females [59.2%]; 213 Chinese [100%] and 0 White individuals), 204 with mild glaucoma (mean age, 66.9 years; 95% CI, 66.0-67.8 years; 91 females [44.6%]; 178 Chinese [87.3%] and 26 White [12.7%] individuals), 118 with moderate glaucoma (mean age, 68.1 years; 95% CI, 66.8-69.4 years; 49 females [41.5%]; 97 Chinese [82.2%] and 21 White [17.8%] individuals), and 118 with advanced glaucoma (mean age, 68.5 years; 95% CI, 67.1-69.9 years; 43 females [36.4%]; 53 Chinese [44.9%] and 65 White [55.1%] individuals). The majority of ONH structural differences occurred in the early glaucoma stage, followed by a plateau effect in the later stages. Using a deep neural network, 3-D ONH structural differences were found to be present in both neural and connective tissues. Specifically, a mean of 57.4% (95% CI, 54.9%-59.9%, for no to mild glaucoma), 38.7% (95% CI, 36.9%-40.5%, for mild to moderate glaucoma), and 53.1 (95% CI, 50.8%-55.4%, for moderate to advanced glaucoma) of ONH landmarks that showed major structural differences were located in neural tissues with the remaining located in connective tissues.

Conclusions and Relevance

This study uncovered complex 3-D structural differences of the ONH in both neural and connective tissues as a function of glaucoma severity. Future longitudinal studies should seek to establish a connection between specific 3-D ONH structural changes and fast visual field deterioration and aim to improve the early detection of patients with rapid visual field loss in routine clinical care.

The origins of the full-field flash electroretinogram b-wave

The electroretinogram (ERG) measures the electrical activity of retinal neurons and glial cells in response to a light stimulus. Amongst other techniques, clinicians utilize the ERG to diagnose various eye diseases, including inherited conditions such as cone-rod dystrophy, rod-cone dystrophy, retinitis pigmentosa and Usher syndrome, and to assess overall retinal health. An ERG measures the scotopic and photopic systems separately and mainly consists of an a-wave and a b-wave. The other major components of the dark-adapted ERG response include the oscillatory potentials, c-wave, and d-wave. The dark-adapted a-wave is the initial corneal negative wave that arises from the outer segments of the rod and cone photoreceptors hyperpolarizing in response to a light stimulus. This is followed by the slower, positive, and prolonged b-wave, whose origins remain elusive. Despite a large body of work, there remains controversy around the mechanisms involved in the generation of the b-wave. Several hypotheses attribute the origins of the b-wave to bipolar or Müller glial cells or a dual contribution from both cell types. This review will discuss the current hypothesis for the cellular origins of the dark-adapted ERG, with a focus on the b-wave.

Using texture based features from the continuous wavelet transform of the electroretinogram to predict glaucoma. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023;2023:1-4. [PMID: 38082633 DOI: 10.1109/embc40787.2023.10341019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Glaucoma is an optic neuropathy resulting in the progressive loss of retinal ganglion cells (RCGs). The photopic negative response (PhNR) of the electroretinogram (ERG) has been used to objectively measure RCG function. This study sought to explore whether the usage of textural features extracted from the continuous wavelet transform of the ERG combined with ERG amplitude markers were more effective at predicting glaucoma severity than using the ERG markers alone. One-hundred and three eyes of 55 participants were included in this study, who underwent ERG testing with a protocol targeted at the PhNR. Predictive models for glaucoma severity based on the estimated RGC count were fitted using multiadaptive regression splines (MARS). The models informed by a combination of amplitude markers and texture analysis had a better predictive performance; R2 = 0.492, compared to models informed by markers alone having an R2 = 0.349 (p = 0.009).Clinical Relevance- As a direct measure of retinal function, the ERG has potential to determine the health of RGCs. This study demonstrates there is additional data within the ERG available to clinicians, which has the potential to improve the diagnosis and management of glaucoma.

Analysis of the Clinical Effect of Visual Electrophysiological Examination Combined with Targeted Health Education Nursing in Children

Objective

To analyze the clinical effect of visual electrophysiological examination combined with targeted health education nursing in children.

Methods

A total of 100 children who underwent visual electrophysiological examinations in the Ophthalmology Department of our hospital from March 2019 to March 2021 were selected as the study subjects. The children were randomly divided into two groups, the control group and the observation group, with 50 children in each group. Children in the control group received routine nursing, while those in the observation group received a combination of routine nursing and targeted health education nursing. The nursing satisfaction, degree of cooperation with examination, examination time, changes in the psychological state, and the stress response of the children and their families were then compared and analyzed.

Results

The nursing satisfaction of the observation group was higher than that of the control group (94.0% vs. 80.0%) (P < 0.05). The degree to which children in the observation group cooperated with examination was higher than that of children in the control group (96.0% vs. 78.0%) (P < 0.05). The average time spent on VEP and ERG examinations by children in the observation group was 6.33 ± 1.37 hours and 55.25 ± 4.92 hours, respectively, significantly lower than that of 12.45 ± 1.02 hours and 70.36 ± 5.31 hours, respectively, spent by children in the control group (P < 0.05). After intervention, the depression, hostility, anxiety, and obsession scores of children in the observation group were all significantly lower than those of children in the control group (P < 0.05). There was an increase in the heart rate, respiratory rate, and mean arterial pressure in children from both groups, but the magnitude of increase in the observation group was much smaller than that in the control group (P < 0.05).

Conclusion

The combination of visual electrophysiological examination and targeted health education nursing in children has a remarkable clinical effect. It improves the children's degree of comfort as well as the parents' degree of satisfaction. It also reduces the time spent on examinations, facilitates the smooth completion of examinations, and improves the efficiency of examinations. This nursing method is one that merits more widespread promotion and clinical application.

Time-Frequency Analysis of ERG With Discrete Wavelet Transform and Matching Pursuits for Glaucoma

Purpose

To examine the performance of two time-frequency feature extraction techniques applied to electroretinograms (ERGs) for the prediction of glaucoma severity.

Methods

ERGs targeting the photopic negative response were obtained in 103 eyes of 55 patients with glaucoma. Features from the ERG recordings were extracted using two time-frequency extraction techniques based on the discrete wavelet transform (DWT) and the matching pursuit (MP) decomposition. Amplitude markers of the time-domain signal were also extracted. Linear and multivariate adaptive regression spline (MARS) models were fitted using combinations of these features to predict estimated retinal ganglion cell counts, a measure of glaucoma disease severity derived from standard automated perimetry and optical coherence tomography imaging.

Results

Predictive models using features from the time-frequency analyses-using both DWT and MP-combined with amplitude markers outperformed predictive models using the markers alone with linear (P = 0.001) and MARS (P ≤ 0.011) models. For example, the proportions of variance (R2) explained by the MARS model using the DWT and MP features with amplitude markers were 0.53 and 0.63, respectively, compared to 0.34 for the model using the markers alone (P = 0.011 and P = 0.001, respectively).

Conclusions

Novel time-frequency features extracted from the photopic ERG substantially added to the prediction of glaucoma severity compared to using the time-domain amplitude markers alone.

Translational Relevance

Substantial information about retinal ganglion cell dysfunction exists in the time-frequency domain of ERGs that could be useful in the management of glaucoma.

Sodium Hyaluronate-Induced Ocular Hypertension in Rats Damages the Direction-Selective Circuit and Inner/Outer Retinal Plexiform Layers

Purpose

To assess the changes in retinal morphology in a rat model of chronic glaucoma induced by ocular hypertension.

Methods

Intraocular pressure (IOP) was surgically increased through weekly injections of sodium hyaluronate (HYA) in the anterior eye chamber of the left eye of male Wistar rats, whereas the right eyes were sham operated (salt solution). During the 10-week experimental period, IOP was measured weekly with a rebound tonometer. Retinal cryosections were prepared for histological/immunohistochemical analysis and morphometry.

Results

IOP was higher in HYA-treated eyes than in sham-operated eyes along the 10-week period, which was significant from the fourth to the nineth week. Ocular hypertension in HYA-treated eyes was associated with morphologic and morphometric changes in bipolar cells, ON-OFF direction-selective ganglion cells, ON/OFF starburst amacrine cells, and inner plexiform layer sublamina.

Conclusions

Serial HYA treatment in the rat anterior eye chamber results in mild-to-moderate elevated and sustained IOP and ganglion cell death, which mimics most human open-angle glaucoma hallmarks. The reduced number of direction-selective ganglion cells and starburst amacrine cells accompanied by a deteriorated ON/OFF plexus in this glaucoma model could lend insight to the abnormalities in motion perception observed in patients with glaucoma.