Understanding Retinal Changes after Stroke

Association between glaucoma and stroke: A bidirectional mendelian randomization study

Purpose

Observational studies have reported positive associations between glaucoma and stroke; however, controversial results exist. Importantly, the nature of the relationship remains unknown since previous studies were not designed to test causality. Therefore, we aimed to investigate the possible causal relationships between glaucoma and stroke.

Methods

Our two-sample Mendelian randomization (MR) encompassed multi-ethnic large-scale genome-wide association studies with more than 20000 cases and 260000 controls for glaucoma, and more than 80000 cases and 630000 controls for stroke. Individual effect estimates for each SNP were combined using the inverse-variance weighted (IVW) method. To avoid potential pleiotropic effects, we adjusted the main results by excluding genetic variants associated with metabolic factors. The weighted median and MR-Egger methods were also used for the sensitivity analysis.

Results

Our MR analysis revealed that glaucoma and its subtypes, including primary open-angle glaucoma and primary angle-closure glaucoma, exhibited no causal role in relation to any stroke (AS), any ischemic stroke (AIS), large-artery atherosclerotic stroke (LAS), small-vessel stroke (SVS), or cardioembolic stroke (CES) across MR analyses (all P ​> ​0.05). The null associations remained robust even after adjusting for metabolic-related traits and were consistent in both the European and Asian populations. Furthermore, reverse MR analyses also did not indicate any significant causal effects of AS, AIS, LAS, or CES on glaucoma risk.

Conclusions

Evidence from our series of causal inference approaches using large-scale population-based MR analyses did not support causal effects between glaucoma and stroke. These findings suggest that the relationship of glaucoma management and stroke risk prevention should be carefully evaluated in future studies. In turn, stroke diagnosis should not be simply applied to glaucoma risk prediction.

Distinct alterations of retinal structure between thalamic and extra-thalamic subcortical infarction patients: A cross-sectional and longitudinal study

AIMS

Cerebrovascular lesions in the primary visual cortex, the lateral geniculate nucleus, and the optic tract have been associated with retinal neurodegeneration via the retrograde degeneration (RD) mechanism. We aimed to use optical coherence tomography (OCT) to assess the effects of the strategic single subcortical infarction (SSI) location on retinal neurodegeneration and its longitudinal impacts.

METHODS

Patients with SSI were enrolled and stratified by lesion location on cerebral MRI into the thalamic infarction group and extra-thalamic infarction group. Healthy controls from the native communities were also recruited. Retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) were quantified using OCT. Generalized estimating equation (GEE) models were used for cross-sectional analyses and linear mixed models for longitudinal analyses. P < 0.05 was considered statistically significant.

RESULTS

We included a total of 283 eyes from 149 SSI patients. Of these, 115 eyes of 60 patients with follow-up were included in the longitudinal analyses. Cross-sectionally, thalamic-infarction patients had reduced retinal thickness compared with extra-thalamic infarction patients after adjustment for age, gender, disease duration, and vascular risk factors (p = 0.026 for RNFL, and p = 0.026 for GCIPL). Longitudinally, SSI patients showed greater retinal thinning compared with healthy controls over time (p = 0.040 for RNFL, and p < 0.001 for GCIPL), and thalamic infarction patients exhibited faster rates of GCIPL thinning in comparison with extra-thalamic infarction patients (p < 0.001).

CONCLUSION

Our study demonstrates a distinct effect of subcortical infarction lesion site on the retina both at the early stage of disease and at the 1-year follow-up time. These results present evidence of significant associations between strategic infarction locations and retinal neurodegeneration. It may provide novel insights for further research on RD in stroke patients and ultimately facilitate individualized recovery therapeutic strategy.

Differences in retinal microvasculature between large artery atherosclerosis and small artery disease: an optical coherence tomography angiography study

Purpose: Recent reports suggest retinal microvasculature mirror cerebral microcirculation. Using optical coherence tomography angiography (OCTA), we investigated the retinal microvasculature differences between ischemic stroke patients with large artery atherosclerosis (LAA) and small artery disease (SAD). Methods: All patients underwent MR imaging and were classified as SAD and LAA; LAA was subdivided into anterior LAS and posterior LAS depending on the location. Swept-source OCTA (SS-OCTA) was used to image and segment the retina into the superficial vascular complex (SVC) and deep vascular complex (DVC) in a 6 × 6 mm area around the fovea. A deep learning algorithm was used to assess the vessel area density (VAD, %) in the retinal microvasculature. Results: Fifty-eight (mean age = 60.26 ± 10.88 years; 81.03% males) were LAA while 64 (mean age = 55.58 ± 10.34 years; 85.94% males) were SAD. LAS patients had significantly reduced VAD in the DVC (P = 0.022) compared to SAD patients; the VAD in the SVC did not show any significant difference between the two groups (P = 0.580). Anterior LAA ischemic stroke showed significantly lower VAD (P = 0.002) in the SVC compared with posterior LAS patients. There was no significant difference in the DVC between the two groups (P = 0.376). Conclusions: We found LAA patients had significantly reduced DVC density compared with SAD; we also showed anterior LAA patients had significantly reduced SVC density compared with posterior LAA. These findings suggest retinal imaging has the potential to be used to detect microvasculature changes in subtypes of ischemic stroke.

Retinal Neurovascular Changes in Patients With Ischemic Stroke Investigated by Optical Coherence Tomography Angiography

Background

To investigate retinal neurovascular structural changes in patients with ischemic stroke (IS) using optical coherence tomography angiography (OCTA).

Materials and Methods

The cross-sectional study was conducted in Guangdong Provincial People’s Hospital, China, consisting of 159 eyes from IS patients and 109 eyes from age-matched control subjects. Retinal microvascular parameters including the vessel density (VD) of the superficial capillary plexus (SCP), deep capillary plexus (DCP) and radial peripapillary capillary (RPC), and neural parameters such as ganglion cell complex thickness (GCCt) and retinal nerve fibre layer thickness (RNFLt) were measured by OCTA.

Results

The VD of SCP and DCP in the macular area were significantly reduced in IS patients compared to the control group (all p &lt; 0.001). The VD of RPC at the optic disc was also significantly reduced in IS patients (all p &lt; 0.05). IS patients showed reduced GCCt and RNFLt and increased GCC focal loss volume and global loss volume compared with the controls (all p &lt; 0.05). Among patients with IS, the parafovea SCP VD was positively correlated with GCCt (r = 0.346–0.408, all p &lt; 0.001) but not with DCP VD (all p &gt; 0.1). In the optic disc region, the whole image RPC VD was positively correlated with mean RNFLt (r = 0.467–0.548, all p &lt; 0.001).

Conclusion

Reduction of retinal VD, GCCt and RNFLt was observed in patients with IS. The parafovea SCP VD and RPC VD were positively correlated with GCCt and RNFLt, respectively.

A Comparative analysis of stroke diagnosis from retinal images using hand-crafted features and CNN

Stroke is a major reason for disability and mortality in most of the developing nations. Early detection of stroke is highly significant in bio-medical research. Research illustrates that signs of stroke are reflected in the eye and may be analyzed from fundus images. A custom dataset of fundus images has been compiled for formulating an automated stroke detection algorithm. In this paper, a comparative study of hand-crafted texture features and convolutional neural network (CNN) has been recommended for stroke diagnosis. The custom CNN model has also been compared with five pre-trained models from ImageNet. Experimental results reveal that the recommended custom CNN model gives the best performance by achieving an accuracy of 95.8 %.

The Clinical Contribution of Full-Field Electroretinography and 8-Year Experiences of Application in a Tertiary Medical Center

Electroretinography (ERG) is an important and well-established examination for retinal and visual pathway diseases. This study reviewed the medical records of patients who received full-field ERG (ffERG) at a single medical center between 2012 and 2019, which was an 8-year experience in the clinical contribution of ERG. Based on the indication for scheduling ffERG and the final diagnosis, patients could be classified into six groups: ‘retinal dystrophies’, ‘other retinal or macular diseases’, ‘optic neuropathies’, ‘visual complaints’, ‘systemic diseases’, and ‘others’. A total of 1921 full-field electroretinograms (ffERGs) (1655 patients) were included. The average number of ffERGs performed per year was 262 and the number of annual ffERGs was constant. The ‘retinal dystrophies’ group accounted for 36.5% of the studied population, followed by the ‘other retinal or macular diseases’ group (20.2%). The most common systemic disease was central nervous system disease. The rates of abnormal ffERGs in the ‘systemic diseases’, ‘optic neuropathies’, and ‘visual complaints’ groups were 27.3%, 22.6%, and 10.1%, respectively (p < 0.001). Higher rates were found in patients <20 years old in the ‘systemic diseases’ and ‘optic neuropathies’ groups; epilepsy and optic nerve atrophy were the most common diagnoses, respectively. In brief, by quantifying the functional response in the retina, ffERG is indispensable for diagnosis and prognosis in ophthalmologic and multidisciplinary practice.

Evaluation of the "partnership care model" on quality of life and activity of daily living in stroke patients: A randomized clinical trial

BACKGROUND

Stroke is a widespread chronic disease which remains a serious problem for public health and is the cause of major disability and death in adults. Despite valuable efforts, these patients still need new care programs for recovery and rehabilitation.

AIM

The aim of this study is to determine the effect of the partnership care model (PCM) on quality of life (QOL) and activities of daily living (ADL) in stroke participants.

METHOD

The study is a randomized clinical trial carried out in an educational and therapeutic center in 2019. Sixty-seven participants (allocated randomly in intervention and control groups) with cerebrovascular accident who had hospitalization histories were selected. Data collection instruments were the Stroke-Specific QOL scale and Lawton questionnaires. The care plan was developed and implemented for the intervention group after evaluating and recording basic information including demographic variables, care needs, and problems identified in the first PCM-based stage. Ethics approval was obtained from the University / Regional Research Ethics Committee (IR.NIMAD.REC.1397.236).

RESULTS

The results show that the mean scores of the QOL significantly increased after the intervention in the intervention group (before = 130.80; 3 months = 172.19; 6 months = 205.29) compared to the control group (before = 150; 3 months = 144.86; 6 months = 160.66). Also, the mean scores of the ADL significantly increased after the intervention in the intervention group (before = 1.96; 3 months = 3.64; 6 months = 4.87) compared to the control group (p < .05). The effect size is equal to 0.501 and 0.245 for QOL and ADL, respectively.

CONCLUSION

The findings show that the care program based on a PCM recovered the QOL and ADL of stroke participants more than other interventions.