Quantify retinal structure in high-altitude residents with and without high altitude polycythemia

Ma, Jie; Niu, Haoyu; Han, Changjing; Qu, Yi

doi:10.1186/s12886-022-02674-7

Cited by 3 publications

(1 citation statement)

References 42 publications

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“…The assessment of the optic nerve head (ONH) is crucial in evaluating and diagnosing numerous ocular conditions, including myopia, glaucoma and optic nerve oedema, which result in structural changes in the posterior globe. In addition, studies have shown that retinal vascular calibre changes are related to different ocular conditions, 23 24 and that anatomic relationships exist between the ONH and retinal vasculature. 25 Fundus examination of individuals with high hyperopia often shows crowding of the optic disc due to a small disc size in adult populations.…”

Section: Introductionmentioning

confidence: 99%

Quantitative assessment of colour fundus photography in hyperopia children based on artificial intelligence

Luo,

Wang,

et al. 2024

BMJ Open Ophth

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ObjectivesThis study aimed to quantitatively evaluate optic nerve head and retinal vascular parameters in children with hyperopia in relation to age and spherical equivalent refraction (SER) using artificial intelligence (AI)-based analysis of colour fundus photographs (CFP).Methods and analysisThis cross-sectional study included 324 children with hyperopia aged 3–12 years. Participants were divided into low hyperopia (SER+0.5 D to+2.0 D) and moderate-to-high hyperopia (SER≥+2.0 D) groups. Fundus parameters, such as optic disc area and mean vessel diameter, were automatically and quantitatively detected using AI. Significant variables (p<0.05) in the univariate analysis were included in a stepwise multiple linear regression.ResultsOverall, 324 children were included, 172 with low and 152 with moderate-to-high hyperopia. The median optic disc area and vessel diameter were 1.42 mm2and 65.09 µm, respectively. Children with high hyperopia had larger superior neuroretinal rim (NRR) width and larger vessel diameter than those with low and moderate hyperopia. In the univariate analysis, axial length was significantly associated with smaller superior NRR width (β=−3.030, p<0.001), smaller temporal NRR width (β=−1.469, p=0.020) and smaller vessel diameter (β=−0.076, p<0.001). A mild inverse correlation was observed between the optic disc area and vertical disc diameter with age.ConclusionAI-based CFP analysis showed that children with high hyperopia had larger mean vessel diameter but smaller vertical cup-to-disc ratio than those with low hyperopia. This suggests that AI can provide quantitative data on fundus parameters in children with hyperopia.

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Section: Introductionmentioning

confidence: 99%

Quantitative assessment of colour fundus photography in hyperopia children based on artificial intelligence

Luo,

Wang,

et al. 2024

BMJ Open Ophth

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Effects of Acute High-Altitude Exposure on Morphology and Function of Retinal Ganglion Cell in Mice

Yang,

Han,

Sun

et al. 2024

Invest. Ophthalmol. Vis. Sci.

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Purpose High altitude retinopathy (HAR) is a retinal functional disorder caused by inadequate adaptation after exposure to high altitude. However, the cellular and molecular mechanisms underlying retinal dysfunction remain elusive. Retinal ganglion cell (RGC) injury is the most important pathological basis for most retinal and optic nerve diseases. Studies focusing on RGC injury after high-altitude exposure (HAE) are scanty. Therefore, the present study sought to explore both functional and morphological alterations of RGCs after HAE. Methods A mouse model of acute hypobaric hypoxia was established by mimicking the conditions of a high altitude of 5000 m. After HAE for 2, 4, 6, 10, 24, and 72 hours, the functional and morphological alterations of RGCs were assessed using retinal hematoxylin and eosin (H&E) sections, retinal whole mounts, transmission electron microscopy (TEM), and the photopic negative response (PhNR) of the electroretinogram. Results Compared with the control group, the thickness of the ganglion cell layer and retinal nerve fiber layer increased significantly, RGC loss remained significant, and the amplitudes of a-wave, b-wave, and PhNR were significantly reduced after HAE. In addition, RGCs and their axons exhibited an abnormal ultrastructure after HAE, including nuclear membrane abnormalities, uneven distribution of chromatin in the nucleus, decreased cytoplasmic electron density, widening and vacuolization of the gap between axons, loosening and disorder of myelin sheath structure, widening of the gap between myelin sheath and axon membrane, decreased axoplasmic density, unclear microtubule and nerve fiber structure, and abnormal mitochondrial structure (mostly swollen, with widened membrane gaps and reduced cristae and vacuolization). Conclusions The study findings confirm that the morphology and function of RGCs are damaged after HAE. These findings lay the foundation for further study of the specific molecular mechanisms of HAR and promote the effective prevention.

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Quantifying ocular microcirculation in hypertension patients with carotid artery stenosis

Ma,

Gelie,

Zhu

et al. 2024

Front. Neurosci.

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BackgroundCarotid artery stenosis (CAS) is one of the most common macrovascular complications of hypertension. The ophthalmic artery springs from the internal carotid artery; however, the effect of CAS on ocular microcirculation has not been quantified in hypertension patients. This study aimed to quantify ocular microcirculation metrics in hypertension with CAS (HCAS) patients and to explore the relationship between micro- and macroangiopathy in hypertension.MethodsAll participants (community-based) underwent detailed assessments, including carotid ultrasonography, optical coherence tomography angiography (OCTA), and enhanced depth imaging (EDI)-OCT. CAS was diagnosed using carotid ultrasonography. Retinal microcirculation metrics, including vessel density (VD), skeleton density (SD), fractal dimension (FD), and foveal avascular zone (FAZ), were quantified using OCTA and ImageJ software. Choroidal microcirculation metrics, including subfoveal choroidal thickness (SFCT), luminal area (LA), and choroidal vascularity index (CVI), were quantified using EDI-OCT and ImageJ. Retinal vessel caliber metrics, including central retinal artery equivalent (CRAE), central retinal vein equivalent (CRVE), and artery/vein ratio (AVR), were calculated using revised formulas. The above metrics were compared among the HCAS group, hypertension with no CAS (HNCAS) group, and healthy control group. The mutual effects between ocular metrics and CAS were evaluated using regression analyses.ResultsIn a comparison of the HCAS vs. HNCAS groups, retinal metrics including VD, SD, FD, and choroidal metrics including CVI and LA were significantly decreased in the HCAS group (all p < 0.05); however, FAZ, SFCT, and retinal vessel caliber metrics including CRAE, CRVE, and AVR were comparable between groups (all p > 0.05). In a comparison of HNCAS and the healthy control group, VD, SD, and CRAE showed that AVR was significantly decreased in the HNCAS group (all p < 0.05); meanwhile, choroidal metrics were comparable between groups (all p > 0.05). Linear regression analyses showed that intima-media thickness (IMT) (p = 0.01) and peak systolic velocity (PSV) (p = 0.002) were negatively related to retinal VD in hypertension patients. Logistic regression analyses disclosed that older age (p < 0.001), smoking history (p = 0.002), lower VD (p = 0.04), SD (p = 0.02), and CVI (p < 0.001) were related to the presence of CAS in hypertension patients.ConclusionCAS in hypertension-induced hypoperfusion in retinal and choroidal microcirculation and the decreased retinal VD and choroidal CVI were significantly associated with the presence of CAS in patients with hypertension, suggesting that hypertension macro- and microangiopathy were mutually affected and share the common pathophysiology. Furthermore, OCT could be a useful tool to assess hypertension patient’s CAS risk profiles in a non-invasive way.

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Quantify retinal structure in high-altitude residents with and without high altitude polycythemia

Cited by 3 publications

References 42 publications

Quantitative assessment of colour fundus photography in hyperopia children based on artificial intelligence

Quantitative assessment of colour fundus photography in hyperopia children based on artificial intelligence

Effects of Acute High-Altitude Exposure on Morphology and Function of Retinal Ganglion Cell in Mice

Quantifying ocular microcirculation in hypertension patients with carotid artery stenosis

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