AimTo develop a deep learning (DL) model that predicts age from fundus images (retinal age) and to investigate the association between retinal age gap (retinal age predicted by DL model minus chronological age) and mortality risk.MethodsA total of 80 169 fundus images taken from 46 969 participants in the UK Biobank with reasonable quality were included in this study. Of these, 19 200 fundus images from 11 052 participants without prior medical history at the baseline examination were used to train and validate the DL model for age prediction using fivefold cross-validation. A total of 35 913 of the remaining 35 917 participants had available mortality data and were used to investigate the association between retinal age gap and mortality.ResultsThe DL model achieved a strong correlation of 0.81 (p<0·001) between retinal age and chronological age, and an overall mean absolute error of 3.55 years. Cox regression models showed that each 1 year increase in the retinal age gap was associated with a 2% increase in risk of all-cause mortality (hazard ratio (HR)=1.02, 95% CI 1.00 to 1.03, p=0.020) and a 3% increase in risk of cause-specific mortality attributable to non-cardiovascular and non-cancer disease (HR=1.03, 95% CI 1.00 to 1.05, p=0.041) after multivariable adjustments. No significant association was identified between retinal age gap and cardiovascular- or cancer-related mortality.ConclusionsOur findings indicate that retinal age gap might be a potential biomarker of ageing that is closely related to risk of mortality, implying the potential of retinal image as a screening tool for risk stratification and delivery of tailored interventions.

Hypoxia-inducible factor (HIF) is a transcription factor that facilitates cellular adaptation to hypoxia and ischemia. Long-standing evidence suggests that one isotype of HIF, HIF-1α, is involved in the pathogenesis of various solid tumors and cardiac diseases. However, the role of HIF-1α in retina remains poorly understood. HIF-1α has been recognized as neuroprotective in cerebral ischemia in the past two decades. Additionally, an increasing number of studies has shown that HIF-1α and its target genes contribute to retinal neuroprotection. This review will focus on recent advances in the studies of HIF-1α and its target genes that contribute to retinal neuroprotection. A thorough understanding of the function of HIF-1α and its target genes may lead to identification of novel therapeutic targets for treating degenerative retinal diseases including glaucoma, age-related macular degeneration, diabetic retinopathy, and retinal vein occlusions.

Irreversible vision loss is most often caused by the loss of function and subsequent death of retinal neurons, such as photoreceptor cells—the cells that initiate vision by capturing and transducing signals of light. One reason why retinal degenerative diseases are devastating is that, once retinal neurons are lost, they don't grow back. Stem cell-based cell replacement strategy for retinal degenerative diseases are leading the way in clinical trials of transplantation therapy, and the exciting findings in both human and animal models point to the possibility of restoring vision through a cell replacement regenerative approach. A less invasive method of retinal regeneration by mobilizing endogenous stem cells thus is highly desirable and promising for restoring vision. Although many obstacles remain to be overcome, the field of endogenous retinal repair is progressing at a rapid pace with encouraging results in recent years.

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PURPOSE. Neurons carry electrical signals and communicate via electrical activities. The therapeutic potential of electrical stimulation (ES) for the nervous system, including the retina, through improvement of cell survival and function has been noted. Here we investigated the neuroprotective and regenerative potential of ES in a mouse model of inherited retinal degeneration. METHODS. Rhodopsin-deficient (Rho −/−) mice received one or two sessions of transpalpebral ES or sham treatments for 7 consecutive days. Intraperitoneal injection of 5-ethynyl-2-deoxyuridine was used to label proliferating cells. Weekly electroretinograms were performed to monitor retinal function. Retinal morphology, photoreceptor survival, and regeneration were evaluated in vivo using immunohistochemistry and genetic fatemapping techniques. Müller cell (MC) cultures were employed to further define the optimal conditions of ES application. RESULTS. Noninvasive transpalpebral ES in Rho −/− mice improved photoreceptor survival and electroretinography function in vivo. ES also triggered residential retinal progenitorlike cells such as MCs to reenter the cell cycle, possibly producing new photoreceptors, as shown by immunohistochemistry and genetic fate-mapping techniques. ES directly stimulated cell proliferation and the expression of progenitor cell markers in MC cultures, at least partially through bFGF signaling. CONCLUSIONS. Our study showed that transpalpebral ES improved photoreceptor survival and retinal function and induced the proliferation, probably photoreceptor regeneration, of MCs; this occurs via stimulation of the bFGF pathways. These results suggest the exciting possibility of applying noninvasive ES as a versatile tool for preventing photoreceptor loss and mobilizing endogenous progenitors for reversing vision loss in patients with photoreceptor degeneration.

AimsTo test whether vision impairment and major ophthalmic conditions are predictive of frailty.MethodsThe analysis included 5321 participants aged 60–95 years at baseline from the China Health and Retirement Longitudinal Study. Participants were enrolled in 2011 and followed up in 2013, and 2015 through a face-to-face interview. Distance/near vision impairment was defined by reporting poor eyesight and reporting excellent, very good, good or fair eyesight was used as the reference. A history of cataract surgery and glaucoma were also self-reported. Frailty was defined as the presence of ≥3 of the five components of the Fried phenotype: weakness, slowness, exhaustion, inactivity and shrinking.ResultsIn the cross-sectional analysis, both near (odds ratio [OR] (95% confidence interval [CI]): 1.62 (1.30 to 2.00)) and distance (1.59 (1.30 to 1.96)) vision impairment was associated with a higher prevalence of frailty independent of confounders. In the longitudinal analysis, the multivariable-adjusted OR (95% CI) for incident frailty associated with glaucoma, distance vision impairment, near vision impairment and vision problem was 3.41 (1.46 to 7.99), 1.59 (1.17 to 2.17), 1.62 (1.17 to 2.23) and 2.11 (1.41 to 3.15), respectively. Vision problem was associated with decreased handgrip strength (β (95% CI): −1.47 (−2.20 to –0.75) kg) during follow-up. Individuals with glaucoma (−0.11 (−0.16 to –0.05) m/s), distance vision impairment (−0.02 (−0.03 to 0.00) m/s) or vision problem (−0.02 (−0.05 to 0.00) m/s) had decreased gait speed compared with the control group.ConclusionsVision problem, vision impairment and glaucoma are important predictors of frailty in older adults.

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