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Age-related macular degeneration (AMD) is the leading cause of irreversible vision damage among elderly individuals. There is still no efficient treatment for dry AMD. Retinal pigment epithelial (RPE) degeneration has been confirmed to play an important role in dry AMD. Recent studies have reported that ferroptosis caused by iron overload and lipid peroxidation may be the primary causes of RPE degeneration. However, the upstream regulatory molecules of RPE ferroptosis remain largely unknown. Pigment epithelium-derived factor (PEDF) is an important endogenic protective factor for the RPE. Our results showed that in the murine dry AMD model induced by sodium iodate (SI), PEDF expression was downregulated. Moreover, dry AMD-like pathology was observed in PEDF-knockout mice. Therefore, the aim of this study was to reveal the effects and mechanism of PEDF on RPE ferroptosis and investigate potential therapeutic targets for dry AMD. The results of lipid peroxidation and transmission electron microscope showed that retinal ferroptosis was significantly activated in SI-treated mice and PEDF-knockout mice. Restoration of PEDF expression ameliorated SI-induced retinal dysfunction in mice, as assessed by electroretinography and optical coherence tomography. Mechanistically, western blotting and immunofluorescence analysis demonstrated that the overexpression of PEDF could upregulate the expression of glutathione peroxidase 4 (GPX4) and ferritin heavy chain-1 (FTH1), which proved to inhibit lipid peroxidation and RPE ferroptosis induced by SI. This study revealed the novel role of PEDF in ferroptosis inhibition and indicated that PEDF might be a potential therapeutic target for dry AMD. [ABSTRACT FROM AUTHOR]

Purpose: To find a new approach of pan-retinal photocoagulation (PRP) with less damage to the retina in the treatment of severe non-proliferative diabetic retinopathy (NPDR), this study compared functional changes in the retina after subthreshold and threshold PRP treatment in severe NPDR eyes.Methods: Post hoc analysis of a randomized clinical trial was conducted in this study. Seventy eyes of 35 patients with bilateral, symmetric, severe NPDR were enrolled. Two eyes from the same patient were randomized into two groups, one eye received subthreshold PRP (S-PRP) and the other eye received threshold PRP (T-PRP). Comprehensive ophthalmological evaluations were performed on the baseline and every 3 months for 1 year. Visual field (VF) and full-field electroretinography (ERG) were performed on the baseline and repeated at month 12.Results: During the 12-month follow-up, 4 eyes (11.4%) in the S-PRP group and 3 eyes (8.6%) in the T-PRP group progressed to proliferative diabetic retinopathy (PDR) stage, and there was no statistical difference in PDR progression rate between the two groups (P = 0.69). In addition, the changes in best-corrected visual acuity (BCVA) from baseline to month 12 between the two groups had no statistical difference (P = 0.30). From baseline to month 12, changes in central VF between the two groups had no statistical difference (P = 0.25), but changes in total score points of peripheral VF in the S-PRP group (- 242.1 ± 210.8 dB) and the T-PRP group (- 308.9 ± 209.7 dB) were statistically significant (P = 0.03). At month 12, ERG records showed that the amplitude of dark-adapted 0.01 ERG, dark-adapted 3.0 ERG, oscillatory potentials, light-adapted 3.0 ERG, and 30 Hz flicker ERG of both groups were significantly decreased from the baseline (P < 0.05). In addition, the amplitude of each ERG record in the S-PRP group decreased significantly less than those in the T-PRP group (P < 0.05).Conclusions: Subthreshold PRP is as effective as threshold PRP for preventing severe NPDR progress to PDR within 1 year with less damage to periphery VF and retinal function.Trial Registration: Clinicaltrials: gov Identifier: NCT01759121. [ABSTRACT FROM AUTHOR]

Purpose: To predict central serous chorioretinopathy (CSC) recurrence 3 and 6 months after laser treatment by using machine learning. Methods: Clinical and imaging features of 461 patients (480 eyes) with CSC were collected at Zhongshan Ophthalmic Center (ZOC) and Xiamen Eye Center (XEC). The ZOC data (416 eyes of 401 patients) were used as the training dataset and the internal test dataset, while the XEC data (64 eyes of 60 patients) were used as the external test dataset. Six different machine learning algorithms and an ensemble model were trained to predict recurrence in patients with CSC. After completing the initial detailed investigation, we designed a simplified model using only clinical data and OCT features. Results: The ensemble model exhibited the best performance among the six algorithms, with accuracies of 0.941 (internal test dataset) and 0.970 (external test dataset) at 3 months and 0.903 (internal test dataset) and 1.000 (external test dataset) at 6 months. The simplified model showed a comparable level of predictive power. Conclusion: Machine learning achieves high accuracies in predicting the recurrence of CSC patients. The application of an intelligent recurrence prediction model for patients with CSC can potentially facilitate recurrence factor identification and precise individualized interventions. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to investigate the safety and efficacy of intravitreal injection of Tc-MDP, a decay product of Tc-MDP, on the development of laser-induced choroidal neovascularization (CNV) in rhesus monkeys. Methods: Experimental CNV was induced by argon laser with a small high-energy laser spot. Monkeys were given 50 μL of Tc-MDP at a concentration of 0.005 μg/mL ( n = 6) or 0.01 μg/mL ( n = 6) by intravitreal injection once a week immediately after laser injury for a period of 56 days. Control animals were treated with the same volume of PBS ( n = 6) in the same way. Eyes were monitored by ophthalmic examination, color fundus photography, fluorescence fundus angiography (FFA), optical coherence tomography (OCT) and histology. Incidences of grade 4 CNV lesions as well as the leakage areas of grade 4 CNVs on the late-phase of fluorescein angiograms were measured in a standardized, randomized and masked fashion fortnightly. The maximum widths and heights of grade 4 CNVs were also calculated by histology at the end of the experiment. Toxicity of Tc-MDP on the retina was evaluated by electroretinogram (ERG) and histologic analysis. Results: Tc-MDP reduced the incidences of grade 4 CNVs by 33.33 % and 39.40 % in the 0.005 μg/mL and 0.01 μg/mL groups, respectively, compared with the PBS group on day 28 ( P < 0.05; n = 6). The leakage areas of grade 4 CNVs were smaller in the 0.005 μg/mL (0.7136 ± 0.0283 mm, p <0.01; n = 6) and 0.01 μg/mL (0.4351 ± 0.0349 mm, p < 0.01; n = 6) groups than those in the PBS control group (0.9373 ± 0.0455 mm; n = 6) in a dose-dependent manner on day 28. OCT and histology also showed that the sizes of CNVs were smaller in the Tc-MDP treated groups than those in the PBS group. Although intravitreal injection of Tc-MDP led to mild inflammatory reaction in the anterior chamber, histology and ERG findings demonstrated that Tc-MDP did not cause any change in histological structure or function of the retina ( p>0.05). Conclusions: Intravitreal injection of Tc-MDP can inhibit the development of laser-induced CNV without toxic effect on retina, suggesting that Tc-MDP has therapeutic potential for CNV related diseases. [ABSTRACT FROM AUTHOR]