Choroidal neovascularization (CNV) is an important characteristic of advanced wet age‐related macular degeneration (AMD) and leads to severe visual impairment among elderly patients. Previous studies have demonstrated that melatonin induces several biological effects related to antioxidation, anti‐inflammation, and anti‐angiogenesis. However, the role of melatonin in CNV, and its underlying mechanisms, has not been investigated thus far. In this study, we found that melatonin administration significantly reduced the scale and volume of CNV lesions, suppressed vascular leakage, and inhibited the capacity of vascular proliferation in the laser‐induced mouse CNV model. Additionally, the results also show that the melatonin‐treated retinal microglia in the laser‐induced mice exhibited enhanced expression of M1‐type markers, such as iNOS, CCL‐3, CCL‐5, and TNF‐α, as well as decreased production of M2‐type markers, such as Arg‐1, Fizz‐1, IL‐10, YM‐1, and CD206, indicating that melatonin switched the macrophage/microglia polarization from pro‐angiogenic M2 phenotype to anti‐angiogenic M1 phenotype. Furthermore, the RhoA/ROCK signaling pathway was activated during CNV formation, yet was suppressed after an intraperitoneal injection of melatonin. In conclusion, melatonin attenuated CNV, reduced vascular leakage, and inhibited vascular proliferation by switching the macrophage/microglia polarization from M2 phenotype to M1 phenotype via inhibition of RhoA/ROCK signaling pathway in CNV. This suggests that melatonin could be a novel agent for the treatment of AMD.

Retinopathy of prematurity is a vision-threatening disease associated with retinal hypoxia-ischemia, leading to the death of retinal neurons and chronic neuronal degeneration. During this study, we used the oxygen-induced retinopathy mice model to mimic retinal hypoxia-ischemia phenotypes to investigate further the neuroprotective effect of melatonin on neonatal retinal neurons. Melatonin helped maintain relatively normal inner retinal architecture and thickness and preserve inner retinal neuron populations in avascular areas by rescuing retinal ganglion and bipolar cells, and horizontal and amacrine neurons, from apoptosis. Meanwhile, melatonin recovered visual dysfunction, as reflected by the improved amplitudes and implicit times of a-wave, b-wave, and oscillatory potentials. Additionally, elevated cleaved caspase-3 and Bax protein levels and reduced Bcl-2 protein levels in response to hypoxia-ischemia were diminished after melatonin treatment. Moreover, melatonin increased BDNF and downstream phospho-TrkB/Akt/ERK/CREB levels. ANA-12, a TrkB receptor antagonist, antagonized these melatonin actions and reduced melatonin-induced neuroprotection. Furthermore, melatonin rescued the reduction in melatonin receptor expression. This study suggests that melatonin exerted antiapoptotic and neuroprotective effects in inner retinal neurons after hypoxia-ischemia, at least partly due to modulation of the BDNF-TrkB pathway.

Central serous chorioretinopathy (CSC) is a vision‐threatening disease with no validated treatment and unclear pathogenesis. It is characterized by dilation and leakage of choroidal vasculature, resulting in the accumulation of subretinal fluid, and serous detachment of the neurosensory retina. Numerous studies have demonstrated that melatonin had multiple protective effects against endothelial dysfunction, vascular inflammation, and blood–retinal barrier (BRB) breakdown. However, the effect of melatonin on CSC, and its exact pathogenesis, is not well understood thus far. In this study, an experimental model was established by intravitreal injection of aldosterone in rats, which mimicked the features of CSC. Our results found that melatonin administration in advance significantly inhibited aldosterone‐induced choroidal thickening and vasodilation by reducing the expression of calcium‐activated potassium channel KCa2.3, and attenuated tortuosity of choroid vessels. Moreover, melatonin protected the BRB integrity and prevented the decrease in tight junction protein (ZO‐1, occludin, and claudin‐1) levels in the rat model induced by aldosterone. Additionally, the data also showed that intraperitoneal injection of melatonin in advance inhibited aldosterone‐induced macrophage/microglia infiltration, and remarkably diminished the levels of inflammatory cytokines (interleukin‐6 [IL‐6], IL‐1β, and cyclooxygenase‐2), chemokines (chemokine C–C motif ligand 3, and C–X–C motif ligand 1), and matrix metalloproteinases (MMP‐2 and MMP‐9). Luzindole, as the nonselective MT1 and MT2 antagonist, and 4‐phenyl‐2‐propionamidotetraline, as the selective MT2 antagonist, neutralized the melatonin‐induced inhibition of choroidal thickening and choroidal vasodilation, indicating that melatonin might exert the effects via binding to its receptors. Furthermore, the IL‐17A/nuclear factor‐κB signaling pathway was activated by intravitreal administration of aldosterone, while it was suppressed in melatonin‐treated in advance rat eyes. This study indicates that melatonin could serve as a promising safe therapeutic strategy for CSC patients.

BackgroundCongenital ectopia lentis (CEL) usually leads to refractive error and may influence the axial length development. But few investigations have reported patient demographics and the distribution of axial length (AL) before surgery in Chinese pediatric patients with CEL. To describe the distribution of AL before surgery in CEL patients and its relationship with patients’ demographics, such as age, Marfan syndrome, sex, and laterality.MethodsThis retrospective study reviewed 306 CEL patients from January 1, 2006 to December 31, 2015. One eye was randomly selected from each patient if both eyes were EL. The influences of Marfan syndrome, sex, and laterality to AL in different age subgroups were evaluated and compared. The differences of the AL between groups were assessed using the student t test or paired t-test. P-values less than 0.05 were considered statistically significant.ResultsTwo hundred forty-seven eyes were enrolled. 58.3% of all the patients had binoculus EL, 70% of all the patients were male and 36% of all the patients were diagnosed with Marfan syndrome. The mean AL of EL patients was 25.1 ± 2.5 mm. There was no statistical difference in the AL between patients with and without Marfan syndrome, and in the AL between male and female patients. There was statistical difference in AL between the EL-affected eye and the unaffected eye in monocular EL patients younger than 12 years old.ConclusionsThis study suggests that AL can be influenced by CEL, but the influence of CEL may be reduced after the age of 12 years old, which will likely provide a useful reference when considering the most appropriate time of surgery.

This study suggests that CEL patients' corneal astigmatism is higher in patients with Marfan syndrome, and corneal astigmatism of the CEL eye increases with age. Our results are useful for surgeons to make appropriate incision and intraocular lens (IOL) choices for patients, as well as a useful reference for designs of new IOLs.