Aim This study aimed to test whether human platelet lysate (HPL) has neurotrophic ability for corneal nerve regeneration. Methods We measured the neurotrophic factors in human peripheral serum (HPS) and two commercially available HPLs, UltraGRO and PLTMax. In vitro, we compared the growth rates, neuronal differentiation and immunostaining of neuron markers in mouse neuroblastoma cell line (Neuro-2a) and primary culture of mouse trigeminal ganglion cells that were cultivated in different concentrations of fetal bovine serum, HPS and HPL. In vivo, we created corneal wounds on Sprague Dawley rats with a rotating burr and evaluated the effects of topical HPL on wound healing and corneal nerve regeneration by in vivo confocal microscopy and corneal aesthesiometry. Results HPLs had significantly higher concentrations of various neurotrophic factors compared with HPS (p<0.05). In Neuro-2a cells, 3% HPL was better at promoting neuronal growth and differentiation compared with HPS at the same concentration. HPL was also found to have superior neurotrophic effects compared with HPS in primary cultures of mouse trigeminal ganglion cells. In vivo, HPL-treated eyes had better corneal epithelial wound healing rate, nerve regeneration length and corneal touch threshold compared with eyes treated with artificial tears (p<0.05). Conclusion HPL has significantly higher concentrations of neurotrophic factors compared with HPS. It showed not only in vitro but also in vivo corneal neurotrophic abilities. Our results suggest that HPL may have a potential role in the treatment of diseases related to corneal nerve damage or degeneration.

Supplementing with vitamin B3 has been reported to protect against retinal ganglion cell (RGC) damage events and exhibit multiple neuroprotective properties in a mouse model of optic nerve injury. In this study, a rat model of anterior ischemic optic neuropathy was used to assess the neuroprotective benefits of vitamin B3 (rAION). Vitamin B3 (500 mg/kg/day) or phosphate-buffered saline (PBS) was administered to the rAION-induced rats every day for 28 days. The vitamin B3-treated group had significantly higher first positive and second negative peak (P1-N2) amplitudes of flash visual-evoked potentials and RGC densities than the PBS-treated group (p < 0.05). A terminal deoxynucleotidyl transferase dUTP nick end labeling assay conducted on vitamin B3-treated rats revealed a significant reduction in apoptotic cells (p < 0.05). Superoxide dismutase and thiobarbituric acid reactive substance activity showed that vitamin B3 treatment decreased reactive oxygen species (p < 0.05). Therefore, vitamin B3 supplementation preserves vision in rAION-induced rats by reducing oxidative stress, neuroinflammation, and mitochondrial apoptosis.

Traumatic optic neuropathy (TON) may cause severe visual loss following direct or indirect head trauma which may result in optic nerve injuries and therefore contribute to the subsequent loss of retinal ganglion cells by inflammatory mediators and reactive oxygen species (ROS). Granulocyte colony-stimulating factor (G-CSF) provides the anti-inflammatory and anti-oxidative actions but has a short half-life and also induces leukocytosis upon typical systemic administration. The purpose of the present study was to investigate the relationship between the anti-oxidative response and neuroprotective effects of long-acting pegylated human G-CSF (PEG-G-CSF) in a rat model of optic nerve crush (ONC). Adult male Wistar rats (150–180 g) were chosen to have a sham operation in one eye and have ONC in the other. PEG-G-CSF or phosphate-buffered saline (PBS control) was immediately administered after ONC by intravitreal injection (IVI). We found the IVI of PEG-G-CSF does not induce systemic leukocytosis, but increases survival of RGCs and preserves the visual function after ONC. TUNEL assays showed fewer apoptotic cells in the retina in the PEG-G-CSF-treated eyes. The number of sorely ED1-positive cells was attenuated at the lesion site in the PEG-G-CSF-treated eyes. Immunoblotting showed up-regulation of p-Akt1, Nrf2, Sirt3, and HO-1 in the ON of the PEG-G-CSF-treated eyes. Our results demonstrated that one IVI of long-acting PEG-G-CSF is neuroprotective in the rONC. PEG-G-CSF activates the p-Akt1/Nrf2/Sirt3 and the p-Akt1/Nrf2/HO-1 axes to provide the antioxidative action and further attenuated RGC apoptosis and neuroinflammation. This provides crucial preclinical information for the development of alternative therapy with IVI of PEG-G-CSF in TON.

We aimed to evaluate the postoperative visual and refractive outcomes between the first- and second-generation keratorefractive lenticule extraction (KLEx) surgeries. A retrospective cohort study was conducted and patients who had received first- and second-generation KLEx surgeries were enrolled. A total of 80 and 80 eyes were categorized into the first and second KLEx groups after exclusion, respectively. The primary outcomes were the postoperative uncorrected distance visual acuity (UDVA), spherical equivalent (SE), and safety indexes. An independent t-test and generalized estimate equation were implemented to compare the primary outcomes between the two groups. After the KLEx surgery, the UDVA showed no significant difference between the two groups throughout the study period (all p > 0.05), and the postoperative SE and safety index were also statistically identical between the two groups during the follow-up interval (all p > 0.05). There was a similar trend of visual recovery between the two groups (aOR: 0.967; 95% CI: 0.892–1.143; p = 0.844), while the amplitude of the SE change was significantly lower in the second KLEx group (aOR: 0.760; 95% CI: 0.615–0.837; p = 0.005). Nine and two unintended initial dissection of the posterior plane (UIDPP) occurred intraoperatively in the first and second KLEx groups, respectively, and the second group showed a lower risk of UIDPP (p = 0.032). In conclusion, the efficiency, predictability, and safety are similar between first- and second-generation KLEx surgeries.

Emerging roles of exosomes in the pathogenesis of major blindness-threatening diseases, such as age-related macular degeneration, glaucoma, and corneal dystrophy, were discovered by aqueous humor analysis. A new diagnostic method using cellulose-based devices and microfluidic chip techniques for the isolation of exosomes from aqueous humor is less cumbersome and saves time. This method will enable more investigations for aqueous humor analysis in the future.

In this study, we aim to evaluate the risk factors of myopia undercorrection in recipients of second-generation keratorefractive lenticule extraction (KLEx) surgery. A retrospective case–control study was performed, and patients who received second-generation KLEx surgery were enrolled. The cases with myopia undercorrection were matched to non-myopia undercorrection cases with a 1:4 ratio according to age, and a total of 22 and 88 eyes were categorized into the undercorrection and control groups, respectively. Demographic, refractive, topographic, and surgical data were collected preoperatively. A generalized linear model was operated to evaluate the potential risk factors for myopia undercorrection. The uncorrected distance visual acuity (UDVA) at three months postoperation was significantly better in the control group (p = 0.006), and residual myopia and SE were significantly higher in the undercorrection group during the whole follow-up period (all p < 0.001). The UDVA value showed a trend of improvement in the control group (p < 0.001), and the changes to SE and residual myopia were significantly lower in the control group (both p < 0.001). Regarding the risk factors for myopia undercorrection in the whole population and the high-myopia population, a higher manifest sphere power, higher steep keratometry (K), higher topographic cylinder, lower central corneal thickness (CCT) at apex, higher CCT difference and lower residual stromal thickness (RST) correlated to myopia undercorrection (all p < 0.05). In the low-myopia population, only higher myopia and lower RST correlated to myopia undercorrection (both p < 0.05). In conclusion, a high-sphere power and irregular topographic pattern correlated to myopia undercorrection after the second KLEx surgery, especially for individuals with high myopia.