Artificial intelligence improves accuracy, efficiency, and reliability of a handheld infrared eccentric autorefractor for adult refractometry.

AIM: To evaluate the accuracy, efficiency, and reliability of a handheld infrared eccentric autorefractor (hICA) with artificial intelligence (AI) by comparing its refraction measurements to those recorded using hICA and a clinical table-mounted automatic refractor (TAR). METHODS: A cross-sectional study using three optometers, including hICA with or without AI and TAR, for refractometry of adults (aged 19-49 years old) with no signs of ocular disease or trauma in the absence of cycloplegia. Right and left eye refraction data were recorded, including the spherical equivalent (SE), diopter of spherical power (DS), diopter of cylindrical power (DC) decomposed into vectors J0 and J45, and measurement times. To avoid analytical difficulties associated with the interdependence of observations between eyes from the same individual, the Generalized Estimation Equation was used to compare the SE, DS, J0 and J45 measurements, and the times thereof, among the different groups. The intraclass correlation coefficient (ICC) and Spearman's rank correlation coefficient were used to evaluate correlations among the measurements recorded by the three different instruments. Bland-Altman were used to analyze the precision of the equipment by the agreement. RESULTS: A total of 70 patients (140 eyes; mean age: 31.37y; range: 19-49y) were assessed using refractometry. In a brightly lit environment, there was no significant difference between the mean SE recorded using TAR and that recorded using hICA with AI or without AI (both P>0.05). In an intense-light environment, hICA equipped with AI showed a better detection rate than without AI. Light intensity had a greater effect on dioptric measurements recorded using hICA without AI (P<0.001) than on those recorded using the one equipped with AI (P<0.05). Measurement times varied significantly between the different light intensities and instruments (P<0.05). CONCLUSION: For the normal human eyes, AI may improve the accuracy, efficiency, and reliability of measurements recorded using hICA in various light environments.

Axial length/corneal radius of curvature ratio and refractive development evaluation in 3- to 4-year-old children: the Shanghai Pudong Eye Study.

AIM: To measure and analysis axial length (AL)/corneal radius of curvature (CRC) ratio and other refractive parameters, provide a medical reference range for refractive development evaluation and earlier visual impairment screening of 3 to 4y kindergarten students. METHODS: Between April and June 2017, a total of 4350 participants aged 3- to 4-year-old (8700 eyes) from 10 cluster random sampling kindergartens in Shanghai, Pudong District were involved. According to the measurement and analysis of the unaided visual acuity (VA), AL, CRC, AL/CRC ratio, astigmatism and other refractive parameters, the data distribution and reference range were obtained. RESULTS: Uncorrected VA of examined children was 0.23±0.08 (logMAR, mean±SD) [95% confidence interval (CI) range ≤0.36]; AL was 22.10±0.79 mm (95%CI 20.55-23.65); CRC was 7.86±0.26 mm (95%CI, 7.35-8.37); AL/CRC ratio was 2.81±0.12 (95%CI, 2.57-3.05). The median of astigmatism was -0.5 D, a total of 56.3% had astigmatism <-0.50 D, 85.3%<-1.00 D, 6.7%>-1.50 D; 71% were astigmatism with the rule. Eye-specific analyses were conducted. Statistical difference of VA was in right and left eyes. There were no significant differences between two eyes of AL, CRC, AL/CRC ratio and astigmatism (P>0.05). CONCLUSION: VA and AL/CRC ratio reference could be used to assess refractive development in children and screening uncorrected refractive errors or amblyopia. Astigmatism needs to be considered in the diagnosis.

Comparison of the efficacy of anti-VEGF monotherapy versus PDT and intravitreal anti-VEGF combination treatment in AMD: a Meta-analysis and systematic review.

AIM: To compare the effect of anti-vascular endothelial growth factor (VEGF) monotherapy versus photodynamic therapy (PDT) and anti-VEGF combination treatment in age-related macular degeneration (AMD). METHODS: A computerized online search was performed using PubMed, Web of Science and the Cochrane Library. Studies that compared anti-VEGF monotherapy with PDT and anti-VEGF combination treatment of AMD and were designed as randomized controlled trials were included. The means and standard deviations of the best-corrected visual acuity (BCVA), central retinal thickness (CRT), number of treatments and proportions of patients who gained BCVA ≥15, 10, 5, or 0 letters at 12(th) month were extracted. A systematic review and Meta-analysis of the comparison of the two approaches was conducted using Review Manager 5.2. Subgroup. A sensitivity analysis was also performed. RESULTS: Eight studies were included. When the subgroup and sensitivity analysis was conducted, the results indicated that in the findings that included the monotherapy group and PDT (standard fluence, SF) group of Kaiser's study, the patients in the monotherapy group had a better BCVA compared with the combination group at 12(th) month in the PDT (SF) subgroup [weighted mean difference (WMD): 3.54; 95%CI: 0.36 to 6.73; P=0.03], and there were more patients who gained ≥15 letters of BCVA in the monotherapy group compared with the combination group in the total result [odds ratio (OR): 1.41; 95%CI: 1.02 to 1.95; P=0.04]. The same conclusion was obtained in the total result that included the monotherapy group and PDT (reduced fluence, RF) group of Kaiser's study (OR: 1.56; 95%CI: 1.13 to 2.15; P=0.007). However, there were no significant differences in the other indexes between the two therapies. CONCLUSION: We found that anti-VEGF monotherapy is more effective on the recovery of visual acuity than combination therapy and more researches with lager sample size should be performed to study on the effect of the two therapy approaches on CRT and number of injections.

Exogenous NAD(+) decreases oxidative stress and protects H2O2-treated RPE cells against necrotic death through the up-regulation of autophagy.

Increased oxidative stress, which can lead to the retinal pigment epithelium (RPE) cell death by inducing ATP depletion and DNA repair, is believed to be a prominent pathology in age-related macular degeneration (AMD). In the present study, we showed that and 0.1 mM nicotinamide adenine dinucleotide (NAD(+)) administration significantly blocked RPE cell death induced by 300 µM H2O2. Further investigation showed that H2O2 resulted in increased intracellular ROS level, activation of PARP-1 and subsequently necrotic death of RPE cells. Exogenous NAD(+) administration significantly decreased intracellular and intranuclear ROS levels in H2O2-treated RPE cells. In addition, NAD(+) administration to H2O2-treated RPE cells inhibited the activation of PARP-1 and protected the RPE cells against necrotic death. Moreover, exogenous NAD(+) administration up-regulated autophagy in the H2O2-treated RPE cells. Inhibition of autophagy by LY294002 blocked the decrease of intracellular and intranuclear ROS level. Besides, inhibition of autophagy by LY294002 abolished the protection of exogenous NAD(+) against H2O2-induced cell necrotic death. Taken together, our findings indicate that that exogenous NAD(+) administration suppresses H2O2-induced oxidative stress and protects RPE cells against PARP-1 mediated necrotic death through the up-regulation of autophagy. The results suggest that exogenous NAD(+) administration might be potential value for the treatment of AMD.

Four-port bimanual 23-gauge vitrectomy for diabetic tractional retinal detachment.

PURPOSE: Four-port bimanual vitrectomy is a surgical technique that facilitates removal of epiretinal membranes in severe proliferative diabetic retinopathy (PDR). As the illumination is held by the assistant through the fourth scleral incision, fibrovascular membranes are removed by bimanual manipulation techniques. The objective of this study was to evaluate the safety and efficacy of four-port bimanual 23-gauge vitrectomy for patients with tractional retinal detachment (TRD) in severe PDR. DESIGN: Retrospective, comparative, consecutive, interventional case series. METHODS: Sixty-six eyes of 58 consecutive patients who underwent primary vitrectomy for severe diabetic TRD. Thirty-six eyes of 31 cases that were treated with four-port 23-gauge vitrectomy were compared with 30 eyes of 27 cases that were treated with 23-gauge pars plana vitrectomy (PPV). Main outcome measures were best-corrected visual acuity (BCVA), retinal status, intraocular pressure, and incidence of intraoperative and postoperative complications with at least 6 months of follow-up. RESULTS: The primary and ultimate anatomic success rates (94.4% versus 93.3%, and 100% in both groups, respectively) and the mean BCVA changes did not differ significantly between groups. The whole surgical time and the membrane removal time were significantly (p < 0.001, respectively) shorter in the four-port 23-gauge group than in the 23-gauge group. There was no difference in the incidence of intraoperative and postoperative complications in both groups. CONCLUSIONS: Four-port bimanual 23-gauge vitrectomy offers comparable anatomic success and shortens the surgical time compared with conventional 23-gauge PPV in patients with TRD resulting from severe PDR.

Erythropoietin therapy for early diabetic retinopathy through its protective effects on retinal pericytes.

Diabetic retinopathy (DR) is a leading cause of acquired blindness among the people at working age. Although remarkable advances have been made in the treatment of the proliferative form of DR, there is still no effective treatment for the most prevalent early form of DR. The exact etiology and molecular pathogenesis of the early DR are not fully understood, but the selective loss of pericytes is believed to play a major role in the pathological process of DR. Herein we propose a novel approach to the treatment of early form of DR, using erythropoietin (EPO). We hypothesize that EPO reduces the loss of retinal pericytes, and therefore can be used as a novel therapeutic agent for early form of DR, which is based on its antioxidant, anti-inflammatory, and neuroprotective properties. If successful, future studies based on this hypothesis may also help shield the lights on the molecular mechanisms of early DR.

Erythropoietin is increased in aqueous humor of glaucomatous eyes.

PURPOSE: To determine the aqueous concentration of erythropoietin (EPO) in patients with and without glaucoma. METHODS: Prospective, comparative control study. Concentrations of EPO in the aqueous humor were measured using ELISA kits from 75 patients, of whom 55 had glaucoma (14 primary acute angle-closure glaucoma, PAACG; 26 primary chronic angle-closure glaucoma, PCACG; 11 primary open-angle glaucoma, POAG; 4 neovascular glaucoma, NVG), and 20 had cataract only as control. RESULTS: EPO concentrations in eyes with glaucoma (71.0 +/- 12.0 mU/mL) were significantly higher than those in eyes with cataract (6.4 +/- 0.8 mU/mL, P < 0.001). There were no significant differences (P = 0.421) between PCACG (28.84 +/- 3.9 mU/mL) and POAG (20.2 +/- 2.0 mU/mL); however, EPO concentrations in eyes with PAACG (118.5 +/- 14 mU/mL) were significantly higher than these two chronic subtypes of glaucoma (P < 0.001, respectively). Unusually high EPO concentrations were detected in four eyes with NVG (319.5 +/- 47.7 mU/mL). No effect of age, gender, different eyes, body mass index of the aqueous humor EPO concentration could be detected (P > 0.05). No significant correlation was found between aqueous humor and plasma EPO concentrations in PAACG and control group (P = 0.285, 0.500, respectively). CONCLUSION: Our prospective study suggests that the aqueous humor EPO concentrations are increased in eyes with glaucoma.

Elevated erythropoietin in vitreous of patients with rhegmatogenous retinal detachment and proliferative vitreoretinopathy.

AIM: Our purpose was to determine the vitreous erythropoietin (EPO) level in patients with rhegmatogenous retinal detachment (RRD) and proliferative vitreoretinopathy (PVR). METHODS: The levels of EPO in vitreous were measured using a sandwich enzyme-linked immunosorbent assay kit from 64 patients, of whom 40 had RRD, 13 had PVR and 11 had idiopathic macular hole as control. RESULTS: The mean levels of EPO in the RRD group (54.6 +/- 7.3 mU/ml) and PVR group (104.1 +/- 20.8 mU/ml) were significantly higher than that in the idiopathic macular hole control group (14.4 +/- 3.6 mU/ml; p < 0.001, p = 0.003, respectively). The mean EPO level in PVR was higher than that in RRD, but the difference was not significant (p = 0.112). CONCLUSION: The vitreous EPO level was upregulated in eyes with RRD and PVR.

Erythropoietin as a novel therapeutic agent for atrophic age-related macular degeneration.

The purpose of this article is to propose a novel therapeutic approach to the treatment of age-related macular degeneration (ARMD), the leading cause of blindness in the elderly population (over 60 years of age) in developed countries. Although recent advances have been made in the treatment of the neovascular form of ARMD, there is still no effective treatment for the most prevalent atrophic form of ARMD. Although the exact etiology and molecular pathogenesis of the atrophic ARMD are not fully understood, it is believed that oxidative stress and local inflammation play a major role in the pathologic processes and that the disease is triggered by dysfunction in the retinal pigment epithelia, leading to the degeneration of macular photoreceptor cells, followed by irreversible loss of vision. Considering that erythropoietin (EPO) has antioxidant, anti-inflammatory, and neuroprotective properties, we hypothesize that it can be developed as a novel therapeutic agent for the treatment of the atrophic form of ARMD. Future studies are needed to confirm or rule out this hypothesis. If successful, such studies may also help shield the lights on molecular mechanisms of atrophic ARMD.