In vivo quantification of human aqueous veins by enhanced depth imaging optical coherence tomography and optical coherence tomography angiography images.

AIM: To investigate the aqueous vein in vivo by using enhanced depth imaging optical coherence tomography (EDI-OCT) and optical coherence tomography angiography (OCTA). METHODS: In this cross-sectional comparative study, 30 healthy participants were enrolled. Images of the aqueous and conjunctival veins were captured by EDI-OCT and OCTA before and after water loading. The area, height, width, location depth and blood flow of the aqueous vein and conjunctival vein were measured by Image J software. RESULTS: In the static state, the area of the aqueous vein was 8166.7±3272.7 µm2, which was smaller than that of the conjunctival vein (13 690±7457 µm2, P<0.001). The mean blood flow density of the aqueous vein was 35.3%±12.6%, which was significantly less than that of the conjunctival vein (51.5%±10.6%, P<0.001). After water loading, the area of the aqueous vein decreased significantly from 8725.8±779.4 µm2 (baseline) to 7005.2±566.2 µm2 at 45min but rose to 7863.0±703.2 µm2 at 60min (P=0.032). The blood flow density of the aqueous vein decreased significantly from 41.2%±4.5% (baseline) to 35.4%±3.2% at 30min but returned to 45.6%±3.6% at 60min (P=0.021). CONCLUSION: The structure and blood flow density of the aqueous vein can be effectively evaluated by OCT and OCTA. These may become biological indicators to evaluate aqueous vein changes and aqueous outflow resistance under different interventions in glaucoma patients.

The effect of ET1-CTGF mediated pathway on the accumulation of extracellular matrix in the trabecular meshwork and its contribution to the increase in IOP.

PURPOSE: To investigate the effect of endothelin-1 (ET-1) in excessive accumulation of extracellular matrix (ECM) of the trabecular meshwork (TM) and its role in intraocular pressure (IOP) regulation. METHODS: Cultured human TM cells (HTMCs) were treated with ET-1, ET-1 + ETA receptor (ETAR) antagonist BQ123, ET-1 + ETB receptor (ETBR) antagonist BQ788. The expressions of fibronectin (FN) and collagen type IV (Col IV) were evaluated by western blotting and immunofluorescence. A time course effect of ET-1 on the transcription level of connective tissue growth factor (CTGF) was investigated by qRT-PCR. Next, the transcription level of CTGF was downregulated by using antisense oligodeoxynucleotide sequence. Then HTMCs were treated with ET-1, and the expression levels of FN and Col IV were evaluated by western blotting. In addition, by using an ex-vivo model of cultured anterior eye segment, we explored the effect of ET-1 on IOP changes and the expressions of FN and Col IV. RESULTS: In cultured HTMCs, the expressions of FN and Col IV were significantly increased after ET-1 treatment, which were blocked by the pretreatment of ETAR antagonist BQ123, rather than ETBR antagonist BQ788. Besides, the CTGF mRNA level increased significantly and reached a peak after 48 h of ET-1 treatment. However, the effect of ET-1 on increasing the expressions of FN and Col IV in HTMCs could be inhibited by the downregulation of CTGF. In an ex-vivo model, IOP increased significantly after ET-1 administration, which could be blocked by BQ123 but not by BQ788. Furthermore, elevated expressions of FN and Col IV in TM were observed after ET-1 perfusion, and could be inhibited by BQ123 pretreatment. CONCLUSION: Excessive ET-1 in aqueous humor could lead to the abnormal accumulation of FN and Col IV in TM via the ETA-CTGF pathway, thereby increasing IOP.

Deep learning-based classification of the anterior chamber angle in glaucoma gonioscopy.

In the proposed network, the features were first extracted from the gonioscopically obtained anterior segment photographs using the densely-connected high-resolution network. Then the useful information is further strengthened using the hybrid attention module to improve the classification accuracy. Between October 30, 2020, and January 30, 2021, a total of 146 participants underwent glaucoma screening. One thousand seven hundred eighty original images of the ACA were obtained with the gonioscope and slit lamp microscope. After data augmentation, 4457 images are used for the training and validation of the HahrNet, and 497 images are used to evaluate our algorithm. Experimental results demonstrate that the proposed HahrNet exhibits a good performance of 96.2% accuracy, 99.0% specificity, 96.4% sensitivity, and 0.996 area under the curve (AUC) in classifying the ACA test dataset. Compared with several deep learning-based classification methods and nine human readers of different levels, the HahrNet achieves better or more competitive performance in terms of accuracy, specificity, and sensitivity. Indeed, the proposed ACA classification method will provide an automatic and accurate technology for the grading of glaucoma.

Numerical simulation of the flow of aqueous humor in the Schlemm's canal.

Schlemm's canal (SC) is a ring structure responsible for maintaining fluid homeostasis in the anterior chamber of the eye by draining aqueous humor (AH) from the trabecular meshwork (TM) into the collecting channel (CC). Obstruction of the AH flow in this conventional pathway leads to an elevation of intraocular pressure in glaucoma, which is internationally recognized as the most common cause of blindness. Although there are obvious morphological differences between patients and healthy individuals, the AH drainage capacity of SC with specific parameters is difficult to quantitatively evaluate due to the limitations of analyses or experimental technologies. In this paper, the AH flow dynamic features under various SC morphological parameters are studied by numerical simulations of 3D models. The axis length of the SC cross-section and the level of openness are chosen as the main morphological factors according to the clinical data. The flow features, including the velocity, streamline and wall shear stress, are analyzed. This study aimed not only to explore the feasibility of 3D numerical modeling in evaluating the SC drainage capacity, but also to reveal the relationship between SC morphological parameters and the dynamic features of AH drainage.

Association between prenatal exposure to ambient particulate matter and risk of hypospadias in offspring: A systematic review and meta-analysis.

BACKGROUND: Epidemiological studies on whether prenatal exposure to PM2.5, PM2.5-10, and PM10 increases the risk of hypospadias are limited and the results are inconsistent. OBJECTIVES: We conducted this systematic review and meta-analysis to evaluate these associations. METHODS: Relevant studies were identified by searching the PubMed and Embase databases up to the end of February 2020. Observational studies that investigated the relationships between prenatal exposure to PM10, PM2.5, and PM2.5-10 and the risk of hypospadias in offspring were eligible for the review. The risk of bias was evaluated using the Newcastle-Ottawa scale. Random-effects models were used to estimate pooled relative risks (RRs) and 95% confidence intervals (CIs) for the associations. RESULTS: Nine studies (two cohort and seven case-control studies) with a total of 2806 hypospadias cases were included. Eight studies were at low risk of bias and only one study was at high risk of bias. Five studies reported the association between per interquartile range increase in PM2.5 exposure within the first trimester and the risk of hypospadias. The pooled RR was 1.17 (95% CI: 1.00, 1.36). Two studies reported the per interquartile range increase in PM2.5 exposure during 1 month before pregnancy associated with the risk of hypospadias, with a pooled RR of 1.25 (95% CI: 1.03, 1.51). No association was observed between PM2.5-10 and PM10 exposure during pregnancy and the risk of hypospadias in offspring. CONCLUSION: This study suggested a modest association between prenatal PM2.5 exposure during 1 month before pregnancy or within the first trimester and the risk of hypospadias in offspring. Further large-scale cohort studies are required to verify this association.

Guided filtering-based nonlocal means despeckling of optical coherence tomography images.

This Letter presents a guided filtering (GF)-based nonlocal means (NLM) method for despeckling of optical coherence tomography (OCT) images. Unlike existing NLM methods that determine weights using image intensities or features, the proposed method first uses the GF to capture both grayscale information and features of the input image and then introduces them into the NLM for accurate weight computation. The boosting and iterative strategies are further incorporated to ensure despeckling performance. Experiments on the real OCT images demonstrate that our method outperforms the compared methods by delivering sufficient noise reduction and preserving image details well.

Dual effect of the Valsalva maneuver on autonomic nervous system activity, intraocular pressure, Schlemm's canal, and iridocorneal angle morphology.

BACKGROUND: The Valsalva maneuver (VM) is widely used in daily life, and has been reported to cause high intraocular pressure (IOP). This study aimed to assess changes in IOP, the Schlemm's canal (SC), autonomic nervous system activity, and iridocorneal angle morphology in healthy individuals during different phases of the VM. METHODS: The high frequency (HF) of heart rate (HR) variability, the ratio of low frequency power (LF) and HF (LF/HF), heart rate (HR), IOP, systolic (SBP) and diastolic blood pressure (DBP), the area of SC (SCAR), pupil diameter (PD), and some iridocorneal angle parameters (AOD500, ARA750, TIA500 and TISA500) were measured in 29 young healthy individuals at baseline, phase 2, and phase 4 of the VM. SBP and DBP were measured to calculate mean arterial pressure (MAP) and mean ocular perfusion pressure (MOPP). HF and the LF/HF ratio were recorded using Kubios HR variability premium software to evaluate autonomic nervous system activity. The profiles of the anterior chamber were captured by a Spectralis optical coherence tomography device (anterior segment module). RESULTS: Compared with baseline values, in phase 2 of the VM, HR, LF/HF, IOP (15.1 ± 2.7 vs. 18.8 ± 3.5 mmHg, P < 0.001), SCAR (mean) (7712.112 ± 2992.14 vs. 8921.12 ± 4482.79 µm2, P = 0.039), and PD increased significantly, whereas MOPP, AOD500, TIA500, and TISA500 decreased significantly. In phase 4, DBP, MAP, AOD500, ARA750, TIA500and TISA500 were significantly lower than baseline value, while PD and HF were remarkably larger than baseline. The comparison between phase 2 and phase 4 showed that HR, IOP (18.8 ± 3.5 vs. 14.7 ± 2.9 mmHg, P < 0.001) and PD decreased significantly from phase 2 to phase 4, but there were no significant differences in other parameters. CONCLUSIONS: The expansion and collapse of the SC in different phases of the VM may arise from changes in autonomic nervous system activity. Further, the effects of the VM on IOP may be attributed to changes in blood flow and ocular anatomy. TRIAL REGISTRATION: This observational study was approved by the ethics committee of Tongji Hospital (Registration Number: ChiCTR-OON-16007850, Date: 01.28.2016).

[Prevalence of simple obesity and its high-risk factors in preschool children in Fuzhou, China].

OBJECTIVE: To investigate the prevalence of simple obesity and its risk factors in preschool children in Fuzhou, China. METHODS: The physical examination data of 14 kindergartens in Fuzhou, China were collected by stratified cluster random sampling. The detection rate of simple obesity was calculated. The children with normal body weight were selected as the control group by 1:1 case-control method. The risk factors for childhood simple obesity were investigated by self-made questionnaire and multivariate logistic regression analysis. RESULTS: A total of 5 767 children aged 3-6 years were enrolled in this study. A total of 289 (5.01%) children with simple obesity were screened out, including 153 with mild obesity and 136 with moderate to severe obesity. The prevalence rate of simple obesity gradually increased with the age of children. The multivariate logistic regression analysis showed that the following factors were independent risk factors for simple obesity: preference for fried food (OR=4.789, P<0.05), caregivers' over-concern about diet (OR=4.620, P<0.05), eating before sleep (OR=4.006, P<0.05), eating fast (OR=3.221, P<0.05), preference for sweets (OR=2.282, P<0.05), high birth weight (OR=2.202, P<0.05), overweight or obesity in father (OR=2.074, P<0.05), overweight or obesity in mother (OR=2.047, P<0.05), more than 1.2 times the food intake at the same age (OR=2.013, P<0.05), watching TV (OR=1.665, P<0.05), and lack of exercise (OR=1.463, P<0.05). CONCLUSIONS: The prevalence rate of simple obesity is 5.01% in preschool children in Fuzhou, China. The development of simple obesity is multifactorial. It is suggested that doctors, parents, and teachers should strengthen health education for preschool children, help them develop good living and eating habits, and encourage them to take more exercise, in order to reduce the development of simple obesity.

[Efficacy of clonidine transdermal patch in treatment of moderate to severe tic disorders in children].

OBJECTIVE: To investigate the difference in the efficacy between clonidine transdermal patch and haloperidol tablets in the treatment of moderate to severe tic disorders in children. METHODS: A total of 134 children with moderate to severe tic disorders were randomly divided into clonidine group (n=70) and haloperidol group (n=64). The clonidine and haloperidol groups were treated with clonidine transdermal patch and haloperidol tablets respectively, and the treatment lasted for 8 weeks in both groups. The Yale Global Tic Severity Scale (YGTSS) was used to evaluate the conditions of the children before and after treatment, and the adverse events during the treatment were recorded. RESULTS: The haloperidol group had a significantly better treatment outcome than the clonidine group after one week of treatment (P<0.05); the treatment outcome showed no significant difference between the two groups after 3, 5, and 8 weeks of treatment (P>0.05). The clonidine group had significantly less reductions in the motor tics, vocal tics, and function impairment scores and total score of YGTSS than the haloperidol group after one week of treatment (P<0.05); there were no significant differences in YGTSS score reductions between the two groups after 3, 5, and 8 weeks of treatment (P>0.05). The clonidine group had a significantly lower overall incidence of adverse events than the haloperidol group (8% vs 37%; P<0.01). CONCLUSIONS: Clonidine transdermal patch and haloperidol are both effective in the treatment of moderate to severe tic disorders in children. The clonidine transdermal patch, despite slow action, has comparable efficacy and fewer adverse effects compared with haloperidol.

Choroidal area assessment in various fundus sectors of patients at different stages of primary open-angle glaucoma by using enhanced depth imaging optical coherence tomography.

To compare the choroidal area in different eye fundus sectors of subjects with normal eyes, early-stage primary open-angle glaucoma (POAG) eyes, and 10° tubular visual field POAG eyes using enhanced depth imaging optical coherence tomography.Twenty-five normal, 25 early-stage POAG, and 25 ten-degree tubular visual field POAG eyes were recruited. Enhanced depth imaging optical coherence tomography was used to measure the choroidal area in different fundus sectors (fovea; 10° superior, inferior, temporal, and 24° superior, inferior, temporal, nasal to the fovea) and the peripapillary sector.There were neither significant differences in the choroidal area at any of the 8 measured fundus sectors, nor significant differences in the percentage change between the choroidal area of the fovea and other 7 measured fundus sectors among the 3 groups (all P > 0.05). For the total peripapillary choroidal area, no significant difference was found among the 3 groups (P > 0.05); however, the temporal peripapillary choroidal area of 10° tubular visual field POAG eyes was significantly thicker than that of normal eyes (4,46,213 ±â€Š1,16,267 vs 3,74,164 ±â€Š1,21,658 µm; P = 0.048).Our study showed that there was no significant difference in the choroidal area of the 8 measured fundus sectors among normal, early-stage POAG, and 10° tubular visual field POAG eyes, suggesting that there might be no blood redistribution from the peripheral choroid to the subfoveal choroid. However, the thicker temporal peripapillary choroidal area might play a role in the central visual acuity protection in patients with POAG.

Lacrimal Duct Occlusion Is Associated with Infectious Keratitis.

Background: To explore the prevalence of lacrimal duct obstruction in patients with infectious keratitis, and the necessity of lacrimal duct dredge in the treatment of human infectious keratitis. Methodology/Principle Findings: The design is prospective, non-control case series. Thirty-one eyes from twenty-eight continuous patients with infectious keratitis were included in this study. The presence/absence of lacrimal duct obstruction was determined by the lacrimal duct irrigation test. The diagnosis of infectious keratitis was made based on clinical manifestations, cornea scraping microscopic examination and bacterial/fungus culture. Diagnosis of viral keratitis was set up based on the recurrent history, deep neovascularization and typical outlook of the cornea scar. The treatment of keratitis included drugs, eye drops or surgery, while treatment of chronic dacryocystitis was lacrimal duct dredging with supporting tube implantation surgery. In the thirty-one eyes with infectious keratitis, fifteen suffered from fungal keratitis (48%), two bacterial keratitis (6%), and fourteen viral keratitis (45%). Eleven eyes (35%) from ten patients with infectious keratitis also suffered from lacrimal duct obstruction. In those cases, six eyes also suffered from lower canalicular obstruction, three nasolacrimal duct obstruction and chronic dacryocystitis, one a combination of upper and lower canalicular obstruction, one upper canalicular obstruction. After local and systemic applications of anti-bacterial, anti-viral, anti-fungal and anti-inflammatory drugs, twenty-eight eyes (90%) recovered within three weeks, while the ulceration of three patients required the lacrimal duct dredging and supporting tube implantation surgery for the healing. Conclusions: Herein, we first report that the prevalence of infectious keratitis is closely correlated to the occurrence of lacrimal duct obstruction. When both confirmed, simultaneous treatment of keratitis and lacrimal duct obstruction promptly is required. Further evaluation of mechanism, prevention and control of the diseases are warranted.

Influence of Exercise on Intraocular Pressure, Schlemm's Canal, and the Trabecular Meshwork.

PURPOSE: We aimed to assess the changes in IOP, Schlemm's canal (SC), and the trabecular meshwork (TM) in healthy individuals after exercise. METHODS: The area and perimeter of SC, TM thickness, IOP, pupil diameter, blood pressure (BP), heart rate, and plasma catecholamine concentrations were measured in 29 young healthy individuals before and after exercise by jogging for 20 minutes. The TM and SC in the superior, inferior, nasal, and temporal regions were evaluated by 80-MHz ultrasound biomicroscopy. RESULTS: In comparison with the baseline values, the post-exercise values of IOP had significantly reduced, and those of the pupil diameter, systolic and diastolic BP, and plasma catecholamine concentrations had significantly increased (all, P < 0.05). There were no significant differences in the proportions of eyes with observable SC before (81.9%) and after (90.5%; X = 3.652; P = 0.057) exercise. In comparison with the baseline values, the mean values of area (132.83 ± 19.67 vs. 155.33 ± 21.46 pixels; P < 0.001) and perimeter (54.94 ± 4.95 vs. 60.23 ± 4.19 pixels; P < 0.001) of SC and TM thickness (10.30 ± 1.28 vs. 11.48 ± 1.07 pixels; P < 0.001) after exercise were increased. The increase in area (r = 0.019, P = 0.923) and perimeter (r = -0.109, P = 0.573) of SC and TM thickness (r = -0.088, P = 0.651) were not significantly correlated with the decrease in IOP. CONCLUSIONS: Aerobic exercise could cause sympathetic nerve stimulation, consequently causing the expansion of the TM and SC, which, in turn, leads to IOP reduction. Furthermore, SC and the TM might have an autonomic regulation function, and their expansion and collapse might not be completely dependent on the IOP.

Anterior segment changes after pharmacologic mydriasis using Pentacam and optical coherence tomography in angle closure suspects.

AIM: To compare the dynamic changes of anterior segment parameters especially iris morphology induced by pharmacologic mydriasis between angle closure suspects and normal controls. METHODS: The study group comprised 19 eyes of 19 angle closure suspects and 19 eyes of 19 age- and sex-matched normal open-angle eyes. Pentacam and optical coherence tomography measurements before and 30min after instillation of compound tropicamide eye drop were performed and compared. Biometric evaluations of iris tomography and anterior chamber angle were estimated by a customized image-processing software. RESULTS: Baseline axial length, iris cross sectional area and volume did not differ significantly between angle closure suspects and normal controls. Angle closure suspects had smaller pupil size, narrower anterior segment dimension and axial length, thinner iris with greater curve in comparison with normal controls. Pharmacologic mydriasis led to significant increments in iris thickness at 750 µm, anterior chamber depth and volume, whereas significant decrements in iris curve, cross sectional area and volume in both groups. Angle opening distance at 500 µm was increased significantly in normal controls (from 0.465±0.115 mm to 0.539±0.167 mm, P=0.009), but not in angle closure suspects (from 0.125±0.100 mm to 0.145±0.131 mm, P=0.326). Iris volume change per millimeter of pupil dilation (ΔIV/ΔPD) decreased significantly less in angle closure suspects than normal controls (-2.47±1.33 mm(2) vs -3.63±1.58 mm(2), P=0.019). Linear regression analysis showed that the change of angle opening distance at 500 µm was associated most with the change of central anterior chamber depth (ß=0.841, P=0.002) and ΔIV/ΔPD (ß=0.028, P=0.002), followed by gender (ß=0.062, P=0.032). CONCLUSION: Smaller iris volume decrement per millimeter of pupil dilation is related significantly with the less anterior angle opening in angle closure suspects after pharmacologic mydriasis. Dynamic iris change may be as a prospective indicator of iris compressibility and angle closure glaucoma.

Autologous sclera-muscle flaps technique in evisceration with hydroxyapatite implantation.

AIM: To provide superior cosmetic results and reduce complications, unlike traditional evisceration coupled with implant insertion technique and its modifications, we have developed a novel and simple technique for anophthalmic patients. METHODS: All patients who underwent the scleral-muscle flaps procedure in evisceration with the placement of hydroxyapatite implant were included in the study. Main outcome measures were complications such as exposure, infection, chemosis, conjunctival inclusion cysts, granulomas. Meanwhile, implant motility was indirectly measured and the results were collected and analyzed. RESULTS: A total of twenty-eight patients were enrolled in the study. Eighteen were men (64.29%) and ten were women (35.71%). Ages ranged from 18 to 65y (mean age, 32 years old). Mean follow-up was 12.32mo (range, 9-16mo). All patients received a hydroxyapatite implant. The average diameter of the implant was 19.29±1.36 mm (range, 18-22 mm). Minor complications occurred in 3 patients, and a major complication was observed in 1 patient. Mean motility were 11.04±1.45 mm horizontally (range, 7-14 mm) and 8.57±1.50 mm vertically (range, 5-12 mm). CONCLUSION: The sclera-muscle flaps technique in evisceration with hydroxyapatite implantation is simple and practical that eases the surgical procedure, enables a proper size hydroxyapatite implantation, distinctively reduces complications and provides superior surgery results, especially the motility of the implant.

[Numerical Simulation of Heat Transfer in the Human Anterior Chamber at Different Corneal Temperatures].

A three-dimensional (3D) model of human anterior chamber is reconstructed to explore the effect of different corneal temperatures on the heat transfer in the chamber. Based on the optical coherence tomography imaging of the volunteers with normal anterior chamber, a 3D anterior chamber model was reconstructed by the method of UG parametric design. Numerical simulation of heat transfer and aqueous humor flow in the whole anterior chamber were analyzed by the finite volume methods at different corneal temperatures. The results showed that different corneal temperatures had obvious influence on the temperature distribution and the aqueous flow in the anterior chamber. The temperature distribution is linear and axial symmetrical around the pupillary axis. As the temperature difference increases, the symmetry becomes poorer. Aqueous floated along the warm side and sank along the cool side which forms a vortexing flow. Its velocity increased with the addition of temperature difference. Heat fluxes of cornea, lens and iris were mainly affected by the aqueous velocity. The higher the velocity, the bigger more absolute value of the above-mentioned heat fluxes became. It is practicable to perform the numerical simulation of anterior chamber by the optical coherence tomography imaging. The results are useful for studying the important effect of corneal temperature on the heat transfer and aqueous humor dynamics in the anterior chamber.