Automated detection of steps in videos of strabismus surgery using deep learning.

BACKGROUND: Learning to perform strabismus surgery is an essential aspect of ophthalmologists' surgical training. Automated classification strategy for surgical steps can improve the effectiveness of training curricula and the efficient evaluation of residents' performance. To this end, we aimed to develop and validate a deep learning (DL) model for automated detecting strabismus surgery steps in the videos. METHODS: In this study, we gathered 479 strabismus surgery videos from Shanghai Children's Hospital, affiliated to Shanghai Jiao Tong University School of Medicine, spanning July 2017 to October 2021. The videos were manually cut into 3345 clips of the eight strabismus surgical steps based on the International Council of Ophthalmology's Ophthalmology Surgical Competency Assessment Rubrics (ICO-OSCAR: strabismus). The videos dataset was randomly split by eye-level into a training (60%), validation (20%) and testing dataset (20%). We evaluated two hybrid DL algorithms: a Recurrent Neural Network (RNN) based and a Transformer-based model. The evaluation metrics included: accuracy, area under the receiver operating characteristic curve, precision, recall and F1-score. RESULTS: DL models identified the steps in video clips of strabismus surgery achieved macro-average AUC of 1.00 (95% CI 1.00-1.00) with Transformer-based model and 0.98 (95% CI 0.97-1.00) with RNN-based model, respectively. The Transformer-based model yielded a higher accuracy compared with RNN-based models (0.96 vs. 0.83, p < 0.001). In detecting different steps of strabismus surgery, the predictive ability of the Transformer-based model was better than that of the RNN. Precision ranged between 0.90 and 1 for the Transformer-based model and 0.75 to 0.94 for the RNN-based model. The f1-score ranged between 0.93 and 1 for the Transformer-based model and 0.78 to 0.92 for the RNN-based model. CONCLUSION: The DL models can automate identify video steps of strabismus surgery with high accuracy and Transformer-based algorithms show excellent performance when modeling spatiotemporal features of video frames.

Digital measuring the ocular morphological parameters of guinea pig eye in vivo with Python.

AIM: To quantitatively measure ocular morphological parameters of guinea pig with Python technology. METHODS: Thirty-six eyeballs of eighteen 3-week-old guinea pigs were measured with keratometer and photographed to obtain the horizontal, coronal, and sagittal planes respectively. The corresponding photo pixels-actual length ratio was acquired by a proportional scale. The edge coordinates were identified artificially by ginput function. Circle and conic curve fitting were applied to fit the contour of the eyeball in the sagittal, coronal and horizontal view. The curvature, curvature radius, eccentricity, tilt angle, corneal diameter, and binocular separation angle were calculated according to the geometric principles. Next, the eyeballs were removed, canny edge detection was applied to identify the contour of eyeball in vitro. The results were compared between in vivo and in vitro. RESULTS: Regarding the corneal curvature and curvature radius on the horizontal and sagittal planes, no significant differences were observed among results in vivo, in vitro, and the keratometer. The horizontal and vertical binocular separation angles were 130.6°±6.39° and 129.8°±9.58° respectively. For the corneal curvature radius and eccentricity in vivo, significant differences were observed between horizontal and vertical planes. CONCLUSION: The Graphical interface window of Python makes up the deficiency of edge detection, which requires too much definition in Matlab. There are significant differences between guinea pig and human beings, such as exotropic eye position, oblique oval eyeball, and obvious discrepancy of binoculus. This study helps evaluate objectively the ocular morphological parameters of small experimental animals in emmetropization research.

Microvasculature evaluation of anisometropic amblyopia children by Angio-OCT.

To compare and assess the choroidal and retinal microstructural vascularity in amblyopic eyes with the fellow eyes in anisometropic amblyopic children using angiography optical coherence tomography (Angio-OCT). Twenty-seven children (54 eyes; 5.59 ± 1.08 years old; 59.3% girls) were enrolled in this study. Choroidal thickness (CT) was measured with the use of the enhanced depth imaging mode in Angio-OCT. Parafoveal/peripapillary vascular density indices and the foveal avascular zone (FAZ) size were analyzed by MATLAB code programming on Angio-OCT images. The mean FAZ size of the amblyopic eyes were larger both in superficial and deep capillary plexus layer (SCPL/DCPL). Compared with the contralateral eyes (BCVA were normal), all the vascular density indices of SCPL and DCPL in the parafoveal and peripapillary zones were lower in the amblyopic eyes, however, the difference was insignificant (p > 0.05). No significant decrease was observed in four quadrants analyses of the amblyopic eyes (p > 0.05). Except for the measurement at 2000 µm and 1500 µm from the fovea in temple, CT in amblyopic eyes were significantly thicken than the fellow eyes (p < 0.05). Compared with the fellow eyes, the CT of certain areas were thicker in the amblyopic eyes. Though the FAZ size of the amblyopic eyes was larger in SCPL/DCPL layers, the retinal vascular density indices in SCPL/DCPL were lower in amblyopia eyes without statistical difference. Angio-OCT may be an effective way to evaluate the status of the choroidal and retinal vascular system in amblyopic children.

Development and Validation of a Simple Nomogram for Predicting Rapid Myopia Progression in Children with Orthokeratology Management.

PURPOSE: To develop and validate an ideal nomogram and an online calculator for predicting rapid myopia progression risk in children managed with orthokeratology (ortho-k). METHODS: Data of children undergoing ortho-k treatment at Shanghai Children's Hospitals between January 2018 and April 2021 were retrospectively assessed. Potential predictors were screened using univariable analyses and a bidirectional stepwise procedure based on Akaike's information criterion. The final model was constructed using multivariable logistic regression and validated using an internal validation cohort. A nomogram and an online calculator were used to present the final model. RESULTS: In this retrospective study with 1051 eyes of 560 myopia patients, the training cohort included 735 eyes, and the validation cohort included 316 eyes. Among 11 potential predictors of rapid myopia progression considered, the following four variables identified as independent predictive factors were included in the nomogram: age (odds ratio [OR], 0.69; 95% confidence interval [CI], 0.61-0.79), baseline spherical equivalent (OR, 1.53; 95% CI, 1.31-1.79), pupil diameter (OR, 0.56; 95% CI, 0.32-0.97), and horizontal visible iris diameter (OR, 0.57; 95% CI, 0.33-0.97). The mean concordance statistics for the training and validation cohorts were 0.705 (95% CI 0.664-0.747) and 0.707 (95% CI 0.639-0.774), respectively. The online calculator is publicly available (https://hycalculatoronline.shinyapps.io/dynnomapp/). CONCLUSION: This study developed a simple-to-use nomogram and online calculator that predicted rapid myopia progression risk in children treated with ortho-k, who will likely benefit from early intervention and improved surveillance.

Secondary in-the-bag Intraocular Lens Implantation in Aphakic Eyes After Vitrectomy and Silicone Oil Tamponade for Rhegmatogenous Retinal Detachment.

PURPOSE: To describe a novel technique for capsular bag reopening and secondary in-the-bag intraocular lens (IOL) implantation in aphakic eyes after vitreoretinal surgery and intraocular tamponade. METHODS: We enrolled 14 eyes of 14 patients who underwent primary vitreoretinal surgery with silicone oil tamponade for rhegmatogenous retinal detachment between September 2018 and September 2019. The novel technique was used for capsular bag reopening and foldable single-piece IOL implantation. Patients were followed up at least 24 weeks with routine ophthalmic examinations, corneal endothelial cell density, and IOL tilt and decentration measurement. RESULTS: The procedure was successfully completed in 13 cases; in one case, because of posterior capsular tear, the IOL was implanted with ciliary sulcus fixation. After a mean follow-up of 48.8 ± 14.8 (range, 24.9-65.9) weeks, the best-corrected visual acuity (before 20/76 Snellen, 0.63 ± 0.23 logarithm of the minimum angle of resolution equivalent and after 20/35 Snellen, 0.32 ± 0.32 logarithm of the minimum angle of resolution equivalent; P = 0.001) and spherical equivalent (before +8.22 ± 4.08, after -2.39 ± 1.77 D; P < 0.001) improved, intraocular pressure (before 15.93 ± 4.40, after 16.25 ± 4.25 mmHg; P = 0.743) remained unchanged. The IOL was well centered with a mean horizontal and vertical tilt of 0.5070 ± 0.3319° and 0.4652 ± 0.3465°, respectively, and decentration of 0.1705 ± 0.1334 mm and 0.1712 ± 0.1576 mm, respectively. CONCLUSION: With this technique, capsular bag reopening and secondary in-the-bag IOL implantation could be achieved in most cases with satisfactory visual outcome and IOL position.

Surgical treatment of Pitt-Hopkins syndrome associated with strabismus and early-onset myopia: Two case reports.

BACKGROUND: Pitt-Hopkins syndrome (PTHS; MIM #610954) is a rare genetic neurological disorder. Myopia and strabismus have been reported in approximately 50% of PTHS patients. No studies have reported details about the required surgery for PTHS with strabismus and early-onset myopia. Here, we retrospectively reviewed the surgical management of two patients with PTHS combined with strabismus and/or early-onset myopia. CASE SUMMARY: A 5-year-old girl presented with congenital esotropia and left eye myopia, and the second girl was a 5-year-old girl who presented with intermittent exotropia. Genetic testing performed on both patients showed a mutation in transcription factor 4, which is a diagnostic marker of PTHS. The first girl underwent bilateral medial rectus recession combined with posterior scleral reinforcement (PSR) in the left eye and the second patient underwent bilateral lateral rectus recession strabismus surgery. We made key innovations in surgical timing and strategy, and the results were satisfactory. The combination of strabismus and PSR surgery is an innovative strategy for patients with both strabismus and early-onset myopia. CONCLUSION: Early treatment of strabismus and myopia positively influence motor development and should be included in rehabilitation programs for patients with PTHS.

Optic nerve head: A gatekeeper for vitreous infectious insults?

The axons of retinal ganglion cells (RGCs) pass through the optic nerve head (ONH) and form the optic nerve (ON). The ONH serves as an anatomical interface between the vitreous cavity and subarachnoid space. After inducing acute neuroinflammation by intravitreal injection of lipopolysaccharides (LPS), we observed inflammatory activation in the retina, but detect no signs of inflammation in the posterior ON or infiltration of inflammatory cells in the ONH. Therefore, we hypothesized that the ONH functions as a barrier to vitreous inflammation. Using transmission electron microscopy, we identified significant increase in G-ratio in the posterior ON on day 7 post intravitreal injection (PII) of LPS compared with the phosphate buffered saline (PBS) group. Moreover, using confocal imaging of ex vivo tissue extracted from Aldh1L1-eGFP reporter mice, we observed that the ONH astrocytes altered their spatial orientation by elongating their morphology along the axonal axis of RGCs in LPS- versus PBS-treated eyes; this was quantified by the ratio of longitudinal (DL) and transverse (DT) diameter of astrocytes and the proportion of longitudinally locating astrocytes. Supportive evidences were further provided by transmission electron microscopic imaging in rat ONH. We further conducted RNA sequencing of ONH on day 1 PII and found LPS induced clear upregulation of immune and inflammatory pathways. Furthermore, gene set enrichment analysis revealed that astrocyte and microglia contributed prominently to the transcriptomic alterations in ONH. Here, we report that the vitreous infectious insults induce morphological changes of ONH astrocytes and transcriptomic alterations in the ONH. Glial responses in the ONH may defend against vitreous infectious insults and serve as a barrier to inflammation for the central nervous system.

Activation of the GABA-alpha receptor by berberine rescues retinal ganglion cells to attenuate experimental diabetic retinopathy.

Purpose: The aim of this study was to investigate the role and mechanism of berberine (BBR) in the protection of injured retinal ganglion cells (RGCs) in diabetic retinopathy (DR). Methods: Experimental diabetic retinopathy rat model was successfully induced by a single intraperitoneal injection of streptozotocin (STZ, 60 mg/kg) in male SD rats with sufficient food and water for 8 weeks. Animals were randomly divided into four groups: (1) non-diabetic, (2) diabetic, (3) diabetic + BBR + PBS, and (4) diabetic + BBR + SR95531. BBR (100 mg/kg) was given daily by gavage to rats in the group (3) and group (4) for 8 weeks, and weekly intravitreal injections were conducted to rats in the group (3) with 5 µL of 1×PBS and rats in the group (4) with 5 µL of GABA-alpha receptor antagonist SR95531 to investigate the underlying mechanisms. The survival and apoptosis of RGCs were observed by fluorescence gold labeling technology and TUNEL staining. Visual function was evaluated by visual electrophysiological examination. Western blotting and immunofluorescence staining were used to analyze the expression of GABA-alpha receptors in RGCs. Results: In an animal model, BBR can increase the survival of RGCs, reduce RGCs apoptosis, and significantly improve the visual function. The reduction of GABA, PKC-α, and Bcl-2 protein expression caused by DR can be considerably increased by BBR. SR95531 inhibits BBR's protective effect on RGC and visual function, as well as its upregulation of PKC-α and Bcl-2. Conclusion: BBR is a promising preventive or adjuvant treatment for DR complications, and its key protective effect may involve the regulation of RGC apoptosis through the GABA-alpha receptor/protein kinase C-alpha (GABAAR/PKC-α) pathway.

A Weakly Supervised Deep Learning Approach for Leakage Detection in Fluorescein Angiography Images.

Purpose: The purpose of this study was to design an automated algorithm that can detect fluorescence leakage accurately and quickly without the use of a large amount of labeled data. Methods: A weakly supervised learning-based method was proposed to detect fluorescein leakage without the need for manual annotation of leakage areas. To enhance the representation of the network, a residual attention module (RAM) was designed as the core component of the proposed generator. Moreover, class activation maps (CAMs) were used to define a novel anomaly mask loss to facilitate more accurate learning of leakage areas. In addition, sensitivity, specificity, accuracy, area under the curve (AUC), and dice coefficient (DC) were used to evaluate the performance of the methods. Results: The proposed method reached a sensitivity of 0.73 ± 0.04, a specificity of 0.97 ± 0.03, an accuracy of 0.95 ± 0.05, an AUC of 0.86 ± 0.04, and a DC of 0.87 ± 0.01 on the HRA data set; a sensitivity of 0.91 ± 0.02, a specificity of 0.97 ± 0.02, an accuracy of 0.96 ± 0.03, an AUC of 0.94 ± 0.02, and a DC of 0.85 ± 0.03 on Zhao's publicly available data set; and a sensitivity of 0.71 ± 0.04, a specificity of 0.99 ± 0.06, an accuracy of 0.87 ± 0.06, an AUC of 0.85 ± 0.02, and a DC of 0.78 ± 0.04 on Rabbani's publicly available data set. Conclusions: The experimental results showed that the proposed method achieves better performance on fluorescence leakage detection and can detect one image within 1 second and thus has great potential value for clinical diagnosis and treatment of retina-related diseases, such as diabetic retinopathy and malarial retinopathy. Translational Relevance: The proposed weakly supervised learning-based method that automates the detection of fluorescence leakage can facilitate the assessment of retinal-related diseases.

Unsupervised domain adaptation model for lesion detection in retinal OCT images.

Background and objective.Optical coherence tomography (OCT) is one of the most used retinal imaging modalities in the clinic as it can provide high-resolution anatomical images. The huge number of OCT images has significantly advanced the development of deep learning methods for automatic lesion detection to ease the doctor's workload. However, it has been frequently revealed that the deep neural network model has difficulty handling the domain discrepancies, which widely exist in medical images captured from different devices. Many works have been proposed to solve the domain shift issue in deep learning tasks such as disease classification and lesion segmentation, but few works focused on lesion detection, especially for OCT images.Methods.In this work, we proposed a faster-RCNN based, unsupervised domain adaptation model to address the lesion detection task in cross-device retinal OCT images. The domain shift is minimized by reducing the image-level shift and instance-level shift at the same time. We combined a domain classifier with a Wasserstein distance critic to align the shifts at each level.Results.The model was tested on two sets of OCT image data captured from different devices, obtained an average accuracy improvement of more than 8% over the method without domain adaptation, and outperformed other comparable domain adaptation methods.Conclusion.The results demonstrate the proposed model is more effective in reducing the domain shift than advanced methods.

Weakly supervised anomaly segmentation in retinal OCT images using an adversarial learning approach.

Lesion detection is a critical component of disease diagnosis, but the manual segmentation of lesions in medical images is time-consuming and experience-demanding. These issues have recently been addressed through deep learning models. However, most of the existing algorithms were developed using supervised training, which requires time-intensive manual labeling and prevents the model from detecting unaware lesions. As such, this study proposes a weakly supervised learning network based on CycleGAN for lesions segmentation in full-width optical coherence tomography (OCT) images. The model was trained to reconstruct underlying normal anatomic structures from abnormal input images, then the lesions can be detected by calculating the difference between the input and output images. A customized network architecture and a multi-scale similarity perceptual reconstruction loss were used to extend the CycleGAN model to transfer between objects exhibiting shape deformations. The proposed technique was validated using an open-source retinal OCT image dataset. Image-level anomaly detection and pixel-level lesion detection results were assessed using area-under-curve (AUC) and the Dice similarity coefficient, producing results of 96.94% and 0.8239, respectively, higher than all comparative methods. The average test time required to generate a single full-width image was 0.039 s, which is shorter than that reported in recent studies. These results indicate that our model can accurately detect and segment retinopathy lesions in real-time, without the need for supervised labeling. And we hope this method will be helpful to accelerate the clinical diagnosis process and reduce the misdiagnosis rate.

Erratum: Weakly supervised anomaly segmentation in retinal OCT images using an adversarial learning approach: publisher's note.

[This corrects the article on p. 4713 in vol. 12.].

Nicotinamide ameliorates energy deficiency and improves retinal function in Cav-1-/- mice.

Caveolin-1(Cav-1) is involved in lipid metabolism and energy homeostasis, which is important for the energetically demanding retina. Although retinal function deficits were noted in Cav-1 knockout (Cav-1-/- ) mice, the underlying causes remain largely unknown. Here, we investigate if the disruption in energy homeostasis presents a potential mechanism for retinal function deficits in Cav-1-/- retina and if it can be ameliorated by nicotinamide (NAM). In this study, NAM was administrated orally for 2 weeks in Cav-1-/- mice before experiments. Oxidative lipidomics was conducted to detect the oxylipin changes, the retinal energy flux was measured by seahorse assay, and the retinal function was assessed by electroretinogram (ERG). Cav-1 deficiency induced the dysregulation of oxidative lipidomics and reduction in energy consumption/production in the retina by decreasing Na+ /K+ -ATPase, oxidative phosphorylation CII, cytochrome c, and oxygen consumption rate (OCR). A decrease in Sirt1 was also detected. Therapeutic administration of NAM significantly increased Sirt1 expression and improved energy deficiency by increasing Na+ /K+ -ATPase, cytochrome c, and OCR. The dysregulation of oxidative lipidomics was partially recovered, and the retinal function was improved as assessed by ERG compared to Cav-1-/- mice. Our study demonstrated the dysregulation of oxidative lipidomics in Cav-1-/- retina and established a link between energy deficiency and retinal function deficits in Cav-1-/- mice. Administration of NAM ameliorated energy deficiency, increased the expression of Sirt1, and improved retinal function, which presents a potential therapeutic strategy for Cav-1 deficiency-induced retinal function deficits.

Microscope-integrated Intraoperative Optical Coherence Tomography for Anterior Segment Surgical Maneuvers.

Purpose: To evaluate the potential value of microscope-integrated optical coherence tomography (MI-OCT) in anterior segment surgical maneuvers. Methods: Twenty-four ophthalmology residents, who were randomly and evenly divided into two groups, performed four anterior segment surgical maneuvers (corneal tunnel, scleral tunnel, simple corneal suture, and corneal laceration repair) on porcine eyes with (group B) or without (group A) real-time MI-OCT feedback. All residents performed the maneuvers again without MI-OCT. Results: Compared with group A, group B (with MI-OCT) showed better accuracy in the length/depth of the corneal tunnel and the length of the scleral tunnel. However, both groups showed similar performances in the depth of both the simple corneal suture and the corneal laceration suture. When both groups performed the maneuvers again without MI-OCT, group B still showed better results than group A for the length of both the corneal and scleral tunnels. Conclusions: Primary results suggest that real-time MI-OCT images are valuable for some anterior segment surgical maneuvers and could be helpful in surgical training. Translational Relevance: MI-OCT systems can be valuable in improving accuracy and decision making during anterior segment surgery and will be useful in surgical training.

Modified Intrascleral Fixation for Repositioning the Dislocated Single-Piece, Rigid PMMA Intraocular Lens.

PURPOSE: To describe a modified intrascleral fixation technique for repositioning single-piece rigid polymethyl methacrylate intraocular lenses (IOLs). METHODS: Four patients with dislocated IOLs were enrolled. Surgical modifications included using ≤1-mm scleral incision for haptic externalization, placing the IOL haptic placement in scleral tunnels, and using 8-0 absorbable sutures. Patients were followed up for 6 months with routine ophthalmic examinations, corneal endothelial cell counts, and ultrasound biomicroscopy (UBM). RESULTS: The mean follow-up time was 13.5 ± 5.45 months. The IOL was well centered and the spherical refraction improved (+10.25 ± 2.21 vs. -0.81 ± 1.59 D, P < 0.05), whereas the best-corrected visual acuity (pre 20/43 Snellen, 0.42 ± 0.33 logarithm of the minimum angle of resolution equivalent and post 20/36 Snellen, 0.31 ± 0.22 logarithm of the minimum angle of resolution equivalent; P = 0.235), intraocular pressure (pre 13.8 ± 3.21, post 13.55 ± 5.14 mmHg), corneal endothelium density (pre 2,423.8 ± 279.6/mm, post 2,280.25 ± 350.7/mm), and total astigmatism (pre -1.94 ± 0.43, post -1.69 ± 0.59 D) remained unchanged. The average horizontal and vertical IOL tilt was 0.33 ± 0.22° and 0.81 ± 0.38°, respectively. Intraocular lens decentration was 0.10 ± 0.03 mm horizontally and 0.13 ± 0.06 mm vertically. CONCLUSION: The modified intrascleral fixation technique shows encouraging midterm results in patients with dislocated single-piece, rigid polymethyl methacrylate IOLs. Larger samples and longer follow-up are required to confirm the outcomes of this technique.

Feasibility of microscope-integrated swept-source optical coherence tomography in canaloplasty.

BACKGROUND: Several researchers have used commercial microscope-integrated optical coherence tomography (OCT) systems in glaucoma surgery, including ab interno trabeculectomy and canaloplasty. However, the 840 nm wavelength light source of the OCT systems is not ideal for imaging the anterior chamber angle structures because of its limited penetration. We evaluated the potential value of a microscope-integrated swept-source OCT system with a 1,310 nm center-wavelength light in canaloplasty for glaucoma. METHODS: Sixteen porcine eyes were used to simulate canaloplasty. The critical surgical steps were monitored using a prototype microscope-integrated OCT system with a 1,310 nm light source and a high axial scan rate of 100 kHz. The images from swept-source OCT and three-dimensional images from the microscope were projected simultaneously onto a liquid crystal display three-dimensional monitor (LMD-4251TD, Sony, Japan). The changes in the collector vessel (aqueous drainage structure in the porcine eye, similar to Schlemm's canal in humans) were measured using Image J software. Histological sections stained with hematoxylin and eosin were used to assess surgical efficacy. RESULTS: High-resolution real-time images of the anterior segment were acquired during canaloplasty using the microscope-integrated OCT system. With the real-time OCT images, the position of the collector vessel was identified and the scleral flap could be created at the ideal location. The expansion of the collector vessel after viscoelastic injection was also visualized in real time. Compared with baseline, there was a significant increase in the cross-sectional area (from 14,502.98±9,242.55 to 59,499.04±20,506.41 µm2, P<0.001) of the collector vessel. CONCLUSIONS: Using the microscope-integrated OCT system, real-time images of the anterior segment were successfully acquired during the operation. The microscope-integrated OCT system might be useful in future anti-glaucoma surgery.

A high-salt diet aggravates retinal ischaemia/reperfusion injury.

Ischaemia/reperfusion contributes to the pathophysiological process of many retinal diseases. Previous studies have shown that retinal ischaemia/reperfusion mainly results in neuronal degeneration, including thinning of the retina, retinal ganglion cell death and reductions in electroretinography. A high-salt diet contributes to the inflammatory response and tissue hypoperfusion and may be associated with ischaemia/reperfusion injury. In the present study, we investigated the influence of a high-salt diet on retinal ischaemia/reperfusion injury and explored the potential mechanism in a rat model. The results revealed that the high-salt diet aggravated ischaemia/reperfusion-induced thinning of the retina. A TUNEL assay and Brn-3a staining revealed substantially more severe cell death and loss of retinal ganglion cells, and electroretinography confirmed worse retinal function in the ischaemia/reperfusion eyes of rats fed the high-salt diet. These effects may be associated with upregulation of Caspase-3, Bax, Interleukin-1ß and Interleukin-6 and decreased expression of nitric oxide. In summary, a high-salt diet aggravates ischaemia/reperfusion-induced retinal neuronal impairment by activating pro-apoptotic and pro-inflammatory signalling pathways and inhibiting vasodilation.

Automated choroid segmentation of three-dimensional SD-OCT images by incorporating EDI-OCT images.

BACKGROUND AND OBJECTIVE: The measurement of choroidal volume is more related with eye diseases than choroidal thickness, because the choroidal volume can reflect the diseases comprehensively. The purpose is to automatically segment choroid for three-dimensional (3D) spectral domain optical coherence tomography (SD-OCT) images. METHODS: We present a novel choroid segmentation strategy for SD-OCT images by incorporating the enhanced depth imaging OCT (EDI-OCT) images. The down boundary of the choroid, namely choroid-sclera junction (CSJ), is almost invisible in SD-OCT images, while visible in EDI-OCT images. During the SD-OCT imaging, the EDI-OCT images can be generated for the same eye. Thus, we present an EDI-OCT-driven choroid segmentation method for SD-OCT images, where the choroid segmentation results of the EDI-OCT images are used to estimate the average choroidal thickness and to improve the construction of the CSJ feature space of the SD-OCT images. We also present a whole registration method between EDI-OCT and SD-OCT images based on retinal thickness and Bruch's Membrane (BM) position. The CSJ surface is obtained with a 3D graph search in the CSJ feature space. RESULTS: Experimental results with 768 images (6 cubes, 128 B-scan images for each cube) from 2 healthy persons, 2 age-related macular degeneration (AMD) and 2 diabetic retinopathy (DR) patients, and 210 B-scan images from other 8 healthy persons and 21 patients demonstrate that our method can achieve high segmentation accuracy. The mean choroid volume difference and overlap ratio for 6 cubes between our proposed method and outlines drawn by experts were -1.96µm3 and 88.56%, respectively. CONCLUSIONS: Our method is effective for the 3D choroid segmentation of SD-OCT images because the segmentation accuracy and stability are compared with the manual segmentation.

Spironolactone versus observation in the treatment of acute central serous chorioretinopathy.

PURPOSE: To evaluate the efficacy of oral spironolactone in patients with acute central serous chorioretinopathy (CSC). METHODS: This is a prospective, randomised controlled clinical study. Thirty patients with acute CSC were the participants, including 18 patients who were treated with spironolactone (40 mg orally, twice daily) for 2 months in the experimental group and 12 patients who received observation in the control group. Main outcome measures included the proportion of eyes achieving complete resolution of subretinal fluid (SRF), changes in central macular thickness (CMT), the height of SRF (SRFH), best corrected visual acuity (BCVA) and subfoveal choroidal thickness (SFCT). The follow-up period was 2 months. RESULTS: Complete resolution of SRF was achieved in 55.6% (10/18) and 8.3% (1/12) of the eyes in the treatment group and the control group, respectively, at 2 months (p=0.018). The mean CMT and SRFH decreased significantly at each visit in both groups (p<0.05), and there was significant difference between the two groups at 2 months (p<0.05 and p<0.05, respectively). BCVA (in logarithm of the minimum angle of resolution; mean) improved in both groups at 2 months (p<0.05). In the treatment group, the mean baseline SFCT significantly decreased from 502.50±87.38 µm to 427.44±74.37 µm at 2 months (p<0.01), while the change from baseline (from 480.33±102.38 µm to 463.75±100.63 µm) was not significant in the control group (p=0.195). But the differences between the two groups in BCVA and SFCT were not significant. CONCLUSIONS: Oral spironolactone is more effective with a faster absorption of SRF than observations. It is a promising treatment for acute CSC. TRIAL REGISTRATION NUMBER: ChiCTR-IPR-16008428, Results.