Investigation of hand tremor suppression by a customized passive surgical support robot during internal limiting membrane peeling.

PURPOSE: To construct a quantitative evaluation system for hand tremor during internal limiting membrane (ILM) peeling and investigate changes in hand tremor attributable to the use of the customized passive surgical support robot. METHODS: This analytical and experimental study developed a hand tremor evaluation system that synchronizes three elements: surgical microscope images, an artificial eye module with a force sensor to simulate ILM peeling, and microforceps with an inertial measurement unit. Two surgeons used this system to measure hand tremor during ILM peeling with and without the robot. RESULTS: The horizontal, vertical, and combined vertical and horizontal components of hand tremor were 8.1 ± 6.1, 1.7 ± 1.8, and 8.5 ± 6.2 mG, respectively, in the no robot group. These components decreased to 7.2 ± 6.0, 1.5 ± 1.7, and 7.5 ± 6.1 mG, respectively, in the robot group. In particular, hand tremor was significantly suppressed by 11.9% for the horizontal component using the robot (p = 0.0006). CONCLUSION: The newly constructed system helps to quantitatively evaluate hand tremor during ILM peeling. The customized passive surgical support robot enables to decrease hand tremor during ILM peeling.

Alteration of treatment choices and the visual prognosis for diabetic macular edema in the era of anti-VEGF drugs: Analysis of the STREAT-DME 2 study.

PURPOSE: To assess the real-world outcome of best-corrected visual acuity (BCVA) following 2-year intervention for treatment-naïve diabetic macular edema (DME) since the approval of anti-vascular endothelial growth factor (VEGF) therapy. METHODS: A total of 1,780 treatment-naïve eyes with DME for which intervention was initiated between 2015 and 2019, and which were followed for 2 years, were extracted from the longitudinal medical records of 37 retinal disease institutions in Japan. Interventions included anti-VEGF therapy, topical corticosteroid therapy, macular photocoagulation, and vitrectomy. The baseline and final BCVA, and the number and timing of interventions were recorded. Eyes were classified according to the year in which intervention was initiated. RESULTS: Over a 2-year period, BCVA improved annually, finally reaching 7 letters. The proportion of eyes in which good vision was maintained (BCVA >20/40) increased to 73.3% in the latest period. The administration of anti-VEGF therapy remained stable, accounting for approximately 90% of eyes. Notably, the proportion of eyes receiving anti-VEGF drugs as first-line treatment increased dramatically to approximately 80%. CONCLUSION: Anti-VEGF therapy has become the first-line treatment since the approval of anti-VEGF drugs for DME. These findings reflect the evolution of DME treatment and highlight the superiority of anti-VEGF therapy and its increased uptake over time.

Diagnosis and clinical course of ocular ischemic syndrome with retinal vascular abnormalities due to unilateral ocular artery and internal carotid artery stenosis in a child with neurofibromatosis type 1: a case report.

BACKGROUND: Neurofibromatosis type 1 (NF1) is a hereditary disease that causes neurofibromas generally, but it has been reported to sometimes be associated with various forms of blood vessel stenosis, occlusion and vascular abnormalities of unknown mechanism. However, a symptomatic case with simultaneous ophthalmic artery stenosis and internal carotid artery stenosis is an extremely rare pathogenesis in a child with NF1. In this report, we performed the diagnosis and observation using various imaging modalities for this rare pediatric case. CASE PRESENTATION: A 6-year-old girl diagnosed with NF1 presented with gradual visual loss in the right eye. Best corrected visual acuity (BCVA) was 20/40 OD and the intraocular pressure (IOP) was normal in both eyes. Retinal vascular abnormalities with tortuous vessels and optic disc pallor were observed in the right fundus. Widefield fluorescein angiography revealed multiple sites of neovascularization and a large non-perfusion area in the peripheral retina. Optical coherence tomography angiography showed retinal vascular abnormalities in the right eye and revealed differences in inner retinal thickness and blood flow signal between the left and right eyes. Laser speckle flowgraphy showed that chorioretinal blood flow was significantly decreased in the right eye. Cerebral angiography revealed the right ophthalmic artery was significantly narrowed throughout. In addition, Magnetic resonance angiography revealed that the right internal carotid artery was significantly narrowed in the ophthalmic segment. We diagnosed ophthalmic artery and internal carotid artery stenosis with retinal vascular abnormalities and ocular ischemic syndrome in NF1. Because IOP increased to 35 mmHg, due to neovascular glaucoma in addition to mild vitreous hemorrhage occurred, panretinal photocoagulation was performed after intravitreal bevacizumab injection. After treatments, IOP normalized, but BCVA decreased to 20/100 OD. Arterial spin labeling showed normal cerebral blood flow. The patient is currently being carefully monitored. CONCLUSIONS: We have described the diagnosis and treatment of ocular ischemic syndrome due to multiple arteries stenosis in a child with NF 1. Utilization of various imaging modalities was helpful in diagnosing the complicated pathogenesis. However, since direct intervention by neurosurgery is not possible in this case, it is expected that treatment will be extremely difficult in the future.

Mesenchymal cells and fluid flow stimulation synergistically regulate the kinetics of corneal epithelial cells at the air-liquid interface.

PURPOSE: In vivo microenvironments are critical to tissue homeostasis and wound healing, and the cornea is regulated by a specific microenvironment complex that consists of cell-cell interactions, air-liquid interfaces, and fluid flow stimulation. In this study, we aimed to clarify the effects of and the correlations among these three component factors on the cell kinetics of corneal epithelial cells. METHODS: Human corneal epithelial-transformed (HCE-T) cells were cocultured with either primary rat corneal fibroblasts or NIH 3T3 fibroblasts. We employed a double-dish culture method to create an air-liquid interface and a gyratory shaker to create fluid flow stimulation. Morphometric and protein expression analyses were performed for the HCE-T cells. RESULTS: Both the primary rat fibroblasts and the NIH 3T3 cells promoted HCE-T cell proliferation, and the presence of fluid flow synergistically enhanced this effect and inhibited the apoptosis of HCE-T cells. Moreover, fluid flow enhanced the emergence of myofibroblasts when cocultured with primary rat fibroblasts or NIH 3T3 cells. Extracellular signal-regulated kinase and p38 signaling were regulated either synergistically or independently by both fluid flow and cellular interaction between the HCE-T and NIH 3T3 cells. CONCLUSION: The cell-cell interaction and fluid flow stimulation in the air-liquid interface synergistically or independently regulated the behavior of HCE-T cells. Fluid flow accelerated the phenotypic change from corneal fibroblasts and NIH 3T3 cells to myofibroblasts. Elucidation of the multicomponent interplay in this microenvironment will be critical to the homeostasis and regeneration of the cornea and other ocular tissues.

Development of a novel noninvasive system for measurement and imaging of the arterial phase oxygen density ratio in the retinal microcirculation.

PURPOSE: This study was conducted in order to develop a novel noninvasive system for measurement and imaging of the arterial oxygen density ratio (ODR) in the retinal microcirculation. METHODS: We developed a system composed of two digital cameras with two different filters, which were attached to a fundus camera capable of simultaneously obtaining two images. Actual measurements were performed on healthy volunteer eyes (n = 61). A new algorithm for ODR measurement and pixel-level imaging of erythrocytes was constructed from these data. The algorithm was based on the morphological closing operation and the line convergence index filter. For system calibration, we compared and verified the ODR values in arterioles and venules that were specified in advance for 56 eyes with reproducibility. In 10 additional volunteers, ODR measurements and imaging of the arterial phase in the retinal microcirculation corresponding to changes in oxygen saturation of the peripheral arteries at normal breathing and breath holding were performed. RESULTS: Estimation of incident light to erythrocytes and pixel-level ODR calculation were achieved using the algorithm. The mean ODR values of arterioles and venules were 0.77 ± 0.060 and 1.02 ± 0.067, respectively. It was possible to separate these regions, calibrate at the pixel level, and estimate the arterial phase. In each of the 10 volunteers, changes in the arterial phase ODR corresponding to changes in oxygen saturation of the peripheral arteries were observed before and after breath holding on ODR images. The mean ODR in 10 volunteers was increased by breath holding (p < 0.05). CONCLUSIONS: We developed a basic system for arterial phase ODR measurement and imaging of the retinal microcirculation. With further validation and development, this may provide a useful tool for evaluating retinal oxygen metabolism in the retinal microcirculation.

Genome-wide association study suggests four variants influencing outcomes with ranibizumab therapy in exudative age-related macular degeneration.

To identify factors associated with ranibizumab responses in patients with exudative age-related macular degeneration (AMD), we performed a genome-wide association study (GWAS) and a replication study using a total of 919 exudative AMD patients treated with intravitreal ranibizumab in a Japanese population. In the combined analysis of GWAS and the replication study, no loci reached genome-wide significant level; however, we found four variants showed suggestive level of associations with visual loss at month three (rs17822656, rs76150532, rs17296444, and rs75165563: Pcombined < 1.0 × 10-5). Of the candidate genes within these loci, three were relevant to VEGF-related pathway (KCNMA1, SOCS2, and OTX2). The proportions of patients who worsened visual acuity were 13.7%, 38.8%, 58.0%, and 80.0% in patients with 0, 1, 2, and 3 or more identified risk variants, respectively. Changes in visual acuity decreased linearly as the number of risk variants increased (P = 1.67 × 10-12). The area under the curve using age, baseline visual acuity, and history of previous treatment was 0.607, and improved significantly to 0.713 in combination with identified variants (P < 0.0001). Although further study is needed to confirm their associations, our results offer candidate variants influencing response to ranibizumab therapy.

INTERNAL LIMITING MEMBRANE PEELING-DEPENDENT RETINAL STRUCTURAL CHANGES AFTER VITRECTOMY IN RHEGMATOGENOUS RETINAL DETACHMENT.

PURPOSE: To examine retinal changes after vitrectomy with internal limiting membrane (ILM) peeling, we used 3-dimensional optical coherence tomography (3D-OCT) in rhegmatogenous retinal detachment cases. METHODS: The 68 eyes from 67 patients with rhegmatogenous retinal detachment were studied, including 35 detached macula cases (51%) and 33 attached macula cases. Internal limiting membrane peeling was performed with fine forceps after brilliant blue G staining. The 3D-OCT images were obtained with volume-rendering technologies from cross-sectional OCT images. RESULTS: The 3D-OCT detected 45 eyes (66%) with ILM peeling-dependent retinal changes, including dissociated optic nerve fiber layer appearance, dimple sign, temporal macular thinning, ILM peeling area thinning, or forceps-related retinal thinning. The ILM peeled area was detectable in only 9 eyes with 3D-OCT, whereas it was undetectable in other 59 eyes. The dissociated optic nerve fiber layer appearance was detected in 8 of the total cases (12%), and dimple signs were observed in 14 cases (21%). Forceps-related thinning was also noted in eight cases (24%) of attached macula cases and in four cases (11%) of detached macula cases. No postoperative macular pucker was noted in the observational period. CONCLUSION: The 3D-OCT clearly revealed spatial and time-dependent retinal changes after ILM peeling. The changes occurred in 2 months and remained thereafter.

INCOMPLETE REPAIR OF RETINAL STRUCTURE AFTER VITRECTOMY WITH INTERNAL LIMITING MEMBRANE PEELING.

PURPOSE: To examine retinal changes after vitrectomy with internal limiting membrane (ILM) peeling, we used a cynomolgus monkey model and focused on surgical damages of ILM peeling for long observational period of 3 years. METHODS: Vitrectomy was performed followed by ILM peeling similar to clinical settings in humans. Ultrastructural changes of the retina were investigated by light, transmission, and scanning electron microscopy at 3 months and 3 years after ILM peeling. RESULTS: Ultrastructural study showed that the ILM peeled area was still clearly recognized after 3 years. The Müller cell processes covered most of the retina; however, the nerve fiber layer was partly uncovered and exposed to the vitreous space. The arcuate linear nerve fiber bundles were observed as comparable with dissociated optic nerve fiber layer appearance. Small round retinal surface defects were also observed around macula, resembling the dimple sign. Forceps-related retinal thinning was also found on the edge of ILM peeling, where we started peeling with fine forceps. CONCLUSION: The ultrastructural studies showed that most of ILM peeling area was covered with glial cells during wound healing processes. Retinal changes were found comparable with dissociated optic nerve fiber layer appearance or dimple sign, which were clinically observed with optical coherence tomography.

Astrocyte-mediated ischemic tolerance.

Preconditioning (PC) using a preceding sublethal ischemic insult is an attractive strategy for protecting neurons by inducing ischemic tolerance in the brain. Although the underlying molecular mechanisms have been extensively studied, almost all studies have focused on neurons. Here, using a middle cerebral artery occlusion model in mice, we show that astrocytes play an essential role in the induction of brain ischemic tolerance. PC caused activation of glial cells without producing any noticeable brain damage. The spatiotemporal pattern of astrocytic, but not microglial, activation correlated well with that of ischemic tolerance. Interestingly, such activation in astrocytes lasted at least 8 weeks. Importantly, inhibiting astrocytes with fluorocitrate abolished the induction of ischemic tolerance. To investigate the underlying mechanisms, we focused on the P2X7 receptor as a key molecule in astrocyte-mediated ischemic tolerance. P2X7 receptors were dramatically upregulated in activated astrocytes. PC-induced ischemic tolerance was abolished in P2X7 receptor knock-out mice. Moreover, our results suggest that hypoxia-inducible factor-1α, a well known mediator of ischemic tolerance, is involved in P2X7 receptor-mediated ischemic tolerance. Unlike previous reports focusing on neuron-based mechanisms, our results show that astrocytes play indispensable roles in inducing ischemic tolerance, and that upregulation of P2X7 receptors in astrocytes is essential.

[Efficacy and Safety of A0001 (Brilliant Blue G250) for Internal Limiting Membrane Staining and Peeling: Phase III Investigator-initiated Multicenter Clinical Trial].

PURPOSE: To investigate the efficacy and safety of A0001 (brilliant blue G250) for visualization of the internal limiting membrane (ILM) during and after vitrectomy. METHODS: Patients (n = 31) requiring ILM peeling during vitrectomy were enrolled in this clinical trial. After injection of A0001 (range: 0.0625 to 0. 125 mg), the staining grade and the peeling ease of the ILM were evaluated in five steps (levels 0 to 4). The safety of A0001 was investigated for 7 days after surgery. RESULTS: From the evaluation of a primary endpoint by the Independent Data Monitoring Committee (IDMC) and a secondary endpoint by each surgeon, A0001 was effective in all cases at three or more levels ( ≥ level 2 was defined as effective) for evaluation of the grade of visualization and operating ease. Adverse events occurring in two or more cases included elevated intraocular pressure, eye pain, eye discharges, and retinal bleeding. One serious adverse event was a case of unclosed macular hole after vitrectomy, but the patient recovered after reoperation. CONCLUSIONS: A0001 was effective and safe for visualization of the ILM during vitrectomy, and there was an improvement in ease of operation.

Periostin promotes the generation of fibrous membranes in proliferative vitreoretinopathy.

Proliferative vitreoretinopathy (PVR) is a severe, vision-threatening disorder characterized by the fibrous membrane formation that leads to tractional retinal detachment. There has been no effective therapeutic approach other than vitreoretinal surgery. In this study, DNA microarray analysis of the fibrous membranes revealed significant up-regulation of periostin. We also found increased periostin expression in the vitreous and retinal pigment epithelial (RPE) cells from fibrous membranes of PVR patients. In vitro, periostin increased proliferation, adhesion, migration, and collagen production in RPE cells through integrin αV-mediated FAK and AKT phosphorylation. Periostin blockade suppressed migration and adhesion induced by TGFß2 and PVR vitreous. In vivo, periostin inhibition had the inhibitory effect on progression of experimental PVR in rabbit eyes without affecting the viability of retinal cells. These results identified periostin as a pivotal molecule for fibrous membrane formation as well as a promising therapeutic target for PVR.

Brilliant Blue G double staining enhances successful internal limiting membrane peeling with minimal adverse effect by low cellular permeability into live cells.

PURPOSE: Brilliant Blue G is used as a surgical adjuvant for retinal surgery. Although BBG double or multiple staining was reported, the effectiveness and safety of repeated staining is still elusive. To further examine the effectiveness and safety, we examined BBG in clinical cases in vivo, primary cell culture in vitro, and surgically resected specimen ex vivo. METHODS: A retrospective interventional case series with in vitro and ex vivo studies were performed. Vitrectomy was performed in 28 cases of epiretinal membrane with BBG single to multiple staining. The surgically resected membranes were stained by BBG with or without cellular fixation. Primary cell cultures were examined with BBG and live/death cell markers, such as Calcein AM and TUNEL. RESULTS: Single staining provided satisfactory staining in seven cases. Double or multiple staining substantially visualized internal limiting membrane (21 cases), especially the edges of remaining internal limiting membrane (11 cases). Adverse retinal staining was not noted and the final visual acuity showed no difference with multiple staining. The live cells barely stained with BBG, while some dead cells were stained. CONCLUSION: Brilliant Blue G multiple staining substantially enhanced the visualization of internal limiting membrane. The absence of abnormal staining supports the safety of repeated BBG staining.

Hyphema is a risk factor for failure of trabeculectomy in neovascular glaucoma: a retrospective analysis.

BACKGROUND: Several retinal ischemic diseases can cause neovascular glaucoma (NVG). Trabeculectomy with mitomycin C (MMC) is a relatively better treatment modality in the management of eyes with NVG than other glaucoma surgeries. The aim of this study was to investigate the factors that may influence the outcome of trabeculectomy with MMC for NVG. METHODS: Forty-nine NVG eyes from 43 patients (26 males and 17 females) underwent primary trabeculectomy with MMC. The mean follow-up period was 16.8 ± 8.1 months (range, 6 to 34 months). Twenty-one eyes of 21 patients received intravitreal bevacizumab (IVB) 3.6 ± 1.8 days before trabeculectomy with MMC. A Kaplan-Meier survival-curve analysis was used to summarize the cumulative probability of success. We examined the relationship between the surgical outcome and the following surgical factors: gender, age, history of panretinal photocoagulation, history of cataract surgery, history of vitrectomy, preoperative IVB, NVG in the fellow eye, and postoperative complications (hyphema, choroidal detachment, and formation of fibrin) by multivariate analysis. RESULTS: The survival rate was 83.7% after 6 months, 70.9% after 12 months, and 60.8% after 24 months. The Kaplan-Meier survival curves showed no significant difference in the survival rate between the eyes with preoperative IVB (n = 21) and the eyes without preoperative IVB (n = 28) (p = 0.14). The multiple logistic regression analysis showed that postoperative hyphema (odds ratio, 6.54; 95% confidence interval, 1.41 to 35.97) was significantly associated with the surgical outcome (p = 0.02). CONCLUSIONS: Postoperative hyphema was significantly correlated with the outcome of trabeculectomy for NVG. There was no significant association between preoperative IVB and postoperative hyphema or the results of trabeculectomy.

Survey on Findings and Utilization of Preoperative Chest Radiography in Ophthalmic Surgery.

Objective: The objective of this paper is to reconsider the significance of preoperative chest radiography (CXR) before ophthalmic surgery through investigation of imaging findings and usage status. Methods: This retrospective observational clinical study involved 1616 patients who underwent ophthalmic surgery at Saga University Hospital from 1 January 2019 to 31 December 2020. The patients' radiology reports were obtained from the electronic medical records, and their CXR findings, therapeutic interventions, and progress were investigated. Results: Among all patients, 539 (33.4%) had abnormal preoperative CXR findings. Of these patients, 74 (4.6%) had newly identified abnormal findings. In both patient groups, approximately 70% of patients with abnormal findings were aged ≥70 years, and interstitial shadows were the most common finding. Among all patients with abnormal findings, three (0.19%) received preoperative therapeutic interventions, and all surgeries were performed safely. Forty-three patients with abnormal findings were referred to our hospital or other hospitals for further investigation and treatment postoperatively. Among those patients, eight (0.5%) had primary lung cancer, seven underwent surgery, and one received chemoradiation. The other patients were also followed up and received appropriate therapeutic interventions. Conclusions: Before ophthalmic surgery, few patients required actual therapeutic interventions based on their CXR results. However, many abnormal findings were revealed in elderly patients, including some serious diseases. Furthermore, research has suggested that appropriate therapeutic intervention after ophthalmologic surgery may reduce the risk of a poor life prognosis. This study clearly shows that preoperative CXR is not only useful for perioperative systemic management but also ultimately benefits patients. It is also considered particularly meaningful for patients aged ≥70 years.

Developing quantitative analysis program of blood flow velocity according to vessel diameter for neovascular age-related macular degeneration using OCTA-VISTA.

This study aimed to develop a quantitative analysis program of blood flow velocity by vessel diameter in neovascular age-related macular degeneration (nAMD) subjects using high-speed swept-source optical coherence tomography angiography. This retrospective, observational, cross-sectional study included 10 eyes of healthy volunteers and 4 eyes of patients with representative nAMD. Novel scan patterns and variable interscan time analysis were utilized to measure the flow parameter, a surrogate marker of blood flow velocity, by vessel diameter within different depths. Detected vessels at superficial and deep as well as outer retinal regions were categorized into three vessel diameters (major vessels (> 40 µm), medium vessels (20-40 µm), and capillaries (< 20 µm)). The flow parameter increased with enlarged vessel diameter in all participants at superficial and deep layer. All nAMD subjects, except for type 3 macular neovascularization (MNV), contained a structure dominated by medium vessels at outer retinal region. The mean flow parameter at outer retinal region was type 1 MNV (1.46 ms-1), type 1 + 2 MNV (0.98 ms-1), and polypoidal choroidal vasculopathy, including branching vascular networks (1.46 ms-1). This program provides the possibility to extract the blood flow information at different depths by vessel diameter types, which is considered to be useful tool for evaluating nAMD pathology and activity.

Clinical features of 26 cases of COVID-19-associated conjunctivitis.

PURPOSE: To explore the clinical features of COVID-19-associated conjunctivitis with the objective of preventing the spread of infection. STUDY DESIGN: Retrospective cohort study. METHODS: From March 2020 to March 2021, we retrospectively reviewed 26 (9.8%) consecutive COVID-19 patients with conjunctivitis among 282 COVID-19 cases admitted to our hospital. Clinical symptoms, onset date of conjunctivitis, time to patient recovery, and eye drop intervention were investigated. In addition, risk factors for developing conjunctivitis were statistically examined among 206 inpatients available for within 5 days of the onset. A multivariate analysis of conjunctivitis risk factors was performed. RESULTS: Among the 282 COVID-19 patients, 4 (1.4%) had conjunctival hyperemia as the primary symptom. The median time of onset was 4 days after the COVID-19 onset. Hyperemia was observed in all cases, but other ocular symptoms were rare. The median duration of hyperemia was 3 days. A multiple logistic regression analysis revealed that a young age (p=0.005) and current smoking habit (p=0.027) were independent risk factors for conjunctivitis after COVID-19. CONCLUSIONS: COVID-19-associated conjunctivitis is rare in the elderly and strongly associated with a history of smoking. It often occurs in the early stages of infection, and while hyperemia is recognized as a clinical symptom, other ocular symptoms are rare or non-existent. Many cases recover within a short time.

Clinical evidence of sustained chronic inflammatory reaction in retinitis pigmentosa.

PURPOSE: To study the nature of inflammatory reaction in eyes of patients with retinitis pigmentosa (RP) and its possible role in the pathogenesis of RP. DESIGN: Retrospective, observational study. PARTICIPANTS AND CONTROLS: Three hundred seventy-one consecutive patients diagnosed with typical RP were included in this study. We included 165 patients without active inflammatory diseases, including 20 patients diagnosed with cataract, and 36 patients diagnosed with idiopathic epiretinal membrane as controls. METHODS: Density of the inflammatory cells in the anterior vitreous cavity was measured and graded by slit-lamp biomicroscopy. A multiplex enzyme-linked immunosorbent assay (ELISA) was performed to evaluate the concentration of cytokines and chemokines in aqueous humor and vitreous fluid of patients with RP and controls. In addition, we investigated the relationship between visual function and anterior vitreous cells in these patients. MAIN OUTCOME MEASURES: Slit-lamp biomicroscopic analysis, best-corrected visual acuity, visual field analysis, and multiplex ELISA. RESULTS: In 190 of 509 eyes with RP (37.3%), "1+" (5-9 cells per field) or more cells were observed in the anterior vitreous cavity. Strong inflammatory reaction with "2+" cells (10-30 cells per field) was associated with younger age. In the elderly patients with RP, significantly decreased visual function was seen in a group with "1+" or more cells (P<0.05). Moreover, the levels of a variety of proinflammatory cytokines and chemokines, including monocyte chemotactic protein-1, were increased both in the aqueous humor and vitreous fluid of RP patients compared with the levels in control patients. CONCLUSIONS: Sustained chronic inflammatory reaction may underlie the pathogenesis of RP, suggesting interventions for ocular inflammatory reaction as a potential treatment for patients with RP. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any of the materials discussed in this article.

Laboratory evidence of sustained chronic inflammatory reaction in retinitis pigmentosa.

PURPOSE: To study the nature of retinal inflammatory response in rd10 mice, an animal model of retinitis pigmentosa (RP), and to investigate the effect of an antioxidant on retinal inflammation and photoreceptor apoptosis. DESIGN: Experimental study. PARTICIPANTS AND CONTROLS: This study included 42 untreated rd10 mice, 30 N-acetylcysteine (NAC)-treated rd10 mice, and 20 C57BL/6 mice as controls. METHODS: Real-time polymerase chain reaction (PCR) was performed to evaluate the expression levels of inflammatory factors (proinflammatory cytokines and chemokines) in rd10 mouse retinas. Rd10 mice were treated with an antioxidant NAC, and its effect on retinal inflammation and photoreceptor apoptosis were examined by immunohistochemistry. MAIN OUTCOME MEASURES: Real-time PCR and immunohistochemistry. RESULTS: We demonstrated sequential events involving increased expression of proinflammatory cytokines and chemokines, activation of microglia, and photoreceptor apoptosis during retinal degeneration of rd10 mice. Furthermore, antioxidant treatment with NAC prevented the photoreceptor cell death along with suppression of inflammatory factors and microglial activation. CONCLUSIONS: Sustained chronic inflammatory reaction may contribute to the pathogenesis of retinal degeneration in rd10 mice, suggesting interventions for ocular inflammatory reaction using antioxidants as a potential treatment for patients with RP. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any of the materials discussed in this article.

Development and preclinical evaluation of a new viewing filter system to control reflection and enhance dye staining during vitrectomy.

PURPOSE: We developed a new artificial image enhancement system and evaluated its usefulness in controlling intraoperative reflection and enhancing of Brilliant Blue G (BBG) staining. METHODS: The system was composed of three kinds of filters (a polarizing filter, a blue-enhancing filter, and a sharp-cut filter Y) and attached to the inferior surface of the operating microscope. Twenty-seven post-mortem extracted porcine eyes were used for a series of examinations. We performed surgery using the 23G-vitrectomy system with a halogen light and xenon lights and compared the reduction of intraoperative reflection under air condition and visibility and BBG contrast with and without this system. The evaluation of images was calculated in CIE 1976 (L*, a*, b*) color space (CIELAB) carried out by ImageJ software. The transmission of each filter and absorbance of BBG was measured by a spectrophotometer. We measured spectral irradiance at each wavelength about each filter from each light source with a spectroradiometer. RESULTS: Under both light sources, intraoperative reflection was controlled using a polarizing (PL) filter or combination of filters under air condition. Evaluation of the value of L* within the cutter surface was changed by 37.8 % under the halogen light, and 61.6 % (averaged) under the xenon light with inserted filters versus no filter. The BBG intensity difference was obtained with sharp-cut Y filter under both light source and PL with blue enhancing filter under the halogen light using each L*, a*, b* parameter with statistically significant (p < 0.01, 0.05). However, there was a relative decrease in the observation illuminance when the filter inserted according to the attenuation total spectral irradiance. CONCLUSIONS: This system can reduce intraoperative reflections under the air condition and obtain an excellent BBG staining intensity induced by various light sources.