Seasonal Variation in Human Adenovirus Conjunctivitis: A 30-Year Observational Study.

PURPOSE: The aim of this study is to measure the seasonal trends of adenovirus conjunctivitis. METHODS: A total of 926 positive cases of HAdV conjunctivitis were reviewed at the University of Pittsburgh Medical Center (UPMC) in Pittsburgh (Allegheny County, Pennsylvania, USA) from 11th March 1987 to 15th December 2016. To determine seasonal variation, daily counts were adjusted for yearly changes in Allegheny County population size, modelled as a function of long-term trend using Basis-spline (B-spline), and analysed for seasonal trend by quarter (1Q = January to March, 2Q = April to June, 3Q = July to September, 4Q = October to December). RESULTS: The number of adenovirus conjunctivitis cases in 3Q was 45% higher than that of 2Q (95% confidence interval [CI] 1.21-1.74, P = 0.0001). When 3Q is compared to 1Q and 4Q, it was not statistically significant (95% CI 0.96-1.42, P = 0.1209 and 95% CI 0.96-1.41, P = 0.1180, respectively). CONCLUSION: To the best of our knowledge, this is the first report and the longest time-series evaluating the potential seasonality of adenovirus conjunctivitis in the USA. We observed the highest number of cases from July to September and the lowest number of cases from April to June in our study population. Knowledge of seasonality can be used to guide outbreak expectations, limit antibiotic over-prescription, and enhance disease prevention.

Tortuous Pore Path Through the Glaucomatous Lamina Cribrosa.

The lamina cribrosa is a primary site of damage in glaucoma. While mechanical distortion is hypothesized to cause reduction of axoplasmic flow, little is known about how the pores, which contains the retinal ganglion cell axons, traverse the lamina cribrosa. We investigated lamina cribrosa pore paths in vivo to quantify differences in tortuosity of pore paths between healthy and glaucomatous eyes. We imaged 16 healthy, 23 glaucoma suspect and 48 glaucomatous eyes from 70 subjects using a swept source optical coherence tomography system. The lamina cribrosa pores were automatically segmented using a previously described segmentation algorithm. Individual pore paths were automatically tracked through the depth of the lamina cribrosa using custom software. Pore path convergence to the optic nerve center and tortuosity was quantified for each eye. We found that lamina cribrosa pore pathways traverse the lamina cribrosa closer to the optic nerve center along the depth of the lamina cribrosa regardless of disease severity or diagnostic category. In addition, pores of glaucoma eyes take a more tortuous path through the lamina cribrosa compared to those of healthy eyes, suggesting a potential mechanism for reduction of axoplasmic flow in glaucoma.

Seeing the Hidden Lamina: Effects of Exsanguination on the Optic Nerve Head.

Purpose: To introduce an experimental approach for direct comparison of the primate optic nerve head (ONH) before and after death by exsanguination. Method: The ONHs of four eyes from three monkeys were imaged with spectral-domain optical coherence tomography (OCT) before and after exsanguination under controlled IOP. ONH structures, including the Bruch membrane (BM), BM opening, inner limiting membrane (ILM), and anterior lamina cribrosa (ALC) were delineated on 18 virtual radial sections per OCT scan. Thirteen parameters were analyzed: scleral canal at BM opening (area, planarity, and aspect ratio), ILM depth, BM depth; ALC (depth, shape index, and curvedness), and ALC visibility (globally, superior, inferior, nasal, and temporal quadrants). Results: All four ALC quadrants had a statistically significant improvement in visibility after exsanguination (overall P < 0.001). ALC visibility increased by 35% globally and by 36%, 37%, 14%, and 4% in the superior, inferior, nasal, and temporal quadrants, respectively. ALC increased 4.1%, 1.9%, and 0.1% in curvedness, shape index, and depth, respectively. Scleral canals increased 7.2%, 25.2%, and 1.1% in area, planarity, and aspect ratio, respectively. ILM and BM depths averaged -7.5% and -55.2% decreases in depth, respectively. Most, but not all, changes were beyond the repeatability range. Conclusions: Exsanguination allows for improved lamina characterization, especially in regions typically blocked by shadowing in OCT. The results also demonstrate changes in ONH morphology due to the loss of blood pressure. Future research will be needed to determine whether there are differences in ONH biomechanics before and after exsanguination and what those differences would imply.

In-vivo effects of intraocular and intracranial pressures on the lamina cribrosa microstructure.

There is increasing clinical evidence that the eye is not only affected by intraocular pressure (IOP), but also by intracranial pressure (ICP). Both pressures meet at the optic nerve head of the eye, specifically the lamina cribrosa (LC). The LC is a collagenous meshwork through which all retinal ganglion cell axons pass on their way to the brain. Distortion of the LC causes a biological cascade leading to neuropathy and impaired vision in situations such as glaucoma and idiopathic intracranial hypertension. While the effect of IOP on the LC has been studied extensively, the coupled effects of IOP and ICP on the LC remain poorly understood. We investigated in-vivo the effects of IOP and ICP, controlled via cannulation of the eye and lateral ventricle in the brain, on the LC microstructure of anesthetized rhesus monkeys eyes using the Bioptigen spectral-domain optical coherence tomography (OCT) device (Research Triangle, NC). The animals were imaged with their head upright and the rest of their body lying prone on a surgical table. The LC was imaged at a variety of IOP/ICP combinations, and microstructural parameters, such as the thickness of the LC collagenous beams and diameter of the pores were analyzed. LC microstructure was confirmed by histology. We determined that LC microstructure deformed in response to both IOP and ICP changes, with significant interaction between the two. These findings emphasize the importance of considering both IOP and ICP when assessing optic nerve health.

Lamina Cribrosa Pore Shape and Size as Predictors of Neural Tissue Mechanical Insult.

Purpose: The purpose of this study was to determine how the architecture of the lamina cribrosa (LC) microstructure, including the shape and size of the lamina pores, influences the IOP-induced deformation of the neural tissues within the LC pores using computational modeling. Methods: We built seven specimen-specific finite element models of LC microstructure with distinct nonlinear anisotropic properties for LC beams and neural tissues based on histological sections from three sheep eyes. Changes in shape (aspect ratio and convexity) and size (area and perimeter length) due to IOP-induced hoop stress were calculated for 128 LC pores. Multivariate linear regression was used to determine if pore shape and size were correlated with the strain in the pores. We also compared the microstructure models to a homogenized model built following previous approaches. Results: The LC microstructure resulted in focal tensile, compressive, and shear strains in the neural tissues of the LC that were not predicted by homogenized models. IOP-induced hoop stress caused pores to become larger and more convex; however, pore aspect ratio did not change consistently. Peak tensile strains within the pores were well predicted by a linear regression model considering the initial convexity (negative correlation, P < 0.001), aspect ratio (positive correlation, P < 0.01), and area (negative correlation, P < 0.01). Significant correlations were also found when considering the deformed shape and size of the LC pores. Conclusions: The deformation of the LC neural tissues was largely dependent on the collagenous LC beams. Simple measures of LC pore shape and area provided good estimates of neural tissue biomechanical insult.

Location of the Central Retinal Vessel Trunk in the Laminar and Prelaminar Tissue of Healthy and Glaucomatous Eyes.

Glaucoma is a leading cause of blindness that leads to characteristic changes in the optic nerve head (ONH) region, such as nasalization of vessels. It is unknown whether the spatial location of this vessel shift inside the ONH occurs within the lamina cribrosa (LC) or the prelaminar tissue. The purpose of this study was to compare the location of the central retinal vessel trunk (CRVT) in the LC and prelaminar tissue in living healthy and glaucomatous eyes. We acquired 3-dimensional ONH scans from 119 eyes (40 healthy, 29 glaucoma suspect, and 50 glaucoma) using optical coherence tomography (OCT). The CRVT location was manually delineated in separate projection images of the LC and prelamina. We found that the CRVT in glaucoma suspect and glaucomatous eyes was located significantly more nasally compared to healthy eyes at the level of the prelamina. There was no detectable difference found in the location of the CRVT at the level of the LC between diagnostic groups. While the nasal location of the CRVT in the prelamina has been associated with glaucomatous axonal death, our results suggest that the CRVT in the LC is anchored in the tissue with minimal variation in glaucomatous eyes.

Freeze-thaw decellularization of the trabecular meshwork in an ex vivo eye perfusion model.

OBJECTIVE: The trabecular meshwork (TM) is the primary substrate of outflow resistance in glaucomatous eyes. Repopulating diseased TM with fresh, functional TM cells might be a viable therapeutic approach. Decellularized TM scaffolds have previously been produced by ablating cells with suicide gene therapy or saponin, which risks incomplete cell removal or dissolution of the extracellular matrix, respectively. We hypothesized that improved trabecular meshwork cell ablation would result from freeze-thaw cycles compared to chemical treatment. MATERIALS AND METHODS: We obtained 24 porcine eyes from a local abattoir, dissected and mounted them in an anterior segment perfusion within two hours of sacrifice. Intraocular pressure (IOP) was recorded continuously by a pressure transducer system. After 72 h of IOP stabilization, eight eyes were assigned to freeze-thaw (F) ablation (-80 °C × 2), to 0.02% saponin (S) treatment, or the control group (C), respectively. The TM was transduced with an eGFP expressing feline immunodeficiency viral (FIV) vector and tracked via fluorescent microscopy to confirm ablation. Following treatment, the eyes were perfused with standard tissue culture media for 180 h. TM histology was assessed by hematoxylin and eosin staining. TM viability was evaluated by a calcein AM/propidium iodide (PI) assay. The TM extracellular matrix was stained with Picro Sirius Red. We measured IOP and modeled it with a linear mixed effects model using a B-spline function of time with five degrees of freedom. RESULTS: F and S experienced a similar IOP reduction of 30% from baseline (P = 0.64). IOP reduction of about 30% occurred in F within 24 h and in S within 48 h. Live visualization of eGFP demonstrated that F conferred a complete ablation of all TM cells and only a partial ablation in S. Histological analysis and Picro Sirius staining confirmed that no TM cells survived in F while the extracellular matrix remained. The viability assay showed very low PI and no calcein staining in F in contrast to many PI-labeled, dead TM cells and calcein-labeled viable TM cells in S. CONCLUSION: We developed a rapid TM ablation method that uses cyclic freezing that is free of biological or chemical agents and able to produce a decellularized TM scaffold with preserved TM extracellular matrix in an organotypic perfusion culture.

Microstructural Crimp of the Lamina Cribrosa and Peripapillary Sclera Collagen Fibers.

Purpose: Although collagen microstructural crimp is a major determinant of ocular biomechanics, no direct measurements of optic nerve head (ONH) crimp have been reported. Our goal was to characterize the crimp period of the lamina cribrosa (LC) and peripapillary sclera (PPS) at low and normal IOPs. Methods: ONHs from 11 sheep eyes were fixed at 10-, 5-, or 0-mm Hg IOP and crimp periods measured manually from coronal cryosections imaged with polarized light microscopy (PLM). Using linear mixed-effect models, we characterized the LC and PPS periods, and how they varied with distance from the scleral canal edge. Results: A total of 17,374 manual collagen crimp period measurements were obtained with high repeatability (1.9 µm) and reproducibility (4.7 µm). The periods were smaller (P < 0.001) and less variable in the LC than in the PPS: average (SD) of 13.8 (3.1) µm in the LC, and 31.0 (10.4) µm in the PPS. LC crimp period did not vary with distance from the scleral canal wall (P > 0.1). PPS period increased with the square root of the distance to the canal (P < 0.0001). Conclusions: Small, uniform crimp periods within the sheep LC and immediately adjacent PPS may indicate that these tissues are setup to prevent large or heterogeneous deformations that insult the neural tissues within the canal. An increasing more variable period with distance from the canal provides a smooth transition of mechanical properties that minimizes stress and strain concentrations.

Rapid learning curve assessment in an ex vivo training system for microincisional glaucoma surgery.

Increasing prevalence and cost of glaucoma have increased the demand for surgeons well trained in newer, microincisional surgery. These procedures occur in a highly confined space, making them difficult to learn by observation or assistance alone as is currently done. We hypothesized that our ex vivo outflow model is sensitive enough to allow computing individual learning curves to quantify progress and refine techniques. Seven trainees performed nine trabectome-mediated ab interno trabeculectomies in pig eyes (n = 63). An expert surgeon rated the procedure using an Operating Room Score (ORS). The extent of outflow beds accessed was measured with canalograms. Data was fitted using mixed effect models. ORS reached a half-maximum on an asymptote after only 2.5 eyes. Surgical time decreased by 1.4 minutes per eye in a linear fashion. The ablation arc followed an asymptotic function with a half-maximum inflection point after 5.3 eyes. Canalograms revealed that this progress did not correlate well with improvement in outflow, suggesting instead that about 30 eyes are needed for true mastery. This inexpensive pig eye model provides a safe and effective microsurgical training model and allows objective quantification of outcomes for the first time.

Signal Normalization Reduces Image Appearance Disparity Among Multiple Optical Coherence Tomography Devices.

PURPOSE: To assess the effect of the previously reported optical coherence tomography (OCT) signal normalization method on reducing the discrepancies in image appearance among spectral-domain OCT (SD-OCT) devices. METHODS: Healthy eyes and eyes with various retinal pathologies were scanned at the macular region using similar volumetric scan patterns with at least two out of three SD-OCT devices at the same visit (Cirrus HD-OCT, Zeiss, Dublin, CA; RTVue, Optovue, Fremont, CA; and Spectralis, Heidelberg Engineering, Heidelberg, Germany). All the images were processed with the signal normalization. A set of images formed a questionnaire with 24 pairs of cross-sectional images from each eye with any combination of the three SD-OCT devices either both pre- or postsignal normalization. Observers were asked to evaluate the similarity of the two displayed images based on the image appearance. The effects on reducing the differences in image appearance before and after processing were analyzed. RESULTS: Twenty-nine researchers familiar with OCT images participated in the survey. Image similarity was significantly improved after signal normalization for all three combinations (P ≤ 0.009) as Cirrus and RTVue combination became the most similar pair, followed by Cirrus and Spectralis, and RTVue and Spectralis. CONCLUSIONS: The signal normalization successfully minimized the disparities in the image appearance among multiple SD-OCT devices, allowing clinical interpretation and comparison of OCT images regardless of the device differences. TRANSLATIONAL RELEVANCE: The signal normalization would enable direct OCT images comparisons without concerning about device differences and broaden OCT usage by enabling long-term follow-ups and data sharing.

Thick Prelaminar Tissue Decreases Lamina Cribrosa Visibility.

Purpose: Evaluation of the effect of prelaminar tissue thickness on visualization of the lamina cribrosa (LC) using optical coherence tomography (OCT). Methods: The optic nerve head (ONH) region was scanned using OCT. The quality of visible LC microstructure was assessed subjectively using a grading system and objectively by analyzing the signal intensity of each scan's superpixel components. Manual delineations were made separately and in 3-dimensions quantifying prelaminar tissue thickness, analyzable regions of LC microstructure, and regions with a visible anterior LC (ALC) boundary. A linear mixed effect model quantified the association between tissue thickness and LC visualization. Results: A total of 17 healthy, 27 glaucoma suspect, and 47 glaucomatous eyes were included. Scans with thicker average prelaminar tissue measurements received worse grading scores (P = 0.007), and superpixels with low signal intensity were associated significantly with regions beneath thick prelaminar tissue (P < 0.05). The average prelaminar tissue thickness in regions of scans where the LC was analyzable (214 µm) was significantly thinner than in regions where the LC was not analyzable (569 µm; P < 0.001). Healthy eyes had significantly thicker average prelaminar tissue measurements than glaucoma or glaucoma suspect eyes (both P < 0.001), and glaucoma suspect eyes had significantly thicker average prelaminar tissue measurements than glaucoma eyes (P = 0.008). Significantly more of the ALC boundary was visible in glaucoma eyes (63% of ONH) than in healthy eyes (41%; P = 0.005). Conclusions: Thick prelaminar tissue was associated with impaired visualization of the LC. Healthy subjects generally had thicker prelaminar tissue, which potentially could create a selection bias against healthy eyes when comparing LC structures.

TSP1-CD47 signaling is upregulated in clinical pulmonary hypertension and contributes to pulmonary arterial vasculopathy and dysfunction.

AIMS: Thrombospondin-1 (TSP1) is a ligand for CD47 and TSP1-/- mice are protected from pulmonary hypertension (PH). We hypothesized the TSP1-CD47 axis is upregulated in human PH and promotes pulmonary arterial vasculopathy. METHODS AND RESULTS: We analyzed the molecular signature and functional response of lung tissue and distal pulmonary arteries (PAs) from individuals with (n = 23) and without (n = 16) PH. Compared with controls, lungs and distal PAs from PH patients showed induction of TSP1-CD47 and endothelin-1/endothelin A receptor (ET-1/ETA) protein and mRNA. In control PAs, treatment with exogenous TSP1 inhibited vasodilation and potentiated vasoconstriction to ET-1. Treatment of diseased PAs from PH patients with a CD47 blocking antibody improved sensitivity to vasodilators. Hypoxic wild type (WT) mice developed PH and displayed upregulation of pulmonary TSP1, CD47, and ET-1/ETA concurrent with down regulation of the transcription factor cell homolog of the v-myc oncogene (cMyc). In contrast, PH was attenuated in hypoxic CD47-/- mice while pulmonary TSP1 and ET-1/ETA were unchanged and cMyc was overexpressed. In CD47-/- pulmonary endothelial cells cMyc was increased and ET-1 decreased. In CD47+/+ cells, forced induction of cMyc suppressed ET-1 transcript, whereas suppression of cMyc increased ET-1 signaling. Furthermore, disrupting TSP1-CD47 signaling in pulmonary smooth muscle cells abrogated ET-1-stimulated hypertrophy. Finally, a CD47 antibody given 2 weeks after monocrotaline challenge in rats upregulated pulmonary cMyc and improved aberrations in PH-associated cardiopulmonary parameters. CONCLUSIONS: In pre-clinical models of PH CD47 targets cMyc to increase ET-1 signaling. In clinical PH TSP1-CD47 is upregulated, and in both, contributes to pulmonary arterial vasculopathy and dysfunction.

Using spatio-temporal modeling for exposure assessment in an investigation of fine particulate air pollution and cardiovascular mortality.

BACKGROUND: U.S. urban air quality has improved dramatically over the past decades. We evaluated acute effects of fine particulate matter (PM2.5) on cardiovascular (CVD) mortality among residents of Allegheny County in SW Pennsylvania (1999-2011) using spatio-temporal modeling of air pollutants (AP) to reduce misclassification error in exposure assessment. METHODS: Spatio-temporal kriging of daily PM2.5 and ozone (O3) was used to produce daily exposure estimates at the residence ZIP code. Time-stratified case-crossover analysis was conducted to examine short-term effects of PM2.5 on CVD mortality, adjusting for O3 and apparent mean temperature. We studied both single and distributed lags for days 0-5. All CVD mortality and subcategories of ischemic heart disease (IHD), acute myocardial infarction, cerebrovascular disease, peripheral vascular disease (PVD), heart failure and cardiac arrhythmia were examined. RESULTS: A total of 62,135 deaths were identified. We found significant associations of PM2.5 with IHD and PVD mortality at lag day 5: (2.1% (95% CI, 0.2-4.1%) and (7.6%, 95% CI, 0.05-15.7%) per 10µg/m3 increase of PM2.5 in single lag models and for IHD in distributed lag models. There were no statistically significant associations with PM2.5 for any of the other outcomes. CONCLUSIONS: The application of finer scale geographically resolved AP exposures made it possible to study acute effects of PM2.5 on CVD mortality in a large metropolitan area. Our study results demonstrated the continued presence of a dose response relationship of increased risk of CVD mortality within this lower range of PM2.5 exposure.

Retinal Structures and Visual Cortex Activity are Impaired Prior to Clinical Vision Loss in Glaucoma.

Glaucoma is the second leading cause of blindness worldwide and its pathogenesis remains unclear. In this study, we measured the structure, metabolism and function of the visual system by optical coherence tomography and multi-modal magnetic resonance imaging in healthy subjects and glaucoma patients with different degrees of vision loss. We found that inner retinal layer thinning, optic nerve cupping and reduced visual cortex activity occurred before patients showed visual field impairment. The primary visual cortex also exhibited more severe functional deficits than higher-order visual brain areas in glaucoma. Within the visual cortex, choline metabolism was perturbed along with increasing disease severity in the eye, optic radiation and visual field. In summary, this study showed evidence that glaucoma deterioration is already present in the eye and the brain before substantial vision loss can be detected clinically using current testing methods. In addition, cortical cholinergic abnormalities are involved during trans-neuronal degeneration and can be detected non-invasively in glaucoma. The current results can be of impact for identifying early glaucoma mechanisms, detecting and monitoring pathophysiological events and eye-brain-behavior relationships, and guiding vision preservation strategies in the visual system, which may help reduce the burden of this irreversible but preventable neurodegenerative disease.

Visual Outcomes after Endoscopic Endonasal Approach for Craniopharyngioma: The Pittsburgh Experience.

This series of patients has been published in the neurosurgical literature earlier this year, detailing multiple aspects of both the surgical technique and postoperative outcomes. Our aim in this series is not to revisit all the aspects of this publication, but rather to analyze more specifically the benefits of this procedure as it pertains to the preservation of neurological structures of vision-specifically the optic chiasm-and provide a more detailed analysis of visual outcomes in these patients.

Clinical and health promotion asthma management: an intervention for children and adolescents.

BACKGROUND: Asthma is the leading chronic condition among children. Given this international burden, clinicians and public health professionals applied the Expanded Chronic Care Model to address health adversities of pediatric patients with asthma. OBJECTIVE: This study examined the influence of a clinical health promotion initiative on asthma control and appropriate medication management among pediatric patients. METHODS: Patients (n = 304) were recruited and screened for participation in this study. All the patients participated in a motivational interview, received clinical care, and were monitored longitudinally. Eligible patients (n = 53) were referred to one or more intervention pathways regarding physical activity, nutrition, smoking cessation, and psychosocial wellness. A comparison group (n = 90) was eligible for an intervention but chose not to participate. This analysis focused on patients who were identified as needing a health intervention beyond asthma clinical care. RESULTS: Among patients who were invited to participate in the health promotion pathways, significant decreases in asthma exacerbation were achieved by the patients who participated in the intervention compared with those who did not participate (p = 0.018). Significant improvements in asthma exacerbation, activity limitations, and asthma control were attributed to the time in clinical care (p < 0.001). In this group, asthma control significantly improved with medication (p = 0.002), and age was associated with a significant decrease in asthma exacerbation (p = 0.011). CONCLUSIONS: This pilot study demonstrated preliminary benefits in a child asthma population. In addition, this experience addressed the chronicity of pediatric asthma through patient-centered care.

Decreased Lamina Cribrosa Beam Thickness and Pore Diameter Relative to Distance From the Central Retinal Vessel Trunk.

PURPOSE: To investigate how the lamina cribrosa (LC) microstructure changes with distance from the central retinal vessel trunk (CRVT), and to determine how this change differs in glaucoma. METHODS: One hundred nineteen eyes (40 healthy, 29 glaucoma suspect, and 50 glaucoma) of 105 subjects were imaged using swept-source optical coherence tomography (OCT). The CRVT was manually delineated at the level of the anterior LC surface. A line was fit to the distribution of LC microstructural parameters and distance from CRVT to measure the gradient (change in LC microstructure per distance from the CRVT) and intercept (LC microstructure near the CRVT). A linear mixed-effects model was used to determine the effect of diagnosis on the gradient and intercept of the LC microstructure with distance from the CRVT. A Kolmogorov-Smirnov test was applied to determine the difference in distribution between the diagnostic categories. RESULTS: The percent of visible LC in all scans was 26 ± 7%. Beam thickness and pore diameter decreased with distance from the CRVT. Glaucoma eyes had a larger decrease in beam thickness (-1.132 ± 0.503 µm, P = 0.028) and pore diameter (-0.913 ± 0.259 µm, P = 0.001) compared with healthy controls per 100 µm from the CRVT. Glaucoma eyes showed increased variability in both beam thickness and pore diameter relative to the distance from the CRVT compared with healthy eyes (P < 0.05). CONCLUSIONS: These findings results demonstrate the importance of considering the anatomical location of CRVT in the assessment of the LC, as there is a relationship between the distance from the CRVT and the LC microstructure, which differs between healthy and glaucoma eyes.

SCLERAL BUCKLE SURGERY FOR PRIMARY RETINAL DETACHMENT WITHOUT POSTERIOR VITREOUS DETACHMENT.

PURPOSE: To present and analyze the anatomical and functional outcomes for scleral buckling (SB) in a group of patients with rhegmatogenous retinal detachment without posterior vitreous detachment. METHODS: A total of 244 patients underwent SB from 2005 through 2014 by a single surgeon (A.W.E.). Forty patients (45 eyes) were identified as fulfilling the criteria of presenting with a rhegmatogenous retinal detachment without posterior vitreous detachment. Visual outcomes, preoperative retinal findings, and the SB technique were analyzed. The main outcome measure was the primary reattachment rate at 6 months after single surgery. RESULTS: The mean age was 29 years (range 11-51 years). The mean follow-up period was 20 months. The mean refractive error was -5.16 diopters. Subretinal fluid drainage was performed in 17 eyes (37.8%). The anatomical success rate after single SB surgery at 6 months was 91.1%. The only factor that had statistically significant correlation with primary anatomical failure was development of subretinal hemorrhage during the drainage procedure (P = 0.03). CONCLUSION: Despite an increasing trend toward primary vitrectomy for rhegmatogenous retinal detachment, an indication for SB is in younger patients without a preexisting posterior vitreous detachment. We showed a 91.1% success rate with a primary SB and 100% with a second surgery.

Virtual Averaging Making Nonframe-Averaged Optical Coherence Tomography Images Comparable to Frame-Averaged Images.

PURPOSE: Developing a novel image enhancement method so that nonframe-averaged optical coherence tomography (OCT) images become comparable to active eye-tracking frame-averaged OCT images. METHODS: Twenty-one eyes of 21 healthy volunteers were scanned with noneye-tracking nonframe-averaged OCT device and active eye-tracking frame-averaged OCT device. Virtual averaging was applied to nonframe-averaged images with voxel resampling and adding amplitude deviation with 15-time repetitions. Signal-to-noise (SNR), contrast-to-noise ratios (CNR), and the distance between the end of visible nasal retinal nerve fiber layer (RNFL) and the foveola were assessed to evaluate the image enhancement effect and retinal layer visibility. Retinal thicknesses before and after processing were also measured. RESULTS: All virtual-averaged nonframe-averaged images showed notable improvement and clear resemblance to active eye-tracking frame-averaged images. Signal-to-noise and CNR were significantly improved (SNR: 30.5 vs. 47.6 dB, CNR: 4.4 vs. 6.4 dB, original versus processed, P < 0.0001, paired t-test). The distance between the end of visible nasal RNFL and the foveola was significantly different before (681.4 vs. 446.5 µm, Cirrus versus Spectralis, P < 0.0001) but not after processing (442.9 vs. 446.5 µm, P = 0.76). Sectoral macular total retinal and circumpapillary RNFL thicknesses showed systematic differences between Cirrus and Spectralis that became not significant after processing. CONCLUSION: The virtual averaging method successfully improved nontracking nonframe-averaged OCT image quality and made the images comparable to active eye-tracking frame-averaged OCT images. TRANSLATIONAL RELEVANCE: Virtual averaging may enable detailed retinal structure studies on images acquired using a mixture of nonframe-averaged and frame-averaged OCT devices without concerning about systematic differences in both qualitative and quantitative aspects.

Glaucoma Structural and Functional Progression in American and Korean Cohorts.

PURPOSE: To compare the rate of glaucoma structural and functional progression in American and Korean cohorts. DESIGN: Retrospective longitudinal study. PARTICIPANTS: Three hundred thirteen eyes from 189 glaucoma and glaucoma suspects, followed up for an average of 38 months. METHODS: All subjects were examined semiannually with visual field (VF) testing and spectral-domain optical coherence tomography. All subjects had 5 or more reliable visits. MAIN OUTCOME MEASUREMENTS: The rates of change of retinal nerve fiber layer (RNFL) thickness, cup-to-disc (C/D) ratios, and VF mean deviation (MD) were compared between the cohorts. Variables affecting the rate of change for each parameter were determined, including ethnicity, refraction, baseline age and disease severity, disease subtype (high- vs. normal-tension glaucoma), clinical diagnosis (glaucoma vs. glaucoma suspect), and the interactions between variables. RESULTS: The Korean cohort predominantly demonstrated normal-tension glaucoma, whereas the American cohort predominantly demonstrated high-tension glaucoma. Cohorts had similar VF parameters at baseline, but the Korean eyes had significantly thicker mean RNFL and larger cups. Korean glaucoma eyes showed a faster thinning of mean RNFL (mean, -0.71 µm/year vs. -0.24 µm/year; P < 0.01). There were no detectable differences in the rate of change between the glaucoma cohorts for C/D ratios and VF MD and for all parameters in glaucoma suspect eyes. Different combinations of the tested variables significantly impacted the rate of change. CONCLUSIONS: Ethnicity, baseline disease severity, disease subtype, and clinical diagnosis should be considered when comparing glaucoma progression studies.