Regions Of Visual Field Research Articles

Diagnostic performance of pupil perimetry in detecting hemianopia under standard and virtual reality viewing conditions.

To determine the diagnostic performance and reliability of two pupil perimetry (PP) methods in homonymous hemianopia. This cross-sectional monocenter cohort study performed gaze-contingent flicker PP (gcFPP) and a virtual reality version of gcFPP (VRgcFPP) twice on separate occasions in all patients suffering from homonymous hemianopia due to neurological impairment. The main outcomes were (1) test accuracy and (2) test-retest reliability: (1) was measured through area under the receiver operating characteristics curve (AUC) calculation of (VR)gcFPP results with comparators being SAP and healthy controls, respectively; (2) was evaluated by comparing tests 1 and 2 of both methods within patients. Both gcFPP and VRgcFPP were performed in 15 patients (12 males, MAge = 57, SDAge = 15) and 17 controls (6 males, MAge = 53, SDAge = 12). Mean test accuracy was good in separating damaged from intact visual field regions (gcFPP: Mauc = 0.83, SDauc = 0.09; VRgcFPP: Mauc = 0.69,SDauc = 0.13) and in separating patients from controls (gcFPP: Mauc = 0.92,SDauc = 0.13; VRgcFPP: Mauc = 0.96,SDauc = 0.15). A high test-retest reliability was found for the proportion intact versus damaged visual field (gcFPP: r = 0.95, P < .001, VRgcFPP: r = 1.00, P < .001). Overall, these results can be summarized as follows: (1) the comparison of pupil response amplitudes between intact versus damaged regions per patient indicate that gcFPP allows for cleaner imaging of intact versus damaged visual field regions than VRgcFPP, (2) the comparisons of average differences in intact versus damaged amplitudes between patients and controls demonstrate high diagnostic performance of both gcFPP and VRgcFPP, and (3) the test-retest reliabilities confirm that both gcFPP and VRgcFPP reliably and consistently measure defects in homonymous hemianopia. KEY MESSAGES: What is known Standard automated perimetry is the current gold standard for visual field examination, but not always suited for the evaluation of the VF in neurologically impaired patients. Pupil perimetry consists of the measurement of pupillary responses to light stimuli as a measure of visual sensitivity. What is new This study reports the highest diagnostic accuracy of pupil perimetry so far in patients with homonymous hemianopia. Gaze-contingent flicker pupil perimetry reliably and consistently measures defects in homonymous hemianopia under standard and virtual reality viewing conditions.

A Phosphenotron Device for Sensoric Spatial Resolution of Phosphenes within the Visual Field Using Non-Invasive Transcranial Alternating Current Stimulation.

This study presents phosphenotron, a device for enhancing the sensory spatial resolution of phosphenes in the visual field (VF). The phosphenotron employs a non-invasive transcranial alternating current stimulation (NITACS) to modulate brain activity by applying weak electrical currents to the scalp or face. NITACS's unique application induces phosphenes, a phenomenon where light is perceived without external stimuli. Unlike previous invasive methods, NITACS offers a non-invasive approach to create these effects. The study focused on assessing the spatial resolution of NITACS-induced phosphenes, crucial for advancements in visual aid technology and neuroscience. Eight participants were subjected to NITACS using a novel electrode arrangement around the eye orbits. Results showed that NITACS could generate spatially defined phosphene patterns in the VF, varying among individuals but consistently appearing within their VF and remaining stable through multiple stimulations. The study established optimal parameters for vibrant phosphene induction without discomfort and identified electrode positions that altered phosphene locations within different VF regions. Receiver Operating characteristics analysis indicated a specificity of 70.7%, sensitivity of 73.9%, and a control trial accuracy of 98.4%. These findings suggest that NITACS is a promising, reliable method for non-invasive visual perception modulation through phosphene generation.

Correlation between Residual Sensitivity in the Central Inferior Nasal Visual Field and Visual Function in Chronic Leber Hereditary Optic Neuropathy Patients

Introduction: Leber hereditary optic neuropathy (LHON) is a maternally inherited, acute or subacute, optic neuropathy. The typical symptoms include reduced visual acuity and central scotoma. Despite the presence of deep central scotoma, some patients with LHON are able to perform daily activities. This study aimed to investigate the correlation between the residual visual field and visual acuity, critical flicker frequency, and fixation ellipse in patients with chronic LHON. Methods: Residual visual function (defined as sensitivity points where patients sensed the size V stimulus) of both eyes was evaluated in 10 patients with LHON carrying the m.11778 mitochondrial DNA mutation and with median age of onset and disease duration of 29 and 16.5 years, respectively. The central visual field was measured as static perimetry using the Humphrey visual field testing 30-2 program with the size III or V stimulus. Moreover, best-corrected visual acuity, critical flicker frequency, and the correlation between fixation ellipse and residual central visual fields were determined. The analysis was performed through a linear mixed-effects model. Results: The residual visual sensitivity in the inferior nasal visual field was significantly correlated with the logMAR (p < 0.05). The fixation ellipse fell within the residual visual field region with higher sensitivity. Conclusions: Patients with chronic LHON tended to retain the sensitivity detectable with the size V stimulus at the central inferior nasal visual field regions, where the fixation ellipse fell. Visual acuity, which influences daily activity, was spatially correlated with residual visual sensitivity.

Visual field improvement after endoscopic transsphenoidal surgery in patients with pituitary adenoma.

To analyze and predict the possibility of visual field (VF) recovery after endoscopic transsphenoidal surgery (ETSS) in patients with pituitary adenoma, we investigated the factors affecting the improvement of the visual field defect (VFD) and built a nomogram predictive model based on these risk factors. We further investigated specific recovery regions of VF associated with the improvement of VFD. The clinical data of patients who underwent ETSS for pituitary adenomas at a single center between the January 2021 and April 2022 were retrospectively analyzed. Univariate and multivariate analyses were used to determine the predictive factors affecting the improvement in the VF defect and specific recovery regions in patients with pituitary adenomas after ETSS. We enrolled 28 patients (56 eyes) who were hospitalized at our institution. Four clinical features, including compression of the optic chiasm, preoperative mean defect (MD), diffuse defect, and duration of the visual symptom, were chosen from the least absolute shrinkage and selection operator regression analysis to establish the predictive nomogram. The nomogram's area under the curve (AUC) was 0.912, indicating a good degree of differentiation. A calibration plot was used to evaluate the predictive model's calibration, and a decision curve was used to evaluate its clinical application value. The VF defects were improved in the 270-300° range (270-300: RR = 361.00, 95% CI: 21.01-6,202.41). We developed a predictive nomogram model based on significant visual field improvement-associated factors after ETSS in patients with pituitary adenoma. Postoperative visual field improvement is likely to begin at 270-300° in the inferior temporal quadrant. This improvement would enable personalized counselling for individual patients by precisely predicting the visual field recovery after surgery.

Synaptic gradients transform object location to action

To survive, animals must convert sensory information into appropriate behaviours1,2. Vision is a common sense for locating ethologically relevant stimuli and guiding motor responses3–5. How circuitry converts object location in retinal coordinates to movement direction in body coordinates remains largely unknown. Here we show through behaviour, physiology, anatomy and connectomics in Drosophila that visuomotor transformation occurs by conversion of topographic maps formed by the dendrites of feature-detecting visual projection neurons (VPNs)6,7 into synaptic weight gradients of VPN outputs onto central brain neurons. We demonstrate how this gradient motif transforms the anteroposterior location of a visual looming stimulus into the fly’s directional escape. Specifically, we discover that two neurons postsynaptic to a looming-responsive VPN type promote opposite takeoff directions. Opposite synaptic weight gradients onto these neurons from looming VPNs in different visual field regions convert localized looming threats into correctly oriented escapes. For a second looming-responsive VPN type, we demonstrate graded responses along the dorsoventral axis. We show that this synaptic gradient motif generalizes across all 20 primary VPN cell types and most often arises without VPN axon topography. Synaptic gradients may thus be a general mechanism for conveying spatial features of sensory information into directed motor outputs.

Head-tracking of freely-behaving pigeons in a motion-capture system reveals the selective use of visual field regions

Using a motion-capture system and custom head-calibration methods, we reconstructed the head-centric view of freely behaving pigeons and examined how they orient their head when presented with various types of attention-getting objects at various relative locations. Pigeons predominantly employed their retinal specializations to view a visual target, namely their foveas projecting laterally (at an azimuth of ± 75°) into the horizon, and their visually-sensitive “red areas” projecting broadly into the lower-frontal visual field. Pigeons used their foveas to view any distant object while they used their red areas to view a nearby object on the ground (< 50 cm). Pigeons “fixated” a visual target with their foveas; the intervals between head-saccades were longer when the visual target was viewed by birds’ foveas compared to when it was viewed by any other region. Furthermore, pigeons showed a weak preference to use their right eye to examine small objects distinctive in detailed features and their left eye to view threat-related or social stimuli. Despite the known difficulty in identifying where a bird is attending, we show that it is possible to estimate the visual attention of freely-behaving birds by tracking the projections of their retinal specializations in their visual field with cutting-edge methods.

Optic flow in the natural habitats of zebrafish supports spatial biases in visual self-motion estimation

Animals benefit from knowing if and how they are moving. Across the animal kingdom, sensory information in the form of optic flow over the visual field is used to estimate self-motion. However, different species exhibit strong spatial biases in how they use optic flow. Here, we show computationally that noisy natural environments favor visual systems that extract spatially biased samples of optic flow when estimating self-motion. The performance associated with these biases, however, depends on interactions between the environment and the animal's brain and behavior. Using the larval zebrafish as a model, we recorded natural optic flow associated with swimming trajectories in the animal's habitat with an omnidirectional camera mounted on a mechanical arm. An analysis of these flow fields suggests that lateral regions of the lower visual field are most informative about swimming speed. This pattern is consistent with the recent findings that zebrafish optomotor responses are preferentially driven by optic flow in the lateral lower visual field, which we extend with behavioral results from a high-resolution spherical arena. Spatial biases in optic-flow sampling are likely pervasive because they are an effective strategy for determining self-motion in noisy natural environments.

Objective perimetry and progression of multiple sclerosis.

IntroductionWe re-examined the per-region response amplitudes and delays obtained from multifocal pupillographic objective perimetry (mfPOP) after 10 years in 44 persons living with multiple sclerosis (PwMS), both to examine which parts of the visual field had progressed in terms of response properties and to examine if the baseline data could predict the overall progression of disease.MethodsExpanded Disability Status Scale (EDSS) scores were assessed in 2009 and 2019. Both eyes of each participant were concurrently tested at 44 locations/eye on both occasions. Several measures of clinical progression were examined, using logistic regression to determine the odds of progression.ResultsAt the second examination the 44 PwMS (31 females) were aged 61.0 ± 12.2 y. Mean EDSS had not changed significantly (3.69 ± 1.23 in 2009, 3.81 ± 2.00 in 2019). mfPOP delay increased progressively from inferior to superior regions of the visual fields while amplitudes demonstrated a temporal to nasal gradient. The mean of the 3 most delayed visual field regions was correlated with progression of MS by 2019 (p = 0.023). Logistic regression indicated a significant association between delay and odds of progression (p = 0.045): an individual with 3 regions at least 1 SD (40 ms) slower than the mean in 2009 had 2.05× (±SE: 1.43× to 2.95×) the odds of progression by 2019. A 1 SD shorter delay was associated with 2.05× lower odds of progression. Amplitude changes were not predictive of progression.SignificancemfPOP may provide a rapid, convenient method of monitoring and predicting MS progression.

Rapid, non-contact multifocal visual assessment in multiple sclerosis

ObjectivePrevious work on temporally sparse multifocal methods suggests that the results are correlated with disability and progression in people with multiple sclerosis (PwMS). Here, we assess the diagnostic power of three cortically mediated sparse multifocal pupillographic objective perimetry (mfPOP) methods that quantified response-delay and light-sensitivity at up to 44 regions of both visual fields concurrently.MethodsOne high-spatial-resolution mfPOP method, P129, and two rapid medium-resolution methods, W12 and W20, were tested on 44 PwMS and controls. W12 and W20 took 82 s to test both visual fields concurrently, providing response delay and sensitivity at each field location, while P129 took 7 min. Diagnostic power was assessed using areas under the receiver operating characteristic (AUROC) curves and effect-size (Hedges’ g). Linear models examined significance. Concurrent testing of both eyes permitted assessment of between-eye asymmetries.ResultsPer-region response delays and asymmetries achieved AUROCs of 86.6% ± 4.72% (mean ± SE) in relapsing–remitting MS, and 96.5% ± 2.30% in progressive MS. Performance increased with increasing disability scores, with even moderate EDSS 2 to 4.5 PwMS producing AUROCs of 82.1 to 89.8%, Hedge’s g values up to 2.06, and p = 4.0e − 13. All tests performed well regardless of any history of optic neuritis. W12 and W20 performed as well or better than P129.ConclusionOverall, the 82-s tests (W12 and W20) performed better than P129. The results suggest that mfPOP assesses a correlate of disease severity rather than a history of inflammation, and that it may be useful in the clinical management of PwMS.

Highly accurate retinotopic maps of the physiological blind spot in human visual cortex.

The physiological blind spot is a naturally occurring scotoma corresponding with the optic disc in the retina of each eye. Even during monocular viewing, observers are usually oblivious to the scotoma, in part because the visual system extrapolates information from the surrounding area. Unfortunately, studying this visual field region with neuroimaging has proven difficult, as it occupies only a small part of retinotopic cortex. Here, we used functional magnetic resonance imaging and a novel data-driven method for mapping the retinotopic organization in and around the blind spot representation in V1. Our approach allowed for highly accurate reconstructions of the extent of an observer's blind spot, and out-performed conventional model-based analyses. This method opens exciting opportunities to study the plasticity of receptive fields after visual field loss, and our data add to evidence suggesting that the neural circuitry responsible for impressions of perceptual completion across the physiological blind spot most likely involves regions of extrastriate cortex-beyond V1.

Response characteristics of objective perimetry in persons living with epilepsy

PurposeTo investigate safety and visual-field changes in people with epilepsy undergoing multifocal Pupillographic Objective Perimetry (mfPOP). Methods15 people with epilepsy and 15 controls underwent mfPOP in the context of routine clinical EEG testing. Safety measures comprised the proportion of participants developing an aura or seizure, a photoparoxysmal response, or increased epileptiform activity on their EEG during mfPOP. Pupil responses were obtained concurrently from 44 regions/field of each eye. Changes in standardised amplitude of constriction and time-to-peak were compared between people with generalised and focal epilepsy, and controls. ResultsNo participant developed an epileptic aura or clinical seizure during (or after) testing. One participant demonstrated EEG evidence of a focal subclinical seizure which began before mfPOP testing and continued unchanged during testing. Regional field sensitivities were increased in people with generalised epilepsy (+3.80 ± 1.43 dB compared to controls) but were reduced in individuals taking antiepileptic medication (−4.04 ± 1.74 dB). An extra delay of 24.9 ± 10.2 ms was seen in the time-to-peak of the responses in people with focal epilepsy. Based on receiver-operating characteristic analyses, discrimination of people with epilepsy from controls was greatest when using the 4 to 10 most abnormal visual field regions of each eye (%AUC 77.3 ± 9.70). SignificanceIn the absence of any safety signal, mfPOP appears harmless in people with epilepsy. The observed abnormalities in per-region sensitives and delays suggest that mfPOP may provide significant new insights into the study of epilepsy.

Combining OCT and OCTA for Focal Structure–Function Modeling in Early Primary Open-Angle Glaucoma

PurposeTo investigate modeling of the focal visual field (VF) loss by combining structural measurements and vascular measurements in eyes with early primary open-angle glaucoma (POAG).MethodsIn this cross-sectional study, subjects with early glaucoma (VF mean deviation, ≥−6 dB) underwent optical coherence tomography (OCT) imaging, optical coherence tomography angiography (OCTA) imaging, and Humphrey 24-2 VF tests. Capillary perfusion densities (CPDs) were calculated after the removal of large vessels in the OCTA images. Focal associations between VF losses at the individual VF test locations, circumpapillary retinal nerve fiber layer (RNFL) thickness measurements from OCT, and CPDs were determined using nerve fiber trajectory tracings. Linear mixed models were used to model focal VF losses at each VF test location.ResultsNinety-seven eyes with early POAG (VF mean deviation, −2.47 ± 1.64 dB) of 71 subjects were included. Focal VF modeling using a combined RNFL–CPD approach resulted in a median adjusted R2 value of 0.30 (interquartile range [IQR], 0.13–0.55), whereas the RNFL-only and CPD-only approaches resulted in median values of 0.22 (IQR, 0.10–0.51) and 0.26 (IQR, 0.10–0.52), respectively. Seventeen VF locations with the combined approach had an adjusted R2 value greater than 0.50. Likelihood testing at each VF test location showed that the combined approach performed significantly better at the superior nasal VF regions of the eyes compared with the univariate approaches.ConclusionsModeling of focal VF losses showed improvements when structural thickness and vascular parameters were included in tandem. Evaluation of VF defects in early glaucoma may benefit from considering both RNFL and OCTA characteristics.

Theory on The Vision-based Mechanisms of Subjective Time Within The Context of The Neural and Psychological Models of Time Perception

Temporal processing is crucial for interval, duration and motion discrimination, as well as the ability to order events. Humans process temporal information over a large scale ranging from microseconds to daily circadian rhythms. The basic questions in the time perception literature include whether timing is centralized or distributed in the brain and whether different time scales or modalities (such as sensory or motor) are processed by different neural mechanisms. In this review, focus will be on visual timing in the millisecond range and the underlying temporal mechanisms.The classical model of a supramodal centralised clock, in which scaling between real and apparent time is accomplished by a change in the arousal level, has been challenged by our evidence, following Johnston et al. (2006), that the apparent duration can be manipulated in a local region of visual field by adaptation to motion or flicker and that the effects of temporal frequency adaptation on perceived duration and perceived temporal frequency are dissociable. The relationship between time, motion and space supports the idea that time is an attribute of a visual stimulus like any other low level features such as color or motion, which we suggest may imply a time pathway in the brain. Keywords: Visual perception, time perception, visual brain

Characteristics of Central Visual Field Progression in Eyes with Optic Disc Hemorrhage

To investigate the characteristics and rate of central visual field loss after optic disc hemorrhage (DH). Prospective cohort study. Three hundred forty-three eyes of 220 subjects who had ≥3 years of follow-up with a minimum of 5 visits with 10-2 and 24-2 visual field (VF) were recruited. Rates of 10-2 mean deviation (MD) loss in each hemifield and predefined zones were compared using linear mixed-effects models in DH and non-DH eyes. Clustered pointwise regression analysis was also used to define central VF progressors and compared with 24-2 VF loss using guided progression analysis. Thirty-nine eyes with DH and 304 eyes without DH had a mean follow-up of 5.2 years. Eyes with DH had rates of 10-2 MD loss that were 3 times faster than non-DH eyes (mean difference -0.36 dB/year [95% confidence interval 0.54-0.18]; P < .001) and were 3.7 times more likely to progress (P=.002). A larger proportion of glaucomatous eyes showed central VF progression rather than peripheral VF progression in the DH group (30.8% vs. 20.5%) compared with the non-DH group (10.9% vs. 9.2%). In early glaucoma, the rate of 10-2 MD loss was 5.5 times faster in DH eyes than in non-DH eyes (P < .001). Superonasal and superotemporal central VF regions progressed more rapidly than other regions, especially in DH eyes. Central VF loss is accelerated in glaucoma eyes with DH and it corresponds topographically to the DH location. In patients with glaucoma with DH, one should consider supplementing 10-2 VFs with 24-2 VFS to monitor the disease.

Baseline Choroidal Microvasculature Dropout as a Predictor of Subsequent Visual Field Progression in Open-angle Glaucoma.

Choroidal microvasculature dropout (CMvD) is an independent predictor for overall and central visual field (VF) progression in open-angle glaucoma (OAG) eyes. The purpose of this study was to investigate the impact of CMvD identified by optical coherence tomography angiography (OCT-A) at baseline on subsequent VF progression in eyes with OAG. This retrospective observational study included 80 OAG eyes with CMvD [CMvD(+)] and without CMvD [(CMvD(-)] at baseline [40 of each matched for both age (10 y and below) and baseline VF severity (≤1 dB)]. The patients were followed regularly at 6-month intervals. VF progression was defined according to the Early Manifest Glaucoma Trial criteria. Associations of overall VF progression with baseline clinical factors, including the presence of CMvD and other variables, were analyzed by logistic regression with a generalized estimating equation in the entire OAG cohort. Linear mixed models were used to determine the differences in visual field mean sensitivity (VFMS) between the CMvD(+) and CMvD(-) groups globally and regionally at each follow-up point. During a mean follow-up of 35.91±2.51 months, a significant difference was evident in the VF progression rate between the CMvD(-) and CMvD(+) groups (22.5% vs. 70%, P<0.001). CMvD at baseline and a higher visit-to-visit intraocular pressure fluctuation were significant predictors of VF progression. The VFMS differed significantly between the 2 groups at the central and superior central VF regions after 2 years of follow-up. The presence of CMvD at baseline is an independent predictor of subsequent VF progression. CMvD(+) eyes show a faster rate of VFMS loss at the central and superior central VF regions.

Population Receptive Field Shapes in Early Visual Cortex Are Nearly Circular.

The visual field region where a stimulus evokes a neural response is called the receptive field (RF). Analytical tools combined with functional MRI (fMRI) can estimate the RF of the population of neurons within a voxel. Circular population RF (pRF) methods accurately specify the central position of the pRF and provide some information about the spatial extent (diameter) of the RF. A number of investigators developed methods to further estimate the shape of the pRF, for example, whether the shape is more circular or elliptical. There is a report that there are many pRFs with highly elliptical pRFs in early visual cortex (V1-V3; Silson et al., 2018). Large aspect ratios (>2) are difficult to reconcile with the spatial scale of orientation columns or visual field map properties in early visual cortex. We started to replicate the experiments and found that the software used in the publication does not accurately estimate RF shape: it produces elliptical fits to circular ground-truth data. We analyzed an independent data set with a different software package that was validated over a specific range of measurement conditions, to show that in early visual cortex the aspect ratios are <2. Furthermore, current empirical and theoretical methods do not have enough precision to discriminate ellipses with aspect ratios of 1.5 from circles. Through simulation we identify methods for improving sensitivity that may estimate ellipses with smaller aspect ratios. The results we present are quantitatively consistent with prior assessments using other methodologies.SIGNIFICANCE STATEMENT We evaluated whether the shape of many population receptive fields (RFs) in early visual cortex is elliptical and differs substantially from circular. We evaluated two tools for estimating elliptical models of the pRF; one tool was valid over the measured compliance range. Using the validated tool, we found no evidence that confidently rejects circular fits to the pRF in visual field maps V1, V2, and V3. The new measurements and analyses are consistent with prior theoretical and experimental assessments in the literature.

Assessing Functional Disability in Glaucoma: The Relative Importance of Central Versus Far Peripheral Visual Fields.

PurposeTo evaluate the importance of central versus far peripheral visual field (VF) loss in assessing disability in glaucoma.MethodsIn total, 231 patients with glaucoma or suspected glaucoma completed 24-2 VF testing and automated peripheral VFs using the suprathreshold 30- to 60-degree pattern. Questionnaires assessed fear of falling (FoF), quality of life (QOL), instrumental activities of daily living (IADLs), and driving habits; nonsedentary time, reading speed, and gait were objectively measured. Multivariable regression models analyzed the effect of central VF and/or peripheral VF damage on each outcome.ResultsIn models including both central and peripheral VF damage (independent effects), greater central, but not peripheral, VF damage was associated with greater FoF, worse QOL, fewer daily steps, and difficulty with IADLs (P < 0.02 for central; P > 0.5 for peripheral). For gait measures, greater peripheral, but not central, damage was associated with shorter steps and shorter strides, as well as greater variability in step length (P < 0.03 for peripheral; P > 0.14 for central). Model R2 values were not substantially higher (less than 5% additional explained variability) for models including both central and peripheral VF damage as compared to the best models incorporating only one region of VF damage (i.e., central or peripheral).ConclusionsThe relative importance of central 24 degrees versus more peripheral VF damage differs across functional domains in patients with glaucoma. Central damage is more strongly associated with most disability outcomes, although peripheral damage is more associated with specific gait measures. Studies examining the relative importance of various VF regions should assess functional domain separately and eschew integrated measures of quality of life/activity limitation.

The Relationship Between Intraocular Pressure and Rates of Central Versus Peripheral Visual Field Progression.

In this longitudinal prospective cohort study of open-angle glaucoma patients, intraocular pressure (IOP) parameters (mean, fluctuation, and maximum) had a similar effect on glaucomatous progression in the central and peripheral visual field (VF) regions. To study the effects of IOP on rates of glaucomatous central versus peripheral VF progression. The African Descent and Glaucoma Evaluation Study (ADAGES) is a longitudinal prospective cohort study that recruited patients from 3 centers. A sample of those with established glaucoma were included in this study. The mean peripheral sensitivity (MPS) and the mean central sensitivity (MCS) were defined based upon the average total deviation of the peripheral and central (10 degrees) points of the 24-2 VF, respectively. Progression was based upon central and peripheral change from linear mixed-effects models. The relationships between VF progression and IOP mean, maximum, and fluctuation as continuous variables were also investigated. Main outcome measures were MPS and MCS progression rates. A total of 452 eyes of 344 patients were studied. The mean number of VFs (SD) for each eye was 13.3 (6.4) over 9.1 (3.7) years. The mean baseline MD was -5.1 (3.9) dB and the mean rate of MD change was -0.26 dB/y [95% confidence interval (CI): -0.33 to -0.20, P<0.001]. Mean rates of MPS (-0.27 dB/y, 95% CI: -0.33 to -0.22, P<0.001) and MCS change (-0.26 dB/y, 95% CI: -0.31 to -0.21, P<0.001) were similar (P=0.351). Mean, fluctuation, and maximum IOP were significantly associated with MPS and MCS (all P<0.025). The effect of IOP parameters on VF progression was statistically similar between central and peripheral VF regions.

Binocular Encoding in the Damselfly Pre-motor Target Tracking System.

Akin to all damselflies, Calopteryx (family Calopterygidae), commonly known as jewel wings or demoiselles, possess dichoptic (separated) eyes with overlapping visual fields of view. In contrast, many dragonfly species possess holoptic (dorsally fused) eyes with limited binocular overlap. We have here compared the neuronal correlates of target tracking between damselfly and dragonfly sister lineages and linked these changes in visual overlap to pre-motor neural adaptations. Although dragonflies attack prey dorsally, we show that demoiselles attack prey frontally. We identify demoiselle target-selective descending neurons (TSDNs) with matching frontal visual receptive fields, anatomically and functionally homologous to the dorsally positioned dragonfly TSDNs. By manipulating visual input using eyepatches and prisms, we show that moving target information at the pre-motor level depends on binocular summation in demoiselles. Consequently, demoiselles encode directional information in a binocularly fused frame of reference such that information of a target moving toward the midline in the left eye is fused with information of the target moving away from the midline in the right eye. This contrasts with dragonfly TSDNs, where receptive fields possess a sharp midline boundary, confining responses to a single visual hemifield in a sagittal frame of reference (i.e., relative to the midline). Our results indicate that, although TSDNs are conserved across Odonata, their neural inputs, and thus the upstream organization of the target tracking system, differ significantly and match divergence in eye design and predatory strategies. VIDEO ABSTRACT.

Structure-function relationship in a series of glaucoma cases

To map retinal sensitivity and peripapillary retinal nerve fiber layer (RNFL) thickness, as measured by standard automated perimetry (SAP) and optical coherence tomography (OCT) respectively, in patients with various stages of primary open-angle glaucoma (POAG). Ninety patients with POAG were prospectively selected for SAP and for OCT RNFL thickness measurements. Factorial analysis performed independently for each hemifield was used to identify groups of related SAP visual field points. Pearson correlation coefficients were determined between visual field regions and peripapillary RNFL sectors and these data used to construct structure-function correlation maps for the various disease stages. Factorial analysis identified 4 factors or visual field regions for the inferior hemifield and 5 for the superior hemifield. For all patients and the subset of patients with advanced POAG, the strongest correlation was detected between the superior hemifield and the inferior RNFL sectors, while higher correlations for incipient and moderate disease stages were observed between the inferior hemifield and the superior RNFL sectors. In these patients, functional and structural damage can be mapped such that each zone of related SAP points correlates with one or several peripapillary RNFL zones. Such maps could improve our understanding of structure-function relationships in glaucoma.