Visual Field Differences Research Articles

Right hemisphere superiority for executive control of attention

Over forty years have passed since the first evidence showing the unbalanced attentional allocation of humans across the two visual fields, and since then, a wealth of behavioral, neurophysiological, and clinical data increasingly showed a right hemisphere dominance for orienting of attention. However, inconsistent evidence exists regarding the right-hemisphere dominance for executive control of attention, possibly due to a lack of consideration of its dynamics with the alerting and orienting functions. In this study, we used a version of the Attentional Network Test with lateralized presentation of the stimuli to the left visual field (processed by the right hemisphere, RH) and right visual field (processed by the left hemisphere, LH) to examine visual field differences in executive control of attention under alerting and orienting of attention. Analyses of behavioral performance (reaction time and error rate) showed a more efficient executive control (reduced conflict effect) in the RH compared to the LH for the reaction time, under conditions of increased alerting and of informative spatial orienting. These results demonstrate the right-hemisphere superiority for executive control, and that this effect depends on the involvement of the alerting and orienting functions.

Side Biases in Euro Banknotes Recognition: The Horizontal Mapping of Monetary Value.

Money is a special stimulus for humans, because of its relevance in everyday life. However, the basic mechanisms underlying money representation have not yet been fully investigated. Left-right asymmetries in the visual perception and evaluation of monetary value offer such a possibility. The pattern of these asymmetries can contribute to disentangle between numerical and emotional processes possibly involved in banknotes perception. In the present experiment, we tested the recognition of 5€and 100€ banknotes presented in the left and right visual fields. Results show that the 100€ banknote is recognized faster than the 5€ banknote in the Right Visual Field (RVF), while there is no difference in the Left Visual Field (LVF). Our interpretation is that this effect is due to the matching between the positive valence conveyed by the 100€ banknote and the side in which it is mapped (right-positive). We consider this result as evidence of a valence-based recognition of banknotes.

Diffusion Tensor Imaging Detects Microstructural Differences of Visual Pathway in Patients With Primary Open-Angle Glaucoma and Ocular Hypertension.

Ocular hypertension (OHT), the common situation in adult patients in the outpatients, occurs ∼5% worldwide. However, there are still some practical problems in differentiation of OHT with early primary open-angle glaucoma (POAG) using current standard methods. Application of high resolution diffusion tensor imaging (DTI) enables us to the differentiate axonal architecture of visual pathway between POAG and OHT subjects. Among 32 POAG patients recruited (15 OHT and 14 control subjects), 62.5% of glaucoma were in early stage for the current study. All subjects underwent ophthalmological assessments with standard automated perimetry and optical coherence tomography (OCT). DTI was applied to measure fraction anisotropy (FA) and mean diffusivity (MD) of optic tract (OT), lateral geniculate body (LGN) and optic radiation (OR) using voxel-based analysis. Our data demonstrated that FA values of bilateral OR in POAG were significantly lower in the right or left than that of OHT patients (left OR: 0.51 ± 0.04 vs. 0.54 ± 0.03, p < 0.05; right OR: 0.51 ± 0.05 vs. 0.54 ± 0.03, p < 0.05). In right LGN, MD values were higher in POAG patients compared with OHT subjects (9.81 ± 1.45 vs. 8.23 ± 0.62, p < 0.05). However, no significant difference of all of the DTI parameters was observed between OHT and control subjects. DTI parameters in POAG patients were positively correlated with morphological and functional measurements (p < 0.05). Vertical cup to disc ratio (VCDR) was correlated with ipsilateral FA of OT (p < 0.05), ipsilateral MD of OT (p < 0.05), ipsilateral MD of LGN (p < 0.05), and contralateral MD of OT (p < 0.05). Mean deviation of visual field (MDVF) was correlated with ipsilateral FA of OT (p < 0.05), ipsilateral MD of OT (p < 0.05), and ipsilateral FA of LGN (p < 0.05). Our study demonstrated that DTI can differentiate POAG from OHT subjects in optic pathway, particularly in early POAG, and DTI parameters can quantify the progression of POAG.

Genetic Architecture of Primary Open-Angle Glaucoma in Individuals of African Descent: The African Descent and Glaucoma Evaluation Study III

To find genetic contributions to glaucoma in African Americans. Cross-sectional, case-control study. One thousand eight hundred seventy-five primary open-angle glaucoma (POAG) patients and 1709 controls, self-identified as being of African descent (AD), from the African Descent and Glaucoma Evaluation Study (ADAGES) III and Wake Forest School of Medicine. MegaChip genotypes were imputed to Thousand Genomes data. Association of single nucleotide polymorphisms (SNPs) with POAG and advanced POAG was tested by linear mixed model correcting for relatedness and population stratification. Genetic risk scores were tested by receiver operator characteristic curves (ROC-AUCs). Primary open-angle glaucoma defined by visual field loss without other nonocular conditions (n= 1875). Advanced POAG was defined by age-based mean deviation of visual field (n= 946). Eighteen million two hundred eighty-one thousand nine hundred twenty SNPs met imputation quality of r2 > 0.7 and minor allele frequency > 0.005. Association of a novel locus, EN04, was observed for advanced POAG (rs185815146 β, 0.36; standard error, 0.065; P < 3×10-8). For POAG, an AD signal was observed at the 9p21 European descent (ED) POAG signal (rs79721419; P < 6.5×10-5) independent of the previously observed 9p21 ED signal (rs2383204; P < 2.3×10-5) by conditional analyses. An association with POAG in FNDC3B (rs111698934; P < 3.9×10-5) was observed, not in linkage disequilibrium (LD) with the previously reported ED SNP. Additional previously identified loci associated with POAG in persons of AD were: 8q22, AFAP1, and TMC01. An AUC of 0.62 was observed with an unweighted genetic risk score comprising 11 SNPs in candidate genes. Two additional risk scores were studied by using a penalized matrix decomposition with cross-validation; risk scores of 50 and 400 SNPs were identified with ROC of AUC = 0.74 and AUC = 0.94, respectively. A novel association with advanced POAG in the EN04 locus was identified putatively in persons of AD. In addition to this finding, this genome-wide association study in POAG patients of AD contributes to POAG genetics by identification of novel signals in prior loci (9p21), as well as advancing the fine mapping of regions because of shorter average LD (FNDC3B). Although not useful without confirmation and clinical trials, the use of genetic risk scores demonstrated that considerable AD-specific genetic information remains in these data.

Association of Angle Width With Progression of Normal-Tension Glaucoma

Glaucoma has been dichotomically classified as open or closed angle, and accordingly, distinct therapies have been administered. In this study, the issue of narrow-angle normal-tension glaucoma (NTG), which may be an intermediate-stage or hybrid-stage disease entity, was addressed. To determine whether anterior chamber (AC) angle width plays any role in NTG progression. Retrospective analysis of prospectively collected data at Seoul National University Hospital between January 2004 and December 2009. Fifty-two eyes of narrow-angle NTG and 52 wide-angle NTG eyes matched for age, untreated intraocular pressure, and mean deviation of visual field. Nonindentation gonioscopy was used to grade AC angles: narrow angle was defined as a partially invisible (invisible in ≥90° and <180°) pigmented posterior trabecular meshwork, and wide angle was defined as a fully visible pigmented posterior trabecular meshwork. Data were analyzed in September 2017. Optic disc/retinal nerve fiber layer defect and visual field progression. Of the narrow-angle NTG cohort, the mean (SD) age was 49.5 (9.1) years and 15 individuals (28.8%) were women; of the wide-angle NTG cohort, the mean (SD) age was 48.7 (9.5) years and 19 (36.5%) were women. All participants were Korean. Over the course of the mean (SD) 7.6 (0.4)-year follow-up period, 25 of 52 narrow-angle eyes (48.1%) and 13 of 52 wide-angle eyes (25.0%) showed structural progression (odds ratio [OR], 2.78; 95% CI, 1.21-6.37; P = .02). Meanwhile, 21 of 52 narrow-angle eyes (40.3%) and 9 of 52 wide-angle eyes (17.3%) showed functional progression (OR, 3.24; 95% CI, 1.31-8.00; P = .009). The cumulative probability of both structural and functional progression was significantly greater in the narrow-angle than in the wide-angle group (mean [SD] 5-year survival rates, 0.56 [0.07] vs 0.83 [0.05]; P = .006 and 0.60 [0.07] vs 0.87 [0.05]; P = .007, respectively). The baseline diurnal intraocular pressure's SD was approximately 1.38-times greater in the narrow-angle than in the wide-angle group (1.8 [0.6] vs 1.3 [0.3] mm Hg; mean difference, 0.52; 95% CI, 0.32-0.72; P < .001). For the follow-up intraocular pressure fluctuation, the narrow-angle group showed an approximately 1.75-times greater SD (2.1 [0.5] vs 1.2 [0.3] mm Hg; mean difference, 0.93; 95% CI, 0.77-1.09; P < .001). Narrow-angle NTG showed a greater probability of disease progression than did wide-angle NTG. Further studies determining whether augmented or differentiated treatment strategies would be beneficial for patients with narrow-angle NTG are warranted.

Analysis of peripapillary retinal nerve fiber layer and inner macular layers by spectral-domain optical coherence tomography for detection of early glaucoma

To analyze the diagnostic capabilities of peripapillary retinal nerve fiber layer (pRNFL) thickness and segmented inner macular layer (IML) thickness measured by spectral-domain optical coherence tomography for detection of early glaucoma. Fifty-three patients with primary open angle glaucoma (POAG), 60 patients with normal tension glaucoma (NTG) and 32 normal control subjects were enrolled. Thicknesses of pRNFL, total macular layers (TML), and the IML, including macular RNFL (mRNFL) and macular ganglion cell layer (mGCL) were assessed. The areas under the receiver operating characteristic curves (AROC) were calculated to compare the diagnostic power of different parameters. There were no differences in the parameters of pRNFL, TML, and IML between POAG and NTG groups. The thicknesses of superior and inferior mGCL showed significant correlation with mean deviation of visual field (R2=0.071, P=0.004; R2=0.08, P=0.002). The mGCL thickness significantly correlated with the pRNFL thickness in the superior and inferior quadrants (R2=0.156, P<0.001; R2=0.407, P<0.001). The thickness of the inferior-outer sector of macula had greater AROCs than those in the inferior-inner sector of macula. The AROCs for superior (0.894) and inferior (0.879) pRNFL thicknesses were similar with the AROCs for superior (0.839) and inferior mGCL (0.864) thicknesses. Sensitivities at 80% specificity for global pRNFL, inferior-outer mGCL and inferior-outer mRNFL thicknesses were 0.938, 0.867, and 0.725, respectively. The diagnostic capability of the mGCL thickness is comparable to that of the pRNFL thickness in patients with early glaucoma. The inferior-outer sector of IML has a better diagnostic capability than the inferior-inner sector of IML for detection of early glaucoma.

Long-term visuospatial performance abnormalities among elite athletes reporting history of concussion

Elevated risk for musculoskeletal injury after concussion may relate to impaired responsiveness to changing environmental conditions, which might be identified by appropriately designed clinical screening tests. A retrospective cohort study involved 48 elite athletes at an Olympic training center (34 males: 23.8 ± 4.4 years; 14 females: 25.4 ± 4.5 years). A 60-second test of dual-task visuomotor reaction time (VMRT) involved rapid manual contact with illuminated target buttons while simultaneously providing verbal responses to identify the right or left direction indicated by the center arrow of 20 successive trials of the Eriksen flanker test. A whole-body reactive agility (WBRA) test measured side-shuffling movements in response to 20 virtual reality targets that randomly appeared in right or left positions on a large computer monitor. A meaningful association was defined as having a 90% confidence interval lower limit > 1.0. Concussion occurrence prior to testing (2.0 ± 2.3 years) was reported by 44% of the athletes (21/48). Strong univariable associations with concussion history were found for dual-task VMRT asymmetry (left minus right visual field difference ≥ 15 ms; OR = 7.14) and time required to complete the WBRA test (≥ 73 seconds; OR = 6.40). A VMRT asymmetry X WBRA time interaction effect demonstrated 81% sensitivity and 75% specificity (OR = 13.00). A substantial bivariate correlation was also evident between the two continuous variables ( r = .454; P = .001). The occurrence of a lower extremity sprain or strain within the previous 12 months was reported by 67% of the athletes (32/48), which demonstrated an association with concussion history (53% sensitivity, 75% specificity; OR = 3.40). A cause-effect relationship cannot be inferred from retrospective analysis, but the results of both clinical tests suggest that impaired visuospatial performance capabilities may explain the previously reported elevation of musculoskeletal injury risk following concussion.

Repetitive transcranial magnetic stimulation over right intraparietal sulcus enhances emotional face processing in the left visual field.

The frontoparietal network is largely involved in the process of emotional face perception and attention. However, how the right intraparietal sulcus (rIPS) may guide this process is not yet established. The effect of repetitive transcranial magnetic stimulation (rTMS) over the intraparietal sulcus in the perception of emotional faces is still unclear. To address that, we applied a modified Posner attention task where participants discriminated backward-masked emotional faces at the valid side and delivered 10-Hz rTMS over rIPS and vertex. Behavioral results demonstrated a processing advantage for emotional faces compared with neutral ones. rTMS over the rIPS caused a significant emotional difference (emotional-neutral faces) in the left visual field. This result suggests that rTMS over the rIPS enhances emotional face processing in the left visual field compared with neutral faces. The stimulation of rIPS possibly enhanced the functional connectivity between intraparietal sulcus and superior temporal sulcus, and visual cortex. It helps the emotional faces grab attentional resources and reach the conscious awareness.

Association Between the Deep-layer Microvasculature Dropout and the Visual Field Damage in Glaucoma

To compare the visual field (VF) sensitivity according to the presence of parapapillary deep-layer microvasculature dropout (MvD_P) and focal lamina cribrosa (LC) defect. Among 158 open-angle glaucoma patients, 4 groups were formed according to the presence of MvD_P and focal LC defect determined by optical coherence tomography (OCT) angiography and by enhanced depth imaging spectral-domain OCT, respectively: (1) eyes without either focal LC defect or MvD_P (group 1); (2) eyes with focal LC defect but no MvD_P (group 2); (3) eyes without focal LC defect but with MvD_P (group 3); (4) eyes with both focal LC defect and MvD_P (group 4). VF sensitivity and retinal nerve fiber layer (RNFL) thickness were compared among the 4 groups for global area and 6 sectors. Both RNFL thickness and VF sensitivity differed among the 4 groups in all areas other than the nasal and superonasal sectors for RNFL thickness. On post hoc analysis, eyes with MvD_P (groups 3 and 4) had significantly worse VF sensitivity than group 2 [P<0.05, 1-way analysis of variance (ANOVA)] in all areas except the superotemporal and temporal sectors, whereas the RNFL thicknesses did not differ (P>0.05, 1-way ANOVA) in any areas except the superotemporal sector. Eyes with MvD_P had worse VF sensitivity than those without MvD_P, and VF difference was more distinguished than differences of axonal loss and focal LC change. Further studies on the temporal relationship between the MvD_P and glaucomatous VF progression are warranted.

White Matter Abnormalities and Correlation With Severity in Normal Tension Glaucoma: A Whole Brain Atlas-Based Diffusion Tensor Study.

To detect injury of whole brain white matter (WM) in normal tension glaucoma (NTG) patients by using diffusion tensor imaging (DTI) and to analyze the correlations between DTI parameters and glaucoma indices. Twenty mild, 17 moderate, and 18 severe NTG patients as well as 25 normal subjects were enrolled in this study. Atlas-based diffusion tensor analysis was performed to measure the fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). One-way analyses of variance were used for comparisons of DTI parameters between NTG subgroups and normal control (NC) group. The relationships between DTI parameters and glaucoma indices were also assessed by Pearson's correlation and "broken-stick" analyses. As compared with NC subjects, significantly decreased FA and AD and increased MD and RD were observed in the bilateral posterior thalamic radiation, bilateral sagittal stratum, bilateral cingulum-hippocampus, and bilateral fornix/stria terminalis in NTG patients. The DTI parameters of these WM regions correlated with the mean deviation of visual field (MDVF) and retinal nerve fiber layer (RNFL) thickness. Additionally, there was a tipping point between MDVF and DTI parameters as well as between MDVF and RNFL thickness. Atlas-based DTI analysis was capable of indicating WM damage in the four regions associated with visual and visual-related functions in NTG patients, and it could also be used for investigating disease progression and pathologic changes. In addition, WM impairment and RNFL thinning occurred before patients showed detectable visual field loss.

Short-term Intraocular Pressure Spikes Induced by Pneumoperitoneum are Safe for the Optic Nerve in a Healthy Eye

The aim of this study was to determine the effects of the pneumoperitoneum used in colorectal procedures on peripapillary retinal nerve fibre layer (RNFL) thickness. We also analysed the dynamics of ocular anterior segment structures. In this prospective clinical pilot study, 29 patients aged between 45 and 85 years old underwent laparoscopic surgery for selected colorectal diseases. The pneumoperitoneum induced a mean intraocular pressure (IOP) increase of 4 mmHg. Visual acuity, IOP, corneal thickness, angle opening distance (AOD) and the trabeculo-iris space area (TISA) at 500 microns and 750 microns anterior to the scleral spur, RNFL thickness and visual field were measured before and after surgery using Sloan charts, Visante™ optical coherence tomography (OCT) (Zeiss, Oberkochen, Germany), Spectralis® OCT (Heidelberg Engineering, Heidelberg, Germany) and Humphrey Visual Field System® (Zeiss, Oberkochen, Germany). Patients were categorised in two groups to understand the behaviour of IOP: in group one (n=17), patients were in Trendelenburg position; in group two (n=12), patients were in reverse Trendelenburg position. The IOP was measured during surgery by the Icare® Tonometer (Icare, Vantaa, Finland) according to a standardised protocol; the IOP was measured before and after surgery by Goldmann applanation tonometer (Haag-Streit, Koniz, Switzerland). Patients with previous diagnosis of both open or angle-closure glaucoma or anterior segment anomalies were excluded. No statistically significant differences in increase of IOP were found between the two groups (p&gt;0.05); no statistically significant differences in RNFL thickness, visual field, AOD and TISA were found before and after surgery in all patients (p&gt;0.05). In our study we have demonstrated that a mean IOP increase of 4 mmHg over a short period of time is safe for a healthy optic nerve.

What Drives Bird Vision? Bill Control and Predator Detection Overshadow Flight.

Although flight is regarded as a key behavior of birds this review argues that the perceptual demands for its control are met within constraints set by the perceptual demands of two other key tasks: the control of bill (or feet) position, and the detection of food items/predators. Control of bill position, or of the feet when used in foraging, and timing of their arrival at a target, are based upon information derived from the optic flow-field in the binocular region that encompasses the bill. Flow-fields use information extracted from close to the bird using vision of relatively low spatial resolution. The detection of food items and predators is based upon information detected at a greater distance and depends upon regions in the retina with relatively high spatial resolution. The tasks of detecting predators and of placing the bill (or feet) accurately, make contradictory demands upon vision and these have resulted in trade-offs in the form of visual fields and in the topography of retinal regions in which spatial resolution is enhanced, indicated by foveas, areas, and high ganglion cell densities. The informational function of binocular vision in birds does not lie in binocularity per se (i.e., two eyes receiving slightly different information simultaneously about the same objects) but in the contralateral projection of the visual field of each eye. This ensures that each eye receives information from a symmetrically expanding optic flow-field centered close to the direction of the bill, and from this the crucial information of direction of travel and time-to-contact can be extracted, almost instantaneously. Interspecific comparisons of visual fields between closely related species have shown that small differences in foraging techniques can give rise to different perceptual challenges and these have resulted in differences in visual fields even within the same genus. This suggests that vision is subject to continuing and relatively rapid natural selection based upon individual differences in the structure of the optical system, retinal topography, and eye position in the skull. From a sensory ecology perspective a bird is best characterized as “a bill guided by an eye” and that control of flight is achieved within constraints on visual capacity dictated primarily by the demands of foraging and bill control.

Neuro‐retinal changes evaluation in multiple sclerosis patients: 10 years follow‐up

PurposeTo analyze functional and structural changes in the retina and optic nerve (ON) in patients with multiple sclerosis (MS) compared to healthy controls (C) and after 10 years of follow‐up.MethodsFifty eyes of patients with mild‐moderate MS were evaluated and compared to 50 eyes of C at a baseline visit and at 10 years of follow‐up. The following functional parameters were evaluated: best‐corrected visual acuity (BCVA), color vision examined with the Ishihara test, and mean deviation of visual field (VF) analyzed using the Humphrey perimetry. The structural parameters of the ON were also studied using the NSITE axonal application of the optical coherence tomograph (OCT) Heidelberg Spectralis.ResultsNo differences were found in the functional parameters in MS patients compared to C, neither at 10 years of follow‐up (p &gt; 0.05). However a statistically significant decrease was observed in the structural parameters between C and MS patients at 10 years of follow‐up: mean, nasal‐inferior (NI), temporal‐inferior (TI), temporal (T), temporal‐superior (TS), papillomacular bundle and nasal/temporal (N/T) ratio thickness (p &lt; 0.001), but also in the axonal thickness, specifically in the mean, TI, T, TS, papillomacular bundle and N/T ratio thickness (p &lt; 0.001) measured with OCT in patients with MS after 10 years of disease progression. A higher functional disability using the Expanded Disability Status Scale was also recorded.ConclusionsAxonal damage can be analyzed and quantified in the retina and ON using the OCT in MS. Patients with MS showed significant decrease in the retina nerve fiber layer at 10 years of follow–up compared to C and a progressive axonal death (without outbreaks) that could be detected and quantified using the OCT, but not with the functional tests (BCVA, color and VF).

Quantitative assessment of optic nerve in patients with Leber’s hereditary optic neuropathy using reduced field-of-view diffusion tensor imaging

PurposeTo quantitatively analyze the optic nerve alterations in chronic Leber’s hereditary optic neuropathy (LHON) using reduced field-of-view diffusion tensor imaging (rFOV-DTI) and evaluate the correlation of diffusion parameters with visual functional and peripapillary retinal nerve fiber layer (RNFL) thickness. MethodsTwenty-five patients (50 affected optic nerves) with chronic LHON and 28 healthy controls (56 normal optic nerves) were enrolled. The rFOV-DTI was performed in the bilateral optic nerves for all the subjects. The fractional anisotropy (FA), mean diffusivity (MD), principal eigenvalue (λ//), and orthogonal eigenvalue (λ⊥) were calculated for quantitative analysis. Visual field (VF) and visual acuity (VA) were measured in all subjects. The peripapillary RNFL thickness was assessed using optical coherence tomography (OCT). The correlation of DTI diffusion parameters with visual function and peripapillary RNFL thickness was evaluated. ResultsCompared with optic nerves in the control group, the mean FA was significant decreased (P<0.005), and the mean MD, λ//and λ⊥ significant increased (P<0.005). The average and temporal peripapillary RNFL thickness were significantly thinned in LHON patients. There was a significant correlation between optic nerve FA and VA, mean deviation of visual field (MDVF) (P<0.005). Also, optic nerve FA correlated significantly with average RNFL thickness (P<0.05) but not with MD, λ//and λ⊥ (P>0.05). However, none of the DTI parameters correlated with age and disease duration (P>0.05). ConclusionsOur study has demonstrated that rFOV-DTI could provide information of optic nerve damage in chronic LHON, and can serve as technique for detecting and evaluating pathological changes in the optic nerve in LHON.

Sneaking a peek: pigeons use peripheral vision (not mirrors) to find hidden food.

A small number of species are capable of recognizing themselves in the mirror when tested with the mark-and-mirror test. This ability is often seen as evidence of self-recognition and possibly even self-awareness. Strangely, a number of species, for example monkeys, pigs and dogs, are unable to pass the mark test but can locate rewarding objects by using the reflective properties of a mirror. Thus, these species seem to understand how a visual reflection functions but cannot apply it to their own image. We tested this discrepancy in pigeons-a species that does not spontaneously pass the mark test. Indeed, we discovered that pigeons can successfully find a hidden food reward using only the reflection, suggesting that pigeons can also use and potentially understand the reflective properties of mirrors, even in the absence of self-recognition. However, tested under monocular conditions, the pigeons approached and attempted to walk through the mirror rather than approach the physical food, displaying similar behavior to patients with mirror agnosia. These findings clearly show that pigeons do not use the reflection of mirrors to locate reward, but actually see the food peripherally with their near-panoramic vision. A re-evaluation of our current understanding of mirror-mediated behavior might be necessary-especially taking more fully into account species differences in visual field. This study suggests that use of reflections in a mirrored surface as a tool may be less widespread than currently thought.

Optical coherence tomography angiography of the peripapillary retina and optic nerve head in dominant optic atrophy

Peripapillar and nerve head vessel density (VD) was measured in 10 patients affected by Dominant optic atrophy (DOA) using optical coherence tomography angiography (OCT-A) and compared to the measurements of 15 age- and gender-matched controls.DOA patients showed VD reduction, mostly in the temporal and inferotemporal peripapillary sectors, according to the preferential involvement of the papillomacular bundle. Despite poor best-corrected visual acuity (BCVA), OCT-A revealed good repeatability. VD correlated with functional (mean deviation of visual field and BCVA) and structural (retinal nerve fiber layer thickness) parameters and could be a non-invasive, quantitative tool for the monitoring of the disease and of the therapeutic approaches.

Surveillance of sight loss due to delay in ophthalmic treatment or review: frequency, cause and outcome.

PurposeTo determine the frequency of patients suffering harm due to delay in ophthalmic care in the UK over a 12-month period.MethodsPatients with deterioration in vision in at least one eye of 3 lines of Snellen acuity or 15 letters on ETDRS chart or deterioration in visual field deviation of 3 decibels due to health service initiated delay in review or care were ascertained through the BOSU using prospective active surveillance involving all UK consultant ophthalmologists. Demographic details, diagnosis, cause and length of delay, and vision loss were then sought by questionnaire.Results238 cases reported between March 2015 and February 2016. 197/238 questionnaires were returned (83%). Twenty-eight reports were out of the study period or did not meet the case definition. Median age was 76 years (range: 1 to 98 years). Median delay was 22 weeks (range: 2 days to 5½ years). Seventy two per cent experienced permanent reduction in visual acuity, 23% permanent deterioration in visual field. Main diagnoses were Glaucoma 42%, Age-related Macular Degeneration (AMD) 23%, and Diabetic Retinopathy (DR) 16%. Eighteen patients were eligible for Severely Sight Impaired (SSI) or Sight Impaired (SI) registration. Main causes were delayed follow-up (76%), lost referral (7%), and delayed treatment (8%).ConclusionPatients are suffering preventable harm due to health service initiated delay leading to permanently reduced vision. This is occurring in patients of all ages, but most consistently in those with chronic conditions. Delayed follow-up or review is the cause in the majority of cases indicating a lack of capacity within the hospital eye service.

Prevalence of posterior vitreous detachment in glaucoma patients and controls.

To evaluate the impact of oxidative stress - present in glaucoma - on the vitreous. We therefore compare the presence of early and late stages of posterior vitreous detachment (PVD) between patients with glaucoma and controls. The vitreous state was evaluated by the combination of optical coherence tomography and ultrasound. The main outcome was the vitreous state classified into 'no PVD', 'initial PVD' and 'advanced PVD'. We evaluated the vitreous state in 48 patients with glaucoma (age: mean 66.5±11.9years; visual field deviation: mean 10.4±6.8dB) and compared the results with 101 previously investigated controls (age: mean 73.6±9.3years). After one-to-one matching on age and sex, ordinal logistic regression revealed that patients with glaucoma were significantly more likely to exhibit advanced PVD stages compared to non-glaucoma patients (OR 2.60, 95% confidence interval: 1.06-6.36, p=0.037). Our results suggest that the presence or absence of PVD might be a valuable hint for diagnosing glaucoma - however, further research is needed to determine whether PVD can be used to supplement current glaucoma screening guidelines.

Developing new automated alternation flicker using optic disc photography for the detection of glaucoma progression.

PurposeTo evaluate a progression-detecting algorithm for a new automated matched alternation flicker (AMAF) in glaucoma patients.MethodsOpen-angle glaucoma patients with a baseline mean deviation of visual field (VF) test>-6 dB were included in this longitudinal and retrospective study. Functional progression was detected by two VF progression criteria and structural progression by both AMAF and conventional comparison methods using optic disc and retinal nerve fiber layer (RNFL) photography. Progression-detecting performances of AMAF and the conventional method were evaluated by an agreement between functional and structural progression criteria. RNFL thickness changes measured by optical coherence tomography (OCT) were compared between progressing and stable eyes determined by each method.ResultsAmong 103 eyes, 47 (45.6%), 21 (20.4%), and 32 (31.1%) eyes were evaluated as glaucoma progression using AMAF, the conventional method, and guided progression analysis (GPA) of the VF test, respectively. The AMAF showed better agreement than the conventional method, using GPA of the VF test (κ=0.337; P<0.001 and κ=0.124; P=0.191, respectively). The rates of RNFL thickness decay using OCT were significantly different between the progressing and stable eyes when progression was determined by AMAF (-3.49±2.86 μm per year vs -1.83±3.22 μm per year; P=0.007) but not by the conventional method (-3.24±2.42 μm per year vs -2.42±3.33 μm per year; P=0.290).ConclusionsThe AMAF was better than the conventional comparison method in discriminating structural changes during glaucoma progression, and showed a moderate agreement with functional progression criteria.

Morphology, orthography, and the two hemispheres: A divided visual field study with Hindi/Urdu biliterates

Although identical on the spoken level, Hindi and Urdu differ markedly on the written level in terms of reading/writing direction and orthographic depth, with discernible processing consequences. The present study used a divided field paradigm to study the impact of writing system characteristics of Hindi and Urdu on word naming latencies in skilled biliterate users of these languages. Hindi (read/written from left to right) was hypothesized to show a larger right field advantage than Urdu (read/written from right to left); Hindi words sharing form overlap with primes were expected to show a significant priming effect in the left visual field, but a significant right field effect for morphologically-primed naming. Both these expectations were confirmed. An overall right field advantage was obtained for one syllable Hindi and Urdu words; two syllable Urdu words showed either no visual field differences or a left field advantage, and the right field advantage for Hindi was significantly greater for two syllable than one syllable words. Further, Hindi words showed significant form priming (relative to control stimuli) in the left visual field and significant morphological priming (relative to form priming) in the right visual field. By contrast, Urdu words showed no significant form priming in either visual field, and significantly greater morphological than form priming in the left visual field. These results are taken to suggest that visual field asymmetries in word naming are sensitive to differences in reading habit-related scanning biases and to orthographic depth-related differences in word recognition processes.