Binocular Visual Field Research Articles

Is Patching After Age 4 Beneficial for Children Born with a Unilateral Congenital Cataract?

The goal of these analyses is to provide evidence that can help parents and health care providers determine whether or not to continue occlusion therapy once a reliable measure of optotype acuity can be obtained in children who are born with a unilateral congenital cataract. Data from the Infant Aphakia Treatment Study (IATS) are used in a cohort design. 105 children who participated in the IATS and did not have a vision-threatening adverse event. We assessed the relationship between visual acuity at age 10.5 years and average daily hours of patching reported by caregivers on quarterly 48-hour recall interviews and annual 7-day patching diaries obtained between 48 and 60 months of age. Monocular visual acuity was assessed at the clinic visit closest to 48 months of age using the Amblyopia Treatment Study-HOTV protocol. Final visual acuity was measured at age 10.5 years using the E-ETDRS testing protocol. Visual acuity measurements obtained at age 4 were reliable, with a single measure intraclass correlation coefficient of 0.83 (95% CI 0.78,0.88) and were predictive of those obtained at age 10.5 (rSpearman = 0.83 (p<0.01)). Forty percent (n=48) of the children, the visual acuity measured at age 10.5 years was within +0.15 logMAR of the measurement obtained at age 4. The amount of patching that was received between the 4th and 5th birthdays was unrelated to changes in visual acuity. These analyses suggest that optotype acuity measures obtained early in the 5th year of life are reliable and are predictive of final visual outcomes. Additionally, our results suggest that less aggressive patching protocols, or discontinuing patching altogether, may be justified in some children, particularly those with poor vision, once optotype acuity can be measured. However, the potential impact of latent nystagmus on uniocular visual acuity measurement and the effect of patching on the child's quality of life, family relationships, and binocular visual field need to be considered before discontinuing occlusion therapy.

Paediatric visual impairment in Western Australia: Results and lessons from a registry analysis.

Clinical registries are an important research tool to enhance our understanding of vision loss in the Australian paediatric population. We aim to provide an update on the epidemiology of visual impairment among Western Australian children using registry data analysis, and to highlight the challenges of registry data collection. This is a retrospective study of visual impairment and blindness registrations of children aged 0-16 years in Western Australia from 1996 to 2015. Blindness was defined as visual acuity ≤6/60 in the better-seeing eye or binocular visual field ≤20° diameter, with all other certifications labelled as visual impairment. Certificates were assessed for primary causes of vision loss by age strata and sex. Registration rate trends were analysed across three discrete registration periods. Of 11 800 certificates issued between 1996 and 2015, 728 certificates (6.2%) were issued to 710 children. Five hundred and twenty-nine (74.5%) certificates were issued for visual impairment and 181 (25.5%) for blindness. The leading cause of certification was inherited retinal disease (73, 10.3%), followed by cortical visual impairment (57, 8.0%) and albinism (56, 7.9%). The annual registration rate of visual impairment increased from 0.5 to 9.8 per 100 000 person-years across the study period, whereas blindness rates fell from 2.7 to 1.3. Overall registration rates of paediatric visual impairment in Western Australia are increasing, but these trends should be interpreted with caution given the known limitations of registry data. Enhancements of the registration process could be achieved through digitisation, inclusion of patient outcome data, and incentives for greater practitioner engagement.

Validation of the European visual field standards for driving: A driving simulator-based study.

To determine whether we could establish evidence-based pass/fail criteria for perimetry in the context of the European visual field standards for driving. This two-centre, cross-sectional study included participants with binocular visual field loss that had led to revocation of a group-1 driving licence. The participants underwent cognitive and binocular visual testing, including the European Driving Test (EDT), a perimetry algorithm that adheres to the European visual field standards. We used a high-fidelity driving simulator to compare the driving ability of these participants with healthy controls. Two driving instructors classified each driving test as passed or failed. Receiver operating characteristic (ROC) analysis and area under the curve (AUC) determined the ability of perimetry to discriminate between passed and failed driving tests. The study included 70 participants with visual field loss and 37 controls. A non-significantly higher proportion of controls passed the driving test (75% vs. 63%; p = 0.22). In ROC analysis, contrast sensitivity performed best (AUC of 0.73), followed by NEI VFQ-25 (AUC of 0.64). Peripheral visual field (AUC of 0.56) and central visual field (AUC of 0.47) performed weaker. Combining the central and peripheral visual field, and their interaction, increased AUC to 0.63. Perimetry was a poor predictor of simulator-based driving test result, and we could not establish appropriate pass/fail criteria for the European visual field standards. Because perimetry is not an accurate diagnostic tool for fitness to drive, a practical driving assessment should be performed in case of doubt.

Timed instrumental activities of daily living tasks in adults with irreversible vision impairment: validation to visual function and self-report

BackgroundInstrumental activities of daily living (IADL) are typically self-reported ability to perform complex tasks vital for independent living. There is a need for a complementary objective, performance-based approach especially in tracking outcomes in visual rehabilitation for patients with irreversible vision impairment (“low vision”). Our goals are: (1) To describe the validity of timed performance of instrumental activities of daily living (timed IADL or TIADL) tasks in individuals with irreversible vision impairment, by examining its association with visual function (visual acuity, contrast sensitivity, visual field), (2) To explore the correlation between TIADL and self-reported IADL.MethodsTwenty TIADL tasks were administered to 88 patients (median age 63.3 years, IQR 37.4–78.0) recruited from the UAB Department of Ophthalmology, Callahan Eye Hospital Clinics. An average Z-score incorporating time and accuracy of task completion was constructed. Minor accuracy errors were penalized 1 standard deviation from their calculated Z-score and major accuracy errors were assigned maximum allotted time. Linear regression was used to analyze the association between TIADL score and measured visual acuity (Early Treatment Diabetic Retinopathy Study, ETDRS chart), contrast sensitivity (Pelli-Robson), and binocular visual field (Esterman) with an unadjusted model and an adjusted model accounting for age, comorbidities, and depression scale (Center for Epidemiological Studies Depression, CES-D). Pearson correlation was used to estimate the correlation between TIADL and IADL.ResultsIncreased time to task completion was associated with decreased visual function. Each decreased line of ETDRS read was associated with an increase of 0.002 (95% CI 0.001, 0.002) Z-score (P < 0.01). A decreased ability to discern each Pelli-Robson letter was associated with an increase of 0.26 (95% CI 0.19, 0.33) Z-score (P < 0.01). For each less Esterman target identified, there was an increase of 0.01 (95% CI 0.003, 0.02) Z-score. Self-reported IADL and TIADL were correlated for reading tasks such as newspapers, nutrients on food can, and microwave timer (P < 0.05).ConclusionsLonger time to perform TIADL is associated with decreased visual acuity, contrast sensitivity, and binocular visual field. TIADL and self-reported IADL are significantly correlated for reading tasks providing an accurate, complementary outcome measure in clinical practice and research.

Simultaneous bilateral purtscher like retinopathy with systemic lupus erythematosus: a case

BackgroudSystemic lupus erythematosus is an unexplained autoimmune disease involving multiple systems throughout the body, and its ocular changes include dry eye, monocular or binocular visual field defects, vaso-occlusive diseases, or ischemic optic neuropathy.Case presentationThis article reports a patient with SLE complicated with bilateral Purtscher like retinopathy, who had a sudden decrease in ocular vision as the first symptom, the autoantibodies related to phospholipid syndrome showed no abnormality, and both anti-dsDNA antibodies and anti-SM antibodies were significantly positive, indicating that anti-dsDNA antibodies and anti-SM antibodies were also important factors in the pathogenesis of Purtscher like retinopathy.ConclusionThe close relationship between SLE retinopathy and systemic inflammatory activities and emphasize the importance of systemic immunotherapy.

Reference Database for a Novel Binocular Visual Function Perimeter: A Randomized Clinical Trial

PurposeTo construct a comprehensive reference database for a novel binocular automated perimeter. DesignA four-site prospective randomized clinical trial. Subjects and controls356 healthy subjects without ocular conditions that might affect visual function were categorized into 7 age groups. MethodsSubjects underwent comprehensive ocular examination of both eyes before enrollment. Using the TEMPO/IMOvifa automated perimeter (Topcon Healthcare/CREWT Medical Systems, Tokyo, Japan), each subject completed four binocular threshold visual field (VF) tests during a single visit: First, practice 24-2 and 10-2 tests were obtained from both eyes. Next, study 24-2 and 10-2 tests were obtained from both eyes. Test order of each sequence was randomized, and the tests were conducted under Standard Automated Perimetry testing conditions (SAP): Goldmann stimulus size III, 3183 cd/m2 maximum stimulus intensity, and background intensity of 10 cd/m2, using AIZE-Rapid test strategy. Standard VF reliability indices were assessed. For each subject, 24-2 and 10-2 test results from one randomly selected eye were analyzed. Main Outcome MeasuresPerimetric threshold sensitivity and reference limits for each test analysis parameter. ResultsThe ages of the study cohort were widely distributed, with a mean age (SD) of 52.3 (18.5) years. Sex assignment was 44.0% male and 56.0% female. The majority of subjects self-identified as White (67.4%), followed by Black or African American (13.5%) and Asian (8.7%), with 14.6% self-identified as Hispanic or Latino ethnicity. Mean sensitivity (MS) (SD) was 29.1 (1.3) decibels (dB) for the 24-2 and 32.4 (1.0) dB for the 10-2 test. For the 24-2 and 10-2, MS (SD) age-related changes averaged -0.06 (0.01) dB and -0.05 (0.01) dB per year, respectively. The normal range of pointwise threshold sensitivity increased with eccentricity and showed asymmetry around the mean, particularly notable in the 24-2 test. Mean (SD) binocular test duration was 3.18 (0.38) minutes (1 minute 35 seconds per eye) for the 24-2 test and 3.58 (0.43) minutes (1minute 47 seconds per eye) for the 10-2 test. ConclusionsA reference database for the TEMPO/IMOvifa perimeter was established, highlighting the significance of considering both age and stimulus eccentricity in interpreting threshold visual field test results.

Measurement of paracentral stereopsis using a new method with the binocular open perimeter imovifa® in normal adults.

No method to quantitatively evaluate stereopsis within the 15º visual field has been clinically established. We developed a program to measure paracentral stereopsis and evaluated its feasibility in visually normal participants. Experimental investigation METHODS: Ten visually normal volunteers with stereopsis of 60 arcseconds or better were included. The Stereo Eccentricity Analysis (SEA) program for stereopsis measurement across the visual field was integrated into the binocular visual field analyzer imovifa®. Subjects with established binocular stereopsis detected a stereoscopic circular target presented with crossed disparity on random dots at the fovea, 3°, 5°, 10°, and 15° on the 45°, 135°, 225°, and 315° meridians. The subjects performed two tasks for measurement in the periphery: a detection task by pressing the response button when the circular target was perceived and a localization task by tilting a joystick to indicate in which quadrant the circular target was perceived. The duration of the target presentation was 500 ms. The stereo thresholds at 0º and 3° did not significantly differ. The thresholds at 10º and 15º were significantly higher than at 0° (P < 0.01). While no inter-individual threshold difference was observed at the fovea, the difference was large at 15°. The stereo thresholds for the detection and localization tasks also did not differ significantly. With the SEA program, paracentral stereopsis can be measured and the stereo threshold increases with eccentricity. The SEA program appears to be a feasible clinical method to evaluate paracentral stereopsis.

Blast injury: Impact to the cornea

Visual disorders are common even after mild traumatic brain injury (mTBI) or blast exposure. The cost of blast-induced vision loss in civilians, military personnel, and veterans is significant. The visual consequences of blasts associated with TBI are elusive. Active military personnel and veterans report various ocular pathologies including corneal disorders post-combat blasts. The wars and conflicts in Afghanistan, Iraq, Syria, and Ukraine have significantly increased the number of corneal and other ocular disorders among military personnel and veterans. Binocular vision, visual fields, and other visual functions could be impaired following blast-mediated TBI. Blast-associated injuries can cause visual disturbances, binocular system problems, and visual loss. About 25% of veterans exposed to blasts report corneal injury. Blast exposure induces corneal edema, corneal opacity, increased corneal thickness, damage of corneal epithelium, corneal abrasions, and stromal and endothelial abnormality including altered endothelial density, immune cell infiltration, corneal neovascularization, Descemet membrane rupture, and increased pain mediators in animal models and the blast-exposed military personnel including veterans. Immune response exacerbates blast-induced ocular injury. TBI is associated with dry eyes and pain in veterans. Subjects exposed to blasts that cause TBI should undergo immediate clinical visual and ocular examinations. Delayed visual care may lead to progressive vision loss, lengthening/impairing rehabilitation and ultimately may lead to permanent vision problems and blindness. Open-field blast exposure could induce corneal injuries and immune responses in the cornea. Further studies are warranted to understand corneal pathology after blast exposure. A review of current advancements in blast-induced corneal injury will help elucidate novel targets for potential therapeutic options. This review discusses the impact of blast exposure-associated corneal disorders.

Evaluation of the photosensory characteristics of the lateral and pineal eyes of Plioplatecarpus (Squamata, Mosasauridae) based on an exceptionally preserved specimen from the Bearpaw Shale (Campanian, Upper Cretaceous) of southern Alberta

ABSTRACT The skull of Plioplatecarpus possesses large orbits and a large parietal foramen. Although the large orbits suggest that Plioplatecarpus possessed large eyes with enhanced visual performance, none of the previously described skulls include a sclerotic ring, and so it has been impossible in the past to reconstruct their size or optical properties. A recently collected skull with a sclerotic ring preserved in situ provides for the first time the data to do so. The dimensions of the sclerotic ring demonstrate that, although the f-number of the eyeball was not low enough to support the hypothesis that Plioplatecarpus was adapted to low light conditions, the eyeball was nevertheless large and possessed increased visual acuity and sensitivity that enabled the mosasaur to operate efficiently in both light-rich and light-poor conditions and possibly other conditions of reduced visibility. Proportions of this skull also suggest that Plioplatecarpus possessed a relatively wide binocular field of vision, providing stereoscopic vision, and further increasing both acuity and sensitivity, enhancing its ability to effectively detect and track quickly moving objects under a wide range of light conditions. A greatly enlarged parietal foramen implies the presence of a large parietal eye, the significance of which is uncertain, but it may have enhanced the ability to regulate migratory behavior.

Gaze tracking of large-billed crows (Corvus macrorhynchos) in a motion capture system.

Previous studies often inferred the focus of a bird's attention from its head movements because it provides important clues about their perception and cognition. However, it remains challenging to do so accurately, as the details of how they orient their visual field toward the visual targets remain largely unclear. We thus examined visual field configurations and the visual field use of large-billed crows (Corvus macrorhynchos Wagler 1827). We used an established ophthalmoscopic reflex technique to identify the visual field configuration, including the binocular width and optical axes, as well as the degree of eye movement. A newly established motion capture system was then used to track the head movements of freely moving crows to examine how they oriented their reconstructed visual fields toward attention-getting objects. When visual targets were moving, the crows frequently used their binocular visual fields, particularly around the projection of the beak-tip. When the visual targets stopped moving, crows frequently used non-binocular visual fields, particularly around the regions where their optical axes were found. On such occasions, the crows slightly preferred the right eye. Overall, the visual field use of crows is clearly predictable. Thus, while the untracked eye movements could introduce some level of uncertainty (typically within 15 deg), we demonstrated the feasibility of inferring a crow's attentional focus by 3D tracking of their heads. Our system represents a promising initial step towards establishing gaze tracking methods for studying corvid behavior and cognition.

A Fish-like Binocular Vision System for Underwater Perception of Robotic Fish.

Biological fish exhibit a remarkably broad-spectrum visual perception capability. Inspired by the eye arrangement of biological fish, we design a fish-like binocular vision system, thereby endowing underwater bionic robots with an exceptionally broad visual perception capacity. Firstly, based on the design principles of binocular visual field overlap and tangency to streamlined shapes, a fish-like vision system is developed for underwater robots, enabling wide-field underwater perception without a waterproof cover. Secondly, addressing the significant distortion and parallax of the vision system, a visual field stitching algorithm is proposed to merge the binocular fields of view and obtain a complete perception image. Thirdly, an orientation alignment method is proposed that draws scales for yaw and pitch angles in the stitched images to provide a reference for the orientation of objects of interest within the field of view. Finally, underwater experiments evaluate the perception capabilities of the fish-like vision system, confirming the effectiveness of the visual field stitching algorithm and the orientation alignment method. The results show that the constructed vision system, when used underwater, achieves a horizontal field of view of 306.56°. The conducted work advances the visual perception capabilities of underwater robots and presents a novel approach to and insight for fish-inspired visual systems.

Reliability of Binocular Esterman Visual Field Test in Patients with Glaucoma and Other Ocular Conditions.

The binocular Esterman visual field test (EVFT) of 120 points was the first method to quantify the defects in the binocular visual field. It is used in many parts of the world as a standard test to determine whether an individual has the visual capabilities to drive safely. In Japan, it is required for the grading and issuance of visual disability certificates. The purpose of this study was to determine the reliability of the EVFT results. We studied 104 patients who had undergone the binocular EVFT at Mie University Hospital. Their mean age was 68.0 ± 11.4 years, and the best-corrected visual acuity of the better eye was 0.18 ± 0.38 logMAR units. The EVFT was performed twice on the same day, and the results of the first and second tests were compared. The mean Esterman scores for the first and second test were 89.3 ± 30.5 and 89.1 ± 30.2, respectively, and the test times were 338.9 ± 86.8 and 336.7 ± 76.4 s, respectively. The differences were not significant (p = 0.69 and p = 0.33). In the Bland-Altman analyses (second-first test) of the Esterman scores, the mean difference was 0.38 without significant fixed errors (p = 0.20) or proportional errors (p = 0.27). The limits of agreement within the 1.96 standard deviation were -8.96 to +9.45 points. The agreement rate for the most peripheral 24 test points was significantly lower than the agreement rate for the other 96 test points (p < 0.01). The agreement rate of the upper visual field was significantly lower than that of the lower field (p < 0.01). The overall reliability rate of the EVFT is acceptable, but the peripheral and upper test points have relatively low reliability rates. These findings are important for interpretations of the EVFT results.

Effects of binocular cue availability on leaping performance in Cheirogaleus medius: implications for primate origins.

Multiple competing hypotheses attribute the evolution of the suite of traits that distinguish primates from their closest relatives, including forward-facing eyes, which create a wide field of binocular vision, to specific behavioral and ecological factors. The grasp-leaping hypothesis suggests that the evolution of these traits in basal primates was driven by the demands of a form of leaping locomotion unique to primates. Whether the grasp-leaping hypothesis provides a viable mechanism for the evolution of primates' forward-facing eyes remains untested. To determine whether grasp-leaping locomotion may have contributed to driving the evolution of primates' forward-facing eyes, the importance of vision within the binocular field for this type of leaping was evaluated experimentally in Cheirogaleus medius, one of the cheirogaleid primate species considered reasonable living analogs of the earliest primates. Availability of binocular visual cues was experimentally restricted using a head-mounted blinder that narrowed the binocular visual field without altering the total visual field. Animals altered their launch behavior, reduced their horizontal leap speed, and were significantly more likely to select paths that offered the shortest available leaps when their binocular field was restricted. Restriction of binocular cue availability also significantly increased the probability of adverse landings even when statistically controlling for potentially confounding variables such as leap distance, horizontal leap speed, learning effects, etc. These results suggest a functional mechanism by which selection for improved grasp-leaping could also have contributed to the evolution of forward-facing eyes in the earliest crown primates.

Effect of binocular visual cue availability on fruit and insect grasping performance in two cheirogaleids: Implications for primate origins hypotheses

Forward-facing eyes with parallel optic axes, which provide a wide field of binocular vision and precise depth perception, are among the diagnostic features of crown primates; however, the adaptive significance of this feature remains contentious. Two of the most prominent primate-origins hypotheses propose that either foraging for fruit or nocturnal predation on insects created selective pressures that led to the evolution of diagnostic primate traits, including a wide binocular field. To determine whether either of these hypotheses provides a viable explanation for the evolution of primates' derived eye orientation, the importance of binocular depth cues for the two tasks invoked by these hypotheses was evaluated experimentally in Microcebus murinus and Cheirogaleus medius, cheirogaleids' considered reasonable living analogs of the earliest euprimates. Performance in grasping insects and fruit was evaluated when the animals made use of their full binocular visual field and when their binocular visual field was restricted using a helmet-mounted blinder. Restriction of the binocular field had no effect on fruit grasping performance; however, restriction of the binocular field resulted in a significant deficit in insect predation performance. Differences in behavioral variables also suggest that insect predation is a more visually demanding task than fruit foraging. These results support the role of insect predation, but not fruit foraging, in contributing to the selective pressures that led to the evolution of parallel optic axes and a wide binocular field in crown primates.

Effect of Nonoverlapping Visual Field Defects on Vision-related Quality of Life in Glaucoma

PurposeGlaucoma patients may be considered to have normal vision as long as each point of visual space is perceived by at least one eye, that is, with an intact binocular visual field. We aimed to investigate the effect of non-overlapping visual field (VF) defects on vision-related quality life (VR-QoL) in glaucoma. MethodsWe evaluated VR-QoL of glaucoma patients (n=269) and controls (n=113) using four different questionnaires (NEI-VFQ-25, NEI-VFQ neuro-ophthalmology supplement, GQL-15, and a luminance-specific questionnaire). We defined ‘differential VF’ (DVF) as a measure of location-specific differences in the VFs of both eyes. Within the group of glaucoma patients, we analysed the relationship between different aspects of VR-QoL and DVF using ordinal multiple regression analysis. Analyses were adjusted for age, gender, integrated VF (IVF; an estimate of the binocular VF from the monocular VFs), and higher visual acuity of both eyes, and corrected for multiple hypothesis testing. ResultsGlaucoma patients had a lower VR-QoL than controls. Within the glaucoma patients, DVF was significantly associated with general vision (odds ratio 0.69, 95% confidence interval 0.54-0.89), peripheral vision (0.68, 0.54-0.86), walking on uneven ground (0.73, 0.58-0.93), crossing the street (0.61, 0.46-0.83), seeing other road users coming from the side (0.67, 0.52-0.85), cycling during the day (0.64, 0.46-0.89) and seeing outside on a sunny day (0.73, 0.57-0.94). In general, IVF was a stronger predictor of VR-QoL than DVF. ConclusionsNon-overlapping VF defects affect VR-QoL. Although IVF is strongly associated with VR-QoL, basing clinical decisions only on IVF leads to overlooking vision problems that patients may have.

Archetypal analysis for dominant optic atrophy visual field loss

Aims/Purpose: Identification of the characteristic visual field loss patterns of dominant optic atrophy (DOA) employing the Archetypal Analysis (AA) machine learning algorithm and further relation with patient‐specific parameters.Methods: For 64 patients affected by molecularly confirmed DOA with OPA1 heterozygous mutation, binocular visual field (VF) tests performed by SITA standard 30–2 or 24–2 Humphrey VF analyser (Carl Zeiss Meditec, Dublin, CA, USA) were collected. For patients that had multiple VF tests, several VFs were collected to enlarge the dataset. Resorting to Python 3.8 (Anaconda) an AA model was developed to determine and quantify the DOA underlying patterns of visual loss. After a careful analysis involving different linear and non‐linear machine Learning models and algorithms, the different archetypes (AT) were related to parameters such as age and visual acuity.Results: Considering 229 VF test, employing the AA, twelve archetypes were detected for the characterization and quantification of visual loss in DOA. Central, ceco‐central, and para‐central ATs revealed to be the most significant ones, matching the common characteristic scotomas for DOA patients, followed by quadrantanopia, altitudinal, and nasal step ATs.Younger patients were related to less severe visual loss representative ATs, while patients with lower visual acuity were related to more severe visual loss representative ATs.Conclusions: Archetypal analysis shows to be a potential powerful tool to support clinicians in the identification of DOA patients by identifying and quantifying visual loss patterns characteristic of this disease. Relation with other patient‐specific parameters might strengthen the differential DOA diagnosis.

The value of assessing progressive loss of red/green and yellow/blue chromatic sensitivity in glaucoma

*Correspondence: franziska.rauscher@medizin.uni-leipzig.deThe value of assessing progressive loss of red/green and yellow/blue chromatic sensitivity in glaucoma.The study employed visual stimuli designed to isolate and reveal how spatial, temporal and chromatic aspects of visual processing change from normal sensitivity to extreme loss in glaucoma. The experiments carried out examined the fovea and each of four paracentral retinal regions, arranged diagonally away from fixation at an eccentricity of 6°. Spatial vision was investigated by measuring both absolute detection thresholds and functional contrast sensitivity using Landolt ring stimuli (Ophthalmic Physiol Opt 2022;42:1363–1378). These psychophysical tests based on Landolt C optotypes measure both detection thresholds and gap orientation discrimination thresholds in the same experiments using randomly interleaved test locations. First‐order motion perception was examined by using moving stimuli embedded in static luminance contrast noise. Red/green (RG) and yellow/blue (YB) colour thresholds were measured with the Colour Assessment and Diagnosis (CAD) test, which makes use of random, dynamic luminance contrast noise (±45%) to isolate the use of RG and YB colour signals. Subjects were normal controls (n = 65) and glaucoma patients with binocular visual field defects (n = 15) classified based on their Humphrey Field Analyser mean deviation (MD) scores. The impairment of visual function varied depending on the stimulus attribute and location tested. The severity of loss increased monotonically with disease progression. For subjects with mild glaucoma (MD −0.01 to −6.00 dB), significantly more data points exceeded the upper normal threshold limits for the corresponding age for RG colour thresholds than for any other visual test (Br Med Bull 2017;122:51–77), followed by motion thresholds. This was particularly the case for the parafoveal locations when compared with the equivalent thresholds measured at the fovea. The results suggest that a multifaceted measure of binocular visual performance based on foveal and parafoveal tests of RG colour vision and first‐order motion, can best inform on the progression of glaucoma and the overall loss of visual performance for comparison with other measures of changes in the quality of life in patients with glaucoma.Keywords: Glaucoma, Visual function, Colour vision, Motion detection, Contrast, Acuity, Colour Assessment and Diagnosis, CAD.

Comparison of the TEMPO binocular perimeter and Humphrey field analyzer

This study compared between TEMPO, a new binocular perimeter, with the Humphrey Field Analyzer (HFA). Patients were tested with both TEMPO 24–2 Ambient Interactive Zippy Estimated by Sequential Testing (AIZE)-Rapid and HFA 24–2 Swedish Interactive Threshold Algorithm (SITA)-Fast in a randomized sequence on the same day. Using a mixed-effects model, visual field (VF) parameters and reliability indices were compared. Retinal nerve fiber layer (RNFL) thickness was measured using Cirrus optical coherence tomography (OCT), and coefficient of determinations for VF and OCT parameters were calculated and compared using Akaike information criteria. 740 eyes (including 68 healthy, 262 glaucoma suspects, and 410 glaucoma) of 370 participants were evaluated. No significant differences were seen in mean deviation and visual field index between the two perimeters (P > 0.05). A stronger association between VF mean sensitivity (dB or 1/L) and circumpapillary RNFL was found for TEMPO (adjusted R2 = 0.25; Akaike information criteria [AIC] = 5235.5 for dB, and adjusted R2 = 0.29; AIC = 5200.8 for 1/L, respectively) compared to HFA (adjusted R2 = 0.22; AIC = 5263.9 for dB, and adjusted R2 = 0.22; AIC = 5262.7 for 1/L, respectively). Measurement time was faster for TEMPO compared to HFA (261 s vs. 429 s, P < 0.001). Further investigations are needed to assess the long-term monitoring potential of this binocular VF test.

Anomalous binocular vision in African Harrier-Hawks

An animal's visual field is the three-dimensional space around its head from which it can extract visual information at any instant1. Bird visual fields vary markedly between species, and this variation is likely to be driven primarily by foraging ecology1,2,3. The binocular visual field is the region in which the visual fields of the two eyes overlap; thus, objects in the binocular field are imaged by both eyes simultaneously. The binocular field plays a pivotal role in the detection of symmetrical optic flow-fields, providing almost instantaneous information on the direction of travel and the time to contact a target towards which the head or feet is travelling; thus, information from the binocular field is crucial in guiding key foraging behaviours2,3. Here, we demonstrate an unusual visual field and binocular extent above the head in African Harrier-Hawks, also known as Gymnogenes (Polyboroides typus) compared to 18 other members of the Accipitridae4,5. We argue that the observed visual field can be attributed to the unusual and specific foraging behaviour of African Harrier-Hawks.

Binocular field configuration in owls: the role of foraging ecology.

The binocular field of vision differs widely in birds depending on ecological traits such as foraging. Owls (Strigiformes) have been considered to have a unique binocular field, but whether it is related to foraging has remained unknown. While taking into account allometry and phylogeny, we hypothesized that both daily activity cycle and diet determine the size and shape of the binocular field in owls. Here, we compared the binocular field configuration of 23 species of owls. While we found no effect of allometry and phylogeny, ecological traits strongly influence the binocular field shape and size. Binocular field shape of owls significantly differed from that of diurnal raptors. Among owls, binocular field shape was relatively conserved, but binocular field size differed among species depending on ecological traits, with larger binocular fields in species living in dense habitat and foraging on invertebrates. Our results suggest that (i) binocular field shape is associated with the time of foraging in the daily cycle (owls versus diurnal raptors) and (ii) that binocular field size differs between closely related owl species even though the general shape is conserved, possibly because the field of view is partially restricted by feathers, in a trade-off with auditory localization.