Perimetry and Visual Fields

In 1870s, the German architect Hermann Eduard Maertens grounded his Optical Scale research on Hermann Helmholtz and Franciscus Donders' works about the physiology of vision and engrafted it in the tradition of Renaissance perspective and proportion theory's applications to architecture and urban planning. This article describes the scientific core of his approach, in the context of a general revision of aesthetic enjoyment of artworks and a deterministic reorientation of human knowledge toward the industrial production; his elaboration of a triad of visual angles to determine size and organization of space according to visual targets; the diffusion of visual cones as a graphic tool to include perceptual values in the project; the immediate success of his formula among architects and urban planners but, at the same time, the critical reception of his static concept of urban perception; the means of transmission of his ideas in the XX century and their often unaware long-term influence on some postwar years researches. En 1870 el arquitecto alemán Eduard Maertens basó su investigación en Escala Óptica en los trabajos de Hermann Helmholtz y Franciscus Donders sobre fisiología de la visión, injertado en la tradición de la perspectiva renacentista y en las aplicaciones en arquitectura y planeamiento urbano de la teoría de las proporciones. Este artículo describe el fundamento científico de este enfoque, en el contexto de una revisión general del disfrute estético de las obras de arte y una reorientación determinista del conocimiento humano hacia la producción industrial; su elaboración de una tríada de ángulos visuales para determinar el tamaño y la organización del espacio según objetivos visuales; la difusión de conos visuales como una herramienta gráfica para incluir valores perceptuales en el proyecto; el éxito inmediato de su fórmula entre arquitectos y urbanistas pero, al mismo tiempo, la recepción crítica de su concepto estático de percepción urbana; los medios de transmisión de sus ideas en el siglo XX y su habitualmente inconsciente y prolongada influencia en algunas investigaciones de los años de postguerra.

Objetivo: Avaliar a associação entre insuficiência cardíaca crônica e alterações do disco óptico. Métodos: Pacientes com insuficiência cardíaca crônica foram submetidos a exame oftalmológico, incluindo medida da pressão intraocular, avaliação da cabeça do nervo óptico e da camada de fibras nervosas da retina com estereofotografia e Tomógrafo Retiniano de Heildelberg, perimetria automatizada padrão e Ultrassonografia Doppler em Cores da artéria oftálmica. Os achados oculares foram correlacionados com a avaliação cardiológica, e comparados com um grupo controle. Resultados: Um total de 59 olhos de 30 pacientes com insuficiência cardíaca crônica e 60 olhos de 30 indivíduos controle foram incluídos neste estudo. A média (devio-padrão [DP]) da pressão intraocular foi 12,3 (2,5) mm Hg no grupo insuficiência cardíaca crônica e 14,7 (2,9) mm Hg no grupo controle (P<0,001). A média (DP) da pressão arterial média foi 86,9 (17,1) mm Hg no grupo insuficiência cardíaca crônica e 103,6 (15,2) mm Hg no grupo controle (P<0,001). A média (DP) da pressão de perfusão ocular foi 45,6 (11,1) mm Hg no grupo insuficiência cardíaca crônica e 54,4 (10,4) mm Hg no grupo controle (P=0,001). A média (DP) da área da rima neural foi1,41 (0,3) mm2 no grupo insuficiência cardíaca crônica e 1,60 (0,26) mm2 no grupo controle (P=0,003). A média (DP) da razão escavação/disco foi 0,51 (0,17) no grupo insuficiência cardíaca crônica e 0,41 (0,18) no grupo controle (P=0,02). A média (DP) do índice de resistência da artéria oftálmica foi 0,76 (0,08) no grupo insuficiência cardíaca crônica e 0,70 (0,08) no grupo controle (P=0,04). A frequência de glaucoma foi de 10% no grupo insuficiência cardíaca crônica, ao passo que nenhum controle preencheu os critérios para glaucoma (P=0,24). Conclusão: A insuficiência cardíaca crônica está associada à pressão de perfusão ocular mais baixa, alterações de fluxo sanguíneo retrobulbar e alterações da cabeça do nervo óptico.

Parrots are exceptional among birds for their high levels of exploratory behaviour and manipulatory abilities. It has been argued that foraging method is the prime determinant of a bird's visual field configuration. However, here we argue that the topography of visual fields in parrots is related to their playful dexterity, unique anatomy and particularly the tactile information that is gained through their bill tip organ during object manipulation. We measured the visual fields of Senegal parrots Poicephalus senegalus using the ophthalmoscopic reflex technique and also report some preliminary observations on the bill tip organ in this species. We found that the visual fields of Senegal parrots are unlike those described hitherto in any other bird species, with both a relatively broad frontal binocular field and a near comprehensive field of view around the head. The behavioural implications are discussed and we consider how extractive foraging and object exploration, mediated in part by tactile cues from the bill, has led to the absence of visual coverage of the region below the bill in favour of more comprehensive visual coverage above the head.

Ricco’s area (the largest area of visual space in which stimulus area and intensity are inversely proportional at threshold) has previously been hypothesised to be a result of centre/surround antagonism in retinal ganglion cell receptive fields, but recent evidence suggests a sizeable cortical contribution. Here, Ricco’s area was measured in amblyopia, a condition in which retinal receptive fields are normal, to better understand its physiological basis. Spatial summation functions were determined at 12 visual field locations in both eyes of 14 amblyopic adults and 15 normal-sighted controls. Ricco’s area was significantly larger in amblyopic eyes than in fellow non-amblyopic eyes. Compared to the size of Ricco’s area in control eyes, Ricco’s area measured significantly larger in amblyopic eyes. Additionally, Ricco’s area in the fellow, non-amblyopic eye of amblyopic participants measured significantly smaller than in control eyes. Compared to controls, Ricco’s area was larger in amblyopic eyes and smaller in fellow non-amblyopic eyes. Amblyopia type, binocularity, and inter-ocular difference in visual acuity were significantly associated with inter-ocular differences in Ricco’s area in amblyopes. The physiological basis for Ricco’s area is unlikely to be confined to the retina, but more likely representative of spatial summation at multiple sites along the visual pathway.

Degrading real-world scenes in the central or the peripheral visual field yields a characteristic pattern: Mean saccade amplitudes increase with central and decrease with peripheral degradation. Does this pattern reflect corresponding modulations of selective attention? If so, the observed saccade amplitude pattern should reflect more focused attention in the central region with peripheral degradation and an attentional bias toward the periphery with central degradation. To investigate this hypothesis, we measured the detectability of peripheral (Experiment 1) or central targets (Experiment 2) during scene viewing when low or high spatial frequencies were gaze-contingently filtered in the central or the peripheral visual field. Relative to an unfiltered control condition, peripheral filtering induced a decrease of the detection probability for peripheral but not for central targets (tunnel vision). Central filtering decreased the detectability of central but not of peripheral targets. Additional post hoc analyses are compatible with the interpretation that saccade amplitudes and direction are computed in partial independence. Our experimental results indicate that task-induced modulations of saccade amplitudes reflect attentional modulations.

PURPOSE. Peripheral vision is important for mobility, balance, and guidance of attention, but standard perimetry examines only <20% of the entire visual field. We report on the relation between central and peripheral visual field damage, and on retest variability, with a simple approach for automated kinetic perimetry (AKP) of the peripheral field.

Which is the most accurate way to depict space in our visual field? Linear perspective, a form of geometrical perspective, has traditionally been regarded as the correct method of depicting visual space. But artists have often found it is limited in the angle of view it can depict; wide-angle scenes require uncomfortably close picture viewing distances or impractical degrees of enlargement to be seen properly. Other forms of geometrical perspective, such as fisheye projections, can represent wider views but typically produce pictures in which objects appear distorted. In this study we created an artistic rendering of a hemispherical visual space that encompassed the full visual field. We compared it to a number of geometrical perspective projections of the same space by asking participants to rate which best matched their visual experience. We found the artistic rendering performed significantly better than the geometrically generated projections.

Glaucoma, an age-related eye disease, can lead to blindness if left untreated. The risk of blindness from glaucoma is relatively low but is determined largely by the severity of disease at diagnosis. It is likely that many of those who present late have rapidly progressing disease. Once diagnosed, a patient must be monitored for life using a machine that detects worsening (‘progression’) of their vision [‘visual field’ (VF)]. Patients with fast VF progression are in greater danger of going blind, in a given time frame, than patients with slow progression. However, VF test measurements can fluctuate considerably, meaning that patients need several tests over a period of time before any change can be detected or acted on – this can be expensive for the NHS. We set out to see if the benefits of extra tests were cost-effective. We first established, using a clinical audit, that patients are tested less frequently than is recommended in guidelines. Next, we found that eye doctors thought the idea of increased testing would be useful but not practical given current NHS resources. Patient interviews (focus groups) indicated that, although patients do not like
VF testing, and some raised concerns about its current delivery, they accepted it as an important part of their clinical care. Another study, making predictions based on statistical analysis of large numbers of VF data, indicated that increasing frequency of VF testing could identify progression sooner than current practice. Furthermore, an examination of costs and benefits (health economics) suggested that increased monitoring of the VF in diagnosed patients is likely to also be cost-effective.

(Italy), after approval of our Ethical Committee, we selected 20 patients affected by open-angle glaucoma. It was a prospective single center open study. Their demographic data were: 10 males and 10 females mean age 59.5 years, standard deviation 11.24 years (Table I). The inclusion criteria were: of age, affected by open-angle glaucoma, pachymetry 550 µm ± 30 µm, best corrected visual acuity 20/20, hyperopia, myopia a/or astigmatism ± 1 diopter. Exclusion criteria were: anterior a/or posterior segment diseases interfering with visual field and IOP assessment, pharmacologic therapy including neuroprotective drugs, ametropia > 1 diopter. All of them were under monotherapy (Table II). They were enrolled in this study and received a complete

Purpose: Automated scotopic, mesopic, and photopic perimetry are likely to be important paradigms in the assessment of emerging treatments of retinal diseases, yet our knowledge of the photoreceptor mechanisms detecting targets under these conditions remains largely dependent on simian data. We therefore aimed to establish the photoreceptor/postreceptoral mechanisms detecting perimetric targets in humans under photopic, mesopic, and scotopic conditions and to make recommendations for suitable clinical testing strategies for selective perimetry. Methods: Perimetric sensitivities within 308 of fixation were determined for eight wavelengths (410, 440, 480, 520, 560, 600, 640, and 680 nm) under scotopic, mesopic (1.3 cd.m À2) and photopic (10 cd.m À2) conditions. Data were fitted with vector combinations of rod, Scone , nonopponent MþL-cone mechanism, and opponent M-versus L-cone mechanism templates. Results: Scotopicperimetric sensitivity was determined by rods peripherally and by a combination of rods and cones at, and immediately around, fixation. Mesopic perimetric sensitivity was mediated by MþL-cones and Scones centrally and by MþL-cones and rods more peripherally. Photopic perimetric sensitivity was determined by an opponent M-versus L-cone, a nonopponent MþL-cone, and an Scone mechanism centrally and by a combination of an Scone and an MþL-cone mechanism peripherally. Conclusions: Under scotopic conditions, a 480-nm stimulus provides adequate isolation (!28 dB) of the rod mechanism. Several mechanisms contribute to mesopic sensitivity: this redundancy in detection may cause both insensitivity to broadband white targets and ambiguity in determining which mechanism is being probed with short-wavelength stimuli. M-and L-cone–derived mechanisms are well isolated at 10 cd.m À2 : these may be selectively probed by a stimulus at 640 nm (! 20 dB isolation). Translation Relevance: In human observers, multiple mechanisms contribute to the detection of Goldmann size III and size V perimetric targets under scotopic, mesopic, and photopic conditions. The relative contribution of these mechanisms appears to differ from those found previously for macaques. Our results furthermore suggest that caution must be exercised when using microperimetric techniques, which are typically conducted under mesopic conditions and which are likely to be important in the assessment of emerging treatments for retinal disease. This is because mesopic background conditions maximize the redundancy of target detection. Furthermore, our results demonstrate that spectral manipulation of the stimulus alone cannot be used to reliably separate rod from cone responses under these conditions.

The brief presentation in the peripheral field of two closely spaced luminous point stimuli, in rapid sequence, induces the illusion of a single dot moving over an extended path. This fine-grain movement illusion (FGMI) is particularly compelling under conditions of dark adaptation. The strength of the motion percept, assessed by a rating-scale procedure, was found to correlate well, over different flash-flash onset delays, with an objective measure of the illusion requiring discrimination of the direction of the flash-flash sequence. A direction-discrimination measure was used to determine the minimum dot separation that would reliably elicit an FGMI at retinal eccentricities of S-25 deg. For comparison, measures of static spatial acuity was made based on the minimum angle of resolution of two simultaneous dot flashes, and on the threshold for discriminating the separation of two simultaneous dot flashes with variable initial spacing. The spatial threshold for FGMI was lower than that for each of the static measures at all peripheral eccentricities, and it increased more slowly with eccentricity than the other spatial thresholds, suggesting the involvement of separate visual pathways for generating percepts of motion and percepts of shape or location. The finding that in the periphery the grain for motion detection was finer than that for spatial discrimination constrains a class of motion-perception models that form an initial spatial description of the stimulus and then compute a temporal derivative.

Glaucoma is a major cause of blindness and its mechanisms are not fully understood. The progression of the disease can be slowed by early diagnosis, but this is a difficult task because available data is typically noisy and has high variability. Several artificial intelligence approaches have been used in this context, although they generally don’t exploit the temporal nature of the data. Here we propose a new algorithm for modeling and clustering time series using the Non-stationary Dynamic Bayesian Network framework. Our method is tested both on a simulated and a glaucoma dataset, obtaining promising performances and enabling meaningful insight in the field.

What must happen so that people like me, who are visually impaired, can work more efficiently is a standardization of the website layout with each category, e.g. citation should always be in the upper left corner and have an orange button, the Download button must be in the center and of light green color with black letters in it, etc.


I find it challenging to gather all information from research articles because every provider of online scientific publications has its own layout, its own functionalities, its own format, etc. But instead of me having to remember the location of each functionality for each provider, it would be much better if all providers would use the same general layout, color coding and a minimum set of function to which each provider is welcome to add whatever deemed beneficial.


E.g. here in ResearchGate it is hard for me to find the "Message" button with my Zoomtext because it is of the same color as the background and the only way to recognize it is by the thin blue letters spelling the word "Message". Even though Academia.edu and ResearchGate.net serve the same purpose, there are a lot of differences in navigating through their sites. Therefore, providers of similar content and functions should be required to offer a user interface option that follows the same standards regarding layout, coloring, contrast enhancing, screen-reader accessibility and other accessibility functions because that way sensory impaired people must only learn once, e.g. how to access scientific journals, figures, citations, supplementary material, PDF files, etc.


Knowledge-exchange and online employment websites must provide an interface for its users to interact. All providers of such kind of interaction interfaces should be required to provide a disability communication mode, which must adhere to strict standards pertaining to accessibility, layout, color coding, use of functions like "Search", "Submit", "Download", "Message Exchange", "User Lookup", etc. Each provider should be free to choose its own communication interface features, which don't need to be standardized to maintain options for commercial innovations, but that must be in addition but never instead a clutter-free interface that allows accessing the same kind of information always the same way across all provider platforms.


Each provider of any kind of web-based functions or services must provide the option to chose any older legacy version of its software, cloud or browser-based functions so that in 20 years I can still use the same method to accomplish the same things as today.

The visual fields of elasmobranch fishes are not well characterized even though this is a fundamental element of the visual
system. The batoid fishes (skates, rays) form a monophyletic clade within the subclass Elasmobranchii and exhibit a broad range
of morphologies and corresponding ecologies. We hypothesized that their visual field characteristics would reflect their diverse
morphology and ecology. This was tested by quantifying the monocular, binocular and cyclopean horizontal and vertical visual
fields of four batoid species (Raja eglanteria, Urobatis jamaicensis, Dasyatis sabina and Rhinoptera bonasus) that encompassed
a range from a basal skate to a more derived ray. The horizontal and vertical visual fields differed significantly among species;
however, all species possessed horizontal anterior and dorsal binocular overlaps. Urobatis jamaicensis, a small reef-associated
stingray, demonstrated a 360° panoramic visual field in the horizontal plane, and R. bonasus, a schooling benthopelagic ray, a
360° panoramic view in the vertical plane. Large anterior binocular overlaps were measured in D. sabina (72°) and R. bonasus (46°)
but came at the expense of large posterior blind areas. The anterior binocular overlaps in R. eglanteria (28°) and U. jamaicensis
(34°) were smaller but were coupled with large monocular fields that provided expansive peripheral views. The most
phylogenetically basal species, the clearnose skate (Raja eglanteria), had the most reduced visual field in contrast to the more
derived ray species. To our knowledge, this study represents the first comparative assessment of visual fields in basal
vertebrates.

In the visual periphery, brief presentation of two very closely spaced luminous point stimuli, in rapid sequence, causes the illusory impression that a single dot moves over a path of considerable extent. The interactions obtainable between two illusions near one another are described for various configurations of the inducing stimuli. Only when such illusions are codirectional are they found not to interfere with one another. The effective field position and extent of the illusion were measured by pitting two suitably separated illusions against one another. The extent varies from about 2 deg to 6 deg as stimulus eccentricity is increased from 10 deg to 24 deg. However, when mapped onto visual cortex by means of human cortical magnification factor, the illusion spans a patch of cortex about 3 mm dia, regardless of stimulus eccentricity; such a region in primate visual cortex corresponds approximately to the locus of cortical cells that “see” a given retinal point. Finally, it is suggested that these fine-grain effects may underlie certain perceptual responses to sequential random-dot displays.

In normal viewing conditions, many objects are often hidden or occluded by others, therefore restricting the information that enters the eye. The human visual system developed the ability to relate the missing piece with surrounding elements to globally interpret the whole scene. The appearance of illusory figures (IF) based on surrounding elements also relies on this similar function. In the present study, we hypothesized that different mechanisms may be used by the brain to process illusory figures from the center and periphery of the visual field. We compared magnetoencephalographic responses to IFs presented at different parts of the visual field under three task loads. For central presentation, IF specific responses peaked first in V1/V2 (96-101 ms), and then in the lateral occipital complex (LOC; 132-141 ms), independent of task. For peripheral presentation, the relative modulation towards IF was markedly reduced in V1/V2 and LOC while prominent activation peaks now shifted to the Fusiform Gyrus (from 200 ms onwards). Additionally, the type of task influenced processing at early stages beginning in V1/V2 (87 ms). Our results show that retinal eccentricity plays a crucial role in IF processing: figural completion at the center of the visual field is achieved in an ‘automatic’ and seemingly effortless fashion whereas peripheral stimulus locations necessitate higher-order object completion stages, which rely more heavily on attentional demands.

The issue of how basic sensory and temporal processing are related is still unresolved. We studied temporal processing, as assessed by simple visual reaction times (RT) and double-pulse resolution (DPR), in patients with partial vision loss after visual pathway lesions and investigated whether vision restoration training (VRT), a training program designed to improve light detection performance, would also affect temporal processing. Perimetric and campimetric visual field tests as well as maps of DPR thresholds and RT were acquired before and after a 3 months training period with VRT. Patient performance was compared to that of age-matched healthy subjects. Intact visual field size increased during training. Averaged across the entire visual field, DPR remained constant while RT improved slightly. However, in transition zones between the blind and intact areas (areas of residual vision) where patients had shown between 20 and 80% of stimulus detection probability in pre-training vis...