yes / Purpose Perimetry is increasingly being used to measure sensitivity at central visual field locations. For many tasks, the central (0°, 0°) location is functionally the most important, however threshold estimates at this location may be affected by masking by the nearby spatial structure of the fixation target. We investigated this effect. Methods First we retrospectively analysed microperimetry (MAIA-2; CenterVue, Padova, Italy) data from 60 healthy subjects, tested on a custom grid with 1° central spacing. We compared sensitivity at (0°, 0°) to the mean sensitivity at the eight adjacent locations. We then prospectively tested 15 further healthy subjects on the same instrument using a cross-shaped test pattern with 1° spacing. Testing was carried out with and without the central fixation target, and sensitivity estimates at (0°, 0°) were compared. We also compared sensitivity at (0°, 0°) to the mean of the adjacent four locations in each condition. Three subjects undertook 10 repeated tests with the fixation target in place to assess within-subject variability of the effect. Results In the retrospective analysis, central sensitivity was median 2.8 dB lower (95% range 0.1–8.8 dB lower, p < 0.0001) than the mean of the adjacent locations. In the prospective study, central sensitivity was median 2.0 dB lower with the fixation target vs without (95% range 0.4–4.7 dB lower, p = 0.0011). With the fixation target in place central sensitivity was median 2.5 dB lower than mean sensitivity of adjacent locations (95% range 0.8–4.2 dB lower, p = 0.0007), whilst without the fixation target there was no difference (mean 0.4 dB lower, S.D. 0.9 dB, p = 0.15). These differences could not be explained by reduced fixation stability. Mean within subject standard deviation in the difference between central and adjacent locations' sensitivity was 1.84 dB for the repeated tests. Conclusions Perimetric sensitivity estimates from the central (0°, 0°) location are, on-average, reduced by 2 to 3 dB, corresponding to a 60–100% increase in stimulus luminance at threshold. This effect can be explained by masking by the nearby fixation target. The considerable within- and between-subject variability in magnitude, and the unknown effects of disease may hamper attempts to compensate threshold estimates for this effect. Clinicians should interpret central perimetric sensitivity estimates with caution, especially in patients with reduced sensitivity due to disease.

Yes / Depictions of vision with AMD in public information material typically show a central region of absolute vision loss. Patients with early and moderate disease frequently do not report this. We aimed to measure how a group of people with AMD perceive everyday scenes in order to produce accurate depictions. We report on six people aged 65-82 years with monocular AMD (visual acuity +0.04 to +1.64 logMAR) and normal vision in the fellow eye. Participants viewed 4 images monocularly, alternating between eyes. The image was digitally altered to approximate participants’ descriptions of their perception with the affected eye. The altered image was viewed with the unaffected eye, and compared with the original image viewed with the affected eye. This was repeated iteratively until a perceptual match was achieved between the modified image/unaffected eye and the original image/affected eye. For five AMD participants with visual acuity +0.04 to +0.50 logMAR the modified images did not resemble those in current public information material. Image modifications required to achieve perceptual similarity with the affected eyes included localised distortion, contrast reduction and blur. Widespread colour desaturation was also required in some cases. One participant with advanced geographic atrophy reported an absolute positive scotoma, similar to existing depictions. Vision in people with AMD may not conform to the common depiction of a central region of absolute vision loss. The accurate representations of AMD patients’ vision produced in this study will enable better understanding of the visual consequences of AMD. / College of Optometrists Postdoctoral Award; National Institute for Health Research Postdoctoral Fellowship

Design and evaluation of real-time descriptive mediation (RTDM) for live aquarium exhibits was proposed to support the participation of visitors with and without vision loss. RTDM was developed to address learning, entertainment, restorative, and social motivations. Data was collected during a lab study with adults to get feedback about the RTDM and compare it to traditional docent presentations and audio tours. Findings show that the RTDM made it possible for participants to address their exhibit motivations and led to specific personal and social aspects of participation. A majority of participants with and without vision loss reported that the RTDM was supportive of their motivations and perceived it to be more effective at supporting learning, social, and restoration motivations compared to audio tour and docent mediation. The main contributions of this work are in: 1) developing evidence-based information design criteria for mediation at live animal exhibits; 2) demonstrating that mediation designed to support exhibit motivations can facilitate participation in adults with and without vision loss; and 3) validating participation as a design goal.

This research is about evaluating vision in the periphery. Peripheral vision is of fundamental importance in the performance of our everyday activities. The aim of this thesis is to develop methods suitable for the evaluation of peripheral vision and to assess how different visual functions vary across the visual field. The results have application both within the field of visual rehabilitation of people with central visual field loss (CFL)and as well as in myopia research. All methods for assessing peripheral vision were implemented with adaptive psychophysical algorithms based on Bayesian statistics. A routine for time-efficient evaluation of peripheral contrast sensitivity was implemented and verified for measurements out to 30° in the visual field. Peripheral vision was evaluated for different properties of the stimuli: sharpness, motion, orientation, and extent. Optical quality was controlled using adaptive optics and/or corrective spectacles specially adapted for the peripheral viewing angle. We found that many peripheral visual functions improved with optical correction, especially in people with CFL. We also found improvements in peripheral contrast sensitivity for low spatial frequencies when stimuli drifted at 5 to 10 Hz; this applies both for people with normal vision and those with CFL. In the periphery, it is easier to see lines that are oriented parallel with respect to the visual field meridian. We have shown that this directional bias is present for both resolution and detection tasks in the periphery, even when the asymmetric optical errors are minimized. For accurate evaluation of peripheral vision, we therefore recommend using gratings that are oriented oblique to the visual  field meridian. The directional bias may have implications in how peripheral image quality affects myopia progression. Another proof that peripheral vision can influence central visual function is the fact that, when the stimulus extent was increased beyond the fovea, the blur in the stimulus was less noticeable. / Denna forskning handlar om att utvärdera synen i periferin. Vår perifera syn är ovärderlig i det dagliga livet. Målsättningen med denna avhandling är dels att utveckla metoder speciellt lämpade för perifer synutvärdering och dels att mäta hur olika synfunktioner varierar över synfältet. Resultaten har tillämpning både inom synrehabilitering för personer med centraltsynfältsbortfall och inom närsynthetsforskning. Adaptiv psykofysisk metodologi baserad på Bayesiansk statistik användes vid all utvärdering av det perifera seendet. Vi implementerade en rutin för tidseffektiv mätning av perifer kontrastkänslighet och verifierade den ut till 30° i synfältet. Den perifera synen utvärderades för olika egenskaper hos objektet: skärpa, rörelse, riktning och utbredning. Skärpan kontrollerades med hjälp av adaptiv optik och/eller glasögonkorrektion speciellt anpassad för den perifera synvinkeln. Vi fann att många periferasynfunktioner förbättras av optisk korrektion, särskilt för personer med centralt synfältsbortfall. Vi hittade även förbättringar i periferkontrastkänslighet för låga ortsfrekvenser när objektet modulerades med hastigheter mellan 5 och 10 Hz, vilket gäller både normalseende och personer med centralt synfältsbortfall. I periferin är det lättare att se linjer som är orienterade parallellt med synfältsmeridianen. Vi har visat att denna riktningsbias gäller både för upplösning och detektion i periferin, även när de asymmetriska optiska felen minimeras. För bästa mätnoggrannhet rekommenderar vi därför att använda randmönster som ligger snett relativt synfältsmeridianen. Denna riktningsbias skulle även kunna påverka hur den perifera bildkvalitén inverkar på utvecklingen av närsynthet. Ytterligare ett bevis för att perifer syn kan påverka den centrala synfunktionen är att, när objektets utbredning ökades, uppfattade personen det som mindre suddigt. / <p>QC 20160826</p>

No description available.

Juvenile neuronal ceroid lipofuscinosis (JNCL, aka. juvenile Batten disease or CLN3 disease), a lethal pediatric neurodegenerative disease without cure, often presents with vision impairment and characteristic ophthalmoscopic features including focal areas of hyper-autofluorescence. In the associated research article “Loss of CLN3, the gene mutated in juvenile neuronal ceroid lipofuscinosis, leads to metabolic impairment and autophagy induction in retinal pigment epithelium” (Zhong et al., 2020) [1], we reported ophthalmoscopic observations of focal autofluorescent lesions or puncta in the Cln3Δex7/8 mouse retina at as young as 8 month old. In this data article, we performed differential interference contrast and confocal imaging analyses in all retinal layers to localize and characterize these autofluorescent lesions, including their spectral characteristics and morphology. We further studied colocalization of these autofluorescent lesions with the JNCL marker mitochondrial ATP synthase F0 sub-complex subunit C and various established retinal cell type markers.

No description available.

La dégénérescence maculaire liée à l'âge (DMLA) touche actuellement un million de Canadiens, ce qui en fait la principale cause de perte de vision au Canada. La DMLA cause l’apparition d’une tache aveugle au niveau de la macula – la zone centrale de la vision. Cette tache aveugle affecte la vision centrale rendant les perceptions visuelles floues ou déformées. L’impact de cette condition est considérable puisqu’elle rend impossible la conduite, difficile la lecture et entraîne ultimement une cécité totale. La DMLA a également été identifiée comme facteur de risque de la dépression et de l’isolement sociale, ce qui porte d’autant plus atteinte à la qualité de vie des patients. Une des avenues de réadaptation pour les patients est d’améliorer leur utilisation de leur fonction visuelle résiduelle, notamment la vision périphérique. Le but de la présente recherche est d’investiguer le potentiel réadaptatif d’un entraînement imposant l’utilisation de la vision périphérique chez des participants en bonne santé en présence d’une perte de vision centrale simulée. Une compréhension des changements dans les comportements des mouvements oculaires en présence d'un scotome artificiel central aidera à développer des programmes de réadaptation pour les personnes atteint de DMLA et plus largement les personnes présentant une perte visuelle centrale. Les résultats démontrent une adaptation des stratégies visuelles des participants, entraînant une augmentation de la performance, une réduction des temps de réponse et une meilleure discrimination, suggérant ainsi que l’entraînement est susceptible de contribuer à la réadaptation des personnes atteintes de pertes visuelles centrales. / Age Macular Degeneration (AMD) currently affects one million Canadians, making it the leading cause of vision loss in Canada. AMD causes the appearance of a blind spot on the macula – the central area of vision. This blind spot affects the central vision making visual perceptions blurry or distorted. The impact of this condition is considerable since it impedes driving as well as reading and ultimately leads to total blindness. AMD has also been shown to be a risk factor for depression and social isolation, further compromising quality of life for patients. One of the avenues of rehabilitation for patients is to improve their use of their residual visual function, in particular their peripheral vision. The purpose of the present research is to investigate the rehabilitative potential of training requiring the use of peripheral vision in healthy participants in the presence of a simulated central vision loss. An understanding of changes in eye movement patterns in the presence of a central artificial scotoma will help develop rehabilitation protocols for people with AMD and more broadly people with central visual loss. Results demonstrate an adaptation of visual strategies among participants, resulting in increased performance, reduced response times and better discrimination, suggesting that training is likely to contribute to the rehabilitation of people with central vision loss.

Malgré des recherches intensives portant sur l’hérédité et les aspects biologiques de la rétinite pigmentaire (RP), peu de recherches fondées ont porté sur les aspects psychologiques. Ces quelques études suggèrent que les personnes atteintes de rétinite pigmentaire s’adaptent différemment à la déficience visuelle. Le but de la présente étude était donc de vérifier si les personnes atteintes de rétinite pigmentaire s’adaptaient différemment d’un point de vue psychologique par rapport à des personnes ayant une déficience visuelle causée par une autre pathologie. Des entrevues téléphoniques incluant des personnes ayant la rétinite pigmentaire, la rétinopathie diabétique (RD) et l’albinisme ont été menées. Cinq questionnaires ont été utilisés afin d’évaluer le bien-être psychologique et de recueillir les données démographique. Les résultats de la première étude démontrent qu’il n’existe aucune différence entre les individus atteints de rétinite pigmentaire et ceux ayant d’autres pathologies visuelles d’un point de vue « bien-être psychologique ». En fait, les facteurs démographiques, la baisse de vision, les fluctuations et le type de perte de vision semblent être les seuls facteurs directement corrélés à l’adaptation et au bien-être psychologique. Dans la deuxième étude, aucune différence n’a pu être établie entre les trois types de pathologies. Ce sont plutôt, des facteurs comme la perception des capacités fonctionnelles, l’identité personnelle, l’appréhension de la perception sociale et le niveau d’indépendance qui étaient davantage reliés au bien-être psychologique associé à la déficience visuelle. Les résultats de cette étude suggèrent que les personnes atteintes de Rétinite pigmentaire ne présentent pas de différences au niveau du bien-être psychologique et de l’adaptation. Les facteurs démographiques et psychologiques sont plus importants que la pathologie elle-même. / While there is extensive research on retinitis pigmentosa (RP) focusing on biological and hereditary aspects of the disease, little research regarding psychological adjustment has been conducted. These few studies suggest that people with RP adapt differently to vision impairment. This study investigated whether those with RP adapt differently to vision loss/impairment than those with other vision disorders. Telephone interviews of those with RP, diabetic retinopathy (DR), and albinism were conducted. Demographic information was gathered and psychological wellbeing was assessed using the Visual Function-14, Centre of Epidemiology Studies Depression-10 symptoms index, Impact of Vision Impairment Profile, Brief COPE, and Adaptation to Vision Loss Scale. In Experiment I it was found that individuals with RP did not differ from those with other diagnoses on any of the measures of psychological wellbeing and adaptation. Rather, demographic factors, visual factors such as declining and fluctuating vision, and pattern of vision loss, were better correlates of adaptation to and psychological wellbeing associated with vision loss/impairment. In Experiment II there was no difference found between those with RP and other diagnoses on any of the measures. Rather, factors such as perceived visual ability, self-identity, fear of social stigma and level of dependence were more closely related to adaptation to and psychological wellbeing associated with vision loss/impairment. The results of this study suggest that individuals with RP do not differ from those with other vision disorders in their adaptation to and psychological wellbeing associated with vision loss/impairment, but that other demographic, visual and psychological factors are more important.

Malgré des recherches intensives portant sur l’hérédité et les aspects biologiques de la rétinite pigmentaire (RP), peu de recherches fondées ont porté sur les aspects psychologiques. Ces quelques études suggèrent que les personnes atteintes de rétinite pigmentaire s’adaptent différemment à la déficience visuelle. Le but de la présente étude était donc de vérifier si les personnes atteintes de rétinite pigmentaire s’adaptaient différemment d’un point de vue psychologique par rapport à des personnes ayant une déficience visuelle causée par une autre pathologie. Des entrevues téléphoniques incluant des personnes ayant la rétinite pigmentaire, la rétinopathie diabétique (RD) et l’albinisme ont été menées. Cinq questionnaires ont été utilisés afin d’évaluer le bien-être psychologique et de recueillir les données démographique. Les résultats de la première étude démontrent qu’il n’existe aucune différence entre les individus atteints de rétinite pigmentaire et ceux ayant d’autres pathologies visuelles d’un point de vue « bien-être psychologique ». En fait, les facteurs démographiques, la baisse de vision, les fluctuations et le type de perte de vision semblent être les seuls facteurs directement corrélés à l’adaptation et au bien-être psychologique. Dans la deuxième étude, aucune différence n’a pu être établie entre les trois types de pathologies. Ce sont plutôt, des facteurs comme la perception des capacités fonctionnelles, l’identité personnelle, l’appréhension de la perception sociale et le niveau d’indépendance qui étaient davantage reliés au bien-être psychologique associé à la déficience visuelle. Les résultats de cette étude suggèrent que les personnes atteintes de Rétinite pigmentaire ne présentent pas de différences au niveau du bien-être psychologique et de l’adaptation. Les facteurs démographiques et psychologiques sont plus importants que la pathologie elle-même. / While there is extensive research on retinitis pigmentosa (RP) focusing on biological and hereditary aspects of the disease, little research regarding psychological adjustment has been conducted. These few studies suggest that people with RP adapt differently to vision impairment. This study investigated whether those with RP adapt differently to vision loss/impairment than those with other vision disorders. Telephone interviews of those with RP, diabetic retinopathy (DR), and albinism were conducted. Demographic information was gathered and psychological wellbeing was assessed using the Visual Function-14, Centre of Epidemiology Studies Depression-10 symptoms index, Impact of Vision Impairment Profile, Brief COPE, and Adaptation to Vision Loss Scale. In Experiment I it was found that individuals with RP did not differ from those with other diagnoses on any of the measures of psychological wellbeing and adaptation. Rather, demographic factors, visual factors such as declining and fluctuating vision, and pattern of vision loss, were better correlates of adaptation to and psychological wellbeing associated with vision loss/impairment. In Experiment II there was no difference found between those with RP and other diagnoses on any of the measures. Rather, factors such as perceived visual ability, self-identity, fear of social stigma and level of dependence were more closely related to adaptation to and psychological wellbeing associated with vision loss/impairment. The results of this study suggest that individuals with RP do not differ from those with other vision disorders in their adaptation to and psychological wellbeing associated with vision loss/impairment, but that other demographic, visual and psychological factors are more important.