no / This study aimed to determine if response times gathered during perimetry can be exploited within a thresholding algorithm to improve the speed and accuracy of the test. Frequency of seeing (FoS) curves were measured at 24 locations across the central 30° of the visual field of 10 subjects using a Method of Constant Stimuli, with response times recorded for each presentation. Spatial locations were interleaved, and built up over multiple 5-min blocks, in order to mimic the attentional conditions of clinical perimetry. FoS curves were fitted to each participant’s data for each location, and response times derived as a function of distance-from-threshold normalised to the slope of each FoS curve. This data was then used to derive a function for the probability of observing response times given the distance-from-threshold, and to seed simulations of a new test procedure (BURTO) that exploited the probability function for stimulus placement. Test time and error were then simulated for patients with various false response rates. When compared with a ZEST algorithm, simulations revealed that BURTO was about one presentation per location faster than ZEST, on average, while sacrificing less precision and bias in threshold estimates than simply terminating the ZEST earlier. Despite response times varying considerably for a given individual and their thresholds, response times can be exploited to reduce the number of presentations required in a visual field test without loss of accuracy.

Yes / PURPOSE. To compare microperimetric sensitivity around the monocular preferred retinal locus (mPRL) in age-related macular degeneration (AMD) to normative data, and to describe the characteristics of visual field defects around the mPRL in AMD. METHODS. Participants with AMD (total n ¼ 185) were either prospectively recruited (n ¼ 135) or retrospectively reviewed from an existing database (n ¼ 50). Participants underwent microperimetry using a test pattern (37 point, 58 radius) centered on their mPRL. Sensitivities were compared to normative data by spatial interpolation, and conventional perimetric indices were calculated. The location of the mPRL relative to the fovea and to visual field defects was also investigated. RESULTS. Location of mPRL varied approximately 158 horizontally and vertically. Visual field loss within 58 of the mPRL was considerable in the majority of participants (median mean deviation 14.7 dB, interquartile range [IQR] 19.6 to 9.6 dB, median pattern standard deviation 7.1 dB [IQR 4.8–9.0 dB]). Over 95% of participants had mean total deviation worse than 2 dB across all tested locations and similarly within 18 of their mPRL. A common pattern of placing the mPRL just foveal to a region of normal pattern deviation was found in 78% of participants. Total deviation was outside normal limits in this region in 68%. CONCLUSIONS. Despite altering fixation to improve vision, people with AMD exhibit considerable visual field loss at and around their mPRL. The location of the mPRL was typically just foveal to, but not within, a region of relatively normal sensitivity for the individual, suggesting that a combination of factors drives mPRL selection. / This report presents independent research funded by the NIHR

Many systems today do not allow the operator to view the environment directly. For example, operators of telerobotic or remote manipulation systems may be far removed from the work site. In these situations, images from cameras at the task site provide the only visual link between the task and operator. Such imaging systems are unable to provide exact representations of the task environment, resulting in a possible degradation of important visual cues. If visual cues are degraded, task performance may be less accurate, require increased completion time, and subject the operator to hazardous conditions. In this study, the field of view and contrast of imagery were manipulated to determine their effects on observers' ability to estimate distances of targets within natural settings. Images were video taped with a rotating camera and the targets were placed between 9.14 m and 60.96 m from the camera. The fields of view ranged from 20 deg to 74 deg. A lightly wooded area and an open field were used to provide either high or low visual contexts, respectively. Participants rated their confidence in the distance estimates on a seven-point scale. / Master of Science

yes / Microperimetry, also referred to as fundus perimetry or fundus-driven perimetry, enables simultaneous acquisition of visual sensitivity and eye movement data. We present sensitivity data collected from 60 participants with normal vision using gaze-contingent perimetry. A custom designed spatially dense test grid was used to collect data across the visual field within 13° of fixation. These data are supplemental to a study in which we demonstrated a spatial interpolation method that facilitates comparison of acquired data from any set of spatial locations to normative data and thus screening of individuals with both normal and non-foveal fixation (Denniss and Astle, 2016)[1].

No description available.

Synfältsundersökningen är den viktigaste metoden för att diagnostisera och identifiera progression av glaukom. Att genomföra synfältsundersökningen är en vanligt förekommande arbetsuppgift för ögonsjuksköterskan. Studier visar att patienter har svårigheter vid genomförandet av undersökningen, men studier på hur patienten själv upplever synfältsundersökningstillfället saknas. Syftet med pilotstudien var att undersöka patientens upplevelse av synfältsundersökningstillfället. Pilotstudien genomfördes med en kvalitativ metod och data samlades in genom semistrukturerade intervjuer av åtta patienter. Materialet analyserades med hjälp av kvalitativ innehållsanalys. Analysen ledde till fem kategorier: upplevelse av rädsla och oro, svårt med fokusering, upplevelse av information, känsla av trygghet, och kroppsligt obehag. Att inte prestera bra och att eventuellt blivit försämrad i sjukdomen var det som främst skapade rädsla och oro. Fokusering krävde mycket koncentration och var ansträngande för ögonen. Informationen upplevdes som både bra och bristfällig. Patienterna kände en trygghet då de hade gjort undersökningen tidigare och att de träffade samma personal. Majoriteten av patienterna upplevde att de satt obekvämt och inte patientvänligt. Fortsatt utveckling och utbildning om hur patienter upplever synfältsundersökningstillfället rekommenderas för att förbättra hur personalen bemöter och informerar patienten, men även för hur ögonsjuksköterskan kan underlätta undersökningen för patienten. Då denna studie utfördes som en pilotstudie behövs vidare forskning och en fullskalig studie för att resultatet ska kunna anses vara tillförlitligt. / Visual field examination is the most important method to diagnose and identify the progression of glaucoma. Conducting visual field examination is a common task for the ophthalmic nurse. Studies show that patients have difficulty in carrying out the visual field examination, but studies on how the patient experiences the visual field examination are scarce. The aim of the pilot study was to examine the patient's experience of the visual field examination. The pilot study was conducted using a qualitative approach and data was collected through semi-structured interviews of eight patients. The material was analyzed using content analysis. The analysis resulted in five categories: experience of fear and anxiety, difficulty with focusing, experience of information, sense of security, and bodily discomfort. Failing to perform well and to possibly become impaired in their disease were major concerns that created fear and anxiety. Focusing demanded a lot of concentration and was straining on the eye. The information was perceived as both good and flawed. Patients felt a sense of security since they had done the examination before and that they met the same staff. The majority of patients felt they sat uncomfortably and that it was not patient friendly. Continued development and training on how patients experience visual field examination is recommended to improve the way the staff treats and informs the patient, but also how the ophthalmic nurse can facilitate the examination of the patient. Since this study was conducted as a pilot study further research and a full-scale study is needed for the results to be considered reliable.

Licentiatavhandling (sammanfattning) Stockholm : Karol. inst., 2005. / Härtill 2 uppsatser.

yes / Purpose: To demonstrate methods that enable visual field sensitivities to be compared with normative data without restriction to a fixed test pattern. Methods: Healthy participants (n = 60, age 19–50) undertook microperimetry (MAIA-2) using 237 spatially dense locations up to 13° eccentricity. Surfaces were fit to the mean, variance, and 5th percentile sensitivities. Goodness-of-fit was assessed by refitting the surfaces 1000 times to the dataset and comparing estimated and measured sensitivities at 50 randomly excluded locations. A leave-one-out method was used to compare individual data with the 5th percentile surface. We also considered cases with unknown fovea location by adding error sampled from the distribution of relative fovea–optic disc positions to the test locations and comparing shifted data to the fixed surface. Results: Root mean square (RMS) difference between estimated and measured sensitivities were less than 0.5 dB and less than 1.0 dB for the mean and 5th percentile surfaces, respectively. Root mean square differences were greater for the variance surface, median 1.4 dB, range 0.8 to 2.7 dB. Across all participants 3.9% (interquartile range, 1.8–8.9%) of sensitivities fell beneath the 5th percentile surface, close to the expected 5%. Positional error added to the test grid altered the number of locations falling beneath the 5th percentile surface by less than 1.3% in 95% of participants. Conclusions: Spatial interpolation of normative data enables comparison of sensitivity measurements from varied visual field locations. Conventional indices and probability maps familiar from standard automated perimetry can be produced. These methods may enhance the clinical use of microperimetry, especially in cases of nonfoveal fixation.

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 / Purpose Flicker-defined form (FDF) stimuli have recently been adopted for visual field testing. A key difference between FDF and traditional perimetric stimuli is that the entire display background contains flickering dots. The purpose of this study was to determine whether the perception of FDF stimuli is influenced by lateral interactions involving regions beyond the stimulus border in young healthy observers. Methods Experiment 1 measured the effect of surround size and retinal eccentricity on the detection of the FDF contour. Psychometric functions were collected for surround diameters of 20°, 30° and 40°, and with stimuli centred at eccentricities of 0°, 10° and 20°. Experiment 2 measured the effect of target-surround temporal phase difference on apparent temporal contrast (flicker strength) of the target for both the FDF stimulus and a solid-field stimulus. Psychometric functions were collected for target-surround phase differences of 0°, 45°, 90°, 135° and 180°. Results Our results show a mild surround-suppression effect for FDF stimuli that is independent of surround size. Magnitudes of FDF surround suppression were consistent with the reduced temporal contrast energy of the stimulus compared to solid-field stimuli. Conclusion FDF stimuli necessarily have both flickering target and background. Our results suggest that visual field defects outside the target are unlikely to markedly influence the detection and perception of the FDF stimulus. Nevertheless, mild surround suppression of contrast arises for FDF stimuli, hence interactions between the background and the target area may influence FDF results in conditions that alter centre-surround perceptual effects.