To describe a new time-saving threshold visual field-testing strategy-Swedish Interactive Thresholding Algorithm (SITA) Faster, which is intended to replace SITA Fast-and to report on a clinical evaluation of this new strategy. Description and validity analysis for modifications applied to SITA Fast. Five centers tested 1 eye of each of 126 glaucoma and glaucoma suspect patients with SITA Faster, SITA Fast, and SITA Standard at each of 2 visits. Outcomes included test time, mean deviation, and the visual field index (VFI), significant test points in probability maps, and intertest threshold variability. Mean (standard deviation) test times were 171.9 (45.3) seconds for SITA Faster, 247.0 (56.7) for SITA Fast, and 369.5 (64.5) for SITA Standard (P < .001). SITA Faster test times averaged 30.4 % shorter than SITA Fast and 53.5 % shorter than SITA Standard. Mean deviation was similar among all 3 tests.VFI did not differ between SITA Fast and SITA Faster tests, mean difference 0%, but VFI values were 1.2% lower with SITA Standard compared to both SITA Fast (P = .007) and SITA Faster (P = .002). A similar trend was seen with a slightly higher number of significant test points with SITA Standard than with SITA Fast and SITA Faster. All 3 tests had similar test-retest variability over the entire range of threshold values. SITA Faster saved considerable test time. SITA Faster and SITA Fast gave almost identical results. There were small differences between SITA Faster and SITA Standard, of the same character as previously shown for SITA Fast vs SITA Standard.
1 May 2014 in Investigative Ophthalmology & Visual Science
Purpose. To introduce a perimetric algorithm (gradient-oriented automated natural neighbor approach [GOANNA]) that automatically chooses spatial test locations to improve characterization of visual field (VF) loss without increasing test times. Methods. Computer simulations were undertaken to assess the performance of GOANNA. GOANNA was run on a 3° grid of 150 locations, and was compared with a zippy estimation by sequential testing (ZEST) thresholding strategy for locations in the 24-2 test pattern, with the remaining 98 locations being interpolated. Simulations were seeded using empirical data from 23 eyes with glaucoma that were measured at all 150 locations. The performance of the procedures was assessed by comparing the output thresholds to the input thresholds (accuracy and precision) and by evaluating the number of presentations required for the procedure to terminate (efficiency). Results. When collated across whole-fields, there was no significant difference in accuracy, precision, or efficiency between GOANNA and ZEST. However, GOANNA targeted presentations on scotoma borders; hence it was more precise and accurate at locations where the sensitivity gradient within the VF was high. Conclusions. Compared with ZEST, GOANNA was marginally less precise in areas of the VF that had spatially uniform sensitivity, but improved accuracy and precision in regions surrounding scotoma edges. GOANNA provides a principled framework for automatic placement of additional test locations to provide spatially denser testing around the borders of VF loss.
1 May 2019 in Investigative Ophthalmology & Visual Science
Purpose: To characterize visual loss across the full visual field in idiopathic intracranial hypertension (IIH) patients with mild central visual loss. Methods: We tested the full visual field (50° nasal, 80° temporal, 30° superior, 45° inferior) of 1 eye of 39 IIH patients by using static perimetry (size V) with the Open Perimetry Interface. Participants met the Dandy criteria for IIH and had at least Frisén grade 1 papilledema with better than −5 dB mean deviation (MD) centrally. Two observers (MW and AS) evaluated the visual field defects, adjudicated any differences, and reviewed optical coherence tomography data. Results: We found a greater MD loss peripherally than centrally (central 26°). The median MD (and corresponding median absolute deviations) was −1.37 dB (1.61 dB) for the periphery and −0.77 dB (0.87 dB) for the central 26°, P < 0.001. There were about 30% more abnormal test locations identified in the periphery (P = 0.12), and the mean defect depth increased with eccentricity (P < 0.001). The most frequent defect found was a temporal wedge (23% of cases) in the periphery with another 23% that included this sector with inferior temporal loss. Although the presence of papilledema limited correlation, 55% of the temporal wedge defects had optical coherence tomography retinal nerve fiber layer deficits in the corresponding superonasal location. Other common visual field defects were inferonasal loss, superonasal loss, and superior and inferior arcuate defects. Seven patients (18%) had visual field defects in the periphery with normal central visual field testing. Conclusion: In IIH patients, we found substantial visual loss both outside 30° of the visual field and inside 30° with the depth of the defect increasing linearly with eccentricity. Temporal wedge defects were the most common visual field defect in the periphery. Static threshold perimetry of the full visual field appears to be clinically useful in IIH patients.
Ocular allergy is an immunoglobulin E-mediated Type I hypersensitivity reaction localised to the ocular surface and surrounding tissues. Primary signs and symptoms of ocular allergy include itching, redness, irritation and inflammation. Eye-rubbing caused by itching has been shown to alter ocular surface protein concentrations in conditions linked to ocular allergy such as keratoconus. In keratoconus, the cornea begins to thin and sag over time, leading to progressive vision loss and blindness in severe conditions. Due to the high incidence of ocular allergy sufferers rubbing their eyes in response to symptoms of itching, the protein landscape of the ocular surface may be significantly altered. Differential protein expression caused by long-term inflammation and eye-rubbing may lead to subsequent changes in ocular surface structure and function over time. This review aims to summarise and explore the findings of current ocular allergy proteome research conducted using techniques such as gel electrophoresis, mass spectrometry and lab-on-a-chip proteomics. Proteins of interest for this review include differentially expressed immunoglobulins, mucins, functional proteins, enzymes and proteins with previously uncharacterised roles in ocular allergy. Additionally, potential applications of this research are addressed in terms of diagnostics, drug development and future research prospects.
1 September 2016 in Translational Vision Science & Technology
Purpose: To validate the performance of a new perimetric algorithm (Gradient-Oriented Automated Natural Neighbor Approach; GOANNA) in humans using a novel combination of computer simulation and human testing, which we call Artificial Scotoma Generation (ASG). Methods: Fifteen healthy observers were recruited. Baseline conventional automated perimetry was performed on the Octopus 900. Visual field sensitivity was measured using two different procedures: GOANNA and Zippy Estimation by Sequential Testing (ZEST). Four different scotoma types were induced in each observer by implementing a novel technique that inserts a step between the algorithm and the perimeter, which in turn alters presentation levels to simulate scotomata in human observers. Accuracy, precision, and unique number of locations tested were measured, with the maximum difference between a location and its neighbors (Max_d) used to stratify results. Results: GOANNA sampled significantly more locations than ZEST (paired t-test, P < 0.001), while maintaining comparable test times. Difference plots showed that GOANNA displayed greater accuracy than ZEST when Max_d was in the 10 to 30 dB range (with the exception of Max_d = 20 dB; Wilcoxon, P < 0.001). Similarly, GOANNA demonstrated greater precision than ZEST when Max_d was in the 20 to 30 dB range (Wilcoxon, P < 0.001). Conclusions: We have introduced a novel method for assessing accuracy of perimetric algorithms in human observers. Results observed in the current study agreed with the results seen in earlier simulation studies, and thus provide support for performing larger scale clinical trials with GOANNA in the future. Translational Relevance: The GOANNA perimetric testing algorithm offers a new paradigm for visual field testing where locations for testing are chosen that target scotoma borders. Further, the ASG methodology used in this paper to assess GOANNA shows promise as a hybrid between computer simulation and patient testing, which may allow more rapid development of new perimetric approaches.
The data were gathered from 98 eyes of 98 ocular healthy subjects. The subject ages ranged from 18 to 79 years with a mean (and standard deviation) of 47 (17) years. Each subject underwent two visual field tests, one of the central visual field (64 locations within 26° of fixation) and one of the peripheral visual field (64 locations with eccentricity from 26° to up to 81°). Luminance thresholds for the Goldmann size V stimulus (with a diameter of 1.72° of visual angle) were obtained with the ZEST Bayesian test procedure. Each test was conducted twice within 90 days.