Dataset Information

Evidence-based Criteria for Assessment of Visual Field Reliability.

ABSTRACT: PURPOSE:Assess the impact of false-positives (FP), false-negatives (FN), fixation losses (FL), and test duration (TD) on visual field (VF) reliability at different stages of glaucoma severity. DESIGN:Retrospective. PARTICIPANTS:A total of 10?262 VFs from 1538 eyes of 909 subjects with suspect or manifest glaucoma and ?5 VF examinations. METHODS:Predicted mean deviation (MD) was calculated with multilevel modeling of longitudinal data. Differences between predicted and observed MD (?MD) were calculated as a reliability measure. The impact of FP, FN, FL, and TD on ?MD was assessed using multilevel modeling. MAIN OUTCOME MEASURES:?MD associated with a 10% increment in FP, FN, and FL, or a 1-minute increase in TD. RESULTS:FL had little impact on ?MD (<0.2 decibels [dB] per 10% abnormal catch trials), and no level of FL produced ?1 dB of ?MD at any disease stage. FP yielded greater than expected MD, with a 10% increment in abnormal catch trials associated with a ?MD = 0.42, 0.73, and 0.66 dB in mild (MD >-6 dB), moderate (-6 ?MD <-12 dB), and severe (-12 ?MD ?-20 dB) disease, respectively, up to 20% abnormal catch trials, and a ?MD = 1.57, 2.06, and 3.53 dB beyond 20% abnormal catch trials. FNs generally produced observed MDs below expected MDs. FN were minimally impactful up to 20% abnormal catch trials (?MD per 10% increment >-0.14 dB at all levels of severity). Beyond 20% abnormal catch trials, each 10% increment in abnormal catch trials was associated with a ?MD = -1.27, -0.53, and -0.51 dB in mild, moderate, and severe disease, respectively. |?MD| ?1 dB occurred with 22% FP and 26% FN in early, 14% FP and 34% FN in moderate, and 16% FP and 51% FN in severe disease. A 1-minute increment in TD produced ?MDs between -0.35 and -0.40 dB. CONCLUSIONS:FL have little impact on reliability in patients with established glaucoma. FP, and to a lesser extent FNs and TD, significantly affect reliability. The impact of FP and FN varies with disease severity and over the range of abnormal catch trials. On the basis of our findings, we present evidence-based, severity-specific standards for classifying VF reliability for clinical or research applications.

SUBMITTER: Yohannan J

PROVIDER: S-EPMC5675138 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature

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Evidence-based Criteria for Assessment of Visual Field Reliability.

Yohannan Jithin J Wang Jiangxia J Brown Jamie J Chauhan Balwantray C BC Boland Michael V MV Friedman David S DS Ramulu Pradeep Y PY

Ophthalmology 20170701 11

<h4>Purpose</h4>Assess the impact of false-positives (FP), false-negatives (FN), fixation losses (FL), and test duration (TD) on visual field (VF) reliability at different stages of glaucoma severity.<h4>Design</h4>Retrospective.<h4>Participants</h4>A total of 10 262 VFs from 1538 eyes of 909 subjects with suspect or manifest glaucoma and ≥5 VF examinations.<h4>Methods</h4>Predicted mean deviation (MD) was calculated with multilevel modeling of longitudinal data. Differences between predicted an ...[more]

PMID: 28676280

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Project description:PurposeTo assess the impact of OCT signal strength (SS) and artifact on retinal nerve fiber layer (RNFL) measurement reliability and to understand whether glaucoma severity modifies this relationship.DesignRetrospective, longitudinal cohort study.ParticipantsTwo thousand nine hundred ninety-two OCT scans from 474 eyes of 241 patients with glaucoma or glaucoma suspect status.MethodsWe extracted mean RNFL thickness and SS and manually graded scans for artifact. To analyze the effect of SS and artifact on OCT reliability, we (1) created a multilevel linear model using measured RNFL thickness values and demographic and clinical data to estimate the true (predicted) RNFL thickness, (2) calculated model residuals (ΔRNFL) as our reliability measure, and (3) created a second multilevel linear model with splines and interaction terms that modeled overall and quadrant specific reliability (ΔRNFL) as the outcome, using SS and artifact as predictors.Main outcome measuresImpact of SS and artifact on ΔRNFL.ResultsFor SS between 10 and 3, the impact of decreases in SS on OCT reliability is modest (-0.67 to -1.25 ΔRNFL per 1-point decrease in SS; P < 0.05). But at less than 3, changes in SS have a large impact on reliability (-15.70 to -16.34 ΔRNFL per 1-point decrease in SS; P < 0.05). At SS between 10 and 3, decreases in SS tend to have a larger impact on reliability in eyes with severe glaucoma (-1.25 per 1-point decrease in SS; P < 0.05) compared with eyes with mild or moderate glaucoma (-0.67 to -0.75 per 1-point decrease in SS; P < 0.05). The presence of artifact has a significant impact on OCT reliability independent of the effects of SS (-4.76 ΔRNFL; P < 0.05). Artifact affects reliability solely in the quadrant in which it occurs, with artifact in one quadrant showing no impact on ΔRNFL in the opposite quadrant (P > 0.05).ConclusionsSignal strength decreases down to 3 have relatively mild impacts on OCT reliability. At less than 3, the impact of further decreases in SS on reliability are substantial. The effect of SS on reliability is greater in severe glaucoma. Artifacts result in a decrease in reliability independent of the effect of SS. We propose evidence-based guidelines to guide physicians on whether to trust the results of an OCT scan.

Project description:PurposeIdentify factors predicting worse or better than expected visual field (VF) performance.MethodsA total of 10,262 VFs from 1538 eyes of 909 subjects with manifest or suspected glaucoma were analyzed. Linear mixed-effects models predicted mean deviation (MD) at each timepoint. Differences between observed and predicted MD (?MD) were calculated and logistic regression identified factors predicting lower than expected (?MD <-1 dB) or higher than expected (?MD >1 dB) sensitivity.ResultsBoth higher and lower than expected sensitivity were more likely in VFs with severe compared with mild damage (relative risk [RR] >1.3, P < 0.05). Higher than expected sensitivity was more likely in VFs with moderate damage (RR = 2.57, P < 0.001). False-positive (FP) errors increased the likelihood of higher than expected sensitivity at all disease stages (RR >2.1 per 10% increase, P < 0.001), whereas false-negative (FN) errors increased the likelihood of lower than expected sensitivity in mild and moderate disease (RR >1.19 per 10% increase, P < 0.05). Fixation loss errors slightly increased the likelihood of higher than expected VF sensitivity in moderate and severe disease (RR >1.1 per 10% increase, P < 0.01). Longer test duration increased likelihood of lower than expected sensitivity at all disease stages (RR >1.36 per minute increase, P < 0.001). Lower than expected sensitivity was more likely in late afternoon tests (RR = 1.27, P < 0.01). A total of 26.6% of VFs had higher or lower than expected sensitivity in the absence of FPs, FNs, or fixation losses.ConclusionsFPs, test duration, and FNs are the primary measures predicting if a VF is likely to be reliable, although tests with normal reliability measures may still be unreliable. Our results help clinicians judge VF reliability and highlight the need to integrate reliability measures with other clinical data when making treatment decisions.Translational relevanceThis likelihood model derived from a large dataset helps clinicians identify VFs that may either falsely suggest disease progression or mask true worsening, thereby improving the utility of VFs in clinical practice.

Project description:Visual deficits in children that result from brain injury, including cerebral/cortical visual impairment (CVI), are difficult to assess through conventional methods due to their frequent co-occurrence with cognitive and communicative disabilities. Such impairments hence often go undiagnosed or are only determined through subjective evaluations of gaze-based reactions to different forms, colors, and movements, which limits any potential for remediation. Here, we describe a novel approach to grading visual health based on eye movements and evidence from gaze-based tracking behaviors. Our approach-the "Visual Ladder"-reduces reliance on the user's ability to attend and communicate. The Visual Ladder produces metrics that quantify spontaneous saccades and pursuits, assess visual field responsiveness, and grade spatial visual function from tracking responses to moving stimuli. We used the Ladder to assess fourteen hospitalized children aged 3 to 18 years with a diverse range of visual impairments and causes of brain injury. Four children were excluded from analysis due to incompatibility with the eye tracker (e.g., due to severe strabismus). The remaining ten children-including five non-verbal children-were tested multiple times over periods ranging from 2 weeks to 9 months, and all produced interpretable outcomes on at least three of the five visual tasks. The results suggest that our assessment tasks are viable in non-communicative children, provided their eyes can be tracked, and hence are promising tools for use in a larger clinical study. We highlight and discuss informative outcomes exhibited by each child, including directional biases in eye movements, pathological nystagmus, visual field asymmetries, and contrast sensitivity deficits. Our findings indicate that these methodologies will enable the rapid, objective classification and grading of visual impairments in children with CVI, including non-verbal children who are currently precluded from most vision assessments. This would provide a much-needed differential diagnostic and prognostic tool for CVI and other impairments of the visual system, both ocular and cerebral.

Project description:PurposeA stroke that includes the primary visual cortex unilaterally leads to a loss of visual field (VF) representation in the hemifield contralateral to the damage. While behavioral procedures for measuring the VF, such as perimetry, may indicate that a patient cannot see in a particular area, detailed psychophysical testing often detects the ability to perform detection or discrimination of visual stimuli ("blindsight"). The aim of this study was to determine whether functional magnetic resonance imaging (fMRI) could be used to determine whether perimetrically blind regions of the VF were still represented in VF maps reconstructed on the basis of visually evoked neural activity.MethodsThirteen patients with hemianopia and nine control participants were scanned using 3T MRI while presented with visual stimulation. Two runs of a dynamic "wedge and ring" mapping stimulus, totaling approximately 10 min, were performed while participants fixated centrally. Two different analysis approaches were taken: the conventional population receptive field (pRF) analysis and micro-probing (MP). The latter is a variant of the former that makes fewer assumptions when modeling the visually evoked neural activity. Both methods were used to reconstruct the VF by projecting modeled activity back onto the VF. Following a normalization step, these "coverage maps" can be compared to the VF sensitivity plots obtained using perimetry.ResultsWhile both fMRI-based approaches revealed regions of neural activity within the perimetrically "blind" sections of the VF, the MP approach uncovered more voxels in the lesioned hemisphere in which a modest degree of visual sensitivity was retained. Furthermore, MP-based analysis indicated that both early (V1/V2) and extrastriate visual areas contributed equally to the retained sensitivity in both patients and controls.ConclusionIn hemianopic patients, fMRI-based approaches for reconstructing the VF can pick up activity in perimetrically blind regions of the VF. Such regions of the VF may be particularly amenable for rehabilitation to regain visual function. Compared to conventional pRF modeling, MP reveals more voxels with retained visual sensitivity, suggesting it is a more sensitive approach for VF reconstruction.

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Evidence-based Criteria for Assessment of Visual Field Reliability.

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Evidence-based Criteria for Assessment of Visual Field Reliability.

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