Publications by authors named "Massof R"
Significance: This work shows the benefits of using two different magnification strategies to improve the reading ability of low-vision patients using a head-mounted technology.
Purpose: The aim of this study was to conduct a comparative clinical trial evaluating the effectiveness of two magnification strategies in a head-mounted virtual reality display.
Methods: Eighty-eight eligible low-vision subjects were randomized into two arms: (1) the full-field magnification display or (2) the virtual bioptic telescope mode.
Purpose: To develop and validate a novel patient-reported outcome (PRO) measure to assess vision-related functioning in individuals with severe peripheral field loss (PFL).
Design: Prospective outcome measure development/validation study.
Methods: A 127-item questionnaire was developed based on a prior qualitative interview study.
Significance: This work validates Rasch analysis of a performance-based low vision outcome measure evaluated in patients' own homes to ensure real-world relevance. Inclusion of sources of variance from the patient's home environment in functional outcome measures introduced nonuniform variance in measurements but did not preclude estimation of valid measures.
Purpose: This study aimed to validate Rasch analysis of a performance-based outcome measure with real-world relevance.
Article Synopsis
- - The study examined how well the EQ-5D-3L health dimensions capture the impact of different eye diseases and vision impairment in a group of 492 individuals with impaired vision from four hospitals in Portugal, with a focus on identifying key predictors of health ratings.
- - Participants filled out the EQ-5D-3L and the Massof Activity Inventory, and logistic regression was used to analyze factors influencing their responses; results showed that visual ability significantly predicted health problems across all dimensions, while the EQ-5D index was less effective in identifying cases of vision impairment.
- - Findings revealed that the most common eye condition was diabetic retinopathy, and while mobility and self-care issues were rare, anxiety and depression were prevalent
Purpose: To improve the usefulness of the National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25) by enabling estimation of measures on an invariant scale and comparisons between patients and across studies.
Methods: Datasets of baseline NEI VFQ-25 responses from nine studies (seven retina randomized trials, n = 2770; two low vision studies, n = 572) were combined. The method of successive dichotomizations was applied to patient ratings of the main NEI VFQ-25 and six supplemental items to estimate Rasch model parameters using the R package 'msd.
The quantification of vision impairments dates to the mid-nineteenth century with standardization of visual acuity and visual field measures in the eye clinic. Attempts to quantify the impact of vision impairments on patients' lives did not receive clinical attention until the close of the twentieth century. Although formal psychometric theories and measurement instruments were well developed and commonplace in educational testing, as well as in various areas in psychology and rehabilitation medicine, the late start applying them to clinical vision research created a vacuum that invited poorly developed and poorly functioning instruments and analytic methods.
View Article and Find Full Text PDFBackground: As the prevalence of trachoma declines worldwide, it is becoming increasingly expensive and challenging to standardize graders in the field for surveys to document elimination. Photography of the tarsal conjunctiva and remote interpretation may help alleviate these challenges. The purpose of this study was to develop, and field test an Image Capture and Processing System (ICAPS) to acquire hands-free images of the tarsal conjunctiva for upload to a virtual reading center for remote grading.
View Article and Find Full Text PDFTo provide meaningful competition that is equitable for Paralympic athletes, classification systems are vital to determine which athletes are eligible to compete in adapted forms of sports and to group athletes for competition. Our discussion has important implications to inform how we should approach visual function assessment in sports performance. Sport participation positively benefits individuals with low vision.
View Article and Find Full Text PDFPurpose: To provide calibrated item measures and rating category thresholds for the Activity Inventory (AI), an adaptive visual function questionnaire, from difficulty ratings obtained from a large sample of new low vision patients at pre-rehabilitation baseline.
Methods: Baseline AI (510 items) rating scale data from five previous low vision rehabilitation outcome studies (n = 3623) were combined, and the method of successive dichotomizations was used to estimate calibrated item measures and rating category thresholds. Infit statistics were analyzed to evaluate the fit of the data to the model.
Background: Existing patient-reported outcome (PRO) measures may not be relevant to the full range of functional and vision-related quality of life (VR-QOL) concerns of individuals with vision impairment due to severe peripheral field loss (PFL). Measurement of VR-QOL in severe PFL is important in order to determine the effectiveness of vision rehabilitation interventions for this population. The purpose of this study was to characterize the impact of severe PFL due to retinitis pigmentosa (RP) and glaucoma on VR-QOL as the initial phase in the development of a novel PRO measure.
View Article and Find Full Text PDFSignificance: Outpatient vision rehabilitation improves function in veterans with vision impairment, but the prevalence of cognitive impairment and the degree to which it may affect rehabilitation outcomes in the Veterans Affairs system are unknown.
Purpose: The purpose of this study was to determine the prevalence of cognitive impairment among veterans receiving outpatient vision rehabilitation in the Veterans Affairs system and compare the benefits of rehabilitation in veterans with and without cognitive impairment.
Methods: We conducted cognitive assessments and a nested longitudinal cohort study in veterans with eye disorders at two outpatient rehabilitation sites.
Signal Detection Theory is the standard method used in psychophysics to estimate person ability in m-alternative forced choice tasks where stimuli are typically generated with known physical properties (e.g., size, frequency, contrast, etc …) and lie at known locations on a physical measurement axis.
View Article and Find Full Text PDFSignificance: One-year follow-up is recommended for patients with macular diseases to assess functional changes associated with disease progression and to modify low-vision (LV) treatment plans, if indicated.
Purpose: The purpose of this study was to observe 255 patients with macular diseases who received LV rehabilitation (rehabilitation with a therapist) or basic LV services (LV devices dispensed without therapy) during Veterans Affairs Low-vision Intervention Trial II after the trial ended at 4 months until 1-year follow-up.
Methods: The primary outcome measure was visual ability measured with the 48-item Veterans Affairs Low-vision Visual Functioning Questionnaire.
Purpose: In an observational clinical outcome study, we tested the effectiveness and use of the combination of two innovative approaches to magnification: a virtual bioptic telescope and a virtual projection screen, implemented with digital image processing in a head-mounted display (HMD) equipped with a high-resolution video camera and head trackers.
Methods: We recruited 30 participants with best-corrected visual acuity <20/100 in the better-seeing eye and bilateral central scotomas. Participants were trained on the HMD system, then completed a 7- to 10-day in-home trial.
Purpose: Provide item calibrations estimated for the Impact of Vision Impairment (IVI) questionnaire by pooling data from several studies of people with vision impairment (VI) representing a variety of countries and causes of VI.
Methods: Eight data sets from six principal investigators representing responses to IVI items from 2867 VI patients were pooled for analysis. Eligible patients were 18 years or older and from Australia, India, and the United States.
Significance: This study explores whether eccentric viewing training (EVT) changes the properties of the retinal area used for fixation in subjects with bilateral macular disease. The data presented demonstrate the feasibility of conducting a randomized controlled trial on EVT.
Purpose: Patients with bilateral central scotomas adopt other retinal area(s) called preferred retinal locus to substitute the blind fovea.
The most commonly used models for estimating measures of latent variables from polytomous rating scale data are the Andrich rating scale model and the Samejima graded response model. The Andrich model has the undesirable property of estimating disordered rating category thresholds, and users of the model are advised to manipulate data to force thresholds to come out ordered. The Samejima model estimates ordered thresholds, but has the undesirable property of estimating person measures on a non-invariant scale-the scale depends on which items a person rates and makes comparisons across people difficult.
View Article and Find Full Text PDFPurpose: We evaluated the validity of a single dry eye severity measure estimated using Rasch analysis from a battery of clinical tests and patient symptoms.
Methods: This study included 203 dry eye patients and 51 controls. Administered tests included the Ocular Surface Disease Index (OSDI), tear osmolarity, Schirmer's test, noninvasive break-up time, and ocular surface staining.
Head-mounted video display systems and image processing as a means of enhancing low vision are ideas that have been around for more than 20 years. Recent developments in virtual and augmented reality technology and software have opened up new research opportunities that will lead to benefits for low vision patients. Since the Visionics low vision enhancement system (LVES), the first head-mounted video display LVES, was engineered 20 years ago, various other devices have come and gone with a recent resurgence of the technology over the past few years.
View Article and Find Full Text PDFImportance: Examining costs and consequences of different low-vision (LV) programs provides important information about resources needed to expand treatment options efficiently.
Objective: To examine the costs and consequences of LV rehabilitation or basic LV services.
Design, Setting, And Participants: The US Department of Veterans Affairs (VA) Low Vision Intervention Trial (LOVIT) II was conducted from September 27, 2010, to July 31, 2014, at 9 VA facilities and included 323 veterans with macular diseases and a best-corrected distance visual acuity of 20/50 to 20/200.
Purpose: To investigate the value of 3 novel autoantibodies [salivary protein 1 (SP1), carbonic anhydrase 6 (CA6), and parotid secretory protein (PSP)] in differentiating Sjögren's syndrome (SS)-related dry eye from non-SS dry eye.
Methods: Forty-six dry eye patients with SS (SS dry eye), 14 dry eye patients without SS (non-SS dry eye), and 25 controls were included. The 2012 American College of Rheumatology classification criteria were used for the diagnosis of SS.
Importance: Updated estimates of the prevalence and incidence rates of low vision and blindness are needed to inform policy makers and develop plans to meet the future demands for low vision rehabilitation services.
Objective: To provide updated estimates of the incidence and prevalence of low vision and blindness in the United States.
Design, Setting, And Participants: Visual acuity measurements as a function of age from the 2007-2008 National Health and Nutrition Examination Survey, with representation of racial and ethnic groups, were used to estimate the prevalence and incidence of visual impairments.
Purpose: To develop and psychometrically evaluate a visual functioning questionnaire (VFQ) in an ultra-low vision (ULV) population.
Methods: Questionnaire items, based on visual activities self-reported by a ULV population, were categorized by functional visual domain (e.g.