Biomedical subjects

Ecosse L Lamoureux

Publications and source records attributed to Ecosse L Lamoureux.

8 recordsLinked to original sources

PubMed2006

The agreement between the Heidelberg Retina Tomograph and a digital nonmydriatic retinal camera in assessing area cup-to-disc ratio.

PURPOSE: To determine the repeatability and agreement between a digital camera (monoscopic and stereoscopic images) and the Heidelberg Retina Tomograph (HRT; Heidelberg Engineering, Heidelberg, Germany) in determining cup-to-disc ratio. A secondary purpose was to determine the monoscopic and stereoscopic thresholds that maximize specificity and sensitivity when compared with the HRT. METHODS: Community living participants aged between 70 and 79 years had their optic discs imaged with a digital nonmydriatic retinal camera (NMRC) and the HRT. Intraclass correlation coefficients (ICCs) and 95% tolerance limits of change were used to determine repeatability characteristics of the instruments. The agreement between the HRT- and NMRC-derived area cup-to-disc ratios was assessed using weighted kappa statistics and receiver operator characteristic (ROC) curves. RESULTS: The agreements between the monoscopic and stereoscopic images and HRT were assessed for 1238 and 1173 eyes, respectively. The reliability measures for both NMRC techniques and HRT were almost perfect (ICC = 0.84-0.99) with narrow tolerance limits of change (9.2%-18.4%) and very small systemic biases (P < 0.05). The agreement between the HRT and both NMRC techniques was substantial, with a weighted kappa = 0.83. The HRT gave a marginally larger area cup-to-disc ratio than the monoscopic and stereoscopic images by 0.008 and 0.006, respectively (P < 0.001). The areas under the ROC curves for both NMRC techniques were 0.98, indicating excellent discriminating characteristics (P < 0.001). An area cup-to-disc ratio cutoff of > or =0.5 for the monoscopic and stereoscopic NMRC was highly specific (94.1% and 91.6%) and sensitive (87.5% and 97.2%, respectively) in determining an HRT-derived area cup-to-disc ratio >0.6. CONCLUSIONS: The monoscopic and stereoscopic digital images showed excellent repeatability and demonstrated substantial agreement with the HRT. The results indicate that the digital NMRC could be a reliable and useful instrument for assessing area cup-to-disc ratio and screening for glaucoma-suspect eyes in the community.

Aged↗

PubMed2006

The Impact of Vision Impairment Questionnaire: an evaluation of its measurement properties using Rasch analysis.

PURPOSE: To explore the psychometric properties of the Impact of Vision Impairment scale (IVI) by using Rasch analysis. METHODS: Three hundred fourteen first-time referrals to low-vision clinics completed the 32-item IVI. The data were Rasch-analyzed with a partial credit model using RUMM2020 software (RUMM Laboratory, Perth, WA, Australia). The overall fit of the model, response scale, individual item fit, differential item functioning, unidimensionality, and person-separation reliability were assessed. RESULTS: Initially, 26 items displayed disordered thresholds. However, collapsing the response scale to three categories (4 items) and four categories (28 items) produced ordered response thresholds for all items. Four items with high proportions of missing responses, poor spread, high skewness, and deviation between observed and expected model curves were then removed. This adjustment produced overall fit to the Rasch model (item-trait interaction chi(2) = 118.3; P = 0.32). The final mean (SD) person and item fit residuals ere 0.06 (0.85) and -0.20 (1.45), respectively. The person-separation reliability was 0.9, indicating that the scale was able to discriminate between several different groups of participants. The revised scale was well targeted to the participants, with similar mean locations for items (0.00) and persons (0.16). A significant difference between participants of mild, moderate, and severe visual impairment (ANOVA; P 0.001) supported the criterion validity of the Rasch-scaled IVI. CONCLUSIONS: The results provide support for the measurement properties of the Rasch-scaled 28-item version of the IVI and of its potential for assessing outcomes of low-vision rehabilitation. A raw score-to-Rasch person measure conversion is supplied.

Adult↗

PubMed2005

Detecting cataract causing visual impairment using a nonmydriatic fundus camera.

PURPOSE: To assess the validity of a digital nonmydriatic fundus camera in detecting cataract as a cause of visual impairment. DESIGN: Diagnostic test comparison. METHODS: Photos of the anterior segment of 72 eyes were taken with a nonmydriatic fundus camera and assessed for cataract by two graders. Dilated biomicroscopy examination of the anterior segment of the same 72 eyes was then performed and cataract graded using the Wilmer scale. RESULTS: Grader 1 and 2 reported 90% and 94% sensitivity and 82% and 77% specificity, respectively, when the digital photos were compared with slit-lamp biomicroscopy in determining visually significant cataract. In addition, both graders showed similar substantial agreement between the digital photos and slit-lamp biomicroscopy when assessed for cataract (unweighted kappa 0.87 and 0.92, respectively, for graders 1 and 2). CONCLUSION: The nonmydriatic fundus camera may be an alternative method for screening for visually significant cataract in the community.

Cataract↗

PubMed2005

Assessment of optic disc cupping with digital fundus photographs.

PURPOSE: To determine the agreement between the assessment of retinal digital images by using an overlay transparency sheet and the Heidelberg retinal tomograph (HRT) in determining cup-disk ratios greater than 0.6. DESIGN: Diagnostic test comparison. METHODS: Computerized topographic and monoscopic digital images of the optic disk of 628 people aged 70 to 79 years were assessed. A grader (M.C.) defined the disk margin on HRT images, and the operation software computed the area cup-disk ratio. The same grader also determined whether the vertical cup-disk ratio on retinal images was greater than 0.6 by superimposing a transparency overlay sheet over the images. Findings of a second grader (J.G.F.) were used to establish reliability measures. RESULTS: The intragrader reliability for the overlay method and HRT was almost perfect (intraclass correlation coefficient [ICC] = 0.96 and 0.99, respectively), whereas the intergrader reliability was good (ICC = 0.77 and 0.92, respectively). A perfect agreement was found on 28 (85%) of 33 eyes between the overlay and HRT methods in determining cup-disk ratios greater than 0.6. CONCLUSIONS: The overlay transparency method appears to be a reliable and promising alternative in determining cup-disk ratios greater than 0.6 in a community screening setting.

Aged↗

PubMed2004

The impact of diabetic retinopathy on participation in daily living.

OBJECTIVE: To determine the restriction of participation in daily activities of people with diabetic retinopathy using the Impact of Vision Impairment questionnaire. METHODS: Individuals with diabetic retinopathy and a visual acuity (VA) worse than 20/40 or 6/12 in the better eye were eligible. Participants answered demographic questions and had VA information abstracted from medical records. If VA information was unavailable, it was assessed by an orthoptist. MAIN OUTCOME MEASURES: All participants completed the Impact of Vision Impairment questionnaire, which was either self-administered or interviewer administered. The physical and mental health components were assessed using the Medical Outcomes Study 12-Item Short Form (SF-12) questionnaire. RESULTS: Forty-five participants (mean age, 67.5 years) were recruited, with almost 70% (30/45) recording a VA worse than 20/60 or 6/18 in the better eye. The median duration of vision loss was 2.0 years. The highest restriction was reported for the Leisure and Work, Mobility, and Consumer and Social Interaction domains (mean, 3.0, 2.8, and 2.8, respectively), compared with the Emotional Reaction to Visual Loss and Household and Personal Care domains (mean, 2.3 and 2.1, respectively) (P<.005). The activities with the greatest restriction of participation were reading print, mobility, work, and leisure. A poorer VA in the better eye correlated independently with increased restriction of participation, as measured by the Impact of Vision Impairment questionnaire scores (partial correlations, 0.29-0.41; P< or =.03). CONCLUSION: Low-vision rehabilitation services aiming to improve outdoor mobility, print reading, participation in leisure activities, and psychological health may be an effective strategy to help people with diabetic retinopathy increase their participation in daily activities.

Activities of Daily Living↗

PubMed2004

The determinants of participation in activities of daily living in people with impaired vision.

PURPOSE: To investigate the determinants of participation in daily activities in people with impaired vision using the Impact of Vision Impairment (IVI) instrument. DESIGN: Cross-sectional study. METHODS: We recruited 319 participants with no vision rehabilitation history, distance visual acuity (VA) <6/12 (better eye), the ability to converse in English, and 18 years or older. Participants completed the 32-item IVI questionnaire and provided demographic, personal, cultural, and environmental details on vision-related functioning. Visual acuity data were either abstracted from the participants' files or assessed by qualified personnel. Participants also completed the SF-12 to evaluate physical (PCS-12) and mental health (MCS-12). RESULTS: The areas of greatest restriction of participation were associated with reading, outdoor mobility, participation in leisure activities, and shopping. In stepwise linear regression presenting VA, the PCS-12 and MCS-12 explained the variance in leisure and work (60 participants or 19%), consumer and social interaction (92 participants or 30%), household and personal care (76 participants or 24%), mobility (92 participants or 30%), emotional reaction to visual loss and (106 participants or 33%), and total IVI score (114 participants or 36%). Having age-related macular degeneration contributed marginally to the IVI domains and total score (P <.05-.01), except for the emotional domain. Belonging to a social group explained 3% and 2% of the variance in the consumer and social interaction and emotional domains, respectively (P <.05). CONCLUSIONS: Distance VA and physical and mental health explained more than a third of the variance of the total score, suggesting that an intervention aimed at improving quality of life may include strategies to improve not only vision-related rehabilitation but also mental and physical health.

Activities of Daily Living↗

PubMed2003

Barriers to accessing low vision services.

AIM: To investigate barriers to accessing low vision services in Australia. METHODS: Adults with a vision impairment (<6/12 in the better eye and/or significant visual field defect), who were current patients at the Royal Victorian Eye and Ear Hospital (RVEEH), were interviewed. The questions investigated self-perceived vision difficulties, duration of vision loss and satisfaction with vision and also examined issues of awareness of low vision services and referral to services. Focus groups were also conducted with vision impaired (<6/12 in the better eye) patients from the RVEEH, listeners of the Radio for the Print Handicapped and peer workers at Vision Australia Foundation. The discussions were recorded and transcribed. RESULTS: The questionnaire revealed that referral to low vision services was associated with a greater degree of vision loss (p = 0.002) and a greater self-perception of low vision (p = 0.005) but that referral was not associated with satisfaction (p = 0.144) or difficulties related to vision (p = 0.169). Participants with mild and moderate vision impairment each reported similar levels of difficulties with daily activities and satisfaction with their vision (p > 0.05). However, there was a significant difference in the level of difficulties experienced with daily activities between those with mild-moderate and severe vision impairment (p < 0.05). The participants of the focus groups identified barriers to accessing low vision services related to awareness of services among the general public and eye care professionals, understanding of low vision and the services available, acceptance of low vision, the referral process, and transport. CONCLUSION: In addition to the expected difficulties with lack of awareness of services by people with low vision, many people do not understand what the services provide and do not identify themselves as having low vision. Knowledge of these barriers, from the perspective of people with low vision, can now be used to guide the development and content of future health-promotion campaigns.

Activities of Daily Living↗

PubMed2002

The relationship between lower body strength and obstructed gait in community-dwelling older adults.

OBJECTIVES: To determine the relationship between lower body strength of community-dwelling older adults and the time to negotiate obstructed gait tasks. DESIGN: A correlational study. SETTING: The Biomechanics Laboratory, Deakin University, Australia. PARTICIPANTS: Twenty-nine women and 16 men aged 62 to 88 were recruited using advertisements placed in local newspapers. The participants were independent community dwellers, healthy and functionally mobile. MEASUREMENTS: Maximal isometric strength of the knee extensors and dynamic strength of the hip extensors, hip flexors, hip adductors, hip abductors, knee extensors, knee flexors, and ankle plantar flexors were assessed. The times to negotiate four obstructed gait tasks at three progressively challenging levels on an obstacle course and to complete the course were recorded. The relationship between strength and the crossing times was explored using linear regression models. RESULTS: Significant associations between the seven strength measures and the times to negotiate each gait task and to walk the entire course at each level were obtained (r = -0.38 to -0.55; P < .05). In addition, the percentage of the variance explained by strength (R(2)), consistently increased as a function of the progressively challenging level. This increase was particularly marked for the stepping over task (R(2) = 19.3%, 25.0%, and 27.2%, for levels 1, 2, and 3, respectively) and the raised surface condition (R2 = 17.1%, 21.1%, and 30.8%, for levels 1, 2, and 3, respectively). CONCLUSION: The findings of the study showed that strength is a critical requirement for obstructed locomotion. That the magnitude of the association increased as a function of the challenging levels suggests that intervention programs aimed at improving strength would potentially be effective in helping community-dwelling older adults negotiate environmental gait challenges.

Age Factors↗