Thomas R. Stelmack

Use of Rasch person-item map in exploratory data analysis: a clinical perspective.

The National Institutes of Health (NIH) includes visual impairment in the 10 most prevalent causes of disability in America. As rehabilitation programs have the potential to restore independence and improve the quality of life for affected persons, NIH research priorities include evaluating their effectiveness. This paper demonstrates a clinical perspective on the use of the Rasch person-item map to evaluate the range and precision of a new vision function questionnaire in early analysis (prior to full sample). A self-report questionnaire was developed to measure the difficulty that persons with different levels of vision loss have performing daily activities. This 48-item Veterans Affairs Low-Vision Visual Functioning Questionnaire (VA LV VFQ-48) was administered to 117 low-vision patients. Preliminary analysis indicates that the questionnaire items are applicable to persons of differing abilities. The Rasch person-item map demonstrates that the field-test version of the VA LV VFQ-48 has good range and is well centered with respect to the person measure distribution. Construct validity and reliability are also demonstrated.

Is there a standard of care for eccentric viewing training

A study was conducted to determine the current Department of Veterans Affairs (VA) standard of practice for eccentric viewing (EV) training. EV training is the process of teaching patients to realign the visual image away from a diseased foveal/macular region onto healthier retina. Optometrists and Visual Skills Instructors at all VA blind rehabilitation centers (BRCs) and VICTORS (vision impairment centers to optimize remaining sight) programs were asked to rate preference for EV prescription criteria, evaluation, and training techniques. Responses were received from 70% of BRCs and 67% of VICTORS. The respondents reported that all programs include EV training. The average minutes of training per patient varied from 20 minutes to nearly 24 hours, with instructors within a single center varying by as much as two orders of magnitude. Routinely, 82% of optometrists prescribe EV training, yet no consensus was found among these practitioners as to the criteria for selecting the best EV area. The results of this survey reveal an inconsistent standard of practice across VA centers and demonstrate the need for prospective studies of the efficacy, effectiveness, and cost-effectiveness of EV training.

Hollenhorst plaques: Retinal manifestations and the role of carotid endarterectomy

The ocular examinations and hospital records of 64 patients with Hollenhorst plaques were retrospectively reviewed to document any associated visual defects and to determine if carotid endarterectomy prevented the occurrence of new plaques or symptoms. One hundred nine Hollenhorst plaques were seen in 75 eyes; 18 had multiple plaques simultaneously. Visual field defects were noted in 14 eyes, four of which corresponded to the location of Hollenhorst plaques. Twenty-eight carotid endarterectomies were performed ipsilateral to a Hollenhorst plaque: 24 patients had no symptoms; four patients developed new ipsilateral asymptomatic Hollenhorst plaques at 1 to 50 months after operation. Two late strokes occurred, one of which was ipsilateral to a new Hollenhorst plaque, during a mean follow-up of 50 months (range 8 to 102 months). Thirty-seven eyes with asymptomatic Hollenhorst plaques did not undergo ipsilateral operation. Two eyes developed new Hollenhorst plaques during a mean follow-up of 23 months (range 1 to 132 months). Eight eyes in patients with no symptoms had multiple Hollenhorst plaques, one of which was associated with a subsequent stroke. Of the 29 eyes with a single Hollenhorst plaque, one subsequently experienced an ipsilateral stroke, and another had a transient ischemic attack (1 and 3 years later, respectively). Visual field defects infrequently corresponded to locations of Hollenhorst plaques. The cerebral hemisphere ipsilateral to asymptomatic plaques had a slightly increased risk of subsequent transient ischemic attack or stroke compared to the contralateral side without Hollenhorst plaques. The number of simultaneous Hollenhorst plaques in the retinal circulation did not predict clinical outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical use of the Pepper visual skills for reading test in low vision rehabilitation

ABSTRACT The Pepper Visual Skills for Reading Test (VSRT) is an assessment instrument designed by Whittaker et al.1 to evaluate the reading skills of patients with macular degeneration who were able to read to their satisfaction before their vision loss. The VSRT was administered to 10 patients with macular degeneration and central scotomas from the Low Vision Optometry Program at the Hines Veterans Administration Hospital Central Blind Rehabilitation Center and the Visual Impairment Center to Optimize Remaining Sight (VICTORS) at Westside Veterans Administration Medical Center, Chicago. Reading skills were measured before and after a low vision treatment program. Results indicate that this test may be useful in designing low vision training programs, evaluating the progress of individual patients receiving low vision services, and evaluating low vision programs designed to rehabilitate those with reading difficulty.

Preliminary examination of the reliability and relation to clinical state of a measure of low vision patient functional status.

An evaluation of the reliability and relation to clinical state of a measure of low vision patient functional status was conducted. The measure included discrete tasks aggregated into three different areas: identifying objects, reading, and daily/leisure activities. Data were obtained retrospectively from case records of 247 low vision patients and 144 complete cases were used for statistical analyses. Evidence of reliability was found with coefficient alpha scores for the three areas ranging from 0.90 to 0.96. Significant relations between functional status and clinical states (acuity, contrast sensitivity, and visual field) were found with R2 values ranging from 0.39 to 0.58, p<0.001.

Development and sensitivity to visual impairment of the Low Vision Functional Status Evaluation (LVFSE)

BACKGROUND Functional limitation because of visual impairment is one of the most important measures of low vision rehabilitation outcome because it represents the true impact of visual impairment upon the daily lives of individuals. The Low Vision Functional Status Evaluation (LVFSE) was designed to evaluate functional limitation because of visual impairment using both observed and self-reported performance on daily activities. METHODS Performance on 27 daily activities was evaluated for 155 visually impaired subjects. Subjects also provided ratings of task difficulty. RESULTS Correlations between observed performance and visual acuity, contrast sensitivity, and visual field loss severity were moderate, r = -0.60 to r = 0.34. Correlations between self-reported task performance difficulty and measures of visual clinical state were weaker, r = -0.44 to r = 0.21. CONCLUSIONS The LVFSE shows promise as a sensitive measure of low vision-related functional status but more work is needed to refine the measure.

Change in contrast sensitivity functions with Corning CPF filters in patients with age related macular degeneration

Do Corning CPF filters change contrast sensitivity in patients with age related macular degeneration (AMD)? A retrospective review was conducted of 54 charts of veterans with AMD receiving comprehensive low vision services at VICTORS (VA Chicago West Side). CSF measurements with the VISTECH 6500 test system were compared before and after introduction of Corning CPF filters. Veterans were asked if filters made a noticeable change in contrast. Pre/post-filter CSF data was obtained for 63 trials at 1 m test distance and 60 trials at the 3 m test distance. To evaluate the data we used an analytic function to fit the contrast sensitivity data previously described by Lakshminarayanan [Optom. Vis. Sci. 72 511 (1995)]. An index was used to compare pre- and post-filter information. Veterans were prescribed filters if improvement in contrast was noted, or a subjective improvement was made. Patients were then contacted post-filter during this retrospective study to determine if the filters still enhanced daily activities. Mean improvement in the contrast sensitivity for each spatial frequency ranged from +0.344 to +0.422 patches with the filters at 1 m and +0.183 to +0.548 patches at 3 m. 87.5% of patients reported improvement in contrast while performing activities of daily living with Corning filters. Paired t test are t = −3.8298 (p = 0.003) at 1 m and t = −4.957 (p = 0.000 01) at 3 m test distance. While the changes in the CSF with filters are statistically significant and consistent with report of self-improvement by patients, the change in the number of patches on the VISTECH 6500 chart is not clinically significant. Clinical implications are that the chart in its current format is not useful for the prescription of filters leaving patient perception of change as a better guideline.