Self-reported importance and difficulty of driving in a low-vision clinic population.

PURPOSE: To validate estimates of self-perceived driving ability from difficulty ratings of driving tasks and to determine the association of the importance and difficulty of driving with the magnitude of visual impairments. METHODS: A consecutive series of 851 patients at a low-vision clinic rated the importance of driving on a four-point scale. Those who gave nonzero importance ratings then rated driving difficulty on a five-point scale. Those who gave nonzero difficulty ratings then rated the difficulty of each of 21 driving tasks on a five-point scale. Visual acuity was measured with the Early Treatment of Diabetic Retinopathy Study (ETDRS) chart, and contrast sensitivity was measured with the Pelli-Robson chart. Rasch analysis was used to test the validity and reliability of self-perceived driving ability estimates from difficulty ratings of tasks. RESULTS: Patients who rated driving as not important (41%) had worse visual acuity (logMAR = 0.88) and worse contrast sensitivity (log CS = 0.83) than did those who rated driving as extremely important (55%; logMAR = 0.62; log CS =1.03; multivariate analysis of variance [MANOVA]; P = 0.003). Self-perceived driving ability correlated negatively with the overall rating of driving difficulty (r = -0.69; P < 0.001) and with logMAR (r = -0.28; P < 0.001), and correlated positively with log CS (r = 0.35; P < 0.001). The most difficult driving tasks were navigating in parking ramps, parking in the correct space, seeing lane markings, and reading signs. The least-difficult driving tasks were seeing traffic and reading the speedometer. Rasch analysis confirmed instrument validity and reliability. CONCLUSIONS: Low-vision patients appeared to devalue the goal of driving when visual impairments were more severe. Valid measures of self-perceived driving ability can be estimated from difficulty ratings of specific driving tasks.

Red contact lenses for alleviation of photophobia in patients with cone disorders.

PURPOSE: To describe the use of red contact lenses to alleviate photophobia in patients with cone disorders. DESIGN: Retrospective interventional case series. METHODS: Twenty-three patients with achromatopsia or an acquired cone disorder with complaints of severe photophobia were fit with absorptive red soft contact lenses to alleviate photophobia and improve their ability to use their remaining vision more effectively RESULTS: The contact lenses immediately resolved the aversion to light, with dramatic improvement in visual function in all patients (determined by observation of the patient and by patient report). It allowed eight patients to become eligible to drive. CONCLUSIONS: Red contact lenses successfully alleviate photophobia in patients with cone disorders.

Rehabilitation of hospital inpatients with visual impairments and disabilities from systemic illness.

OBJECTIVES: To describe the comorbidity of visual impairment and disability among patients hospitalized for systemic illness and to discuss rehabilitation. DESIGN: Retrospective study. SETTING: Hospital-based, academic tertiary medical center with referring neurology, ophthalmology, and rehabilitation units. PARTICIPANTS: Ninety-three hospitalized patients referred to the low vision rehabilitation clinic primarily by the physical medicine and rehabilitation and neurology units. INTERVENTIONS: Measurements of best-corrected visual acuity and other visual function testing. Referrals were made for prescriptive glasses, assistive devices, rehabilitation, resources, and ophthalmologic evaluation. MAIN OUTCOME MEASURES: Specialized services, presence of comorbidities, and visual function measurements. RESULTS: The mean admitting visual acuity revealed a moderate visual impairment. The primary diagnosis for admission (51%) was cerebrovascular accidents. There was a mean of 3.5 other comorbidities. CONCLUSIONS: The majority of patients admitted to the hospital for systemic diseases also had visual impairments. In many patients, this visual disability (either from the systemic and/or ocular disease) interfered with their activities of daily living.

Visual disability variables. I: the importance and difficulty of activity goals for a sample of low-vision patients.

OBJECTIVE: To test the validity and reliability of latent trait measures estimated from ratings by low-vision patients of the importance and difficulty of selected activity goals. DESIGN: Validation of a telephone-administered functional assessment instrument using Rasch analysis of self-assessment ratings. SETTING: Telephone interviews of respondents in their homes. Participants Consecutive series of 600 outpatients with low vision. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Ratings of the importance and difficulty of achieving 41 activity goals. Person and item traits were measured with the Andrich rating scale model. Measurement validity and reliability were tested statistically by comparing response patterns and distributions with measurement model expectations. RESULTS: Patients could distinguish only 3 categories of importance and 4 categories of difficulty. The distributions of person and item measure fit statistics were consistent with 2 unidimensional constructs: value of independence estimated from importance ratings and visual ability estimated from difficulty ratings. However, 8 of 41 activity goals were poor estimators of value of independence and 7 of 41 activity goals were poor estimators of visual ability. Person measure distributions could be divided into 3 statistically distinct strata for estimates from both importance ratings and difficulty ratings. Item measure distributions could be divided into 21 strata for estimates from importance ratings and 7 strata for estimates from difficulty ratings. CONCLUSIONS: The 2 variables that define visual disability-value of independence and visual ability-are valid constructs that can be estimated accurately and reliably from patient ratings of the importance and difficulty of activity goals.

Visual disability variables. II: The difficulty of tasks for a sample of low-vision patients.

OBJECTIVES: To test the validity and reliability of measures of visual ability and to evaluate the relation between measurements made at the task level and measurements made at the goal level of a hierarchical model for visual disability. DESIGN: Validation of a telephone-administered functional assessment instrument using Rasch analysis on self-assessment ratings. SETTING: Telephone interviews of respondents in their homes. PARTICIPANTS: Consecutive series of 600 outpatients with low vision. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Ordinal ratings of the difficulty in performing a subset of 337 tasks. Measures of the visual ability of each patient and the required visual ability to perform each task were made using the Andrich rating scale model. Measurement validity and reliability were tested statistically by comparing response patterns and distributions to measurement model expectations. RESULTS: Results were consistent with a single visual ability construct. Patients' visual ability estimated from task difficulty ratings agreed with estimates from goal difficulty ratings ( r =.74); the difficulty of individual goals was equal to the weighted average of the difficulties of subsidiary tasks ( r =.79). However, conclusions from the Rasch analysis were not confirmed by principal components analysis of item residuals, which indicated that visual ability had a 2-dimensional structure, with 1 factor related to mobility and the other related to reading. Factor analysis on person measures estimated from subsets of functionally grouped items confirmed the 2-dimensional structure of visual ability. CONCLUSIONS: Our study results confirm the hierarchical structure of the Activity Breakdown Structure model and show how the individualized Activity Inventory can produce measures of limitations in functional vision.

Uveal melanoma and poor treatment compliance: an atypical outcome with literature review.

BACKGROUND: A uveal melanoma is the most common primary intraocular malignancy and is the primary intraocular disease that can be fatal in adults. Until recently, data were limited regarding growth characteristics and at what stage metastases are likely to occur. CASE REPORT: A 49-year-old white male presented on January 19, 1989, for a second opinion regarding a spot that had been discovered in the right eye 13 months prior. Ophthalmologic evaluation and echography were consistent for a uveal melanoma of 5 mm elevation and 13.5 x 6 mm in diameter. The patient refused treatment or enrollment into the Collaborative Ocular Melanoma Study. On December 9, 1991, the eye was enucleated with a modified exenteration due to severe proptosis, tumor thickness of 22 mm, and three areas of extrascleral extension. The patient refused postoperative radiation treatment and refused clinical follow-up. This case was reviewed from the initial evaluation date through the last clinical visit. The patient was recently interviewed with respect to his use of homeopathic medicine, change in lifestyle, and the effect he felt it might have had on his life. DISCUSSION: The literature published by the Collaborative Ocular Melanoma Study regarding the histopathologic characteristics of eyes enucleated and the initial mortality findings of a large choroidal melanoma indicate that this is a most unusual case. The patient has defied the mortality findings of the most recent and largest study to date (mean survival rate, 82 months). The patient is still alive 181 months after the original finding of the lesion and refusal of advised treatment recommendations in favor of homeopathic medicine.