Driving behaviour and visual compensation in glaucoma patients: Evaluation on a driving simulator.

BACKGROUND: To assess the driving performance and both the visual scanning and driving compensations of glaucoma patients. METHODS: In this case-control pilot study, the driving behaviour and performance of 14 patients with glaucoma and nine healthy age- and sex-similar control subjects were compared in a fixed-base driving simulator. All subjects performed in four scenarios with one to two hazardous situations on urban streets, for a total of five hazards. Measurements taken during the tests included reaction times, longitudinal regulation, lateral control and eye and head movements. RESULTS: Glaucoma patients showed poor driving performance with longer reaction time to hazardous situations than control subjects: pedestrians crossing the road from the left (p < 0.022) or from the right (p = 0.013), and vehicles coming from the left (p = 0.002). Their mean duration of lateral excursion was longer (p = 0.045), and they showed more lane excursions in a wide left curve (p = 0.045). Glaucoma patients also showed a higher standard deviation of time-headway (p = 0.048) with preceding vehicles. Analyses of driving behavioural compensations on curved roads showed that glaucoma patients stayed closer to the centre line in large (p = 0.006) and small (p = 0.025) left curves and on small right curves (p = 0.041). Additionally, on straight roads, as compared to control subjects, glaucoma patients showed longer mean time-headway (p = 0.032) and lower mean speed (p = 0.04). Finally, the glaucoma group exhibited a larger standard deviation of horizontal gaze (p = 0.034) than the control subjects. CONCLUSIONS: In a virtual driving environment, glaucoma patients exhibited unsafe driving behaviours, despite their driving and eye-scanning compensations.

Development and Validation of a Novel Mobility Test for Rod-Cone Dystrophies: From Reality to Virtual Reality.

PURPOSE: To validate a novel mobility test (MOST, MObility Standardized Test) and performance outcomes in real (RL) and virtual (VR) environments to be used for interventional clinical studies in order to characterize vision impairment in rod-cone dystrophies, also known as retinitis pigmentosa (RP). DESIGN: Prospective, interventional, noninvasive, reliability and validity analysis. METHODS: We designed MOST to be used in both VR and RL and conducted 3 experimental studies with 89 participants to (1) validate the difficulty of the mobility courses (15 controls), (2) determine the optimal number of light levels and training trials (14 participants with RP), and (3) validate the reproducibility (test-retest), reliability (VR/RL), sensitivity, and construct/content validity of the test (30 participants with RP and 30 controls). A comprehensive ophthalmologic examination was performed in all subjects. Outcomes of interest included MOST performance score, visual acuity, contrast sensitivity, dark adaptation thresholds, visual field parameters, and correlation between the performance score and visual function. RESULTS: The mobility courses exhibited statistically similar difficulty, and 5 trials are sufficient to control for the learning effect. MOST is highly reproducible (test-retest correlations >0.98) and reliable (correlations VR/RL = 0.98). MOST achieved a discrimination between participants with RP and controls (accuracy >95%) and between early and late stages of the disease (82.3% accuracy). The performance score is correlated with visual function parameter (0.57-0.94). CONCLUSION: MOST is a validated mobility test, with the controlled learning effect, excellent reproducibility, and high agreement between RL and VR conditions, as well as sensitivity and specificity to measure disease progression and therapeutic benefit in rod-cone dystrophies.

Glare and Mobility Performance in Glaucoma: A Pilot Study.

PRCIS: Glare disability affects patients with moderate and severe glaucoma. Under glare conditions, mobility performances of glaucoma patients are reduced. PURPOSE: The aim of this study was to evaluate glare disability and its impact on mobility and orientation in glaucoma patients. METHODS: Twenty-two glaucoma patients and 12 age-matched control subjects were included. All patients underwent a clinical evaluation of visual function and halo size measurements to determine glare disability with a glare score (GS) of the best eye and worse eye. Mobility was evaluated by 4 mobility courses on an artificial street (StreetLab) under photopic conditions (P) and mesopic conditions with an additional light source in front of the patient to mimic dazzling conditions (M+G). Mobility time, mobility incidents, trajectory segmentation, distance traveled, preferred walking speed on trial (WS) and percentage of preferred walking speed (PPWS) were recorded, and the Nasa task load index (Nasa-TLX) was evaluated. RESULTS: GS of the worse eye and GS of the best eye were significantly higher in glaucoma patients than in the control group (P=0.001 and 0.003). It was significantly different between moderate glaucoma patients and controls (P=0.001 and 0.010, respectively) and between severe glaucoma patients and controls (P=0.049 and 0.016). In locomotion tasks, comparing performance under M+G and P conditions, mobility performance was significantly different concerning mobility time (P=0.010), distance traveled (P=0.008), WS (P=0.007), PPWS (P=0.006), and Nasa-TLX (P=0.017) in the glaucoma group. Under M+G lighting conditions, mobility performance for glaucoma patients was significantly worse than controls with regard to WS (P=0.038), PPWS (P=0.0498), mobility time (P=0.046), and Nasa-TLX (P=0.006). CONCLUSION: Glare disability was observed in patients with moderate and severe glaucoma and had an impact on their mobility performance.

Correlations Between Subjective Evaluation of Quality of Life, Visual Field Loss, and Performance in Simulated Activities of Daily Living in Glaucoma Patients.

PRECIS: Glaucoma patients displayed alterations in their quality of life (QoL) and their ability to perform activities of daily living. The visual field (VF) of the worse eye might serve as a good marker for QoL evaluation. PURPOSE: The purpose of this study was to explore the correlations between VF defects, performance in simulated activities of daily living, and subjective evaluation of QoL in glaucoma patients. METHODS: Thirty-two patients with glaucoma and 10 age-matched control subjects were included. All participants answered a QoL questionnaire and underwent an assessment of visual function including monocular and binocular best-corrected visual acuity, binocular contrast sensitivity test (LogCS), and monocular and binocular VF. All subjects also carried out a series of simulated activities of daily living in a controlled environment. RESULTS: Glaucoma patients had lower QoL scores compared with controls for the composite score, near and distance activities, social functioning, mental health, role difficulties, dependency, and color vision. With regard to performance in the simulated mobility task, the number of mobility incidents was higher for glaucoma patients than for control subjects. For the reaching and grasping tasks, the overall movement duration for small objects was significantly longer in glaucoma patients compared with controls. The VF mean deviation of the worse eye was correlated with most of the QoL subscores. Mobility incidents as well as the reaching and grasping task parameters were not significantly correlated with QoL scores. CONCLUSIONS: Glaucoma patients showed an alteration of performance in simulated daily living activities, associated with a decreased QoL. There was no clear correlation between alterations in QoL and ability to perform activities of daily living. The QoL related to vision was mostly correlated to the visual function of the worse eye.

Correlation Between Visual Function and Performance of Simulated Daily Living Activities in Glaucomatous Patients.

PURPOSE: To analyze the correlations between functional clinical tests and the performance of glaucoma patients in simulated daily living activities. PATIENTS AND METHODS: Thirty-two patients with chronic glaucoma, followed at the Quinze-Vingts National Ophthalmology Hospital, were included. All patients had a clinical evaluation of visual function including best-corrected visual acuity, contrast sensitivity, and monocular and binocular visual field (VF) tests. Four different simulated activities of daily living were evaluated in standardized artificial platforms (StreetLab and HomeLab): "mobility" and an obstacle avoidance task in an artificial street, "reaching and grasping" large and small objects on a kitchen work surface, "localization of people" and "face orientation recognition." Patient performance in the different tasks was correlated with VF evaluation including integrated binocular visual field (IVF), VF mean deviation (MD) of the better and the worse eye, Esterman binocular VF, best-corrected visual acuity, and contrast sensitivity. RESULTS: The IVF score was significantly correlated with "localization of people" time (r=0.49; P=0.003), "face orientation recognition" time (r=0.50; P=0.002), and "movement onset" for reaching and grasping small objects (r=0.38; P=0.029). The MD of the better eye appeared significantly correlated with "face orientation recognition" time (r=-0.44; P=0.009) and "localization of people" time (r=-0.46; P=0.005). The Esterman score appeared significantly correlated with "mobility time" (r=-0.40; P=0.018), "localization of people" (r=-0.37; P=0.030), "face orientation recognition" times (r=-0.39; P=0.024), and "movement onset" for reaching and grasping large objects (r=-0.43; P=0.015). CONCLUSIONS: The IVF score and the MD of the better eye appeared to better evaluate "reaching and grasping," "face orientation recognition," and "localization of people" simulated tasks, whereas for the "mobility" task, the Esterman VF seemed more useful. The precise evaluation of the glaucoma patient's ability to perform everyday life tasks is complex and may require both monocular and binocular VF tests.