Connecting Research on Retinitis Pigmentosa to the Practice of Orientation and Mobility

Geruschat, Duane R.; Turano, Kathleen A.

doi:10.1177/0145482x0209600202

Cited by 20 publications

(20 citation statements)

References 32 publications

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“…Peripheral field loss (PFL) results in difficulties with orientation and mobility (Geruschat & Turano, 2002; Turano, Geruschat, Stahl, & Massof, 1999). Mobility difficulties of people with PFL include tripping over stationary obstacles in their path and collisions with other pedestrians (Haymes, Johnston, & Heyes, 2002; Lisboa et al, 2013; Lovie-Kitchin, Mainstone, Robinson, & Brown, 1990; Lovie-Kitchin, Soong, Hassan, & Woods, 2010; Turano et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

The risk of pedestrian collisions with peripheral visual field loss

et al. 2016

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Patients with peripheral field loss complain of colliding with other pedestrians in open-space environments such as shopping malls. Field expansion devices (e.g., prisms) can create artificial peripheral islands of vision. We investigated the visual angle at which these islands can be most effective for avoiding pedestrian collisions, by modeling the collision risk density as a function of bearing angle of pedestrians relative to the patient. Pedestrians at all possible locations were assumed to be moving in all directions with equal probability within a reasonable range of walking speeds. The risk density was found to be highly anisotropic. It peaked at ≈45° eccentricity. Increasing pedestrian speed range shifted the risk to higher eccentricities. The risk density is independent of time to collision. The model results were compared to the binocular residual peripheral island locations of 42 patients with forms of retinitis pigmentosa. The natural residual island prevalence also peaked nasally at about 45° but temporally at about 75°. This asymmetry resulted in a complementary coverage of the binocular field of view. Natural residual binocular island eccentricities seem well matched to the collision-risk density function, optimizing detection of other walking pedestrians (nasally) and of faster hazards (temporally). Field expansion prism devices will be most effective if they can create artificial peripheral islands at about 45° eccentricities. The collision risk and residual island findings raise interesting questions about normal visual development.

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Section: Introductionmentioning

confidence: 99%

The risk of pedestrian collisions with peripheral visual field loss

et al. 2016

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“…This disorder specifically implies night blindness, peripheral restrictions and/or scotomas (scattered spots in which vision is absent or deficient) in the visual field (VF) [1][2][3], frequent reduction of visual acuity (VA) [1][2][3][4], and alterations in contrast sensitivity (CS) [5][6], showing a significant reduction of CS in a wide range of spatial frequencies. These symptoms affect daily visual functioning, lifestyle, and social development and influence the emotional state [7][8], as well as the visual-perceptual state [9]; therefore, paying attention to these aspects is fundamental in our study.…”

Section: Introductionmentioning

confidence: 99%

Visual training and emotional state of people with retinitis pigmentosa

Chacón-López

Pelayo²,

López-Justicia³

et al. 2013

J Rehabil Res Dev

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The purpose of the study was to improve the visual functioning of people with restriction in contrast sensitivity (CS), such as retinitis pigmentosa (RP), by means of a visual training program. Twenty-six volunteers with RP participated, distributed in two groups: 15 who made up the experimental group (who received the training program) and 11 who participated as a control group (without training). Participants were evaluated before beginning training, on completion, and 3 mo following completion for CS with the Pelli-Robson Contrast Sensitivity (P&R) test, visual functioning with the Visual Function Questionnaire (VFQ), and in emotional state with the Beck Depression Inventory (BDI). The training program is based on software that generates luminous stimuli of varying duration and intensity and registers the stimuli perceived by the subject. The outcomes showed significant differences posttraining in the experimental group in depression (F1,14 = 5.42; p < 0.04), VFQ (Z = -2.27; p < 0.02), and P&R in the right eye (Z = -1.99; p < 0.046) and left eye (Z = -2.30; p < 0.02) but not in binocular (Z = -0.96; p < 0.34). The outcomes showed that the experimental group made significant progress in all variables and these effects remained after 3 mo, which suggests that the program could be a helpful addition to RP rehabilitation and help mitigate the damage.

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“…They manifest slower reaction time [3] and avoid night time travel [4]. They often travel without mobility aid, even when their vision is not functional enough to walk without a tool; this behaviour can modify posture [5].…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, functional consequences of RP on posture, balance and gait are seen in behaviours such as an increase of postural sway [5], 460% lost of balance in dark lighting conditions [6], shortened length of stride, a stiff and hesitant walking [7] and an altered head and body alignment.…”

Section: Introductionmentioning

confidence: 99%