Safety on stairs: influence of a tread edge highlighter and its position

BACKGROUND: Falls sustained when descending stairs are the leading cause of accidental death in older adults. Highly visible edge highlighters/friction strips (often set back from the tread edge) are sometimes used to improve stair safety, but there is no evidence for the usefulness of either

Analysis of gait kinematics to determine the effect of manipulating the appearance of stairs to improve safety: a linked series of laboratory-based, repeated measures studies

Background: Falls on stairs are a common and dangerous problem for older people. This series of studies evaluated whether or not selected changes to the appearance of stairs could make them safer for older people to negotiate. Objectives: To determine the effect of (1) a step edge highlighter and its position and (2) an optimised horizontal–vertical (H–V) visual illusion placed on a step riser on gait safety during stair descent and ascent. Design: A series of studies using a repeated measures, laboratory-based design, investigating gait control and safety in independently mobile older people. Setting: The University of Bradford Vision and Mobility Laboratory. Participants: Fit and healthy older people aged 60 years of age or more, independently mobile, reasonably active and with normal healthy eyes and corrected vision. Interventions: A step edge highlighter in a variety of offsets from the stair edge and an optimised H–V visual illusion placed on the stair riser. The H–V illusion was provided on a staircase by horizontal step edge highlighters on the tread edges and vertical stripes on the step risers. Main outcome measures: Gait parameters that are important for safe stepping in ascent and descent, measured using three-dimensional lower limb segmental kinematic data

What you see is what you step: the horizontal-vertical illusion increases toe clearance in older adults during stair ascent

PURPOSE Falls on stairs are a significant cause of morbidity and mortality in elderly people. A simple safety strategy to avoid tripping on stairs is increasing foot clearance. We determined whether a horizontal–vertical illusion superimposed onto stairs to create an illusory perceived increase in stair-riser height would increase stair ascent foot clearance in older participants

The addition of stripes (a version of the 'horizontal-vertical illusion') increases foot clearance when crossing low-height obstacles

Trips over obstacles are one of the main causes of falling in older adults, with vision playing an important role in successful obstacle negotiation. We determined whether a horizontal-vertical illusion, superimposed onto low-height obstacles to create a perceived increase in obstacle height, increased foot clearances during obstacle negotiation thus reducing the likelihood of tripping. Eleven adults (mean±1SD: age 27.3±5.1 years) negotiated obstacles of varying heights (3, 5, 7 cm) with four different appearance conditions; two were obstacles with a horizontal-vertical illusion (vertical stripes of different thickness) superimposed on the front, one was a plain obstacle and the fourth a plain obstacle with a horizontal black line painted on the top-edge. Foot clearance parameters were compared across conditions. Both illusions led to a significant increase in foot clearance when crossing the obstacle, compared to the plain condition, irrespective of obstacle height. Superimposing a horizontal-vertical illusion onto low-height obstacles can increase foot clearance and its use on the floor-section of a double-glazing door frame for example, may reduce the incidence of tripping in the home

Experiences following cataract surgery - patient perspectives

PURPOSE: Most patients report being highly satisfied with the outcome of cataract surgery but there are variable reports regarding the impact of cataract surgery on some real-world activities, such as fall rates. We hypothesised that adaptations to changed refractive correction and visual function may cause difficulties in undertaking everyday activities for some patients and used a series of focus groups to explore this issue. METHOD: Qualitative methods were used to explore patients' experiences of their vision following cataract surgery, including adaptation to vision changes and their post-surgical spectacle prescription. Twenty-six participants took part in five focus groups (Mean age = 68.2 ± 11.4 years), and the data were analysed using thematic analysis. RESULTS: We identified three themes. 'Changes to Vision' explores participants' adaptation following cataract surgery. While several had problems with tasks relying on binocular vision, few found them bothersome and they resolved following second eye surgery. Participants described a trial and error approach to solving these problems rather than applying solutions suggested by their eyecare professionals. 'Prescription Restrictions' describes the long-term vision problems that pre-surgery myopic patients experienced as a consequence of becoming emmetropic following surgery and thus needing spectacles for reading and other close work activities, which they did not need before surgery. Very few reported that they had the information or time to make a decision regarding their post-operative correction. 'Information Needs' describes participant's responses to the post-surgical information they were given, and the unmet information need regarding when they can drive following surgery. CONCLUSION: The findings highlight the need for clinicians to provide information on adaptation effects, assist patients to select the refractive outcome that best suits their lifestyle, and provide clear advice about when patients can start driving again. Patients need to be provided with better guidance from clinicians and prescribing guidelines for clinicians would be beneficial, particularly for the period between first- and second-eye surgery

Intermediate addition multifocals provide safe stair ambulation with adequate ‘short-term’ reading

Purpose: A recent randomised controlled trial indicated that providing long-term multifocal wearers with a pair of distance single-vision spectacles for use outside the home reduced falls risk in active older people. However, it also found that participants disliked continually switching between using two pairs of glasses and adherence to the intervention was poor. In this study we determined whether intermediate addition multifocals (which could be worn most of the time inside and outside the home and thus avoid continual switching) could provide similar gait safety on stairs to distance single vision spectacles whilst also providing adequate 'short-term' reading and near vision. Methods: Fourteen healthy long-term multifocal wearers completed stair ascent and descent trials over a 3-step staircase wearing intermediate and full addition bifocals and progression-addition lenses (PALs) and single-vision distance spectacles. Gait safety/caution was assessed using foot clearance measurements (toe on ascent, heel on descent) over the step edges and ascent and descent duration. Binocular near visual acuity, critical print size and reading speed were measured using Bailey-Lovie near charts and MNRead charts at 40 cm. Results: Gait safety/caution measures were worse with full addition bifocals and PALs compared to intermediate bifocals and PALs. The intermediate PALs provided similar gait ascent/descent measures to those with distance single-vision spectacles. The intermediate addition PALs also provided good reading ability: Near word acuity and MNRead critical print size were better with the intermediate addition PALs than with the single-vision lenses (p < 0.0001), with a mean near visual acuity of 0.24 ± 0.13 logMAR (~N5.5) which is satisfactory for most near vision tasks when performed for a short period of time. Conclusions: The better ability to 'spot read' with the intermediate addition PALs compared to single-vision spectacles suggests that elderly individuals might better comply with the use of intermediate addition PALs outside the home. A lack of difference in gait parameters for the intermediate addition PALs compared to distance single-vision spectacles suggests they could be usefully used to help prevent falls in older well-adapted full addition PAL wearers. A randomised controlled trial to investigate the usefulness of intermediate multifocals in preventing falls seems warranted

Visual Predictors of Postural Sway in Older Adults

Purpose: Accurate perception of body position relative to the environment through visual cues provides sensory input to the control of postural stability. This study explored which vision measures are most important for control of postural sway in older adults with a range of visual characteristics. Methods: Participants included 421 older adults (mean age = 72.6 ± 6.1), 220 with vision impairment associated with a range of eye diseases and 201 with normal vision. Participants completed a series of vision, cognitive, and physical function tests. Postural sway was measured using an electronic forceplate (HUR Labs) on a foam surface with eyes open. Linear regression analysis identified the strongest visual predictors of postu-ral sway, controlling for potential confounding factors, including cognitive and physical function. Results: In univariate regression models, unadjusted and adjusted for age, all of the vision tests were significantly associated with postural sway (P < 0.05), with the strongest predictor being visual motion sensitivity (standardized regression coefficient, β = 0.340; age-adjusted β = 0.253). In multiple regression models, motion sensitivity (β = 0.187), integrated binocular visual fields (β =−0.109), and age (β = 0.234) were the only significant visual predictors of sway, adjusted for confounding factors, explain-ing 23% of the variance in postural sway. Conclusions: Of the vision tests, visual motion perception and binocular visual fields were most strongly associated with postural stability in older adults with and without vision impairment. Translational Relevance: Findings provide insight into the visual contributions to postural stability in older adults and have implications for falls risk assessment

Vision in high-level football officials

YesOfficiating in football depends, at least to some extent, upon adequate visual function. However, there is no vision standard for football officiating and the nature of the relationship between officiating performance and level of vision is unknown. As a first step in characterising this relationship, we report on the clinically-measured vision and on the perceived level of vision in elite-level, Portuguese football officials. Seventy-one referees (R) and assistant referees (AR) participated in the study, representing 92% of the total population of elite level football officials in Portugal in the 2013/2014 season. Nine of the 22 Rs (40.9%) and ten of the 49 ARs (20.4%) were international-level. Information about visual history was also gathered. Perceived vision was assessed using the preference-values-assigned-to-global-visual-status (PVVS) and the Quality-of-Vision (QoV) questionnaire. Standard clinical vision measures (including visual acuity, contrast sensitivity and stereopsis) were gathered in a subset (n = 44, 62%) of the participants. Data were analysed according to the type (R/AR) and level (international/national) of official, and Bonferroni corrections were applied to reduce the risk of type I errors. Adopting criterion for statistical significance of p<0.01, PVVS scores did not differ between R and AR (p = 0.88), or between national- and international-level officials (p = 0.66). Similarly, QoV scores did not differ between R and AR in frequency (p = 0.50), severity (p = 0.71) or bothersomeness (p = 0.81) of symptoms, or between international-level vs national-level officials for frequency (p = 0.03) or bothersomeness (p = 0.07) of symptoms. However, international-level officials reported less severe symptoms than their national-level counterparts (p<0.01). Overall, 18.3% of officials had either never had an eye examination or if they had, it was more than 3 years previously. Regarding refractive correction, 4.2% had undergone refractive surgery and 23.9% wear contact lenses when officiating. Clinical vision measures in the football officials were similar to published normative values for young, adult populations and similar between R and AR. Clinically-measured vision did not differ according to officiating level. Visual acuity measured with and without a pinhole disc indicated that around one quarter of participants may be capable of better vision when officiating, as evidenced by better acuity (≥1 line of letters) using the pinhole. Amongst the clinical visual tests we used, we did not find evidence for above-average performance in elite-level football officials. Although the impact of uncorrected mild to moderate refractive error upon officiating performance is unknown, with a greater uptake of eye examinations, visual acuity may be improved in around a quarter of officials.Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013

Some considerations for the communication of results of air pollution health effects tracking

Communicating effectively and efficiently on air quality and its health impacts is an important but difficult and complex task. It requires careful consideration of the audience one wants to reach, the messages one is trying to present, the venue through which the message will be delivered. The audience, context, technique, and content factors may affect how well it is heard and how appropriately it is interpreted. In this short paper, I describe many of these concerns and provide some suggestions for how best to address them. However, since every audience differs in goals, characteristics, and nature, what is most important is implementing an effective communications program. This program should include frequent two-way communication, repeated and on-going evaluation of how well the audience understands the messages, and consideration of how to improve the delivery

How accurate is an LCD screen version of the Pelli–Robson test?

Purpose: To evaluate the accuracy and repeatability of a computer-generated Pelli–Robson test displayed on liquid crystal display (LCD) systems compared to a standard Pelli–Robson chart. Methods: Two different randomized crossover experiments were carried out for two different LCD systems for 32 subjects: 6 females and 10 males (40.5 ± 13.0 years) and 9 females and 7 males (27.8 ± 12.2 years), respectively, in the first and second experiment. Two repeated measurements were taken with the printed Pelli–Robson test and with the LCDs at 1 and 3 m. To test LCD reliability, measurements were repeated after 1 week. Results: In Experiment 1, contrast sensitivity (CS) measured with LCD1 resulted significantly higher than Pelli–Robson both at 1 and at 3 m of about 0.20 log 1/C in both eyes (p < 0.01). Bland–Altman plots showed a proportional bias for LCD1 measures. LCD1 measurements showed reasonable repeatability: ICC was 0.83 and 0.65 at 1 and 3 m, respectively. In Experiment 2, CS measured with LCD2 resulted significantly lower than Pelli–Robson both at 1 and at 3 m of about 0.10 log 1/C in both eyes (p < 0.01). Bland–Altman plots did not show any proportional bias for LCD2 measures. LCD2 measurements showed sufficient repeatability: ICC resulted 0.51 and 0.65 at 1 and 3 m, respectively. Conclusions: Computer-generated versions of Pelli–Robson test, displayed on LCD systems, do not provide accurate results compared to classic Pelli–Robson printed version. Clinicians should consider that Pelli–Robson computer-generated versions could be non-interchangeable to the printed version