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Adaptive gait changes due to spectacle magnification and dioptric blur in older peopleElliott, David, Chapman, Graham J. 02 1900 (has links)
Yes / Purpose. A recent study suggested that updated spectacles could increase falls rate in older people. We hypothesized that this may be due to changes in spectacle magnification and this study assessed the effects of spectacle magnification on adaptive gait.
Methods. Adaptive gait and visual function was measured in 10 older adults (mean age 77.1 ¿ 4.3 years) with the participants¿ optimal refractive correction and when blurred with +1.00DS, +2.00DS, -1.00DS and -2.00DS lenses. Adaptive gait measurements for the lead and trail foot included foot position before the step, toe clearance of the step edge and foot position on the step. Vision measurements included visual acuity, contrast sensitivity and stereoacuity.
Results. The blur lenses led to equal decrements in visual acuity and stereoacuity for the +1.00DS and -1.00DS and the +2.00DS and -2.00DS lenses. However, they had very different effects on adaptive gait compared to the optimal correction: Positive blur lenses led to an increased distance of the feet from the step, increased vertical toe clearance and reduced distance of the lead heel position on the step. Negative lenses led to the opposite of these changes.
Conclusion. The adaptive gait changes did not mirror the effects of blur on vision, but were driven by the magnification changes of the lenses. Steps appear closer and larger with positive lenses and further away and smaller with negative ones. Magnification likely explains the mobility problems some older adults have with updated spectacles and after cataract surgery. / Federation of Ophthalmic and Dispensing Opticians
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What Drives Adaptive Gait Changes to Acutely Presented Monocular Blur?Chapman, Graham J., Scally, Andy J., Elliott, David January 2011 (has links)
No / Purpose. To determine whether gait alterations due to monocular spherical lens blur were a safety strategy or driven by
lens magnification.
Methods. Adaptive gait and visual function were measured in 10 older adults (mean age, 74.9 4.8 years) with the
participants¿ optimal refractive correction and when monocularly blurred with 1.00 DS and 2.00 DS lens over the
dominant eye. Adaptive gait measurements for the lead and trail foot included foot position before the raised surface, toe
clearance of the raised surface edge, and foot position on the raised surface. Vision measurements included binocular
visual acuity, contrast sensitivity, and stereoacuity.
Results. Equal levels of monocular positive and negative spherical lens blur led to very different stepping strategies when
negotiating a raised surface. Positive blur lenses led to an increased vertical toe clearance and reduced distance of the
lead foot position on the raised surface. Negative lenses led to the opposite of these changes.
Conclusions. Findings suggest that step negotiation strategies were driven by the magnification effect provided by the spherical
lenses. Steps appeared closer and larger with magnification from positive lenses and further away and smaller with minification
from negative lenses and gait was adjusted accordingly. These results suggest that previously reported adaptive gait changes
to monocular spherical lens blur were not safety strategies as previously suggested but driven by lens magnification. The
significance of these findings in terms of prescribing large refractive changes in frail older patients is discussed.
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Dizziness and falls rate changes after routine cataract surgery and the influence of visual and refractive factorsSupuk, Elvira January 2015 (has links)
Purpose: To determine whether symptoms of dizziness and fall rates change due to routine cataract surgery and to determine the influence of visual and refractive factors on these common problems in older adults. Methods: Self-reported dizziness and falls were determined in 287 subjects (mean age of 76.5±6.3 years, 55% females) before and after routine cataract surgery for the first (81, 28%), second (109, 38%) and both eyes (97, 34%). Six-month falls rates were determined using self-reported retrospective data. Dizziness was determined using the short-form of the Dizziness Handicap Inventory. Results: The number of patients with dizziness reduced significantly after cataract surgery (52% vs. 38%; χ2 = 19.14 , p < 0.001), but the reduction in number of patients who fell in the 6-months post surgery was not significant (23% vs. 20%; χ2= 0.87, p=0.35). Multivariate logistic regression analyses found significant links between post-operative falls and change in spectacle type (increased risk if switched into multifocal spectacles). Post-operative dizziness was associated with changes in best eye visual acuity and changes in oblique astigmatic correction. Conclusions: Dizziness is significantly reduced by cataract surgery and this is linked with improvements in best eye visual acuity, although changes in oblique astigmatic correction increased dizziness. The lack of improvement in falls rate may be associated with switching into multifocal spectacle wear after surgery.
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Dizziness and falls rate changes after routine cataract surgery and the influence of visual and refractive factorsSupuk, Elvira January 2015 (has links)
Purpose: To determine whether symptoms of dizziness and fall rates change due to
routine cataract surgery and to determine the influence of visual and refractive
factors on these common problems in older adults.
Methods: Self-reported dizziness and falls were determined in 287 subjects (mean
age of 76.5±6.3 years, 55% females) before and after routine cataract surgery for
the first (81, 28%), second (109, 38%) and both eyes (97, 34%). Six-month falls rates
were determined using self-reported retrospective data. Dizziness was determined
using the short-form of the Dizziness Handicap Inventory.
Results: The number of patients with dizziness reduced significantly after cataract
surgery (52% vs. 38%; χ2 = 19.14 , p<0.001), but the reduction in number of patients
who fell in the 6-months post surgery was not significant (23% vs. 20%; χ2= 0.87,
p=0.35). Multivariate logistic regression analyses found significant links between
post-operative falls and change in spectacle type (increased risk if switched into
multifocal spectacles). Post-operative dizziness was associated with changes in best
eye visual acuity and changes in oblique astigmatic correction.
Conclusions: Dizziness is significantly reduced by cataract surgery and this is linked
with improvements in best eye visual acuity, although changes in oblique astigmatic
correction increased dizziness. The lack of improvement in falls rate may be
associated with switching into multifocal spectacle wear after surgery. / The Dunhill Medical Trust
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The Role of vision and refractive correction changes in dizzinessArmstrong, Deborah January 2018 (has links)
Dizziness is a common, multifactorial problem that causes reductions in
quality of life and is a major risk factor for falls, but the role of vision is a very
under-researched area. This study aimed to investigate any link between
dizziness and vision and to establish if changes in spectacle lens correction
could elicit dizziness symptoms.
A link between dizziness and self-reported poor vision was indicated in the
epidemiological literature as shown by a systematic review, provided lightheadedness
was not included in the definition of dizziness. Cases of
individuals who reported vision-related dizziness were investigated to
determine potential areas of research for this thesis and subsequently two
studies investigated the effects of refractive correction changes on dizziness
status. The first study was limited by logistical problems, although it
highlighted limitations in the short form of the Dizziness Handicap Inventory
that was used to quantify dizziness. Results of an optometry practice recheck
study found that oblique cylindrical changes were significantly more likely to
be associated with dizziness symptoms than other spectacle lens changes. It
also highlighted that optometrists do not ask/record about dizziness symptoms
with only 4% of records including “dizziness” as a problem when 38% of
patients reported dizziness symptoms when directly asked. All studies
highlighted a need for a patient-reported outcome measure to be designed to
assess vision-related dizziness. Literature review, interviews with experts and
patients and focus groups led to the development of a pilot questionnaire and
subsequently a 25-item Vision-Related Dizziness instrument, the VRD-25.
This was validated using responses from 223 respondents, with 79
participants completing the questionnaire a second time to provide test-retest
data. Two subscales of VRD-12-frequency (VRD-12f) and VRD-13-severity
(VRD-13s) were shown to be unidimensional and had good psychometric
properties, convergent validity and test-retest repeatability. The VRD-25 is the
only patient-reported outcome measure developed to date to assess vision related
dizziness and will hopefully provide the platform to further grow this
under-researched area that seems likely to provide important clinical
information. / College of Optometrists sponsored the research with a Postgraduate Research Scholarship
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