19 research outputs found
Aggressive Driving Behaviours in Cannabis Users. The Influence of Consumer Characteristics
This study analysed dangerous driving behaviours in twenty young occasional cannabis
users through objective and self-reported data, studying the relationship between the two aspects.
Visual function was assessed in a baseline session and after smoking cannabis, as well as speed-related
behaviour in a driving simulator. The participants responded to questionnaires on sociodemographic
factors, their consumption profile, and the incidence of dangerous behaviours (Dula Dangerous
Driving Index; DDDI). After cannabis use, the results revealed a significant deterioration in visual
function. In terms of speed management, they showed significantly greater acceleration force in
the two different sections of the route, and they drove significantly faster. Our correlations indicate
that males and heavier users display more risky speed management. Likewise, the heavier cannabis
users admitted to increased dangerous driving behaviour, and an accident in the preceding year was
associated with a trend towards aggressive driving behaviour according to the DDDI questionnaire.
The findings of this study suggest that cannabis users adopt dangerous behaviours when driving,
despite the effect this drug has on certain important functions, such as vision. The results suggest a
need for awareness-raising and information campaigns
Effect of peripheral refractive errors on driving performance
The effect of peripheral refractive errors on driving while performing secondary tasks
at 40° of eccentricity was studied in thirty-one young drivers. They drove a driving simulator
under 7 different induced peripheral refractive errors (baseline (0D), spherical lenses of +/- 2D,
+/- 4D and cylindrical lenses of +2D and +4D). Peripheral visual acuity and contrast sensitivity
were also evaluated at 40°. Driving performance was significantly impaired by the addition of
myopic defocus (4D) and astigmatism (4D). Worse driving significantly correlated with worse
contrast sensitivity for the route in general, but also with worse visual acuity when participants
interacted with the secondary task. Induced peripheral refractive errors may negatively impact
driving when performing secondary tasks.FEDER/Junta de Andalucia-Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades MCIN/AEI/10.13039/501100011033
PID2020-115184RB-I00Agencia Estatal de Investigacion A-FQM-532-UGR20Fundacion Seneca PID2019-105684RB-I00/AEI/10.13039/501100011033
19897/GERM/1
Experiment on PMMA models to predict the impact of corneal refractive surgery on corneal shape: comment
Recently, two papers “Dorronsoro et al., Experiment on PMMA models to predict the impact of corneal refractive surgery on corneal shape, Opt. Express 14, 6142 (2006)” and “JR Jiménez et al., Deviations of Lambert-Beer’s law affect corneal refractive parameters after refractive surgery, Opt. Express 14, 5411 (2006)” have been published on an important question in corneal refractive surgery: to explain the differences between post-surgical corneal elevation maps and those predicted after theoretical ablation. An analysis of Dorronsoro et al. data demonstrates that the failures in Lambert-Beer’s law could be in the origin of shape discrepancies. New models and experimental data on deviations of Lambert-Beer’s law might help to minimize post-surgical corneal discrepancies and thus optimise eye emmetropization
Dynamics of the accommodative response after smoking cannabis
This work was supported by the Ministry of Economy and Competitiveness (Spain) and the European Regional Development Fund (ERDF) (FIS2017-85058-R), and by the Ministry of Science, Innovation and Universities (Spain) (Grant FPU15/05571). The authors thank Drager Iberia for lending us the Drager DrugTest 5000 and the Drager Alcotest 7110 MK-III employed in this study. We also thank Tragora SCA for reviewing the English version of the manuscript. Funding for open access charge: Universidad de Granada/Consorcio de Bibliotecas Universitarias de Andalucia (CBUA).Purpose: Cannabis is the most widely consumed illicit drug worldwide. It has been
suggested that cannabis could generate blurred vision during reading tasks. The
goal of this study was to objectively assess the acute effects of smoking cannabis
on the dynamics of ocular accommodation. The influence of other factors, including
target distance and the direction of accommodation, as well as personal characteristics,
were also analysed.
Methods: Nineteen young people who were occasional cannabis users participated
in the study (mean age 22.53 [3.12] years). Their usage profiles were evaluated
by means of the Cannabis Use Disorders Identification Test-revised
(CUDIT-r).
The dynamics of the accommodative response were evaluated using an open-field
auto refractor (Grand Seiko WAM-5500).
The participants completed two different
experimental sessions, one week apart, and in random order (baseline session and
after smoking cannabis). During these sessions, the amplitude of the response (D),
mean velocity (D/s), peak velocity (D/s), response time (s), accommodative lag (D)
and accommodation variability (D) were measured.
Results: The results indicated that cannabis use had a significant main effect on the
mean accommodation/disaccommodation velocity (F1,13 = 7.21; p = 0.02; η
2
p = 0.396).
Cannabis consumption also interacted significantly with other factors. Response
time showed a significant two-way
interaction between condition × target distance
(F1,13 = 11.71; p = 0.005; η
2
p = 0.474) and condition × accommodation direction (F1,13 = 8.71;
p = 0.01; η
2
p = 0.401). For mean velocity, two-way
interactions were found between condition
× age (F1,13 = 6.03; p = 0.03; η
2
p = 0.354), condition × CUDIT-r
score (F1,13 = 6.03;
p = 0.03; η
2
p = 0.356) and condition × target distance (F1,13 = 7.20; p = 0.02; η
2
p = 0.396).
Conclusions: These findings suggest that cannabis use can alter the accommodation
process, although further studies should be carried out to explore the role of
attention deficits. According to these results, certain daily activities that depend
on an accurate accommodative function may be affected by cannabis use.Ministry of Economy and Competitiveness (Spain)European Commission FIS2017-85058-RMinistry of Science, Innovation and Universities (Spain) FPU15/05571Universidad de Granada/Consorcio de Bibliotecas Universitarias de Andalucia (CBUA
Effects of cannabis on visual function and self-perceived visual quality
Cannabis is one of the most used drugs of abuse in the world. The objective of this study was to
analyze the effects of smoking cannabis on vision and to relate these to those perceived by the user.
Thirty-one cannabis users participated in this study. Visual function assessment was carried out
in a baseline session as well as after smoking cannabis. We evaluated static visual acuity, contrast
sensitivity, stereoacuity, accommodative response, straylight, night-vision disturbances (halos) and
pupil size. The participants were also divided into two groups depending on whether they perceived
their vision to have worsened after smoking cannabis. A logistic regression analysis was employed to
identify which visual test could best predict self-perceived visual effects. The study found that smoking
cannabis has significant adverse effects on all the visual parameters analyzed (p < 0.05). Self-perceived
visual quality results revealed that about two thirds of the sample think that smoking cannabis impairs
their vision. Contrast sensitivity, specifically for the spatial frequency 18 cpd, was identified as the
only visual parameter significantly associated with self-perceived visual quality (Odds Ratio: 1.135;
p = 0.040). Smoking cannabis is associated with negative effects on visual function. Self-perceived
visual quality after smoking cannabis could be related to impaired contrast sensitivity
Effects of Smoking Cannabis on Visual Function and Driving Performance. A Driving-Simulator Based Study
Cannabis is the most widely used illegal drug in the world. Limited information about the effects of cannabis on visual function is available, and more detail about the possible impact of visual effects on car driving is required. This study investigated the effects of smoking cannabis on vision and driving performance, and whether these effects are correlated. Twenty drivers and occasional users were included (mean (SE) age, 23.3 (1.0) years; five women). Vision and simulated driving performance were evaluated in a baseline session and after smoking cannabis. Under the influence of cannabis, certain visual functions such as visual acuity (p < 0.001), contrast sensitivity (p = 0.004) and stereoacuity (far, p < 0.001; near, p = 0.013) worsened. In addition, there was an
overall deterioration of driving performance, with the task of keeping the vehicle in the lane proving more difficult (p < 0.05). A correlation analysis showed significant associations between driving performance and visual function. Thus, the strongest correlations were found between the distance driven onto the shoulder and stereoacuity, for near (ρ = 0.504; p = 0.001) and far distances (ρ = 0.408; p = 0.011). This study provides the first evidence to show that the visual e ects of cannabis could impact driving performance, compromising driving safety. The results indicate that information and awareness campaigns are essential for reducing the incidence of driving under the influence of cannabis.This research was funded by the Ministry of Economy and Competitiveness (Spain) and the European
Regional Development Fund (ERDF), grant number FIS2017-85058-R and by the Ministry of Science, Innovation
and Universities (Spain), grant number Grant FPU15/05571
Contrast sensitivity and retinal straylight after alcohol consumption: effects on driving performance
El objetivo de este estudio es investigar los efectos del consumo de alcohol en la función visual y en el rendimiento en la conducción, así como la relación entre ambas funciones. Un total de 40 participantes sanos participaron en las tres sesiones experimentales llevadas a cabo en el estudio: una sesión de control (sin consumo de alcohol), y otras dos sesiones más tras consumir alcohol (una tras consumir 300ml de vino tino y otra tras consumo de 450ml del mismo vino). Se midió el contenido de alcohol en aire espirado (BrAC, en mg/l) usando un etilómetro. Para caracterizar la función visual se midieron la sensibilidad al contraste así como el velo luminoso o luz difundida hacia la retina (retinal straylight), debido este último a la difusión luminosa intraocular. El rendimiento en la conducción fue evaluado en tres escenarios (autovía, carretera de montaña y entorno urbano) usando un simulador de conducción. Los resultados mostraron un deterioro tras consumo de alcohol en la sensibilidad al contraste y en el velo luminoso retiniano (aumento del retinal straylight), además de una deteriorada habilidad para conducir, especialmente para la ingesta mayor de alcohol. También se observó que, bajo los efectos del consumo de alcohol, el rendimiento deteriorado en la conducción dependía de la sensibilidad al contraste y del velo luminoso retiniano, indicando que estas variables visuales pueden parcialmente predecir el rendimiento en la conducción en estas condiciones.In this study, we aimed to investigate the effects of alcohol intake on visual function and driving performance, as well as on the relationship between these. A total of 40 healthy participants took part in three experimental sessions: one baseline session and two further sessions after consuming two different quantities of alcohol (300 ml and 450 ml of red wine). The breath alcohol content (BrAC) was measured using a breath analyzer. The contrast sensitivity and retinal straylight due to the forward intraocular scattering were measured to characterize visual function, and driving performance was assessed in three different scenarios using a driving simulator. The results showed a deterioration in contrast sensitivity and retinal straylight after drinking alcohol, in addition to an impaired ability to drive, especially for the highest alcohol intake. We also observed that the deteriorated driving performance was a function of the contrast sensitivity and retinal straylight under the effects of alcohol, indicating that these visual variables can partially predict driving performance in these conditions.Ministerio de Economía y Competitividad; European Regional Development Fund (ERDF) (referencia FIS2017-85058-R
Intraocular scattering as a predictor of driving performance in older adults with cataracts
Cataracts can limit a person's ability to perform vision-dependent tasks safely, affecting the quality of life of older people. This study examines the relationship between visual function and driving, by studying which visual parameters might be important for predicting driving performance in older drivers with and without cataracts, ascertaining whether the objective measurement of intraocular scattering should be considered in assessment procedures for older drivers. This cross-sectional study involved a total of 20 older drivers (10 patients with bilateral cataracts and 10 control subjects). All participants were examined for visual acuity, contrast sensitivity, visual discrimination capacity, and intraocular scattering. Driving performance was also tested using a driving simulator. To study the relationship between visual parameters and driving performance, a correlation analysis and regression model were used. Drivers with cataracts showed a significantly impaired (p<0.05) visual function, with an Objective Scattering Index (OSI) 3.5 times greater than the control group. Driving performance was also significantly worse (p<0.05) in drivers with cataracts, reflected by a notable deterioration in lane keeping. The correlation analysis showed significant associations between driving performance and all the visual parameters studied. Finally, the regression model revealed that the OSI was the best predictor of driving performance, accounting for 51.3% of its variance. Visual function and driving performance are markedly deteriorated when cataracts are present. Our results demonstrate that the objective scattering index (OSI) has a high predictive power when it comes to simulated driving performance in older drivers, both with and without cataracts, suggesting that scatter measurements could be important in helping better understand visual limitations in older drivers
Impact of Age-Related Vision Changes on Driving
Aging leads to impaired visual function, which can affect driving—a very visually
demanding task—and has a direct impact on an individual’s quality of life if their license is
withdrawn. This study examined the associations between age-related vision changes and simulated
driving performance. To this end, we attempted to determine the most significant visual parameters
in terms of evaluating elderly drivers’ eyesight. Twenty-one younger drivers (aged 25–40) were
compared to 21 older drivers (aged 56–71). Study participants were assessed for visual acuity,
contrast sensitivity, halos, and intraocular straylight, which causes veiling luminance on the retina and
degrades vision. Driving performance was evaluated using a driving simulator. The relationships
between simulated driving performance and the visual parameters tested were examined with
correlation analyses and linear regression models. Older drivers presented impairment in most visual
parameters (p < 0.05), with straylight being the most significantly affected (we also measured the
associated effect size). Older drivers performed significantly worse (p < 0.05) in the simulator test,
with a markedly lower performance in lane stability. The results of the multiple linear regression
model evidenced that intraocular straylight is the best visual parameter for predicting simulated
driving performance (R2 = 0.513). Older drivers have shown significantly poorer results in several
aspects of visual function, as well as difficulties in driving simulator performance. Our results suggest
that the non-standardized straylight evaluation could be significant in driver assessments, especially
at the onset of age-related vision changes.ministry of economy and competitiveness (spain)European Union (EU)
FIS2017-85058-Rministry of science, innovation and universities (spain)
FPU15/0557
Asfericidad corneal y calidad de imagen retiniana en cirugía refractiva
En esta Memoria de Doctorado se ha justificado la necesidad de seguir investiganco sobre los algoritmos que se emplean en cirugía refractiva. Hemos estudiado cómo se modifica la calidad de la imagen retiniana en sujetos sometidos a cirugía refractiva. Para ello, una de nuestras intenciones ha sido caracterizar la superficie corneal anterior mediante el modelo de conicoide, es decir, presentando cierto grado de asfericidad, con objeto de poder modificar algunos parámetros para así optimizar la calidad de imagen tras la cirugía refractiva. Dada la importancia de la asfericidad corneal sobre las aberraciones que presenta el ojo, también nos hemos planteado en este trabajo estudiar cómo afecta introducir un segundo término de asfericidad para representar la superficie corneal a la calidad de la imagen retiniana. Hemos tratado también, de justificar teóricamente el aumento de aberraciones que se produce tras cirugía refractiva. Se ha estudiado, además, la importancia que tiene la incidencia del láser sobre la superficie corneal. Finalmente, con algunos casos experimentales, hemos tratado de comprobar cómo se modifica experimentalmente la visión (curva de sensibilidad al contraste CSF) de los sujetos tras cirugía refractivaUniv. de Granada, Departamento de óptica. Leída 23-05-0