Centro de Desarrollo de Sensores, Instrumentación y Sistemas

Universitat Politècnica de Catalunya

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21/09/2015
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Acomodación proximal y pupilometría

Un estudio realizado por investigadores del CD6 y del DAVALOR Research Centre (DRC) relaciona la acomodación proximal con las medidas del diámetro pupilar, demostrando que el diseño de un pupilómetro es una fuente de variabilidad que puede llegar a generar diferencias clínicamente inaceptables, cuando se comparan diferentes instrumentos.

El trabajo, realizado por Carles Otero, Mikel Aldaba, Joan Carlos Ondategui y Jaume Pujol, se ha realizado con el apoyo del programa de becas para la formación de investigadores de la Generalitat de Catalunya, el Plan Nacional de I+D+i del Ministerio de Economía y Competitvidad (DPI2011-30090-C02-01) que cuenta con fondos FEDER de la Unión Europea y el apoyo de la empresa Davalor Salud.

Los resultados se han presentado en el 31st International Pupil Colloquium celebrado en la Universidad de Oxford en el Pembroke College.



Abstract:

Methods:
Pupil diameter of 18 patients were dynamically recorded (at 25 Hz) during 3 seconds in the following 4 conditions of vision: 1) monocular vision without any proximity clue placed between 1 m and the patient’s eye, 2) monocular vision with proximity clues, 3) monocular vision through a squared aperture of 30x30 mm placed 20 mm away from the eye, 4) binocular vision without proximity clues. All measurements were performed in mesopic (2 Lux) and photopic (1600 Lux) conditions. Randomization of each condition was done. The open-field autorefractor/pupilometer PowerRef II (PlusOptix, Germany) was used.

Results:
Repeated measures ANOVA among configurations 1 to 4 in mesopic conditions showed statistically significant differences: F(df=1.902,error=32.334)=10.544, p<0.001.
The Bonferroni post-hoc test showed that the mean pupil diameter difference [95% confidence limits] between the fourth condition minus the 1, 2 and 3 were respectively (in mm): -0.83 [-1.44, -0.21], -0.53 [-0.80, -0.25], -0.93 [-1.60, -0.26]. Analogously, the mean pupil difference [95% confidence limits] between the second condition minus the 1 were respectively (in Diopters): -0.30 [-0.84, 0.24].
In photopic conditions, the repeated measures ANOVA also turned out to be statistically significant: F(df=3,error=48)=38.675, p<0.001. The Bonferroni post-hoc test showed similar comparisons than the mesopic ones.

Conclusions:
Binocular pupil measurements are significantly different (>0.5 mm) to monocular pupil measurements. It is also shown that pupil measurements with open-field designs can be significantly different to closed-field measurements in some patients.
Moreover, our findings showed a tendency towards a decrease in pupil diameter when proximity clues are present in both illumination conditions, which suggests that proximal accommodation seems to induce significant pupil miosis in some patients (in closed-loop conditions). Nonetheless, further studies that take into account accommodation control and report refraction data in synchronization with pupil data would be beneficial for more robust conclusions.
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