With the advent of corneal refractive surgery, the role of pupillary diameter as a diaphragm aperture of the optical system that controls the aberration of the human visual system,

has gained clinical relevance in the present.

Changes in pupil size (Øp) produced in response to changes in light intensity optimise the amount of light that reaches the retina, maximizing visual perception. This could be

applicated in several ways, First, Myosis obtained can be implemented to improve night driving or visual perception of post-refractive surgery patients, among others. Also, Mydriasis to help

gain access to the eye fundus in a non-invasive manner, thereby achieving a reduction in medication required in these tests. Pupil diameter can be manipulated using optical filters to improve

pupil performance according to the light intensity and the portion of the light spectrum modified by these filters

Knowledge of the specific band of the spectrum that needs to be absorbed or transmitted will have obvious benefits for non-invasively achieving a quantifiable amount of artificial

mydriasis or myosis.

Effect of UV-light filtering lenses on mesopic pupil size

Sánchez-Ramos C1, Viñas-Peña M1, Bonnin-Arias C1, Flores P2, Molina-Gómez C1

1Neuro-Computation and Neuro-Robotics Group. Universidad Complutense de Madrid. 2Pontificia Universidad Católica de Valparaíso. Instituto de Física. Chile.

Winter School Optometry (WSO) Valencia, 2009celiasr@opt.ucm.es

Introduction

Methods

Conclusions References

Results

Pupil size measurements (n=220) were made in 20 eyes of 10 subjects (20-55

years old) at high Mesopic condition (4.0lux).

FILTERS:

SAMPLE:

PUPILLOMETER:

Fig.2 Procyon P2000SA

The instrument used –a portable, binocular, digital Procyon P2000SA Dynamic

Pupillometer9– has an infrared light source and is able to capture 10 images per eye every 2

seconds. The images are then analyzed by PupilFitTM software.

220 pupil measurements were taken using the Procyon P2000SA at high

Mesopic level with and without the use of 10 different filters of varying transmittance (4%-

65%) in a randomised way. The measurement were made with naked eye, also subjects

didn’t wear their prescription. Enviromental lighting was 0.04lux (Scotopic), in which

subjects remained for 15 minutes before the test started.

Filters were then incorporated in the ocular lens of the pupillometer. The

images are then analyzed by PupilFitTM software , later these data were compared using

a post hoc Tukey statistical test, with Statgraphics software.

METHODS:

Fig.3 Variations in Øp produced in

response to the filter/lighting level

1. Kaufman P. La Pupila. EN: Adler P. Fisiología del ojo. 10ª. ED. Elsevier; p. 716-31. 2005

2. Kvansakul J, Edgar DF, Barbur JL, Schalch W, Barker FM, Kópcke W. Assessment of visual performance in relation to

macular pigment density in human vision. Invest Ophthalmol Vis Sci; 45: E-4340 (abstract). 2004

3. Sakai H, Hirata Y, Usui S. Relationship between residual aberration and light adapted pupil size. Optometry Vision

Science; Vol. 84. 06. 2006

4. Chung S. Pease P. Effect of yellow filters on pupil size. Optometry Vision Science; Vol. 76(1) p. 59-62. 1999

5. Ramírez J. Luminotecnia. Enciclopedia CEAC de electricidad. ED. CEAC. 1999

6. Reading VM, Weale RA. Macular pigment and chromatic aberration. J Opt Soc Am; Vol. 64 p. 231-234. 1974

7. Artigas J. Óptica fisiológica. 2ª. ED. MacGraw-Hill; Cap. 4 p. 99. 1995

8. http://www.rosco-iberica.com/roscoiberica.html?page=productos/filtros/. 03, 2008

9. http://www.procyon.co.uk/about.htm. 03, 2008

Some optical filters significantly produce variations in Øp at intermediate

Mesopic lighting levels.

In conclusion, some filters, regardless of how much visible light they

transmit, significantly produce variations in pupil size.

In high Mesopic condition

(4.0lux), significant differences (p=0.00)

were recorded in Øp measurements for

6 of the 10 filters respect to

measurements without filter, the 6 with

lower transmittance characteristics.

No significant differences

were detected when using the high

transmittance filters (neither UV

absorbing, neither UV transmitting).

According to these results,

differences between these 6 filters were

analyze.

Fig.5 Spectral absorption curves for the 5 coloured optical filters (UV absorption) and the 5 coloured filters (UV transmission). Differences

between them are clearly shown in the graphics

Fig.9 Øp variation with/without the filters at intermediate Mesopic and high

Mesopic lighting levels

Absorption curves for filters

F2 and F8 indicated reduced

transmittances in the band 500nm to

600nm.

Fig.12 Spectral absorption curves for F14, F15 and F8 coloured

optical filters (UV absorption) and the F14, F15 and F8 coloured filters

(UV transmission).

The electromagnetic spectrum

comprises several wavelength bands,

being the visible portion of the spectrum

the band from 380 to 780nm5. The shorter

the wavelength, the greater the energy of

the radiation.

Optical filters are an

effective way of eliminating short

wavelength radiation from the light

spectrum.

Fig.4 Transmittances of the 10 filters used in the study (4%-65%,

visible).The first 5 without UV absorption and the second 5 with UV

absorption

Fig.8 Øp variations produced in response to the filters at high Mesopic

(4.0lux) lighting condition

The lighting level

selected was high Mesopic (HM,

4.0lux).

In this pupillometer a

diffuse screen with two fixation tests

(2 white discs with a central black

spot placed at 10m using convex

lenses) subtending an 8º angle in

the central visual field is used as

visual stimulus.

Fig.1 UV-light transmision

10 filters were used in the study:

5 coloured filters (material:PET;E-colour/

Rosco Iberica) and 5 coloured optical filters

(material:Ophthalmic lens;Essilor), both with

similar visible light transmittance

characteristics, but with different UV light

absorption. Measurements in the absence

of a filter served as controls.

UV BLUE UV BLUE

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