CONCLUSIONS

1
FAST AND OBJECTIVE MEASUREMENT OF MACULAR
PIGMENT WITH NATURAL PUPIL Dirk van Norren1, Jan
van de Kraats1, Suze Valen1 Tos T.J.M.
Berendschot1,2 1 Department of Ophthalmology, UMC
Utrecht 2 University Eye Clinic Maastricht
INTRODUCTION
Correlation between the conditions undilated
pupil in light and dark room (r0.96, plt0.01),
and between dark undilated and dark dilated
(r0.99, plt0.01) were high. Mean differences were
2 and 3 respectively.
eye
L6
L5
L7,8
optic fiber
fiber spectrometer
1.0
A
B
Macular Pigment (MP) protects the macular region
by its capability to filter blue light, thereby
possibly decreasing photochemical light damage.
In addition, MP is capable of scavenging free
radicals. The amount of MP can be manipulated.
High intake of lutein and zeaxanthin is probably
related to a decreased risk of age related
macular degeneration. Assessing the amount of MP
is not easy, however. The available
psychophysical method is cumbersome and time
consuming. Methods based on fundus reflectance
are objective and relatively fast, but they
required a dilated pupil.
mirror
L4
0.8
0.6
retinal stop
MPOD dilated
L3
10
MPOD dimly lit room
0.4
pupil mask
reflectance ()
1
0.2
L2
PURPOSE
0.0
0.1
0.0
0.2
0.4
0.6
0.8
1.0
0.0
0.2
0.4
0.6
0.8
1.0
L1
x
To build an apparatus that enables fast,
objective assessment of the macular pigment
optical density (MPOD) in the undilated eye.
MPOD dark room
MPOD undilated
halogen lamp
Fig. 3A Correlation between MPOD with undilated
pupil in dimly lit and dark room. The solid line
shows the equality. Fig 3B Correlation between
MPOD with undilated and dilated pupil. The solid
line shows the equality.
0.01
wavelength (nm)
0.001
METHODS
400
450
500
550
600
650
700
750
800
Mean within subject standard deviation in
conditions 1-3 (6, 8, 6) was much lower than
with HFP (19). Correlation between MPOD measured
with the new instrument (condition 2) and with
heterochromatic flicker photometry was r0.64
(plt0.01).
Fig. 1 Optical scheme and photo of the Macular
Pigment Reflectometer. The inset shows the
reflection spectrum as input for the model
calculation.
Instrument 1 A beam of white light is sent into
the eye, through a relay system of lenses (L1-6),
and returned from a one degree retinal area to an
exit pupil. The exit beam (L5-8) leads to a
commercial fiber optic spectrometer (Ocean
Optics). Entrance and exit pupil fit in an area
of 3 mm. Analysis Spectral fundus reflectance
was analyzed with a model1 that results in a
parameter for the optical density of macular
pigment. Procedure Subjects (N20 age 18-79)
fixated the middle of a bright white spot with
one eye (13 OD, 7 OS). A computer screen
continuously showed the reflectance spectrum.
This allowed the operator to optimize for
highest reflection. This procedure took about one
minute, enough to bleach the visual pigments.
Five measurements were taken in each
condition. Condition 1 undilated pupil, dark
room Condition 2 undilated pupil, room lights on
(3 lux) Condition 3 dilated pupil, dark
room Instrument 2 Condition 4 For comparison
MPOD was also assessed with Heterochromatic
Flicker Photometry, undilated pupil
(HFP).2 Repeat measurement For 10 subjects the
condition 1 measurements were repeated with at
least three days in between sessions.
RESULTS
Measurements were successfully completed in all
subjects. Mean MPOD in the four conditions was
0.630.22, 0.610.22, 0.610.23 and 0.350.20.
Below, MPOD is depicted as a function of age in
condition dark room, undilated pupil. No age
effect is observed. Test - retest results showed
a very high correlation (r0.98, plt0.01). Mean
difference between test and retest was 1.
1.0
B
A
0.8
0.6
MPOD undilated, dark room
Fig. 4 Correlation between MPOD with
fundusreflection (condition 2) and with
heterochromatic flicker photometry. The solid
line is a regression line.
0.4
0.2
CONCLUSIONS
0.0
0
20
40
60
80
0.0
0.2
0.4
0.6
0.8
1.0
age
MPOD test
We succeeded in building a Macular Pigment
Reflectometer for fast and reliable assessment of
macular pigment. The apparatus holds great
promises for epidemiological research.
Fig. 2A MPOD as function of age, undilated pupil,
dark room. The solid line is a regression
line. Fig 2B Test - retest, undilated pupil, dark
room. The solid line shows the equality.
References 1 Van de Kraats et al., Vision Res.
1996362229-2247 2 Mellerio et al., Curr. Eye
Res. 20022537-47