Scotopic threshold microperimetry
E.M. Vingolo, S. Salvatore, D. Domanico E. Rigoni
Rod photoreceptor function is reduced
USA)[15-19], which relies on technologies
in many retinal diseases, such as retinitis
first developed in the 1980s [20] and it’s
pigmentosa, [1-3] congenital stationary night
unsuitable for patients with poor or unstable
blindness, [4] rod-cone dystrophy [5] and
fixation. The second generation HFA is still
macular telangiectasia [6]. Recent evidence
commercially available and includes an
based on histological studies shows that rods
infrared (IR) eye-tracker, which requires to
may be affected prior to cone photoreceptors
override the self calibration program and does
in the early stages of age-related macular
not measure the position of gaze, but only
disease (AMD) [7]. Psychophysical data also
changes in gaze from the initial calibration
show a selective impairment of parafoveal rod
position [21]. The instrument can, therefore,
photoreceptors in AMD [8], which might
identify poor fixation but can’t correct for it.
explain why people with AMD report
In 2011 Nidek Technologies launched
difficulty particularly under dark-adapted
the MP-1 Scotopic (MP-1S) to enable the
conditions [9,10].
study of rod photoreceptors function. Since
Until now, rod function has been measured
in
clinical
studies
only
progress
toward
therapy
for
retinal
by
dystrophies is accelerating and some future
measuring scotopic electroretinogram [11-
therapies are expected to affect rod function,
12], dark adaptation [13-14] or dark-adapted
rod-photoreceptor-mediated
perimetry [15]. The most commonly used
target to determine efficacy as well as safety.
vision
is
the
instrument to perform dark adapted perimetry
In literature upper limit of the scotopic
was a modified first generation Humphrey
region spans from 0.003 to 0.03 asb, or
Field Analyser (HFA, Carl Zeiss Meditec Inc,
equivalently from 0.001 cd/m2 to 0.01 cd/m2 1