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1157
JRRD
JRRD Volume 50, Number 8, 2013
Pages 1157–1168
Visual training and emotional state of people with retinitis pigmentosa
Helena Chacón-López, PhD;1* Francisco J. Pelayo, PhD;2 María D. López-Justicia, PhD;1 Christian A. Morillas,
PhD;2 Raquel Ureña, MSc;2 Antonio Chacón-Medina, PhD;3 Begoña Pino, PhD2
1Department of Developmental and Educational Psychology, Faculty of Educational Sciences, 2Department of Computer
Architecture and Technology, High Technical School of Informatics and Telecommunications, and 3Department of Didactics
and School Organization, Faculty of Educational Sciences, University of Granada, Spain
Abstract—The purpose of the study was to improve the visual
functioning of people with restriction in contrast sensitivity (CS),
such as retinitis pigmentosa (RP), by means of a visual training
program. Twenty-six volunteers with RP participated, distributed
in two groups: 15 who made up the experimental group (who
received the training program) and 11 who participated as a con-
trol group (without training). Participants were evaluated before
beginning training, on completion, and 3 mo following comple-
tion for CS with the Pelli-Robson Contrast Sensitivity (P&R) test,
visual functioning with the Visual Function Questionnaire
(VFQ), and in emotional state with the Beck Depression Inven-
tory (BDI). The training program is based on software that gener-
ates luminous stimuli of varying duration and intensity and
registers the stimuli perceived by the subject. The outcomes
showed significant differences posttraining in the experimental
group in depression (F1,14 = 5.42; p < 0.04), VFQ (Z = 2.27; p <
0.02), and P&R in the right eye (Z = 1.99; p < 0.046) and left
eye (Z = 2.30; p < 0.02) but not in binocular (Z = 0.96; p <
0.34). The outcomes showed that the experimental group made
significant progress in all variables and these effects remained
after 3 mo, which suggests that the program could be a helpful
addition to RP rehabilitation and help mitigate the damage.
Key words: adults, contrast sensitivity, depression, emotional
state, rehabilitation, retinal degenerative diseases, retinitis pig-
mentosa, visual functioning, visual performance, visual training.
INTRODUCTION
The degree of autonomy in personal and social per-
formance is assessed by efficiency in carrying out vari-
ous daily tasks. In conducting these activities, people
with low vision, such as those with retinitis pigmentosa
(RP), can have serious difficulties, which may adversely
affect their social and personal welfare.
RP belongs to a group of degenerative diseases of the
retina characterized by a progressive loss of vision that
can lead to blindness. This disorder specifically implies
night blindness, peripheral restrictions and/or scotomas
(scattered spots in which vision is absent or deficient) in
the visual field (VF) [1–3], frequent reduction of visual
acuity (VA) [1–4], and alterations in contrast sensitivity
(CS) [5–6], showing a significant reduction of CS in a
wide range of spatial frequencies. These symptoms affect
daily visual functioning, lifestyle, and social develop-
ment and influence the emotional state [7–8], as well as
the visual-perceptual state [9]; therefore, paying attention
to these aspects is fundamental in our study.
Abbreviations: BDI = Beck Depression Inventory, CS = con-
trast sensitivity, HMD = head-mounted display, MMSE =
Mini-Mental State Examination, P&R = Pelli-Robson Contrast
Sensitivity, RP = retinitis pigmentosa, SD = standard deviation,
VA = visual acuity, VF = visual field, VFQ = Visual Function
Questionnaire.
*Address all correspondence to Helena Chacón-López, PhD;
Department of Developmental and Educational Psychology,
Faculty of Educational Sciences, University of Granada,
Campus Universitario de La Cartuja, s/n, 18071–Granada,
Spain; +34-958-243-975. Email: helenachacon@ugr.es
http://dx.doi.org/10.1682/JRRD.2012.06.0113
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JRRD, Volume 50, Number 8, 2013
Until now, there have been no medical solutions or
pharmacological treatments for this pathology or for
other degenerative visual problems.
Contrast Sensitivity
One of the parameters used to assess visual function-
ing, which significantly influences the performance of
daily living activities, is CS [10–12], the ability to dis-
criminate between shades of gray [13]. Assessment of CS
is useful for evaluating the effects of some visual deficits
because a person may have good VA but diminished CS
and therefore may experience some difficulties in certain
real-life situations [6–11]. This is the case of some people
with RP.
Improvements in CS can be obtained in subjects with
normal vision by training them with challenging tasks that
involve vision [14]. This training is of great interest to peo-
ple with RP since the loss of CS is one of the main difficul-
ties faced [15] and significantly affects their ability to carry
out daily living tasks [11].
Visual Functioning and Retinitis Pigmentosa
Various studies have indicated that differences in visual
functioning in daily living activities are significant among
people with visual impairments such as RP; therefore, their
functional performance is considered in their assessment
[11,16–18]. It has even been stressed that the outcomes of
this assessment are as valuable and complete as the data
provided by ophthalmological tests [11–18]. Procedures to
evaluate visual functioning include lists or self-report tools
used in the tasks in order to record easily observable behav-
iors. These behaviors make it possible to study visual func-
tioning in daily living activities by measuring visual and
psychosocial aspects. Other studies have shown that daily
visual functioning can be affected by negative emotional
states such as depression [11–18], although depression is
also affected by daily living activities.
Emotional State and Retinitis Pigmentosa
Numerous authors have noted that adults who develop
visual restriction have a greater risk of depression [18–21].
Furthermore, depression constitutes a major source of
functional disability, and the consequences in adults also
affect visual rehabilitation [22–23]. A previous research
study showed that emotional adjustment worsens over
time [24].
Depression in people with RP is frequent [7,11,18].
The prevalence has been estimated at 25.7 percent (while
in the general population it amounts to 10%). Nemshick
et al. showed that the period of greatest crisis or stress
occurs during or immediately following diagnosis [25],
and López-Justicia et al. recommended evaluating the
depression variable just after the diagnosis of the disease
and again over time [7].
Visual Stimulation and Retinitis Pigmentosa
Some years ago, procedures for assessment and for
perceptual and visual training began to be applied to
adults with visual deficiencies (including RP) in order to
improve their visual functioning and performance in cer-
tain situations of everyday life [16–17]. These studies
concluded that practice and training could improve the
functional use of residual vision, although it was also
observed that people who were more actively involved in
training made better use of their residual vision [16].
Thus, both practice and motivation seem to be decisive
factors in improving the use of residual vision.
Visual stimulation and training are highly relevant in
interventions with people affected by low vision, even
when the level of remaining vision is very low. This type
of training has been proven to be effective in enhancing
their quality of life regardless of the patient’s age [26–
27]. The aim of visual stimulation and visual training is
to train affected people in using their visual functions so
that they achieve both a quantitative and a qualitative
enhancement in social functioning [26–27]. Likewise,
visual stimulation and training allow affected people to
use their remaining VA ability [28]; this aspect should
not be disregarded, because it has been confirmed that a
large number of RP-affected individuals maintain some
VA to the end of their lives, even if it is minimal [29].
This fact is undoubtedly valuable for planning education
and rehabilitation activities [30].
On the other hand, methods for training the visual sys-
tem in people with VF deficit have been developed using
computer programs to stimulate, through luminous points,
the edge of the region of the VF situated between a visu-
ally intact area and a damaged area [31], resulting in a sig-
nificant increase in visual function. For a long time, it was
believed that these problems could not be treated since it
was thought that vision required a high degree of neuronal
organization produced during the early stages of life. Nev-
ertheless, despite this specific period for organization, a
considerable degree of plasticity has been documented in
the adult visual system damaged by a lesion: a reorganiza-
tion of the neuron receptive field occurs following lesions
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CHACÓN-LÓPÉZ et al. Visual training, emotional state, and RP
in the retina or cortex, with cortical neurons with receptive
fields associated with the damaged area of the retina
acquiring new fields in adjacent areas [32]. Some of the
criticisms of these procedures have pointed out that the
increase in VF produced could be explained by movement
of the eyes toward the affected area in an attempt to com-
pensate for the deficit in VF [33–34].
Purpose of Study
The final purpose of this study was to improve the
CS of people with limited CS, such as those with RP, by
means of a visual training program.
Assuming as a starting hypothesis that it is possible
to improve the CS of people with difficulties in this func-
tion, we have applied a training program based on the
stimulation of VF with different levels of contrast and
using covert direction of attention. It is known that covert
attention, or orientation of the attention toward visual
stimuli that appear in areas other than the fixation point,
improves the response of the visual system [35]. We also
hypothesized that visual training would lead to an
improvement both in functional vision in daily living
activities (specifically CS) and in emotional state.
METHODS
Participants
A meeting was organized for people with RP, mem-
bers of the RP Association of Andalusia (who participated
in research coordinated by two of the authors), to inform
them about the objectives of the study and the activities
involved. A sample of 26 volunteers with RP was then
selected from all those who agreed to participate and who
fulfilled the inclusion criteria: having bilateral VF loss
ranging between 5° and 40° (binocular), having VA rang-
ing between 20/20 (0.0 logMAR unit) and 20/200 (1.0
logMAR unit) in the better eye, and presenting no cogni-
tive impairment (score greater than 24 measured with
Mini-Mental State Examination [MMSE]). These partici-
pants were asked to provide an ophthalmological report,
including the diagnosis and the degree of VA and VF.
Their VA was measured with Snellen acuity charts, and
their monocular and binocular kinetic VF was measured
with a Goldmann Perimeter (V4, III4, I4, II2). Later, they
were randomly assigned (considering VA and VF) into
two groups: 15 (13 women and 2 men) who made up the
experimental group (who received the training program),
and 11 (8 women and 3 men) who participated as a control
group (without training program). There were no signifi-
cant differences between the groups in VA (right eye: χ2 =
2.36, p = 0.50; left eye: χ2 = 6.36, p = 0.10; binocular:
χ2 = 6.36, p = 0.10) or in VF (χ2 = 11.46, p > 0.99). The
participants were evaluated before starting the training
period (pre-), on completion (post-) and 3 mo following
completion (post 3 mo). At each evaluation, participants
completed the following tests: the Pelli-Robson Contrast
Sensitivity (P&R) test, the Visual Function Questionnaire
(VFQ), and the Beck Depression Inventory (BDI). VA
was measured only before beginning training and on com-
pletion. The participants in the control group were
informed that they could undertake the training program
in a second phase of the study.
Table 1 shows the demographic characteristics of the
participants by groups. Four had associated incipient cata-
racts, one had mild central macular edema in one eye,
another had very incipient macular degeneration in one eye,
and three had photopsia (sensation of seeing lights, sparks,
or colors). The presence of ring scotomas or temporal
islands was not included in the reports. Participants had
been diagnosed between 2 and 57 yr before (mean = 14.58,
standard deviation [SD] = 11.16). None of the participants
Characteristic Experimental
Group Control Group
Age (yr)
22–57 17–57
43.00 ± 10.55 36.64 ± 13.06
Sex
13 8
2 3
VA (logMAR unit)
0.00–1.00 0.00–1.00
0.30–1.00 0.30–1.00
VF
5.00–40.00 5.00–40.00
14.80 ± 9.49 17.73 ± 13.11
Associated Visual Pathologies
2 —
2 1
1 —
1 —
Table 1.
Demographic characteristics of participants by group.
Range
Mean ± SD
Female
Male
RE Range
LE Range
Range
Mean ± SD
Incipient Cataracts
Photopsia
Mild Central Macular Edema
Mild Macular Degeneration
LE = left eye, logMAR = logarithm of minimum angle of resolution, RE =
right eye, VA = visual acuity, VF = visual field.
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JRRD, Volume 50, Number 8, 2013
were receiving any type of treatment for depression at the
time of the study. One participant had mild central macular
edema in one eye.
Materials
Contrast Sensitivity
To evaluate CS, we used the P&R test. The P&R test,
as indicated by Pelli et al. [36], consists of two printed
optotype charts, 97 × 82 cm, with eight lines each show-
ing a different sequence of letters (6 per line). All the let-
ters are the same size and are arranged in groups whose
contrast varies from high to low. Each group has three
letters of the same contrast level, and the contrast is
lower in the group on the right. The test can measure up
to 16 different contrast values in steps of 0.15 log units,
from 0.0 to 2.25.
Visual Functioning
The National Eye Institute VFQ (VFQ-25, version
2000) was used to obtain a measure of the individual
visual functioning in everyday life [37]. This instrument
is composed of 38 items that provide a general measure
of the difficulties associated with vision in daily life in
people with chronic eye diseases, as well as 11 subscales
that evaluate emotional well-being and social function-
ing: general health and general vision, near vision, dis-
tance vision, driving, peripheral vision, color vision,
ocular pain, specific visual limitations (role difficulties),
dependency, social functioning, and mental health. The
questionnaire measures, therefore, visual and psychoso-
cial aspects that belong to visual functioning in everyday
life. The answers to the items range between 1 and
5 points, depending on which best fits the respondent’s
situation. These scores are converted to a 0 to 100 scale,
so higher scores mean better visual functioning. The
questionnaire enabled us to obtain scores in each of the
subscales (although in the present study we have omitted
the results in the driving subscale because only one par-
ticipant could do it) and an overall score.
We chose this scale because it is much used and cited
in recent years and there are studies that underpin its util-
ity in the population with RP [18]. The psychometric
properties of the scale are robust (the reliability ranges
between 0.71 and 0.85 and it has reliability equal to or
greater than 0.70, in all the subscales) [37].
Depression
We used the BDI to evaluate depression [38]. The
BDI is a self-applicable instrument validated for the
Spanish population [39] to quantify symptoms of depres-
sion in normal and clinical populations. The BDI has an
average reliability (alpha coefficient) of 0.86 [40]. The
version used in this study was the abbreviated scale of 13
items, and there is a high correlation (0.96) between both
forms [38]. In this version, the respondent must choose a
sentence from four options, listed in order of severity.
Each item is assessed with different options of answers
from 0 to 3, giving a total possible score of 39 points. The
following scores were taken into account: 0 to 4 =
absence of depression, 5 to 7 = mild depression, 8 to 15 =
moderate depression, and >15 = serious depression [41].
Training Program
The instruments for the training program consisted of
a personal computer, a head-mounted display (HMD),
and software that generates the training patterns and reg-
isters the responses of the user during each session.
Visual stimuli consisted of bright spots of varying inten-
sity, duration, and position generated within the VF of the
HMD, first for each eye in monocular vision and then in
binocular vision.
Using an HMD allowed us greater control over the
illumination conditions, as well as helping to avoid any
possible sources of distraction. The software included in
the training program generated the visual stimuli on the
HMD and registered the response of the participant when
he or she perceived it and pressed a key. The visual field
was divided into a regular grid of eight by eight areas or
cells arranged into four quadrants of the screen, with the
stimuli located at the center of the cells. Stimuli were
shown in all the defined positions at three different levels
of intensity, 1/3, 2/3, and 1, with 1 corresponding to the
highest intensity. During each complete training stage
(either monocular or binocular), the 64 defined areas were
stimulated once with each of the three intensity levels in
each position presented randomly (64 stimuli per intensity
level).
During the whole training session, a fixation point
remained in the center of the screen, where the partici-
pants had to direct his or her gaze at all times. Before pre-
senting each new stimulus, the quadrant in which it was
due to appear was pointed at by an arrow in the center of
the visual field behind the fixation point. The arrow
remained in this position for a random variable time
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CHACÓN-LÓPÉZ et al. Visual training, emotional state, and RP
(400–600 ms) before the stimulus appeared. The stimulus
was then displayed for 200 ms. In some randomly
selected cases, the stimulus was not provided, with the
intention of avoiding any tendency toward false posi-
tives. Once the stimulus disappeared, there was a variable
period of time during which the participant had to press a
computer key to register the event as soon as he or she
saw it. The time for registering events was also chosen
randomly within a range between 400 to 600 ms.
The use of variable temporal ranges both in the stage
prior to the display of the stimulus and in the phase in
which, if it is perceived, it is recorded was intended to cre-
ate a different duration for different stimulation cycles;
we hoped that this would avoid participants registering
stimuli that they had not seen because they were simply
following a repetitive periodic response to the stimuli.
With the information generated in each session, a
complete and detailed analysis of the development of
each participant can be carried out.
Procedure
The procedure followed for applying the P&R test
consisted of all the participants in the study reading (in
monocular and binocular vision) the letters located on the
optotype, beginning with the top row and continuing
until two of the three letters in the same group were read
incorrectly.
The participants sat in front of the chart at a distance
of 1 m with the center of the chart at eye level, avoiding
reflections on the surface of the chart. All participants
were assessed at the same location and under identical
conditions, maintaining the illumination constant and
consistent with that established by the authors. The illu-
mination was measured, following the recommendation
of the test instructions, using a Lumix DMC-L1 camera
with a Leica D Vario-Elmarit 14–50mm f/2.8–3.5 lens
(Panasonic; Kadoma, Japan), adjusted to 100 ASA, so
that the illumination of the room corresponded to the
combination of 1/15 s and aperture of f/5.6.
Next, following a break after the CS test, we pro-
ceeded to evaluate VFQ (VFQ-25, version 2000) [37]
and depression. The evaluation was carried out by the
same researcher, administered in the same laboratory
with the same luminance levels. Approximately 2 h were
required to conduct all the tests.
The training phase for each participant was planned
for a period of 3 mo, with daily 15 min sessions in the par-
ticipant’s home and 1 d off per week. Each session was
divided into three phases: two to train each eye separately
and a third for binocular training. The software program
and HMD were installed on the laptops of all participants
so that they could carry out the training at home, without
having to travel. In the beginning of each phase at every
training session, the software repeated the instructions
through a message displayed on the HMD and a recorded
speech. These instructions consisted of keeping their gaze
on the central fixation point and pressing the laptop key-
board every time a stimulus was perceived. At the end of
the session, when the three phases were completed, a mes-
sage was displayed showing a measure related to the per-
formance of the session, computed using the number of
stimuli at each intensity that the user perceived. For each
session, a file was generated containing all the relevant
information for a later analysis: perceived stimuli (their
intensity and location) and a timestamp to control the
training follow-up. We recommended that participants
complete the training every day during the same time
frame, at a time when they were calm and could concen-
trate and when other factors would not interfere.
The participants were instructed to keep their eyes on
the fixation point and to avoid eye movements during the
intervention, although this was not monitored in every
training session. However, at the beginning of each of the
three stages, participants were reminded of this instruc-
tion with a message displayed on the HMD and with a
spoken message that they carry out the training task by
keeping their eyes on the fixation point.
During the training period, the process was moni-
tored by a telephone call every 15 d, registering the most
notable aspects of the participants’ experience. No proce-
dures were applied to affect the emotional state.
RESULTS
Statistical Analyses
Pretraining Measures
Since the violation of the homogeneity of variance
between the experimental group and control group can
lead to biased results in the analyses of unequal sample
sizes, the Kolmogorov-Smirnov test was performed in
the depression variable in the experimental group (p >
0.90) and in the control group (p > 0.66). No significant
differences were found between the two groups (F =
1.99, p = 0.18). It was also performed for differences
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JRRD, Volume 50, Number 8, 2013
between groups in depression (F = 1.99; p = 0.18) and
VFQ variables (χ2 = 3.08, p > 0.99). The depression
scores and VFQ scores at pretest did not differ between
the experimental group and control group.
Table 2 shows the mean score and SD of both groups
in depression, P&R test, and VFQ before beginning train-
ing, on its completion, and 3 mo following completion.
VA only shows two measures, before beginning training
and after finishing it.
Table 3 shows the mean score and SD of both groups
in VFQ subscales in the three assessments.
Correlation Studies
Spearman correlation analysis between the two
groups showed a negative and significant relationship
between levels of depression and VFQ (ρ = 0.64, p <
0.01) in both the experimental group (ρ = 0.73, p < 0.01)
and in the control group (ρ = 0.84, p < 0.001). No corre-
lation was found between levels of depression and VA in
the right eye (ρ = 0.25, p < 0.26), left eye (ρ = 0.12,
p < 0.59), or binocular (ρ = 0.08, p < 0.97) or between
levels of depression and CS in the right eye (ρ = 0.18,
p < 0.42), left eye (ρ = 0.39, p < 0.09), or binocular (ρ =
0.17, p < 0.47).
Results of Depression Variable
Different linear models of repeated measurements (2 ×
2: two groups × two levels of measurements: pretraining and
posttraining) were carried out for the depression variable.
The main effect of group (F1,24 = 0.34, p < 0.57) and the
two levels of measurements (F1,24 = 0.01, p < 0.91) showed
Measure Pre Post Post 3 mo
EG CG EG CG EG CG
Depression 5.08 ± 4.54 2.56 ± 2.69 3.66 ± 3.89 4.11 ± 5.60 3.25 ± 4.09 4.66 ± 4.82
VA - R E 0.23 ± 0.59 0.21 ± 0.62 0.17 ± 0.55 0.21 ± 0.62 — —
VA - L E 0.19 ± 0.59 0.20 ± 0.64 0.15 ± 0.60 0.20 ± 0.64 — —
VA - B 0.19 ± 0.59 0.20 ± 0.64 0.15 ± 0.60 0.20 ± 0.64 — —
P&R-RE 1.45 ± 0.47 1.53 ± 0.42 1.55 ± 0.46 1.53 ± 0.42 1.58 ± 0.52 1.53 ± 0.42
P&R-LE 1.49 ± 0.33 1.48 ± 0.45 1.57 ± 0.30 1.48 ± 0.45 1.65 ± 0.34 1.48 ± 0.45
P&R-B 1.69 ± 0.26 1.63 ± 0.44 1.73 ± 0.26 1.63 ± 0.44 1.74 ± 0.27 1.63 ± 0.44
VFQ 63.92 ± 15.64 60.64 ± 19.33 67.08 ± 16.01 61.53 ± 18.78 65.60 ± 18.11 61.48 ± 18.99
Subscale Pre Post Post 3 mo
EG CG EG CG EG CG
General Health 68.66 ± 13.39 71.36 ± 22.42 69.83 ± 15.10 72.72 ± 20.44 71.83 ± 16.72 72.00 ± 20.73
General Vision 58.66 ± 15.75 54.54 ± 18.50 57.66 ± 17.71 55.00 ± 20.00 59.33 ± 16.24 54.72 ± 19.93
Ocular Pain 78.33 ± 21.37 76.13 ± 18.07 85.38 ± 16.63 80.07 ± 17.38 84.16 ± 19.17 79.80 ± 17.54
Near Activities 66.10 ± 23.03 59.84 ± 28.52 64.44 ± 23.82 61.66 ± 28.79 63.83 ± 25.05 61.49 ± 28.95
Distance Activities 57.77 ± 19.08 53.37 ± 22.50 55.55 ± 16.49 56.16 ± 22.11 56.10 ± 15.65 56.43 ± 22.22
Social Functioning 63.88 ± 19.83 62.05 ± 21.26 65.55 ± 24.16 62.66 ± 23.59 62.21 ± 23.11 62.57 ± 23.72
Mental Health 67.66 ± 23.05 60.45 ± 29.19 73.00 ± 22.89 65.45 ± 29.10 70.33 ± 23.25 65.45 ± 29.10
Role Difficulties 62.50 ± 19.33 50.00 ± 19.96 58.75 ± 20.16 47.45 ± 14.44 56.25 ± 21.65 47.45 ± 14.44
Dependency 72.50 ± 27.01 63.63 ± 29.02 80.41 ± 23.12 65.45 ± 31.74 71.66 ± 29.77 65.18 ± 31.75
Color Vision 75.00 ± 25.00 77.27 ± 26.11 78.33 ± 20.84 75.00 ± 27.38 80.00 ± 27.05 75.00 ± 27.38
Peripheral Vision 43.33 ± 22.09 36.36 ± 20.50 45.00 ± 16.90 36.36 ± 23.35 43.33 ± 19.97 36.18 ± 23.24
Tab le 2.
Mean ± standard deviation scores in depression, visual acuity (VA), Pelli-Robson Contrast Sensitivity (P&R) test, and Visual Function
Questionnaire (VFQ) of two groups.
B = binocular, CG = control group, EG = experimental group, LE = left eye, RE = right eye.
Tab le 3.
Mean Visual Function Questionnaire subscale scores (mean ± standard deviation) in two groups.
CG = control group, EG = experimental group.
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CHACÓN-LÓPÉZ et al. Visual training, emotional state, and RP
no significant differences, but there was a significant inter-
action between the two variables (F1,24 = 6.12, p < 0.02). A
new linear model of the effects of the two levels of measure-
ments on the levels of groups showed significant differences
in the experimental group (F1,14 = 5.42, p < 0.04) but not in
the control group (F1,10 = 1.89, p < 0.21). This confirms an
improvement in the participants of the experimental group
in the depression variable.
In order to know if the improvement was maintained,
a new analysis posttraining and post 3 mo (using the t-test)
was carried out. Since a decrease in depression can be
expected as a result of training, we used a one-sided test,
that is, halving the p-values found in the two-side t-test.
In the experimental group, no significant differences
were found between posttraining and post 3 mo (t = 0.62,
p = 0.27), but significant differences were found between
pretraining and post 3 mo scores (t = 2.30, p = 0.02). No
significant differences were found in the control group
between posttraining and post 3 mo (t = 1.64, p = 0.07),
but significant differences were found between pretrain-
ing and post 3 mo scores (t = 2.22, p = 0.03), confirming
an increase in the depression variable, contrary to what
was observed in the experimental group.
Results in Visual Function Questionnaire Variable
The Wilcoxon signed-rank test was used to compare
the scores of the two groups in VFQ. The results of this
test in pretraining and posttraining showed significant dif-
ferences in the experimental group (Z = 2.27, p < 0.02),
but not in the control group (Z = 1.12, p < 0.26). No
significant differences were found in posttraining and post
3 mo measurements in the experimental group (Z = 1.36,
p < 0.17), nor in the control group (Z = 0.68, p < 0.50).
Results in Pelli-Robson Contrast Sensory Test Variable
In the P&R test, Wilcoxon signed-rank test showed sig-
nificant differences in pretraining and posttraining scores in
the experimental group in the right eye (Z = 1.99, p <
0.046) and the left eye (Z = 2.30, p < 0.02), but not in bin-
ocular (Z = 0.96, p < 0.34). No significant differences
were found in the control group in the right eye, left eye,
and binocular (Z = 1.00, p < 0.32). In the posttraining and
post 3 mo scores, no significant differences were found in
the experimental group in the right eye score (Z = 0.21, p <
0.83), left eye (Z = 1.49, p < 0.14) and binocular (Z = ,
p > 0.99), although significant differences were found
between pretraining and post 3 mo scores in the right
eye (Z = 2.68, p < 0.01) and in the left eye (Z = 2.30,
p < 0.02), but not in binocular (Z = 0.72, p < 0.47). In
the control group, no significant differences were found
between posttraining and post 3 mo scores, or between
pretraining and post 3 mo scores.
Results in Visual Acuity Variable
In the VA evaluation posttraining, Wilcoxon signed-
rank test showed no significant differences in the experi-
mental group score in the right eye (Z = 0.16, p < 0.11),
left eye (Z = 0.92, p < 0.36), and binocular (Z = 0.18,
p < 0.85). No significant differences were found in the
control group in the right eye, left eye, or binocular,
maintaining the initial mean scores.
Results in Training Program
To assess the gain score for each trained contrast level
(1/3, 2/3, and 1), the average number of stimuli perceived in
the last seven training sessions as compared to the first
seven sessions was calculated over a maximum of 64 shown
stimuli, taking into account the stimuli perceived with each
eye individually and in binocular. Tabl e 4 shows these num-
bers and the average gain score at each contrast level, which
has been calculated individually for each participant with
the following expression: (b – a)/(64 – a), where b is the
average number of stimuli perceived in the last seven ses-
sions, and a the average of the first seven sessions.
The average gain score achieved by the group was
26 percent for low-contrast stimuli, 20 percent for medium-
contrast, and 6 percent for high-contrast. These results
enabled us to confirm that the participants undergoing train-
ing improved in the three contrast levels, but especially in
the low-contrast stimuli, as can be seen from the percentage
values and also from the increase in the average number of
perceived stimuli. The average number of completed train-
ing sessions was 58.1 (74.5%).
Contrast
Level First Week Last Week Gain Score
1/3 23.87 31.76 0.26
2/3 33.37 37.41 0.20
136.85 39.32 0.06
Table 4.
Number of perceived stimuli (average of both eyes and binocular) at
beginning and end of training program, and gain score.
1164
JRRD, Volume 50, Number 8, 2013
DISCUSSION
The final aim of the present study was to improve the
CS of people with restriction in contrast, such as those
with RP, through the training of CS. The results obtained
confirm an improvement in the participants of the experi-
mental group in CS, depression, and visual functioning,
associated with the training. No significant improvement
was found in VA.
Contrast Sensitivity and Visual Acuity
Given the data obtained on CS, we can confirm posi-
tive progression for people who carried out the training
program. That improvement was maintained 3 mo after
the conclusion of the training. There was also an improve-
ment in the three contrast levels, especially in the low-
contrast stimuli. We believe that these results are very
interesting because, as has been widely argued, improve-
ments in CS may facilitate the performance of visual pro-
cessing at different stages of the visual system [13]. It is
important to highlight this because the loss of CS is one of
the main difficulties faced by affected individuals and
seriously affects their daily life [11]. A look at the scores
obtained in the P&R test reveals an improvement in each
eye separately and in binocular vision after training
(Table 2). However, in the case of binocular vision the
improvement is not significant. Perhaps a larger sample or
completing a higher number of training sessions would
have allowed us to detect improvement in binocular
vision. Note that there are no changes between the two
evaluations in the control group, with scores remaining at
the initial levels.
These findings are partially consistent with findings
of Fahle and Poggio [42], who reported improvements in
VA and CS after visual training, proving that perceptual
training, previously considered not applicable to the
treatment of adults, is effective for the treatment of, for
instance, amblyopia and presbyopia [13,43–44], although
in this study we have found no significant differences in
VA. It should be noted that a possible limitation of the
study lies in the wide range of VA and VF. Although a
smaller range would have been desirable, the groups
were, at least, homogeneous as shown by the statistical
tests carried out. Also, in accordance with Hahm et al.
[18] and Szlyk et al. [11], the assessment of visual func-
tioning was as valuable and complete as the data pro-
vided by ophthalmologic tests and the results of VFQ
pretreatment showed no significant differences between
the two groups.
Emotional State and Visual Functioning
The results of Spearman correlation analysis high-
light that there is a negative and significant correlation
between the level of depression and visual functioning,
which is in line with the data found in the studies by
Hahm et al. [18] and Szlyk et al. [11]. For this reason, it
seems reasonable to conclude that an improvement in
visual functioning favors the emotional state and quality
of life. The results obtained in our study showed an
improvement in both variables of those who participated
in the training program compared with the control group.
It should be noted that the initial level of depression was
in the limit range of mild depression and we observed a
decrease in the scores obtained after the training and post
3 mo. This result has to be borne in mind when compared
with those of the control group, which showed a slight
increase (also in post 3 mo evaluation) in an even lower
range of mild depression.
In spite of the great variability and heterogeneity
between the participants in both groups (as demonstrated
by the high SDs) and the slightly higher initial score in
VFQ score in the experimental group, an improvement
was noted in the experimental group. Certainly, the data
from our study do not allow us to confirm emphatically
that the improvement was due to participation in the pro-
gram; however, they seem to confirm that participating in
the program benefitted both visual functioning and emo-
tional well-being. This improvement cannot be ascribed to
the implementation of any psychological procedure to
reduce levels of depression, because no such procedure or
treatment was applied. Instead, the improvement could be
related to the mutual influence of emotional state and
visual functioning, also observed in other studies. For
example, Hahm et al. [18] and Szlyk et al. [11] have
pointed out the negative influence of the emotional state
on visual functioning, which reduces people’s vision-
related quality of life, while Grant et al. [22] also stressed
that the psychological state may influence vision rehabili-
tation programs.
Possibly, the opportunity to participate in the experi-
ment and to make improvements in their training sessions
(once the training session was completed the participants
received an overall evaluation of the use of the session cal-
culated by the number of stimuli perceived at each inten-
sity) had an effect on the improvement of their emotional
1165
CHACÓN-LÓPÉZ et al. Visual training, emotional state, and RP
state. In this sense, it must be stressed that all participants
were volunteers with a moderate level of involvement,
especially those in the experimental group (as evidenced by
the regular and normal development of training for 74.5%
training sessions). This may explain the favorable changes
found, corroborating the results obtained in previous stud-
ies that demonstrate that practice and motivation seem to
determine improvement [16]. Possibly, as stated by Herse
[45], the simplest intervention may prove highly effective
in enhancing quality of life and personal well-being.
Limitations
Although the results obtained seem encouraging, we
are aware that they should be considered with caution
because of the small sample size. Additional studies with
larger samples will be needed to confirm our findings.
Another limitation is the voluntary nature of participation
in the study, which may explain, at least in part, the mod-
erate degree of motivation.
Although the participants were instructed to keep
their eyes on the fixation point and to avoid eye move-
ments during the intervention, it would be desirable to
control this factor. This task would be easier to carry out
with the help of an eye-tracker if the training were carried
out with a conventional monitor instead of the HMD we
used. Nevertheless, we consider that the use of the HMD
not only allows training to be less affected by the condi-
tions of ambient illumination, but also decreases the
effect of possible distractions that divert the attention,
and therefore less effort is required to maintain the fixa-
tion point during the training session.
CONCLUSIONS
The results obtained seem encouraging since they
highlight an improvement in CS, visual functioning, and
emotional state of people with a degenerative retinal dis-
ease for which there is currently no treatment and the
development and prognosis are not favorable. Although
we did not find studies that analyze training to improve
CS in people with RP that would have enabled us to com-
pare our results, we believe that initiatives such as this
can contribute to better functional and emotional well-
being of this population.
For this reason, we think that the training program
applied is a helpful addition to RP rehabilitation and that
the findings of our study have important implications in
planning interventions with people with RP. We should
not forget the repercussions that visual impairments such
as RP have on the emotional state and daily activities of
those who are affected [7,11,18]. Hence, training to
improve visual functioning may favor their personal,
social, and professional integration.
ACKNOWLEDGMENTS
Author Contributions:
Study concept and design: H. Chacón-López, F. J. Pelayo, M. D.
López-Justicia, C. A. Morillas, R. Ureña, A. Chacón-Medina, B. Pino.
Acquisition of data: H. Chacón-López, F. J. Pelayo, M. D. López-
Justicia, C. A. Morillas, R. Ureña, A. Chacón-Medina, B. Pino.
Analysis and interpretation of data: H. Chacón-López, F. J. Pelayo,
M. D. López-Justicia, C. A. Morillas, R. Ureña, A. Chacón-Medina,
B. Pino.
Statistical analysis: H. Chacón-López, F. J. Pelayo, M. D. López-
Justicia, C. A. Morillas, R. Ureña, A. Chacón-Medina, B. Pino.
Critical revision of manuscript for important intellectual content:
H. Chacón-López, F. J. Pelayo, M. D. López-Justicia, C. A. Morillas,
R. Ureña, A. Chacón-Medina, B. Pino.
Financial Disclosures: The authors have declared that no competing
interests exist.
Funding/Support: This material was based on work partially supported
by the Cátedra Bidons Egara, the Spanish MICINN research project
RECVIS (Ref. TIN2008–06893-C03–02), the project GENIL-PYR-
2010–19 funded by CEI BioTIC GENIL CEB09–0010, and the Junta de
Andalucía project P06-TIC02007.
Additional Contributions: The authors wish to express their grati-
tude to Dr. Joaquin López (from Bidons Egara, S.L.) and Dr. Eduardo
Fernández (from the Miguel-Hernández University) for their support
and interest in this research; to Dr. José R. Jiménez from the Depart-
ment of Optics (University of Granada); and to Bridgit McQue for
translating parts of the original manuscript into English.
Institutional Review: This research study was approved by the Insti-
tutional Review Board of the University of Granada (Spain) in 2009.
Informed consent was obtained from all participants.
Participant Follow-Up: The authors plan to inform participants of
the publication of this study.
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Submitted for publication June 15, 2012. Accepted in
revised form February 11, 2013.
This article and any supplementary material should be
cited as follows:
Chacón-López H, Pelayo FJ, López-Justicia MD, Moril-
las CA, Ureña R, Chacón-Medina A, Pino B. Visual
training and emotional state of people with retinitis pig-
mentosa. J Rehabil Res Dev. 2013;50(8):1157–68.
http://dx.doi.org/10.1682/JRRD.2012.06.0113
ResearcherID/ORCID: Helena Chacón-López, PhD: L-
3677-2013; Francisco J. Pelayo, PhD: E-2428-2012
