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Original Article
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Ai-Hong Chen, Ph.D.*, Shauqiah M Jufri, M.Sc.*, Nathan G Congdon, Ph.D.**,***
*Department of Optometry, Faculty of Health Sciences, Universiti Teknologi MARA, Cawangan Selangor, Kampus Puncak Alam, Malaysia,
**Translational Research for Equitable Eyecare (TREE) Center, Centre for Public Health, Queen’s University Belfast, United Kingdom, ***Zhongshan
Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China.
The Impact of Glaucomatous Visual Field Defects
on Speed and Eye Movements during Reading
ABSTRACT
Objective: To investigate the link between glaucomatous visual eld defects and reading performance by assessing
reading speed and eye movements in reading.
Methods: Eight glaucoma patients and 8 normal-sighted participants were recruited using convenience sampling
in this cross-sectional study. e visual eld was evaluated using the Humphrey Matrix 24-2. Reading speed was
assessed in words per minute using Buari-Chen Malay Reading Chart and the SAH reading passages compendium.
Eye movements in reading were recorded using 3D video-oculography.
Results: Glaucoma and control groups displayed signicant dierences in reading speed (t=3.12; p<0.05) and
xation (t=-2.59; p<0.05). Reading speed was signicantly correlated with the total defect areas (r =+0.62, p<0.05)
and the types of glaucomatous eld defects (Analysis of Variance, ANOVA: F =4.65, p<0.05). No correlation was
apparent in eye movements (p>0.05).
Conclusion: e association of defect areas and types with reading speed but not with eye movements might suggest
a dierent coping strategy between eye movement adjustment and reading adaptation in response to visual eld
defects. Signicant association with xation but not with saccades might indicate that the disengaged and engaged
mechanisms of visual attention are aected dierently by visual eld defects.
Keywords: Glaucoma; visual eld defect; reading speed; eye movements (Siriraj Med J 2021; 73: 17-25)
Corresponding Author: Ai-Hong Chen
E-mail: aihong0707@yahoo.com
Received 25 August 2020 Revised 2 October 2020 Accepted 7 October 2020
ORCID ID: http://orcid.org/0000-0003-4568-0495
http://dx.doi.org/10.33192/Smj.2021.03
INTRODUCTION
Reading involves the integration of visual information,
encompassing visual-spatial skills in locating information,
visual recognition of text, and visual encoding of letters,
words, and sentences.
1,2
Intact visual eld facilitates visual
navigation to locate the text and lines during reading.
Visual eld defect has been reported to contribute to daily
living diculties among glaucoma patients.
3,4
Reading
ability is generally found to deteriorate in glaucomatous
eyes with increasing severity.
5
e link between glaucomatous visual eld loss
and reading problems had been established using either
a questionnaire approach or experimental design.
6-11
Some studies reported more reading diculties among
glaucoma patients; while other studies found glaucoma
patients displayed similar reading performance or better
than normal subjects.
8,12
e discrepancy might denote
that the complex mechanism of the relationship. Reading
speed varies widely among patients with glaucomatous
visual eld loss, but does not appear to be predicted by
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standard measures of visual function such as contrast
sensitivity, visual acuity, and visual eld damage.
8,10,12-14
Certain regions of the binocular visual eld impairment
were associated with reading performance even in patients
with preserved visual acuity.
14
e inferior le region of
patient integrated visual elds was suggested as important
for changing lines during reading.
14
We aimed to further investigate this link between
glaucomatous visual eld loss and reading performance.
In this study, we explored the practicality of examining
the reading speed together with the defect types, total
defect area, and eye movements simultaneously in patients
with glaucomatous visual eld loss. We hypothesized
that patients with glaucomatous visual eld loss would
be aected dierently by the types of visual eld defects
and the total defect areas. Dierent types of reading eye
movements were probed to reveal how the eyes navigated
during reading. Tracking words during reading is imperative
to retrieve information.
11,15
Visual information is neatly
integrated during reading by positioning the eyes to
text location.
8,12
Discontinuities are hardly noticed by
readers as the eye moves from one viewing location
to the next.
16,17
e parafoveal information from one
xation is integrated with information from the fovea
during the next xation. Peripheral visual impairment
has been reported to compromise reading performance
even in readers with preserved central visual acuity.
8,12
A peripheral vision problem may functionally inhibit a
person seeing both ends of the line during reading.
8,12
Information processing primarily controls when the eyes
move, while the oculomotor system control where the eyes
move.
13
Eye movements represent the interface between
high-level cognition (language) and the perceptual-motor
loop (visual-oculomotor). Reading skills are associated
with spatial reading parameters, such as the number of
xations per word, the total number of saccades, and
saccadic amplitudes.
17
e eyes are relatively stationary
during xation and all visual input occurs at this time.
e reading eye xates on most content words in a rapid
series of xations (range 50-500 millisecond, ms) and
saccades (20-35 ms).
18
When xated, the eye remains
immobile for a brief period on a content word and takes
in a span of about seven to nine letters to the right of
the xation and three to four letters to the le before
it jumps to the next xation point.
18
Saccades typically
move the eyes forward 7-9-character spaces. More letters
are processed to the right of the xation if the eye is
scanning from le to right.
18
Both the detection of words
in the center eld of vision and awareness of words in the
periphery is essential for procient reading.
19
Diminished
function of certain patterns of peripheral visual eld
defects might induce more challenges to move from
word to word across the line for uent reading. Dierent
congurations might hurl dierent levels of struggles to
enable readers to process a whole word at once. Visual
eld defects very close to xation inhibit reading to a
greater extent than peripheral defects, and the central 5°
is particularly important for reading.
11,15
Defects in the
inferior le hemield and peripheral superior hemield
regions of the binocular visual eld are related to reading
diculty, with damage to the inferior visual eld slowed
reading rates more than abnormalities in the superior,
nasal or temporal eld.
7,20
Information about the role
of eye movements in mediating the eect of the visual
eld defects on reading diculty remains inconclusive.
MATERIALS AND METHODS
Ethical approval was obtained from the Research
Ethics Committee of University (IRB/IEC Certication
600-RMI (5/1/6) REC/108/15). Our study adhered to
the declaration of Helsinki. Written informed consent
was obtained. A sample size of 16 participants with an
eect size of 1.38 was based on the actual power of study
84% and an α error of 0.05. Sixteen participants were
divided into experimental and control groups in this
cross-sectional study. e experimental group consisted
of eight patients with a diagnosis of glaucoma from
the ophthalmology clinic at a public university. e
inclusion criteria for the experimental group was the
best-corrected LogMAR (Logarithm of the Minimum
Angle of Resolution) visual acuity of 0.8 or better; no
known neuro-ophthalmic or other retinal or optic nerve
conditions likely to aect the visual eld. Eight normal
sighted subjects with no known vision disorders, no known
ocular diseases, and normal visual elds were assigned
to the control group. e mean age of participants for
experimental and control groups was 64 ± 8 years old
and 56 ± 8 years old respectively. Any patients who
were unable to read in the Malay language uently were
excluded.
Reading performance was evaluated using “Buari
and Chen AH Reading Investigation Apparatus” (BaCA
RIA with copyright registration code of CR001460).
BaCA RIA consisted of the standardized Malay language
reading materials, the Buari-Chen Malay Reading Chart
(BCMRC), and the SAH reading passages compendium
(SAHRPC).
21,22
Subjects were instructed to read the BCMRC
aloud monocularly from the largest to the smallest print
size. e critical print size was the smallest print size as
reading speed constant across the larger print sizes from
the plateau plot.
23
Critical print size was obtained from a
graph plotted using reading speed to determine the print
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Original Article
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size for the SAHRPC assessment. Four reading passages
from the SAHRPC were employed. e passages from
the SAHRPC subtend 41° x 28° of the visual eld. e
passages contained upper- and lower-case letters and
standard punctuation marks. Each had 50 words over
4-5 lines each, printed on A4 matte paper in landscape
orientation at a size of 30 x 21 cm in 10-point Arial font,
and subtending a visual angle of 0.28° in the lowercase
letters. ey were randomly selected and positioned at
eye level on a reading stand inclined at 45° at a working
distance of 40 cm. e total time used to read the whole
text was measured. Reading errors (mispronunciations,
substitutes, refusals, additions, omissions, and reversals)
were recorded. e reading speed was quantied as
correct words subtracting the total number of reading
errors and divided by the total time taken to read the
text in words per minute (wpm). Digital recordings
were used for post-reading evaluation of reading time
and reading errors.
Eye movements during reading were video recorded
using a 3D Video-oculograph (3D-VOG, SensoMotoric
Instruments GmbH version 5.0 SP8
©
1991-2003, Berlin,
Germany). A head-mounted eye tracking device with
a built-in infrared light video camera was attached to
a goggle and linked to a computer workstation. e
computer workstation was integrated with MS Windows
version 5.04.02 with stimulus soware. e monitor
screen resolution was set at 1024 x 768 pixels with a
refresh rate of 60Hz and 32-bit color depth. e eye
position was calibrated on a target positioned at eye level
at the primary gaze. Eye movement data were extracted
automatically from the 3D-VOG into the spreadsheet.
e visual eld was assessed using a Humphrey
Matrix visual eld analyzer (Carl Zeiss Meditec, Dublin,
Calif) with frequency doubling technology program
24-2 threshold protocol. All measurements were taken
monocularly. Participants were instructed to press the
response button when a stimulus appeared from any
direction in the periphery while maintaining central
xation. Visual eld result was considered reliable when
xation losses were <20%, false positives were <15%
and false negatives were <25%. e eld defects were
determined from the pattern deviation plot. e 16
glaucoma eyes were categorized into one of ve pre-
determined eld defect categories: nasal step, arcuate
defect, centrocecal, pre-perimetric, or advanced.
e statistical analysis was conducted using SPSS
comparing normal and glaucoma using independent
t-test depending on the test of normality Shapiro-Wilk.
Further analysis of the types of glaucomatous visual
eld defects was performed using Analysis of Variance
(ANOVA). e relationship of total defect area with
eye movements and reading speed was examined using
Pearson correlation analysis. A p-value ≤0.05 was used
as the criterion of statistical signicance.
RESULTS
A comparison between experimental and control
groups was summarized in Table 1. Fixation in reading
is a point where the eyes come to rest during reading.
In this study, the total number of eye xations during
the reading of the entire text was recorded to indicate
the eciency of reading performance. Readers with
fewer eye xations were assumed to take in more words
with each xation. Fixation counts showed a signicant
increase in glaucoma eyes. erefore, glaucoma eyes
were less ecient in reading than normal eyes due to
higher xation count. Meanwhile saccadic and regression
showed no signicant dierence between glaucoma and
normal eyes. Reading speed was signicantly lower in
glaucoma eyes.
e contributing factors for the dierence found
between control and glaucoma eyes were dissected
from the perspectives of total defect area in percentages
(Table 2) and the types of visual eld defects (Table 3).
The main feature of glaucoma pathogenesis is the
progressive degeneration of retinal ganglion cells that
leads to irreversible optic nerve damage and eventually
vision eld loss. e progression of visual eld loss can
be captured in terms of threshold sensitivity changes and
total eld defect areas. Hypothetically, those with more
eld defect areas should have experienced the defect for
a longer period. In contrast, those at the early stage of
glaucoma (early arcuate and pre-perimetric) supposedly
had experienced the defect for a shorter period. e
faster reading speed might connect to the duration of
adaptation concerning the progressive degeneration
of retina ganglion cells. e advanced glaucoma eye
displayed the least xation counts and the fastest reading
speed seemed to support further the adaptive reading
ability to longer duration of adaptation.
The arcuate defect was the most common (10/16=62.5%),
followed by pre-perimetric and nasal step (2/16=12.5%
each). e reading speed diered signicantly for the
various types of glaucomatous eld defects (ANOVA:
F
(2,1985)
= 4.90, p<0.05). Post-hoc analysis showed slower
reading speed in pre-perimetric and early arcuate defects;
while advanced defects displayed the fastest reading speed.
Fixation counts also diered signicantly in dierent
eld defects (ANOVA: Welch’s F
(3,5.965)
=5.32, p<0.05).
Post-hoc analysis revealed higher xation counts in
nasal steps, followed by pre-perimetric, centrocecal, and
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TABLE 1. Comparison of reading speed and eye movements between normal and glaucomatous eyes.
Parameters of investigation Control Glaucoma t-test
Mean ± SD Mean ± SD
Reading speed (wpm) 101.0±29.8 71.9±22.7 t=3.12; p<0.05
Eye movement Fixation 46.3±14.2 61.3±18.2 t=-2.59; p<0.05
[counts (n)] Saccadic 28.9±8.82 24.4±9.62 t=1.39; p>0.05
Regression 14.1±6.13 12.2±7.16 t=0.82; p>0.05
Abbreviations: SD - standard deviation; wpm - words per minute
TABLE 2. Comparison of total defect area and the relationship with eye movement counts and reading speed
measurements for 16 glaucomatous eyes.
Eye Code Total defect area* (%) Eye movements (counts, n) Reading speed (wpm)
Fixations Saccades Regressions
G01 44 37 16 4 114
G02 39 65 24 24 84.0
G03 33 77 26 10 105
G04 19 73 36 11 93.0
G05 44 81 34 24 77.4
G06 43 88 26 18 44.9
G07 35 69 27 2 99.9
G08 28 69 15 8 57.2
G09 22 36 17 13 70.9
G10 35 49 21 7 76.2
G11 22 55 11 10 76.1
G12 13 28 16 6 44.9
G13 6 62 41 21 49.1
G14 11 62 41 21 49.1
G15 24 85 12 7 48.5
G16 69 45 25 9 114
*Calculated as the number of depressed points in the eld/54 x 100%
Abbreviation: wpm - words per minute
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TABLE 3. Comparison of the types of glaucomatous eld defects and the relationship with eye movement counts
and reading speed measurements for 16 glaucomatous eyes.
Types of n Percentages from Eye movements Reading Speed
Glaucomatous Field a total of 16 eyes (counts, n) (words/min)
Defect Fixation Saccade Regression
Nasal step 2 12.5% 81 19 8.5 77.0
Arcuate defect* 10 62.5% 64 25 14 76.7
• Early arcuate (1) 6.25% 62 41 21 49.1
• Partial arcuate (6) 37.5% 59 22 13 80.5
• Full Arcuate (3) 18.8% 73 25 11 78.2
Centrocecal 1 6.25% 49 21 7 76.2
Pre-perimetric 2 12.5% 45 29 14 47.0
Advanced 1 6.25% 45 25 9 114
*Arcuate defect was subcategorized to early arcuate, partial arcuate, and full arcuate according to progression stages
Abbreviation: Min- minutes
advanced glaucomatous visual eld defects (Games-Howell
test=31.8, 95% CI [3.74, 59.85], p<0.05). However, the
saccadic and regression counts showed no signicant
dierence (ANOVA: Saccadic, F
(3, 61.55)
=0.598, p>0.05;
and regression, F
(3,17.05)
=0.284, p>0.05).
Further analysis was conducted to examine the
directional element of glaucomatous defects and their
impact on reading speed and eye movements. Two
eyes [early arcuate (G14) and pre-perimetric (G13)]
were excluded due to the nature of the defect that was
unable to be categorized. For horizontal defect impact
analysis, 7 eyes suered defect in the right region, and
7 eyes displayed in the le region. For vertical defect
impact analysis, 6 eyes were categorized as visual eld
defect at the superior region, 5 eyes were categorized as
visual eld defect at the inferior region and 3 eyes were
categorized as mixed. Neither reading speed (t = -0.97,
p>0.05) nor eye movements diered signicantly by
horizontal locality of visual eld defect [Fixation (t=-0.66,
p>0.05); Saccadic (t =-0.40, p>0.05); Regression (t=0.99,
p>0.05)]. Vertical defect impact analysis concluded
similarly [ANOVA: Fixation (F=0.07, p>0.05); Saccadic
(F=1.14, p>0.05); Regression (F=0.41, p>0.05); Reading
speed (F=1.09, p>0.05)].
e correlation of the total percentages of the defect
areas with eye movements and reading speed was shown
in Fig 1. e total defect area caused a signicant positive
correlation with reading speed (r=+0.62, p<0.05). Reading
speed was found to be faster with an increment of the
total defect area. Meanwhile, none of eye movements
was found to correlate with total defect area [xation
(r=+0.05, p>0.05); saccadic (r= -0.16, p>0.05); regression
(r= -0.11, p>0.05)].
DISCUSSION
Diculties with reading in glaucoma aect quality
of life.
24
Glaucomatous VFD has been associated with
more xations, longer search time, more errors, shorter
xation durations, and longer reading duration.
8,16
Our
nding is in agreement with previous studies that reported
slower reading speed in glaucoma than normal.
8,9
Normal
eyes in our study read 30 words more per minute than
glaucoma eyes using SAHRPC. Decrement of reading
speed in glaucoma eyes might due to the restricted visual
span (eld of view) during reading. Glaucoma eyes with
peripheral visual eld defects have a smaller eld of view
than normal eyes, which might cast diculty to read
from one word to another word eciently.
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Fig 1. Correlation of total defect area with eye movements and reading speed. (a) reading speed, (b) xation, (c) saccade, and (d) regression
Undeniably that some readers with glaucomatous
visual eld defects experienced more diculties with
reading; while others remained the same or better than
readers with normal vision.
3,8,9,12
is ambiguity probed us
to further examine the eye movements and reading speeds
concerning dierent types of glaucomatous visual eld
defects and dierent sizes of defect areas in comparison
to normally sighted subjects. Our ndings seem not to
align fully with previous studies because eye movements
remained the same as the increment of the total defect
area. We expect otherwise because the peripheral visual
defect was reported to compromise reading performance
despite preserved fovea acuity.
16
e slower reading speed
in glaucoma was reported to correlate with the reduction
of the visual eld.
9
Greater visual eld defects had been
associated with greater self-reported diculty nding
the next line of text while reading.
5,9
is dissimilarity
of our ndings with previous studies might indicate
the potential of visual adaptation. e key feature of
glaucoma pathogenesis is the progressive degeneration
of retinal ganglion cells.
25
Understandably, visual defect
worsens over time. e progression of visual eld loss is
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usually reported as threshold sensitivity changes and total
eld defect areas.
26
ose with more eld defect areas
logically has experienced the defect for a longer period.
e faster reading speed might connect to the duration
of adaptation concerning the progressive degeneration
of retina ganglion cells. Adaptation might happen to
cope with the visual challenges in daily activities. Our
ndings might denote the possibility of visual adaptation
in glaucoma. Glaucoma was associated with a reduction
in contrast detection and discrimination adaptation in
the early stages.
27
Reduction of visual acuity or contrast
sensitivity caused slower reading speed in glaucoma.
28
Our ndings might suggest that reading speed reduction
in the early stages of glaucoma might be just transient
evidence of coping mechanisms being established. e
brain can be rehabilitated.
29-30
Neuroplasticity research
reveals the ability of the brain to adapt continuously
throughout life.
31-32
e brain exhibited enormous capacities
to adapt to damage. e repetitive visual training in
daily activities might give an impact on visual learning
in glaucoma.
33
Our analysis of reading speed and eye movements
concerning glaucomatous eld defects also revealed
something interesting about the relationship. Besides
reading speed, only xation but not saccades or regressions
were found to vary signicantly with dierent types of
glaucomatous eld defects. Fixation in reading is a point
where the eyes come to rest during reading. Reading is
not just xating on one word aer another, but rather
requires a complex series of xations to see complete
texts.
34
Readers who make fewer eye xations read faster
because they take in more words with each xation. e
visualization of a complete text during reading can benet
from an intact visual eld and ecient eye movements.
Peripheral visual eld defect has been reported to obstruct
readers to see both ends of the line during reading.
16
Before the reader begins to xate at the rst word in the
text, the eyes scan across the reading materials to locate
the rst word of a text. Spatial reading parameters, such
as the number of xations per word, the total number
of saccades have been tied to reading performance.
17
If
visual search plays a role in reading performance, the
le or superior defect areas would have reduced the
reading speed more than right or inferior defect areas
with the presumption that more eorts are required to
locate the text situated at the le and superior region due
to the defect. e inferior eld has been regarded as an
important positioning for reading.
7,11,14
e inferior le
region has been indicated as important for changing lines
during reading.
14
Reading speed had been reported to
be faster in the inferior eld compared to other areas in
normal readers.
7
Hypothetically, the right-eld defect or
inferior eld defect should have a more negative impact
on reading speed.
7,35
Conversely, our ndings were not
in agreement with the previous report that reading
was neither more aected with the presence of right
than le eld defects nor more aected in the inferior
eld defect.
35
Our horizontal and vertical eld analyses
revealed that the location of eld defects did not seem
to play a signicant role in determining reading speed.
Perhaps not the locality or sizes that determined the
outcomes but the individual reading diculty coping
or adaptation mechanism that dictated the outcome.
Parafoveal information from one xation is connected
to the information from the fovea in the next xation
during readings.
16
e integrated activities between the
fovea and parafoveal during xations are illustrated in
Fig 2.
14,36,37
Parafoveal view gives readers partial information
of what is to come next. If this reading assumption is
correct, the right visual eld defect would aect the
reading performance too.
Fig 2. Illustration of the integrated activities between fovea and parafovea during xations. Bold letters denote xations (what the eye is
seeing directly in its foveal view). Underlined letters signify what is subconsciously processed during a xation (not what readers see directly)
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One possible explanation of our ndings was visual
adaptation through perceptual learning.
33
Dierent coping
mechanism might be used to overcome the hindrances
caused by visual eld defect strategy. When the central
vision was compromised, eccentric xation might be
used in the visual rehabilitation of the visual eld defect.
Scanning involving parafoveal and peripheral visual
eld is crucial to navigating reading. Patients with visual
eld defects might have adapted to the condition with
adjusted eye and head movements or compensatory
gaze strategies to improve reading performance.
33,38,39
Fixations and saccades denote how readers acquire
information. Visual attention can be in an engaged or
disengaged state.
40
To move from one point to another,
visual attention should be in the disengaged state. During
engaged visual attention, saccades were inhibited to
provide steady central xation. e disengaged mechanism
seemed to be intact (insignicant saccadic nding in
our study) during visual search in reading despite visual
eld defects. A dierent coping inclination between eye
movement adjustment and reading adaptation might
occur in response to visual eld defects. Future research
with additional measurements on the time length of
each eye movement is essential. Time length for saccade
can estimate how fast the eye moves between xations.
Time length for regression predicts the eort required
to reread a line of text.
In conclusion, reading speed and xation were
aected by dierent types of glaucomatous visual eld
defects patterns. e association of defect areas with
faster reading speed but not signicant in eye movements
might suggest a possible dierent coping strategy between
eye movement adjustment and reading adaptation in
response to visual eld defects.
ACKNOWLEDGMENTS
is study was funded by the Research Entity Initiative
[600-IRMI/REI 5/3 (016/2018)]. anks to Prof Liza-
Sharmini Ahmad Tajudin for constructive comments.
Special thanks to Noor Halilah Buari & Ethan Hoe Tzong
Shuen for technical supports.
Conict of interest: All authors have no conict of
interest.
REFERENCES
1. Pammer K, Hansen PC, Kringelbach ML, Holliday IE, Barnes
G, Hillebrand A, et al. Visual word recognition: the rst half
second. Neuroimage 2004;22:1819-25.
2. Singleton C, Henderson LM. Visual factors in reading. London
Rev Education 2006;4:89-98.
3. Maharajah KR, Tet CM, Yaacob A, Tajudin LSA, Foster PJ.
Modied Bahasa Malaysia version of VF-14 questionnaire:
assessing the impact of glaucoma in rural area of Malaysia.
Clin Exp Ophthalmol 2008;36:222-31.
4. Ramulu P. Glaucoma and disability: which tasks are aected,
and at what stage of disease? Curr Opin Ophthalmol 2009;20:
92-8.
5. Lester M, Zingirin M. Quality of life in patients with early,
moderate and advanced glaucoma. Eye 2002;16:44-9.
6. Freeman EE, Muñoz B, West SK, Jampel HD, Friedman DS.
Glaucoma and quality of life: the Salisbury Eye Evaluation.
Ophthalmol 2008;115:233-8.
7. Murata H, Hirasawa H, Aoyama Y, Sugisaki K, Araie M,
Mayama C, et al. Identifying areas of the visual eld important
for quality of life in patients with glaucoma. PLOS ONE
2013;8:e58695.
8. Ishii M, Seki M, Harigai R, Abe H, Fukuchi T. Reading performance
in patients with glaucoma evaluated using the MNREAD
charts. Jpn J Ophthalmol 2013;57:471-4.
9. Ramulu PY, West SK, Munoz B, Jampel HD, Friedman DS.
Glaucoma and reading speed. Arch Ophthalmol 2009;127:82-7.
10. Roberts K, Haymes S, Leblanc R, Nicolela M, Chauhan B, Artes
P. Contrast sensitivity, visual acuity, reading speed and macular
visual eld damage in glaucoma. Investig Ophthalmol & Vis
Sci 2005;46:4665.
11. Tabrett DR, Latham K. Important areas of the central binocular
visual eld for daily functioning in the visually impaired.
Ophthalmic Physiol Opt 2012;32:156-63.
12. Altangerel U, Spaeth GL, Steinmann WC. Assessment of Function
Related to Vision (AFREV). Ophthalmic Epidemiol 2006;13:
67-80.
13. Burton R, Crabb DP, Smith ND, Glen FC, Garway-Heath DF.
Glaucoma and reading: exploring the eects of contrast lowering
of text. Optom Vis Sci 2012;89:1282-7.
14. Burton R, Saunders LJ, Crabb DP. Areas of the visual eld
important during reading in patients with glaucoma. Jpn J
Ophthalmol 2015;59:94-102.
15. Whittaker SG, Lovie-Kitchin J. Visual requirements for reading.
Optom Vis Sci 1993;70:54-65.
16. Burton R, Smith ND, Crabb DP. Eye movements and reading
in glaucoma: observations on patients with advanced visual
eld loss. Graefes Arch Clin Exp Ophthalmol 2014;252:1621-
30.
17. Krieber M, Bartl-Pokorny K, Pokorny F, Einspieler C, Langmann
A, Korner C, et al. e Relation between reading skills and eye
movement patterns in adolescent readers: evidence from a
regular orthography. PLoS One 2016;11:e145934.
18. Rayner K. Eye movements in reading and information processing:
20 years of research. Psychol Bull 1998;124:372-422.
19. Jampel HD, Friedman DS, Quigley H, Miller R. Correlation
of the binocular visual eld with patient assessment of vision.
Invest Ophthalmol Vis Sci 2002;43:1059-67.
20. Cummings R, Rubin G. Reading speed and saccadic eye movements
with an articial paracentral scotoma. Invest Ophthalmol Vis
Sci 1993;34:1318.
21. Buari NH, Chen AH. Buari-Chen Malay Reading Chart (BCMRC):
Contextual Sentence and Random Words 2-in-1 Design in
Malay Language. Pertanika J Sci & Technol 2017;25:135-50.
Chen et al.
Volume 73, No.1: 2021 Siriraj Medical Journal
https://he02.tci-thaijo.org/index.php/sirirajmedj/index
25
Original Article
SMJ
22. Chen AH, Buari NH, Jufri S. e development of SAH reading
passage compendium: A tool for the assessment of reading
performance related to visual function. Int Educ Stud 2017;10:
30-37.
23. Legge GE, Pelli DG, Rubin GS, Schleske MM. Psychophysics
of reading: I. Normal vision. Vis Res 1985;25:239-52.
24. Goldberg I. Visual disabilities and quality of life in glaucoma
patients. Clin Exp Ophthalmol 2004;32:18-20.
25. Wilson MR. progression of visual eld loss in untreated glaucoma
patients and suspected in St Lucia, West Indies. Trans Am
Ophthalmol Soc 2002;100:365-410.
26. Su WW, Hsieh SS, Cheng ST, Su CW, Wu WC, Chen HSL.
Visual Subeld Progression in Glaucoma Subtypes. J Ophthalmol
2018;2018:7864219. https://doi.org/10.1155/2018/7864219.
27. Lek J, Vingrys A, Mckendrick A. Rapid contrast adaptation
in glaucoma and aging. Invest Ophthalmol Vis Sci 2014;55:
3171-8.
28. Rubin GS, Legge GE. Psychophysics of reading. VI--e role
of contrast in low vision. Vis Res 1989;29:79-91.
29. Livingston LB. Brain mechanisms in conditioning and learning.
Neurosci Res Program Bulletin 1966;4:349-54.
30. Sasmita AO, Kuruvilla J, Ling APK. Harnessing neuroplasticity:
modern approaches and clinical future. Int J Neurosci 2018;
128:1061-77.
31. Voss P, Thomas ME, Cisneros-Franco JM, Villers-Sidani
E. Dynamic Brains and the Changing Rules of Neuroplasticity:
Implications for Learning and Recovery. Front Psychol 2017;8:1-11.
32. Hess RF, ompson B. New insights into amblyopia: binocular
therapy and noninvasive brain stimulation. J AAPOS 2013;17:
89-93.
33. Mueller I, Mast H, Sabel BA. Recovery of visual eld defects:
a large clinical observational study using vision restoration
therapy. Restor Neurol Neurosci 2007;25:563-72.
34. Mishra RK. Attention in sentence processing: a review.
Psychological Stud 2013;58:308-17.
35. Rayner K, Well AD, Pollatsek A. Asymmetry of the eective
visual eld in reading. Percept Psychophys 1980;27:537-44.
36. Moats LC, Tolman C. Language essentials for teachers of
reading and spelling (LETRS), Module 1: the challenges of
learning to read, 2
nd
ed. Longmont: Sopris West, 2009.
37. Weekley TW. e impact of word-study intervention strategies on
students’ measures of reading comprehension and uency.
Electronic eses and Dissertations 2017. [Cited 2020 April
18] Available from: https://egrove.olemiss.edu/etd/493.
38. Sabel BA, Gudlin J. Vision restoration training for glaucoma:
a randomized clinical trial. JAMA Ophthalmol 2014;132:381-9.
39. Proudlock FA, Shekhar H, Gottlob I. Coordination of eye
and head movements during reading. Invest Ophthalmol Vis
Sci 2003;44:2991-8.
40. Fisher B, Breitmeyer BG. Mechanisms of visual attention
revealed by saccadic eye movements. Neuropsychologia 1987;
25:73-83.
