Visual symptoms and convergence insufficiency in university teachers

Abstract

Objective:
To investigate the prevalence of visual discomfort and convergence failure in professors.

Methods:
A cross-sectional study was done, consisting of 60 teachers of both sexes, of the Centro Universitário FAG, which used the Convergence Insufficiency Symptom Survey, validated for the Brazilian population.

Results:
Of those surveyed 55.0% are female. 48.3% respondents spend less than two hours a day reading, with 40.0% of respondents said they do 30-minute breaks for one hour during reading and 63.3% said they spend between 2-5 hours a day in front of the computer. With regard to research on diseases of the visual system, 25.0% reported having myopia, with 55.0% of individuals use these glasses and 41.7% use it frequently. The research of the prevalence of convergence insufficiency, gave an average of 12.4(1.8) %.

Conclusion:
It was found that most respondents presented with visual discomfort and small percentages were affected by CI.

Full text

242
Sintomas visuais e insuficiência de
convergência em docentes universitários
Nágila Cristiana Menigite1, Marcelo Taglietti1
1 Centro Universitário da Fundação Assis Gurgacz, Cacavel, PR, Brasil.
AbstrAct
Objective: To investigate the prevalence of visual discomfort and convergence failure in professors. Methods: A cross-sectional study
was done, consisting of 60 teachers of both sexes, of the Centro Universitário FAG, which used the Convergence Insufficiency Symptom
Survey, validated for the Brazilian population. Results: Of those surveyed 55.0% are female. 48.3% respondents spend less than two
hours a day reading, with 40.0% of respondents said they do 30-minute breaks for one hour during reading and 63.3% said they spend
between 2-5 hours a day in front of the computer. With regard to research on diseases of the visual system, 25.0% reported having myopia,
with 55.0% of individuals use these glasses and 41.7% use it frequently. The research of the prevalence of convergence insufficiency,
gave an average of 12.4(1.8) %. Conclusion: It was found that most respondents presented with visual discomfort and small percentages
were affected by CI.
Keywords: Visual acuity; Ocular motility disorders; Vision disorders; Vision, binocular
Resumo
Objetivo: Investigar a prevalência de desconforto visual e insuficiência de convergência (IC) em docentes universitários. Métodos:
Tratar-se de um estudo transversal, com 60 docentes de ambos os sexos, tendo sido utilizado o questionário Convergence Insufficiency
Symptom Survey, validado para a população brasileira. Resultados: Dos docentes entrevistados 55,0% eram do sexo feminino. 48,3%
responderam dedicar menos que duas horas por dia à leitura, sendo que 40,0% dos entrevistados disseram que fazem pausas de 30
minutos à uma hora durante a leitura e 63,3% afirmaram passar entre 2 a 5 horas por dia em frente ao computador. Em relação à
investigação sobre as doenças do sistema visual, 25,0% relataram apresentar miopia, sendo que 55,0% dos indivíduos usam óculos e
destes 41,7% o usam com frequência. Quanto à investigação da prevalência de insuficiência de convergência, obteve-se frequência de
(1,8) %. Conclusão: Constatou-se que a maioria dos entrevistados se apresentou com desconforto visual e uma pequena porcentagem
foram acometidos pela IC.
Descritores: Acuidade visual; Transtornos da motilidade ocular; Transtornos da visão; Visão binocular
Original article
Recived for publication 15/03/2017 - Accepted for publication 07/09/2017.
The authors declare no conflicts of interests.
Visual symptoms and convergence
insufficiency in university teachers
Rev Bras Oftalmol. 2017; 76 (5): 242-6
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DOI 10.5935/0034-7280.20170050

243
IntRoductIon
The biological visual systems have a feature called visual
attention, which allows us to extract the best information
from the environment, besides having the ability to
decrease the amount of information caught. (1,2) Performance,
processing of visual attention, and school learning can be affected
by visual attention problems. (3)
Among the basic processes of interaction with the
environment, we can mention the eye movements, which allow
us to locate and observe objects around us. (4) Thus, with the
simultaneous adduction of the eyes, called convergence, it is
possible to visualize near objects located approximately 33 cm
apart. The near point of convergence (NPC) is designated as the
closest point at which the eyes are able to converge, and it is not
common to change with age. (5)
When the approach of objects becomes an obstacle
preventing the proper binocular alignment of the eyes, we call
it convergence insufficiency (CI).(1,6) Symptoms are usually
influenced by prolonged near-sighted work, by general health and
anxiety, which include difficulty concentrating and understanding
when performing near-sighted activities, visual discomfort, eye
fatigue, blurred or double vision, drowsiness, headache, among
others. (6,7)
After prolonged near-sighted work such as using the computer
and reading, the symptoms of visual discomfort appear, not only
in students, but also in the general population.(8,9) Due to the high
risk of the progression of myopia or its late development as well
as changes related to near sight, these individuals become a group
of special interest when speaking of convergence insufficiency.(10)
Research has pointed to several factors contributing to visual
discomfort in professions that require near sight (teachers, for
example), which may include uncorrected refractive errors,
cortical cell hypersensitivities, and oculomotor anomalies.(9,11)
According to Tavares (8), when related to health and quality
of life, convergence insufficiency can be seen as a negative factor as
it contributes to low income at work, poor performance at school
and leisure hours. Taking into account that CI interferes with the
ability to read, learn and perform near sighted work(1), the present
study aimed at investigating the prevalence of visual discomfort
and lack of convergence in university teachers.
methods
It is a cross-sectional study selecting a convenience sample
of 60 male and female professors from Centro Universitário da
Faculdade Assis Gurgacz (FAG), in the city of Cascavel - PR
during the year 2016. The research was approved by the Research
Ethics Committee by CAAE: 49529715.7.0000.5219. The inclusion
criteria were: male and female individuals over 40 years of age
who were university professors in full employment and who had
a minimum of four working hours a week and who accepted
to participate in the research. The consent was obtained by the
members of the research through the presentation and signature
of the Free and Informed Consent.
For the data collection, a face-to-face interview with
the individuals was carried out, and the researchers used a
questionnaire validated for the Brazilian population and translated
by Tavares.(8) The questionnaire Convergence Insufficiency
Symptom Survey (CISS) developed by the Convergence
Insufficiency Treatment Trial is the first standardized tool that has
been proven valid and reliable for measuring the frequency and
type of symptoms before and after a convergence insufficiency
therapy or other binocular or accommodative disorder. This
questionnaire is divided into 15 items, using a Likert scale with 5
levels of response. Each item focuses on only one symptom, and
it has the sensitivity to discriminate which symptom the individual
is reporting, having good psychometric properties. The results can
be classified as follows: 0 to 10 points: normal binocular vision; 11
to 36 points: suspected CI; and 37 to 60 points: CI.
Afterwards, questions related to visual symptoms were also
answered as a questionnaire. The researchers interviewed the
teachers during their period of activity interval between classes,
in the morning, afternoon and evening shifts. The individuals of
the research were interviewed in the teaching rooms of Centro
Universitário Assis Gurgacz - FAG.
For statistical analysis, the program Statistical Package for
the Social Sciences (SPSS®) Version 22.0 was used, where normality
distribution tests were performed using the Kolmogorov-Smirnov
test, and the central tendency measures for the quantitative data
were calculated and the frequency distribution for qualitative data
was performed. Quantitative data was presented as average and
standard deviation due to presenting normal distribution. The
qualitative data was presented in frequency. A significance level
of 5% (p<0.05) was considered for the entire study.
Results
Sixty teachers were interviewed, of which 33 were female
(55.0%) and 27 were male (45.0%), with an average age of 45.1
(4.2) years. Regarding residence during class time, 85.0% answered
that the address is not the same as the family’s, with 30.0% residing
at a distance greater than 200 km from the family, and with 26.7%
going to their homes only one weekend per month. Regarding the
average sleeping hours per night compared to the week searched,
an average of 6 to 8 hours (55%) was found.
As to the preference for the study material, paper was
predominant with a percentage of 73.3%, but 63.3% of the
respondents said they spend between 2 and 5 hours a day on
the computer. Regarding the hours devoted to reading, 48.3%
answered that they spent less than two hours a day reading,
40.0% of respondents said that they frequently take breaks during
reading from 30 minutes to one hour. With regard to general
lighting, 83.3% said having good lighting for reading, and 91.7%
reported not using additional lighting.
Of the individuals requiring orthoses, fifty-five percent
wear glasses, 41.7% of whom report wearing it frequently, and
35% wear contact lens. As to the investigation of the prevalence
of convergence insufficiency in university professors, 1.8% of
individuals had CI; 51.6% signs of CI, and 46.6% presented normal
binocular vision.
The majority of respondents had visual discomforts, with
a higher prevalence of tired, aching or uncomfortable eyes,
headaches, blurred or double vision, drowsiness, difficulty to
concentrate, and problems associated with reading.
Regarding research on visual system diseases, 25.0%
reported having myopia, and as for their family history, 23.3% had
cataracts as a predominance in visual diseases. Regarding their
general health, 10.0% of the individuals reported having arterial
hypertension, and 36.7% of their family also had a predominance
of this disease.
Rev Bras Oftalmol. 2017; 76 (5): 242-6
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244
dIscussIon
The convergence insufficiency, the basic exophoria and the
excess convergence are the binocular dysfunctions that are most
related to altered visual function in students(12), and Scheiman(4)
states that the most common non-constricting binocular
dysfunction is the convergence insufficiency in adults. Jeffrey and
Nadine (13) state that CI is a common binocular vision disorder
associated to some symptoms such as double vision, eye fatigue,
headaches, blurred vision, and loss of reading that occur when
performing near-sighted work such as reading and viewing the
computer, and approximately 5% of the population in the United
States are affected by CI.
In the study population composed of 60 university
professors, the prevalence values of CI obtained a frequency
of 1.8%; 51.6% with signs of CI, and 46.6% presented normal
binocular vision. In a pilot study conducted by Tavares(8) in a
population of university students seeking to identify CI with a
sample of 98 individuals aged between 18 and 25 years, it can
be seen that 62% present normal binocular vision, 9.2% lack
of convergence, 3.1% presented binocular problems, 11.2%
accommodative problems, and 14.3% presented non-compensated
refractive errors.
The study of Rouse et al. (14) in a sample of adults between 19
and 30 years of age, 46 individuals had normal binocular vision, and
46 individuals has CI, whereas Borsting et al.(15), in a population
comprising young university students, found 56 individuals
with normal binocular vision, and 47 with CI. Therefore, we can
observe that the samples used by these authors both in the group
of individuals with VBN and in the group of individuals with CI
showed very similar results, which is not verified in the sample of
the present study, which has 46.6 % of individuals with normal
binocular vision, and 1.8% with CI.
In relation to the most frequent visual problems and
associated symptoms, Estepa et al.(16), with a sample of 53
teachers, concluded that CI and the reduction in the amount of
tear produced were the most frequent visual problems associated
to symptoms of eye fatigue and dryness related to the excessive
use of computers, and 39% of the sample had CI, and they also
added that professors reported spending between 1 and 12 hours
on the computer, with the most frequent pauses ranging between
3 and 4 hours.
On the other hand, in the study in question on visual system
diseases, 25.0% of patients reported myopia. In addition, 63.3% of
respondents spend between 2 and 5 hours a day on the computer,
and 40.0% of respondents said they pause when reading with a
frequency of 30 minutes to 1 hour.
Studies indicate that because CI symptoms are most
commonly reported up to the second or third decade of life, CI is
not common in children, as young adults often spend more time
doing near-sighted work, thus they are more likely to complain
of symptoms than children. (13) The symptoms found in most CIs
are secondary to accommodative abnormalities, according to
Marran et al.(17)
In our study comparing the results for myopia, the incidence
was 25%, and among their families, 23.3% had cataracts as
predominance in visual diseases. Moreover, it was possible to
observe that regarding general health both of the individuals
investigated and their antecedents, arterial hypertension was
predominant, being 10.0% and 36.7%, respectively.
Rev Bras Oftalmol. 2017;76 (5): 242-6
The present study showed that, of the individuals requiring
orthoses, fifty-five percent wear glasses, 41.7% of whom report
wearing it frequently, and 35% wear contact lens. According to the
World Health Organization the number of the visually impaired
in the global population is 180 million, of which 135 million have
low visual acuity and 45 million are blind. (18) The International
Dry Eye Workshop(19) states that contact lens wearers have five
times more dry eye symptoms compared to glasses wearers.
In individuals over 40 years of age and after the onset
of presbyopia, the prevalence of glasses seems to increase. (20)
According to Gentil et al. (21), office workers were shown as the
population who suffers the most from ocular discomfort, and it
is due to the fact that they are chronic wearers of contact lenses.
In this study, regarding their general health, 10.0% of
the individuals reported having arterial hypertension, and
36.7% of their family also had a predominance of this disease.
According to Oigman (22), headache is the most frequent and
specific symptom observed in hypertensive individuals, and
hypertensive encephalopathy is characterized by the association
between hypertension with drowsiness, mental confusion, visual
disturbance, nausea and vomiting. Pinto et al. (23) in a study to
determine the frequency of headache in employees of a hospital
in the State of Goiás, emphasized its association to some chronic
disease, in which hypertension was highlighted with 53%.
With regard to general lighting, in the present study 83.3%
said having good lighting for reading, and 91.7% reported not
using additional lighting. The purpose of lighting in the work
environment is to perform the visual task in a comfortable way,
as well as to allow this task to be performed without difficulties. (24)
According to Peixoto et al. (25) good lighting can help an
individual with poor vision increase productivity(26), contributing
to a sense of well-being(27), and hey emphasize that thanks to
visual adaptation it is possible to see well with poor lighting. The
different light conditions caused by the contrast between the
highest luminance and the lowest luminance are responsible for
generating the process of visual adaptation, and when it is not
possible to achieve this visual adaptation, then visual discomfort
occurs due to glare. (25)
One of the ways to have comfort vision during reading
and which requires less ocular accommodative effort is an
environment suitable for such task, also consisting of a good
lighting system, even knowing that the vision is able to adapt
to insufficient light conditions because some inadequacy in the
lighting system can affect not only the visual health of users of
the environment causing visual fatigue, causing discomfort and
tension, but also worsening existing vision problems, as well as
influencing learning, social interaction and in health.(28,29)
Gentil et al. (21)reported that when it comes to damage to the
eyes, it can be said that lighting is one of the factors with significant
influence, since the excess of brightness emitted mainly by the
monitor results in ocular fatigue, and according to Oliveira(30)
the most common symptoms are: congested eyes, blurred vision,
constant tearing, trouble seeing, and headache. Light has effects
on the muscles responsible for the movement and focus of the
eyes and the mechanism of vision, and visual fatigue occurs
when these muscles attached to the eyeball suffer from a kind
of exhaustion. (31,32)
In the present study, as to the preference for the study
material, paper was predominant with a percentage of 73.3%, but
Menigite NC, Taglietti M
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245
Visual symptoms and convergence insufficiency in university teachers
Rev Bras Oftalmol. 2017; 76 (5): 242-6
63.3% of the respondents said they spend between 2 and 5 hours
a day on the computer. According to Oliveira (33), after several
hours on the computer, it is possible to detect different changes
such as eye fatigue, eye pain and burning, and blurred vision. He
further states that 50% to 70% of computer users suffer from
these symptoms after a day’s work where they spent more than
3 hours in front of the screen.
Studies have shown that spending more than 4 hours in front
of video leads to binocular changes and accommodation caused
by severe visual demands of near vision. In addition to regular
pauses, good lighting is recommended so that it does not strain
the visual system. (16)
However, when the computer screen is higher than the eyes,
the accommodative and vergential efforts are greater, leading
to enlargement of the palpebral opening spaces, exposing the
ocular surface and producing visual fatigue, musculoskeletal
discomfort and ocular dryness.(34,35) According to Balci et al.(36),
to reduce asthmatic symptoms when computer work is frequent,
regular breaks should be made, because when the effort is greater
than recommended, the extraocular and intraocular muscles that
interfere in the convergence and accommodation, respectively,
suffer from fatigue or spasm.
In the present study, 48.3% answered that they spent less
than two hours a day reading, 40.0% of respondents said that
they frequently take breaks during reading from 30 minutes to
one hour.
In recent years, eye diseases have become very common
among university professors, whose working hours have been
increasing, thus increasing the time spent on the computer, which
leads to a gradual increase of eye diseases and visual fatigue, and
therefore preventive measures are necessary, and it is important
to have good habits to protect the health of the eyes.
The practice of eye exercises becomes important for visual
health, as they are designed to improve the performance of eye
muscles by reducing the negative impact on daily vision, avoid
headaches, reduce visual stress, promote improved concentration
and, in some aspects of vision, relax the muscles of the eyes;
besides, they are beneficial for a variety of eye diseases, related
or not with the aging of the eyes, such as: myopia, strabismus,
convergence insufficiency, nystagmus, presbyopia, among others.
Further studies shall be proposed, in order to deepen the
correlations between visual symptoms and CI in the population
under study, as well as preventive measures and health promotion
with multiprofessional approaches.
conclusIon
The majority of respondents had visual discomforts, with
a higher prevalence of tired, aching or uncomfortable eyes,
headaches, blurred or double vision, drowsiness, difficulty to
concentrate, and problems associated with reading. Regarding
the investigation of the prevalence of convergence insufficiency,
a small percentage was identified.
Acknowledgements
To Fundação Araucária by fostering the research.
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Corresponding author:
Marcelo Taglietti
Rua Sete de Setembro 2254/401, Centro, Cascavel/PR.
ZIP Code 85802100
E-mail: mtaglietti@fag.edu.br.
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