Abstract in children and to compare theAbstract in children and to compare the




Purpose : To explore the relationship between
convergence insufficiency and academic behaviors in children and to compare the scores on academic behavior
survey (ABS) and convergence insufficiency symptom survey (CISS) between
children with convergence insufficiency (CI) and children with normal binocular
vision (NBV).

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Methods: Detailed orthoptic evaluation was performed among 9 to 16
years old children to determine the children with CIs and classify them into
three different CI groups (1-sign CI, 2-sign CI and 3-sign CI). ABS survey was
done among 205 parents whose children was diagnosed with CIs and among100
parents whose children have NBV. The parents were not allowed to consult with
their child during the survey. Convergence insufficiency symptom survey (CISS)
was also administered to both group of children.

Results: Mean ABS score of CI group (11.39 ± 3.89) was significantly
higher as compared to NBV group (4.8 ± 2.36, p < 0.001). Similarly, mean CISS scores of CI group (25.13 ± 10.04) was also found to be significantly higher than that of NBV group (8.58 ± 3.99, p < 0.001). 3-sign CI group were more symptomatic and scored higher on ABS (13.28 ± 3.79) and CISS (33.47 ± 8.21) as compared to one sign CI and two sign CI. There was a significant positive correlation (r = 0.72, p<0.001) between CISS scores and ABS scores. Conclusion: On comparison of ABS scores and CISS scores between children with CI and children with NBV, CI group scored higher than NBV group. Because of significant positive correlation between CISS scores and ABS scores, convergence insufficiency and academic behaviors are associated. Keywords: convergence insufficiency symptom survey, academic behavior survey, binocular vision, reading   Background Convergence Insufficiency (CI) is a binocular vision anomaly with one or more of these signs including exophoria  at near exceeding that of distance, diminished near point of convergence (NPC), and reduced positive fusional vergence (PFV) for near (1,2). Based on the number of signs one possesses, CI can be divided into three types. If only one among these signs is present, it is termed as one-sign CI while the presence of any two and all three signs make group of two-sign and three- sign CI respectively. Children possessing all three signs of CI are found to be more symptomatic as compared with those having one or two signs. (3,4) CI symptoms are linked with vision, performance and soma. Visual symptoms include blurred vision, diplopia while symptoms on performance are difficulty in concentration and memory, need of repeated reading, and somatic symptoms are headache, eye ache etc.( 1-6). CI can also be classified according to severity of clinical signs as mild, moderate or severe. But in children with all three signs there is no further relationship between severity of clinical signs and symptom level.(7) With the introduction of Convergence insufficiency symptom survey (CISS), it has become easier to measure the quantity of symptoms present. CISS is a 15-item survey with each item scored on an ordinal scale from 0 (never) to 4 (always). All the responses are added to obtain overall CISS score and the score ranges from 0 to 60. Scores of 16 or higher is considered to have symptomatic CI. (1,8,9) Visual functions like refraction, accommodation, visual acuity, saccades, convergence and fusion should work in a team to accomplish reading process (10). There is a significant relationship between reading and binocular status of eye (11). Most of the children with learning difficulties exhibit some form of binocular vision problems including CI (12-19). Academic achievement depends on how easily a child can complete his schoolwork or homework without making mistakes. Moreover the enthusiasm and concentration while reading also determine a child's overall performance in school. These academic behaviors are hampered due to CI (1,6). On contrary some researchers have concluded that there is no significant association between CI and academic achievement (5).  CITT Executive Committee devised six-question survey related to the behaviors shown by a child on performing academic tasks like reading and writing. It was named as Academic behavior survey (ABS).    Each question is  scored on an ordinal scale from 0 (never) to 4 (always) with a variability of scores from 0 to 24. On surveying, parents of children with CI are likely to score higher than those parents whose children have no binocular vision anomalies (1,2,6). The aim of this study was to explore the relationship between convergence insufficiency and academic behaviors in children and to compare the scores on academic behavior survey (ABS) and convergence insufficiency symptom survey (CISS) among children with convergence insufficiency (CI) and children with normal binocular vision (NBV). To date, to the best of our knowledge, this study is first of its kind in Nepal and a very little abroad. This finding of the study will help parents know if the adverse behaviors of their child during reading is due to CI. Then the symptoms on children can be reduced through various vision therapies thus promoting the child's academic behaviors (6,9,15,16,17,20). METHODS This was a cross-sectional descriptive study conducted among 205 children with CI and 100 children with NBV. The study was carried out in orthoptic unit of B.P Koirala Lions Centre for Ophthalmic studies (BPKLCOS), Tribhuvan University Teaching Hospital (TUTH), Nepal for one year duration. Study ethics was approved by the Institutional Review Board of Institute of Medicine, Tribhuvan University and the study adhered to the tenets the declaration of Helsinki. Written informed consent was obtained from all subjects and their parents before the initiation of the survey. Subject selection Children of age 9 to 16 years meeting any of the criteria for CI were selected. The criteria of inclusion were exophoria  of minimum 6 prism diopters greater at near than at distance, positive fusional vergence (PFV) of magnitude less than 15 prism diopters for near and near point of convergence (NPC) greater than 6 cm, best corrected visual acuity (VA) of 20/25 or better in each eye at distance and near, stereopsis of at least 400 seconds of arc, and no CI therapy done before (2,19) Children with amplitude of accommodation reduced by > 2 D for their age, amblyopia, constant
strabismus, history of strabismus surgery, high refractive error (>6 D
myopia, >5 D hyperopia, >4 D astigmatism), anisometropia of >2 D
spherical equivalent, manifest or latent



Visual Acuity (VA)
was assessed both monocularly and binocularly with an ETDRS chart at a distance
of 4 metres.. VA was recorded in the Snellen fraction. Objective and subjective
refractions were performed in all cases. Slit lamp examination was performed
and fundus was evaluated with an ophthalmoscope to rule out glaucoma and any
retinal abnormalities.

Detailed orthoptic
examination was performed. Cover test was done for both near and distance at 40
cm and 6 m respectively to rule out any latent or manifest deviation. Prism
cover test (PCT) for both near and distance was performed to measure amount of
latent or manifest deviation. Near point of convergence (NPC) and near point of
accommodation (NPA) was assessed by Royal Air Force (RAF) ruler. Positive
fusion vergence (PFV) was measured using prism bar at near and distance.
Stereopsis was assessed using Titmus Fly Test at 40 cm using polarized glasses
with the subject’s habitual refraction.

CISS form was
administered to the subject. It was a face to face interview. Each of the
question in CISS was read aloud and described to the child. The child chose the
frequency of occurrence of symptom from five possible responses (never,
infrequently, sometimes, fairly often and always) (4,7,8,8′,9).Similarly,
parent of the subject was given ABS form and was asked to rate each item on the
survey on basis of observation of their child’s behavior during reading, doing
schoolwork or homework. During the survey, neither the child nor the parents
were allowed to discuss with

each other (1,6). Since the questionnaire was in English, we
translated the questions in nepali for those who were not able to understand

Data analysis

Data entry and
analysis was done using Statistical Package for the Social Sciences (SPSS)
version 20. Appropriate statistical tools were implemented as required.
Comparison of the mean score on the ABS between the two patients groups was
performed using paired -t test. Pearson correlations were used to assess the
relationship between ABS score given by parents and CISS scores given by the




 Table 1: Gender distribution of study





CI group


87(42.4) MKD1 x2 x3 








NBV group













The purpose of the
study was to explore the relationship between academic behaviors and
convergence insufficiency in school children. Our results showed that the
children with symptomatic CI scored significantly higher on the ABS
questionnaires when compared to children with NBV. The CISS score also resulted
in similar findings which showed the presence of greater level of symptoms like
feeling discomfort, hurting of eyes, diplopia, difficulty to focus, frequent
need to re-read etc. in children of CI group compared to children with NBV. The
frequency of symptoms reported by the child in CISS was associated with ABS
scores given by the parents. We judged that CI might be the cause of adverse
academic behaviors in children with CI.


We also investigated
the relationship between the clinical signs of CI with CISS as well as ABS. The
result showed significant correlation between them (p < 0.00, Pearson correlation). The three signs CI were found to be more symptomatic compared to those with fewer signs of CI. The results are consistent with previous study (Rouse, 1998).They have reported that there is a potential correlation between patient symptoms and number of CI signs present. Similarly, the three sign CI group scored higher in ABS as compared to those with two sign CI and one sign CI (See Table). So, this study was able to address one of the limitations of previous research done by Eric Borsting et al. (Michael Rouse, 2009) in which only the children with three signs of CI were taken for the study.   The positive correlation between CISS scores and ABS scores showed that CI is associated with the behavioral problems in academic tasks like difficulty completing schoolwork and homework, being inattentive,making careless mistakes thus resulting to reduced level of academic performance. It suggests that if we are able to reduce the symptoms of CI by providing the children with different vision therapies, these behaviors noticed by parents during reading and close work may also be reduced unless associated with cognitive cause (20). There were certain limitations of this study. The correlation of these individual signs with CISS and ABS was not done. The score level might have been different for these individual signs though they all fall upon one sign CI category. Besides, we also did not measure the CISS score in accordance to the severity of the signs. For near exophoria, cut-off points for mild were ? 8 exo (?1SD), moderate >8
exo to <13 exo (>1SD to < 2SD), and severe ?13 exo (?2SD). For PFV, cut-off points for mild were ? 15? (? 1SD), moderate >7? to <15? (>1SD to <2SD), and severe ?7? (?2SD). For NPC, the cut-off points were mild 6 cm to <9 cm (?1SD to <2SD), moderate 9 cm to <12 cm (?2SD to <3SD), and severe ?12 cm (?3SD) (Bade et al, 2013). We could have encountered some differences in both CISS and ABS scores if we also had taken severity of signs of CI into account. The results were fully dependent upon the responses given by children and parents. So there might be biasness from each groups. The responses from children of older age group may be reliable due to their increased intelligence and understanding capability. But the responses given by younger age group may not be reliable. The parents were not allowed to consult with children during the survey. So the responses in ABS score about the child's behavior may not resemble the true behavior for those children whose parents do not stay with them all the time. We didn't investigate for the presence of ADHD in children. Childern with ADHD scored higher in ABS than those without ADHD.(1,6). The symptoms like inability to concentrate during reading and slow reading resemble ADHD behaviors (rouse 2009).After diagnosing the children with CI, home based therapy was given to them for 6 weeks after which they were asked to follow up. But we did not carry out follow up study. The signs, symptoms as well as ABS scores might have been decreased with the appropriate treatment.(BOrsting 2013). . The decrease in these symptoms following Office Based Vergence and Accomodative Therapy (OBVAT) suggest that those symptoms were due to CI and not due to ADHD.   Conclusion Convergence insufficiency might be the cause of adverse behaviors of children during their academic work as they scored significantly higher on ABS as compared to the children with normal binocular vision. The greater the number of CI signs, the greater is the score on CISS and ABS. These behaviors in children with CI can be reduced by providing them with vision therapies, and thus improving their school performance.    MKD1Do in this way  x2  x3