Journal Information
Vol. 7. Issue 4.
Pages 178-192 (October - December 2014)
Share
Share
Download PDF
More article options
Visits
10502
Vol. 7. Issue 4.
Pages 178-192 (October - December 2014)
Review
DOI: 10.1016/j.optom.2014.06.005
Open Access
Symptomatology associated with accommodative and binocular vision anomalies
Sintomatología asociada a las anomalías acomodativas y de la visión binocular
Visits
10502
Ángel García-Muñoz
Corresponding author
ag.munoz@ua.es

Corresponding author at: Apartado 99, Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante, 03080 Alicante, Spain.
, Stela Carbonell-Bonete, Pilar Cacho-Martínez
Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante, Spain
This item has received
10502
Visits

Under a Creative Commons license
Article information
Abstract
Full Text
Bibliography
Download PDF
Statistics
Tables (7)
Table 1. Search strategy used in Medline by PubMed.
Table 2. Methodological characteristics of 56 articles of the review.
Table 3. Characteristics of 11 questionnaires obtained in the review.
Table 4. Example of 15 different expressions used to ask about diplopia named in the 56 studies of the review.
Table 5. Relation of the 34 categories of symptoms found in the 56 articles of the review.
Table 6. Symptoms associated with each binocular dysfunction found in the 56 articles.
Table 7. Symptoms associated with each accommodative dysfunction found in the 56 articles.
Show moreShow less
Abstract
Purpose

To determine the symptoms associated with accommodative and non-strabismic binocular dysfunctions and to assess the methods used to obtain the subjects’ symptoms.

Methods

We conducted a scoping review of articles published between 1988 and 2012 that analysed any aspect of the symptomatology associated with accommodative and non-strabismic binocular dysfunctions. The literature search was performed in Medline (PubMed), CINAHL, PsycINFO and FRANCIS. A total of 657 articles were identified, and 56 met the inclusion criteria.

Results

We found 267 different ways of naming the symptoms related to these anomalies, which we grouped into 34 symptom categories. Of the 56 studies, 35 employed questionnaires and 21 obtained the symptoms from clinical histories. We found 11 questionnaires, of which only 3 had been validated: the convergence insufficiency symptom survey (CISS V-15) and CIRS parent version, both specific for convergence insufficiency, and the Conlon survey, developed for visual anomalies in general. The most widely used questionnaire (21 studies) was the CISS V-15. Of the 34 categories of symptoms, the most frequently mentioned were: headache, blurred vision, diplopia, visual fatigue, and movement or flicker of words at near vision, which were fundamentally related to near vision and binocular anomalies.

Conclusions

There is a wide disparity of symptoms related to accommodative and binocular dysfunctions in the scientific literature, most of which are associated with near vision and binocular dysfunctions. The only psychometrically validated questionnaires that we found (n=3) were related to convergence insufficiency and to visual dysfunctions in general and there no specific questionnaires for other anomalies.

Keywords:
Accommodation, ocular
Review literature as topic
Vision, binocular
Vision disorders
Visual symptoms
Resumen
Objetivo

Determinar los síntomas asociados a las disfunciones acomodativas y binoculares no estrábicas, y evaluar los métodos utilizados para la obtención de los mismos.

Métodos

Se realizó una revisión bibliográfica acotada de los artículos publicados entre 1988 y 2012 que analizaban cualquier aspecto de la sintomatología asociada a las disfunciones acomodativas y binoculares no estrábicas. La búsqueda se realizó en Medline (PubMed), CINAHL, PsycINFO y FRANCIS. Se identificaron un total de 657 artículos, de los que 56 cumplieron los criterios de inclusión.

Resultados

Se encontraron 267 formas diferentes de nombrar a los síntomas relativos a estas anomalías, que se agruparon en 34 categorías de síntomas. De los 56 estudios, 35 utilizaron cuestionarios y 21 de ellos obtuvieron los síntomas de las historias clínicas. Se encontraron 11 cuestionarios, de los que sólo 3 habían sido validados: el cuestionario Convergence Insufficiency Symptom Survey (CISS V-15) y su versión previa CIRS, ambos específicos para la insuficiencia de convergencia, y cuestionario de Conlon, desarrollado para anomalías visuales en general. El cuestionario más ampliamente utilizado (21 estudios) fue el CISS V-15. De las 34 categorías de síntomas, las más frecuentemente mencionadas fueron: dolor de cabeza, visión borrosa, diplopía, fatiga visual, y movimiento o parpadeo de las palabras en la visión de cerca, que se relacionaron fundamentalmente con la visión de cerca y las anomalías binoculares.

Conclusiones

Existe una gran disparidad de síntomas en relación a las disfunciones acomodativas y binoculares en la literatura científica, muchos de las cuales se asocian a la visión de cerca y a las disfunciones binoculares. Los únicos cuestionarios psicométricamente validados (n=3) empleados se refieren a la insuficiencia de convergencia y a las disfunciones visuales en general, no existiendo cuestionarios específicos para otras anomalías.

Palabras clave:
Acomodación
revisión de la literatura
visión binocular
anomalías visuales
síntomas visuales
Full Text
Introduction

In today's society, in which the emphasis on vision is associated with tasks requiring near vision, the visual system may be unable to perform this type of activity efficiently, leading to visual discomfort, fatigue or asthenopia and impaired visual performance.1 In many cases, the cause is an abnormality in any of the accommodative and/or vergence systems, which can lead to the development of what are termed accommodative and non-strabismic binocular dysfunctions.2 Accommodative and vergence dysfunctions can interfere with a child's academic progress or a person's ability to function efficiently in the course of his or her work. Children may abandon a task due to their inability to maintain adequate accommodation and/or vergence in the plane of fixation.1 In addition, those who perform extended periods of close vision work, such as reading or the prolonged use of computers, are more likely to report the symptoms and signs associated with these vision disorders.3,4 Nevertheless, the symptoms associated with prolonged near vision work can be reduced with the correct treatment to improve accommodative and vergence function.4,5

These dysfunctions are commonly encountered in clinical practice6 and present a variety of associated symptoms, including blurred vision, difficulty in focusing at different distances, headache and ocular pain, among others.7–10 In general, all of these symptoms are categorised under the generic name of asthenopia. However, the symptoms that the patient perceives may differ depending on the type of causative disorder2; it would therefore be reasonable to conclude that there are different types of asthenopia.11 In fact, one of the problems that clinicians face when diagnosing these dysfunctions is how to determine which symptoms are associated with each disorder and how to quantify their frequency and severity.12

The aim of this study is to determine by means of a scoping review the most common symptoms associated with accommodative and non-strabismic binocular dysfunctions described in the scientific literature published between 1988 and 2012. A further aim is to determine the manner in which subjects’ symptoms are obtained in order to quantify their frequency and severity. We elected to study a long period of time in this scoping review so as not to omit any possible relevant information on these anomalies.

Methods and materials

We conducted a scoping review through an exhaustive search in health science databases for research published between 1988 and 2012. The search was performed in January 2013 using the Medline database (via PubMed), CINAHL, PsycINFO and FRANCIS.

We designed two search strategies. The first strategy was based on the use of free-text terms related to accommodative and non-strabismic binocular dysfunctions, searching all database fields. The search equation included boolean operators, truncated symbols and wildcard characters specific to the selected databases. The second search strategy combined the use of controlled MeSH terms and free-text terms related to questionnaires, asthenopia, visual symptoms and visual discomfort. This second strategy was only implemented in Medline. Table 1 summarises the search equations employed in the two strategies.

Table 1.

Search strategy used in Medline by PubMed.

Strategy 1: free language search
#1  “convergence insufficiency”[All Fields] 
#2  “convergence excess”[All Fields] 
#3  “divergence excess”[All Fields] 
#4  “divergence insufficiency”[All Fields] 
#5  “vergence disorders”[All Fields] 
#6  “vergence dysfunction”[All Fields] OR “vergence dysfunctions”[All Fields] 
#7  “vergence anomalies”[All Fields] OR “vergence anomaly”[All Fields] 
#8  “binocular disorders”[All Fields] 
#9  “binocular anomalies”[All Fields] 
#10  “binocular dysfunction”[All Fields] OR “binocular dysfunctions”[All Fields] 
#11  #1 OR #2 OR #3 OR #4 OR #5 OR #6 OR #7 OR #8 OR #9 OR #10 
#12  “accommodative excess”[All Fields] 
#13  “accommodative spasm”[All Fields] 
#14  “accommodative insufficiency”[All Fields] 
#15  “accommodative infacility”[All Fields] 
#16  “accommodative disorders”[All Fields] 
#17  “accommodative anomalies”[All Fields] OR “accommodative anomaly”[All Fields] 
#18  “accommodative dysfunction”[All Fields] OR “accommodative dysfunctions”[All Fields] 
#19  #12 OR #13 OR #14 OR #15 OR #16 OR #17 OR #18 
#20  “vertical deviation”[All Fields] OR “vertical deviations”[All Fields] 
#21  “vertical disorder”[All Fields] 
#22  “vertical anomalies”[All Fields] OR “vertical anomaly”[All Fields] 
#23  “hypodeviation”[All Fields] 
#24  “hyperdeviation”[All Fields] 
#25  “hypophoria”[All Fields] 
#26  “hyperphoria”[All Fields] OR “hyperphorias”[All Fields] 
#27  #20 OR #21 OR #22 OR #23 OR #24 OR #25 OR #26 
#28  “strabismus”[All Fields] OR “surgery”[All Fields] 
#29  #27 NOT #28 
#30  #11 OR #19 OR #29 
#31  “1988/01/01”[PDat]: “2012/12/31”[PDat] 
#32  #30 AND #31 
Strategy 2: combining free-text search and controlled vocabulary (MeSH terms)
#1  “Questionnaires”[Mesh] 
#2  “Asthenopia”[Mesh] 
#3  “visual symptoms”[All Fields] 
#4  “visual discomfort”[All Fields] 
#5  #1 OR #2 OR #3 OR #4 
#6  “1988/01/01”[PDat]: “2012/12/31”[PDat] 
#7  #5 AND #6 

The inclusion criteria consisted of research published in English which examined any aspect of the symptoms associated with accommodative and non-strabismic binocular dysfunctions, regardless of the type of population studied, from children to adults. We wanted to obtain any type of studies in which authors described symptoms of patients with these anomalies obtained by means of questionnaires, case histories, or both. We excluded articles on strabismic binocular anomalies, papers on ophthalmic examination tests or eye diseases and non-original publications such as letters to the editor, editorials, theoretical reviews and conference proceedings. Published reports of a unique clinical case were also excluded.

The search identified 657 articles eligible for review. These were analysed in accordance with the established inclusion and exclusion criteria, leading to a final selection of 56 studies7–9,13–65 that reported some aspect of the symptomatology of accommodative and binocular dysfunctions. Two authors independently performed the data extraction (S.C.B. and P.C.M.) so that when there were inconsistencies, they were resolved by consensus. Reference lists from all identified studies were also examined.

Once the articles had been selected, all the terms used in each of the 56 studies to refer to the symptoms associated with the dysfunctions were extracted. Since relatively similar questions were often used to obtain the subjects’ symptoms, once these different ways of asking about the symptoms had been compiled they were grouped into categories that contained or referred to the same symptom.

Results

Table 2 shows the methodological characteristics of the 56 studies analysed. Besides author and year, the table also gives sample characteristics, type of dysfunction analysed and how each author obtained the symptoms referred to in each study. In the 35 studies8,9,13–16,18–20,22–29,32–35,37,41–49,51,55,56,59 which used questionnaires to analyse symptoms, a total of 11 different questionnaires9,24,41,42,48,49,51,55,56,59,66 were employed by the different authors.

Table 2.

Methodological characteristics of 56 articles of the review.

Study(Author, year of publication)  Patient characteristics  Dysfunction  Symptoms obtained 
Borsting E, 201213  218 children. Age: 9–17 years  CI  CISS V-15+Academic Behaviour Survey 
Barnhardt C, 201214  221 children. Age: 9–17 years  CI  CISS V-15 
Pang Y, 201215  29 subjects. Age: 45–68 years  CI  CISS V-15 
Scheiman M, 201116  221 children. Age: 9–17 years  CI+AI  CISS V-15 
Serna A, 201117  42 children. Age: 5–18 years  CI  Case History 
Shin S, 201118  57 children. Age: 9–13 years  CI+AI  19-Item COVD-QOL 
Alvarez T, 201019  13 NBV subjects. Age: 21–35 years4 CI subjects. Age: 20–26 years  CI  CISS V-15 
Scheiman M, 201020  221 children. Age: 9–17 years  CI  CISS V-15 
Wahlberg M, 201021  22 children. Age: 7–17 years  AI  Case History 
Shin S, 200922  1031 children. Age: 9–13 years  AD+BD  19-Item COVD-QOL 
Rouse M, 200923  102 NBV children. Age: 9–17 years221 CI children. Age: 9–17 years  CI  CISS V-15 
Rouse M, 200924  212 children. Age: 9-17years  CI  Academic Behaviour Survey 
Teitelbaum B, 200925  29 subjects. Age: 45–68 years  CI  CISS V-15 
Kulp M, 200926  221 children. Age: 9–17 years  CI  CISS V-15 
Cooper J, 2009 27  43 subjects. Age: 9–33 years  AD+BD  CISS V-15 
Chase C, 200928  88 subjects. Age: 18–22 years  AI  Conlon Survey 
CITT, 200929  79 children. Age: 9–17 years  CI  CISS V-15 
Bartuccio M, 200830  504 subjects. Age: 6–27 years  AI  Case History 
Brautaset R, 200831  24 children. Age: not specifiedMean age: 10.3 years  AI  Case History 
Borsting E, 200832  23 subjects. Age: not specifiedMean age: 19 years, 9 month  AD+BD  Conlon Survey+CISS V-15 
Kulp M, 200833  32 subjects. Age: 9–30 years  CI  CISS V-15 
CITT, 2008a34  221 children. Age: 9–17 years  CI  CISS V-15 
CITT, 2008b35  221 children. Age: 9–17 years  CI  CISS V-15+Academic Behaviour Survey 
Abdi S, 200736  12 children. Age: 8–16 children  AI  Case History 
Borsting E, 200737  571 subjects. Age: 18–22 years  AD+BD  Conlon Survey 
Bodack M, 200738  241 subjects. Age: 26–81 years  AD+BD  Case History 
Aziz S, 200639  78 subjects. Age: 5–73 years  BD  Case History 
Brautaset R, 200640  10 subjects. Age not specifiedMean age: 25.4±4.1 years  CI  Case History 
Marran L, 20068  299 children. Age not specifiedMean age: 11.5±0.63 years  AI  CISS V-15 
Sterner B, 200641  72 subjects. Age: 5.8–9.8 years  AI  Sterner Questionnaire 
Vaughn W, 200642  91 children. Age not specified  AD+BD  19-Item COVD-QOL 
Abdi S, 20057  120 children. Age: 6–16 years  CI+AI  Case History 
Scheiman M, 200543  47 children. Age: 9–18 years  CI  CISS V-15 
Scheiman M, 200544  46 subjects. Age: 19–30 years  CI  CISS V-15 
Scheiman M, 200545  72 children. Age: 9–18 years  CI  CISS V-15 
Rouse M, 200446  46 CI subjects. Age: 19–30 years46 NBV subjects. Age: 19–30 years  CI  CISS V-15 
White T, 200447  129 subjects. Age: 9–19 years  CI  19- Item COVD-QOL 
Borsting E, 20039  392 children. Age: 7.6–14.8 years  CI  CISS 16 Items 
Borsting E, 200348  47 CI children. Age: 9–18 years56 NBV children. Age: 9–18 years  CI  CISS V-15 
Adler P, 200249  92 subjects. Age: 5–35 years  CI  Adler Questionnaire 
Cacho P, 200250  328 subjects. Age: 13–35 years  AI  Case History 
Gallaway M, 200251  25 subjects. Age: 9–51 years  CI  Gallaway Questionnaire 
Garcia A, 200252  69 subjects. Age: 13–35 years  AD+BD  Case History 
Lara F, 200153  265 subjects. Age: 10–35 years  AD+BD  Case History 
Borsting E, 199955  14 CI children. Age: 8–13 years14 NBV children. Age: 8–13 years  CI  CIRS Symptom Questionnaire Parent version 
Birnbaum M, 199956  60 subjects. Age: >40 years  CI  Birnbaum Questionnaire 
Rouse M, 199854  415 children. Age: 8–12 years  CI  Case History 
Porcar E, 199757  65 subjects. Age not specifiedMean age: 22±3 years  AD+BD  Case History 
Gallaway M, 199758  83 subjects. Age: 7–32 years  CE  Case History 
Russell G, 199359  15 subjects. Age: 9–34 years  AI  Russell Questionnaire 
Matsuo T, 199260  9 children. Age: 6–16 years  AI+CI  Case History 
Dwyer, 199261  144 children. Age: 7–18 years  AD+BD  Case History 
Deshpande S, 199162  2162 subjects. Age: 15–35 years  CI  Case History 
Mazow T, 198963  26 subjects. Age: 7–28 years  CI+AI  Case History 
Rutstein R, 198864  17 subjects. Age: 7–39 years  AE  Case History 
Chrousos G, 198865  10 subjects. Age: 10–19 years  AI  Case History 

CI: convergence insufficiency, AI: accommodative insufficiency, AD: accommodative dysfunction, BD: binocular dysfunction, CE: convergence excess, AE: accommodative excess, NBV: normal binocular vision.

Table 3 shows the characteristics of the 11 questionnaires found in the 56 studies, indicating the authors who developed each questionnaire, which authors used each of them, the type of dysfunction to which they refer, the target population on which they were used, the number of items they contain and how many of these items are associated with far or near vision. It also shows the characteristics of each individual questionnaire, specifying the number of questions asked and how they are calibrated, what scoring system is used and whether the questionnaire has been psychometrically validated.

Table 3.

Characteristics of 11 questionnaires obtained in the review.

Questionary(developed by)  Number of studies which used the questionnaire  Dysfunction  Target poblation  No items far visión  No items near vision  Characteristics  Score system  Type of validation 
Convergence insufficiency symptom survey (CISS V-15)(Borsting E, 200348218,13–16,19,20,23,25–27,29,32–35,43–46,48  CI  Children and Adults  15  15 questions, each of them specific of one symptom.Liker scale of 5 response choices  Each item scored between 0 and 4Total score ranged from 0 to 60 points.A total score16 is related with symptoms associated with CI  ROC analysis to test the ability of CISS V-15 questionnaire to discriminate between CI and NBV groups 
19 Item college of optometrists in vision development quality of life(COVD-QOL) questionnaire(Vaughn W, 200642418,22,42,47  Visual anomalies  Children  18  19 questions, each of them is not specific of one symptom, taking up 3 symptoms in the same question.Liker scale of 5 response choices  Each item scored between 0 and 4Total score ranged from 0 to 76 points.A total score of 20 and above is a concern, and further evaluation is indicated  – 
Academic Behaviour Survey(Rouse M, 200923313,24,35  CI  Children  6 questions, each of them specific of one symptom.Liker scale of 5 response choices  Each item scored between 0 and 4.Total score ranged from 0 to 24 points  – 
Conlon Survey(Conlon E, 199966328,32,37  Visual anomalies  Adults  23  23 questions, each of them is not specific of one symptom, taking up 8 symptoms in the same question.Liker scale of 4 response choices  Each item scored between 0 and 3.Total score ranged from 0 to 69 points, with 3 groups defined:Low discomfort: scored 0–24Moderate discomfort: 25–48High visual discomfort: 49–69  RASCH analysis 
Convergence insufficiency and ready study (CIRS) symptom questionnaire parent version(Borsting E, 199955155  CI  Children  15  15 questions, each of them specific of one symptom.Liker scale of 4 response choices  Each item scored between 0 and 3.Total score ranged from 0 to 36 points.A total score9 indicates more likely to be CI  Sensitivity, specificity and Odds ratio analysis 
CISS 16 Items questionnaire(Borsting E, 2003919  CI  Children  13  16 questions, each of them specific of one symptom.Liker scale of 3 response choices  Each item scored between 0 and 2.Total score ranged from 0 to 24 points  – 
Sterner questionnaire(Sterner B, 200641141  AI  Children  4 questions, each of them specific of one symptom  Answer with “yes” or “no.”It is necessary to have the symptom at least occasionally, and not just once  – 
Adler questionnaire(Adler P, 200249149  CI  Children and Adults  14  15 questions, each of them specific of one symptom  Answer with “yes” or “no”  – 
Gallaway questionnaire(Gallaway M, 200251151  CI  Children and Adults  10  10 questions, each of them specific of one symptom.Liker scale of 3 response choices  Each item scored between 0 and 2.Maximum score of 20 points  – 
Birnbaum questionnaire(Birnbaum M, 199956156  CI  Adults  3 questions, 1 specific of one symptom and 2 questions are not specific of each symptom, taking up 10 symptoms in the same question  Answer with “yes” or “no”  – 
Rusell questionnaire(Russell G, 199359159  AI  Children and Adults  4 questions, each of them specific of one symptom.1 question of reading ability.Scale from 0 to 10 points  Of the 4 questions, each item scored between 0 and 100.The question about reading ability scored between 0 and 10  – 

CI: convergence insufficiency, AI: accommodative insufficiency; NBV: normal binocular vision.

An analysis of the different symptoms named in the 56 studies revealed that up to 267 different expressions were used to ask about symptoms, both in the case histories and in the 11 questionnaires related to these dysfunctions. Of these, 162 expressions appeared in publications reporting the use of questionnaires while the remaining 105 were employed in publications which did not use a questionnaire.

Due to this high number of different ways to name the symptoms (267), it was decided to group terms which described the same symptom by category. The aim was to obtain categories of symptoms in order to summarise those which actually referred to the same concept and thus avoid duplication of information. Table 4 shows an example of this phenomenon as regards the category of “double vision”. The 15 different ways used to name the symptom of double vision were grouped into the same category, called “diplopia”. Table 4 also shows the different ways employed to ask about double vision, the different studies that used them and whether they were compiled using a questionnaire.

Table 4.

Example of 15 different expressions used to ask about diplopia named in the 56 studies of the review.

Expression  Author and year  Questionnaire used 
Do you have double vision when reading or doing close work?  Borsting E, 201213, Barnhardt C, 201214, Pang Y, 201215, Scheiman M, 201116, Alvarez T, 201019, Scheiman M, 201020, Rouse M, 200923, Teitelbaum B, 200925, Kulp M, 200926, Cooper J, 200927, CITT, 200929, Borsting E, 200832, Kulp M, 200833, CITT, 200834, CITT, 200835, Marran L, 20068, Scheiman M, 200543, Scheiman M, 200544, Scheiman M, 200545, Rouse M, 200446, Borsting E, 200348  CISS V-15 
Diplopia  Serna A, 201117, Bodack M, 200738,Aziz S, 200639, Cacho P, 2002 50,Gallaway M, 199758, Dwyer P, 199261,Rouse M, 199854  None(Case History) 
Do the letters on a page ever appear as a double image when you are reading?  Chase C, 200928, Borsting E, 200832,Borsting E, 200737  Conlon Survey 
Occasional diplopia  Brautaset R, 200640, Rutstein R, 198864  None(Case History) 
Intermittent diplopia  Abdi S, 20057, Porcar E, 199757  None(Case History) 
Do you ever see double when you read?  Birnbaum M, 199956  Birnbaum questionnaire 
When you do near work, do you (at least 25% of the time) get headaches, double vision or eyestrain; do you lose concentration; do your eyes feel tired, pull, ache, or jump or run together?  Birnbaum M, 199956  Birnbaum questionnaire 
Is it difficult to do near work (reading, writing, etc.) for at least 1 half hour without discomfort (i.e., headaches, eyestrain, tiredness, eye ache,burning, stinging, wateriness, blurring, double vision, or loss of concentration)?  Birnbaum M, 199956  Birnbaum questionnaire 
Do you have double vision or see words split into two (or demo) when you read or study?  Borsting E, 20039  CISS 16 items 
¿Has your child reported double vision when reading or studying?  Borsting E, 199955  CIRS Symptom questionnaire parent version 
Do you ever see 2 numbers or words on the paper when you know there is only one?  Adler P, 200249  Adler questionnaire 
Asthenopia and diplopia during close work  Matsuo T, 199260  None(Case History) 
When I read the material appears to split apart into two pieces.  Russell G, 199359  Russell questionnaire 
Double vision  Abdi S, 20057  None(Case History) 
Double vision when reading  Gallaway M, 200251  Gallaway questionnaire 

Following a qualitative process, each of 267 expressions used to ask about symptoms were reviewed and designated to a category that embodied the meaning of the symptom. Thus, the 267 different forms were grouped into 34 categories of symptoms. Table 5 shows the 34 categories of symptoms established, and specifies how many different forms refer to each category and the number of studies that report on this symptom. For each category, it also indicates the number of studies which referred to children, adults or both, accommodative dysfunction, binocular dysfunction or both, and whether each category is associated with far vision, near vision or both, according to the number of authors who specified this.

Table 5.

Relation of the 34 categories of symptoms found in the 56 articles of the review.

Category  Number of studies  Different expressions  Number of studies
      Children  Adults  Children and adults  AD  BD  AD+BD  Far vision only  Near vision only  Far and near vision  Distance not specified 
Headache  53  20  27  12  14  30  14    45 
Blurred vision  46  34  20  12  14  28    35 
Diplopia  41  15  20  12  30    36   
Visual fatigue  40  25  20  10  10  28    36   
Words appear to move or jump at near vision  40  25  24  11  27  10    40     
Reading problems  39  17  22  26    39     
Lack of concentration  36  16  23  26    35   
Loss of place when reading  33  15  20    25    32   
Sore eyes  32  21  23    28   
Difficulty performing schoolwork  31  10  22  24  26   
Visual discomfort  29  16  23    25 
Ocular pain  25  15  24      24   
Feel sleepy  23  15    23      23     
Pulling eyes  22  14    22      22     
Avoid near tasks  13    13     
Asthenopia     
Change reading distance         
Excessive sensitivity to light         
Close one eye           
School performance problems     
Difficulty focusing from one distance to another     
Rubbing of eyes         
Head or book tilt           
Inability to estimate distance accurately               
Be distracted               
Red eye               
Watery eyes               
Dry or gritty eyes               
Tearing             
Dizziness or nausea         
Excessive blinking             
Eye turn noticed               
Get faint colours around words               
Extraordinary Reading or writing posture               

AD: accommodative dysfunction, BD: binocular dysfunction.

Tables 6 and 7 show the symptoms associated with each particular binocular and accommodative dysfunction. There have only been included the anomalies for which the authors described symptoms particularly associated with each dysfunction. In both of them there is also information about the number of studies which refer to each symptom and if the category has been named by a particular questionnaire or by means of the case histories with their number of studies.

Table 6.

Symptoms associated with each binocular dysfunction found in the 56 articles.

Dysfunction  Symptom category  Number of studies  Questionnaire or case history(Number of studies) 
CI  Headache  31  CISS V-15 (21), CIRS Symptom questionnaire parent version (1), CISS 16 Item (1), 19 item COVD-QOL (1), Gallaway (1), Birnbaum (1), Case History (5) 
CI  Words appear to move or jump at near vision  29  CISS V-15 (21), CIRS Symptom questionnaire parent version (1), CISS 16 Item (1), 19 item COVD-QOL (1), Gallaway (1), Adler (1), Birnbaum (1), Case History (2) 
CI  Diplopia  29  CISS V-15 (21), CIRS Symptom questionnaire parent version (1), CISS 16 Item (1), Adler (1), Gallaway (1), Birnbaum (1), Case History (3) 
CI  Lack of concentration  27  CISS V-15 (19), Academic Behaviour Survey (ABS) (1),CISS V-15 and ABS (2), CIRS Symptom questionnaire parent version (1), CISS 16 Item (1), 19 item COVD-QOL (1), Birnbaum (1), Case History (1) 
CI  Visual fatigue  27  CISS V-15 (21), CIRS Symptom questionnaire parent version (1), Gallaway (1), Birnbaum (1), Case History (3) 
CI  Lose of place when reading  26  CISS V-15 (21), CIRS Symptom questionnaire parent version (1), CISS 16 Item (1), 19 item COVD-QOL (1), Gallaway (1), Case History (1) 
CI  Reading problems  26  CISS V-15 (21), CIRS Symptom questionnaire parent version (1), CISS 16 Item (1), 19 item COVD-QOL (1), Gallaway (1), Adler (1) 
CI  Blurred vision  26  CISS V-15 (21), CIRS Symptom questionnaire parent version(1), Gallaway (1), Birnbaum (1),Case History (2) 
CI  Sore eyes  25  CISS V-15 (21), CIRS Symptom questionnaire parent version (1), CISS 16 Item (1), 19 item COVD-QOL (1), Case History (1) 
CI  Difficulty performing schoolwork  24  CISS V-15 (19), Academic Behaviour Survey (1), CISS V-15 and ABS (2), CIRS Symptom questionnaire parent version (1), CISS 16 Item (1) 
CI  Ocular pain  24  CISS V-15 (21), CIRS Symptom questionnaire parent version (1), CISS 16 Item (1), Birnbaum (1) 
CI  Feel sleepy  23  CISS V-15 (21), CIRS Symptom questionnaire parent version (1), CISS 16 Item (1) 
CI  Visual discomfort  23  CISS V-15 (21), CISS 16 Item (1), Birnbaum (1) 
CI  Pulling eyes  22  CISS V-15 (21), CIRS Symptom questionnaire parent version (1) 
CI  Avoid near tasks  Academic Behaviour Survey (3), CIRS Symptom questionnaire parent version (1),19 item COVD-QOL (1), Gallaway (1), Case History (1) 
CI  Change reading distance  19 item COVD-QOL (1), Gallaway (1), Adler (1) 
CI  School performance problems  Academic Behaviour Survey (3) 
CI  Rubbing of eyes  Adler (1), Case History (1) 
CI  Head or book tilt  Adler (1), 19 item COVD-QOL (1) 
CI  Close one eye  19 item COVD-QOL (1), Case History (1) 
CI  Excessive blinking  Adler (1), Case History (1) 
CI  Asthenopia  Case History (2) 
CI  Tearing  Birnbaum (1) 
CI  Dizziness or nausea  CISS 16 Item (1) 
CI  Get faint colours around words  Adler (1) 
CI  Be distracted  19 item COVD-QOL (1) 
CE  Headache  Case History (3) 
CE  Blurred vision  Case History (3) 
CE  Asthenopia  Case History (2) 
CE  Diplopia  Case History (1) 
CE  Avoid near task  Case History (1) 
CE  Visual fatigue  Case History (1) 
CE  Tearing  Case History (1) 
CE  Close one eye  Case History (1) 
CE  Loss of place when reading  Case History (1) 
CE  Reading problems  Case History (1) 
Basic exophoria  Asthenopia  Case History (1) 
Basic exophoria  Blurred vision  Case History (1) 

CI: convergence insufficiency, CE: convergence excess.

Table 7.

Symptoms associated with each accommodative dysfunction found in the 56 articles.

Dysfunction  Symptom category  Number of studies  Questionnaire or case history(Number of studies) 
AI  Blurred vision  10  Conlon survey (1), Russell (1), Case History (8) 
AI  Headache  Conlon survey (1), Russell (1), Sterner (1)Case History (6) 
AI  Visual discomfort  Case History (5) 
AI  Visual fatigue  Conlon survey (1), Sterner (1), Case History (3) 
AI  Reading problems  Conlon survey (1), Russell (1), Case History (2) 
AI  Diplopia  Conlon survey (1), Russell (1), Case History (1) 
AI  Lack of concentration  Case History (3) 
AI  Words appear to move or jump at near vision  Conlon survey (1), Sterner (1), Case History (1) 
AI  Asthenopia  Case History (2) 
AI  Avoid near task  Case History (2) 
AI  Excessive sensitivity to light  Conlon survey (1), Case History (1) 
AI  Sore eyes  Conlon survey (1), Sterner (1) 
AI  Difficulty focusing from one distance to another  Sterner (1) 
AI  Difficulty performing schoolwork  Case History (1) 
AI  Rubbing of eyes  Conlon survey (1) 
AI  Change Reading distance  Case History (1) 
AI  Red eye  Conlon survey (1) 
AI  Watery eyes  Conlon survey (1) 
AI  Dry or gritty eyes  Conlon survey (1) 
AI  Lose of place when reading  Conlon survey (1) 
AI  School performance problems  Case History (1) 
AE  Headache  Case History (3) 
AE  Visual fatigue  Case History (3) 
AE  Blurred vision  Case History (3) 
AE  Difficulty focusing from one distance to another  Case History (2) 
AE  Excessive sensitivity to light  Case History (2) 
AE  Difficulty performing schoolwork  Case History (1) 
AE  Diplopia  Case History (1) 
AE  Ocular pain  Case History (1) 
AE  Change reading distance  Case History (1) 
AE  Words appear to move or jump at near vision  Case History (1) 
AE  Reading problems  Case History (1) 
Accommodative infacility  Asthenopia  Case History (1) 
Accommodative infacility  Difficulty focusing from one distance to another  Case History (1) 
Accommodative infacility  Blurred vision  Case History (1) 

AI: accommodative insufficiency, AE: accommodative excess.

Discussion

The results of this scoping review show the disparity of symptoms associated with accommodative and non-strabismic binocular dysfunctions, and that these are fundamentally related to binocular dysfunctions and mainly associated with close vision tasks. There is no consensus concerning which symptoms should be considered in the diagnosis of each of these anomalies. The review also revealed that there are no specific questionnaires for most of the accommodative and binocular dysfunctions except for convergence insufficiency (CI).

CI is the dysfunction which has received most research attention; 50% of the studies analysed concerned this binocular anomaly. According to the scientific literature, CI is one of the most common anomalies of binocular vision, with prevalence values in the clinical population that range between 2.25% and 33%.6 It is also one of the binocular vision anomalies that has received most research attention, not only in studies related to its diagnosis8,46,48,52,55 but also in several recent clinical trials concerning this disorder.34,43–45 It is therefore logical that it should be the dysfunction on which most information is available about its symptomatology. In fact, the scientific literature shows that the remaining accommodative and non-strabismic binocular dysfunctions have been studied to a lesser extent.5,6,10

When analysing symptoms related to different populations, the review shows that most of the studies are related to children (29 reports), with 12 studies about adults and 15 articles related to both populations. It should be noticed that symptoms reported by adults and children could be different between them, not only when considering the case history but using a particular questionnaire. Moreover, a child's response to a certain question could be different if it was administered by a parent versus the examiner. However, the review shows that authors have not differentiated questions for case histories nor for the questionnaires reported by adults and children.

As regards the way in which symptoms are obtained, we observed that 21 studies7,17,21,30,31,36,38–40,50,52–54,57,58,60–65 analysed symptoms using patients’ descriptions of their case histories or on the basis of questions posed by the person conducting the examination. Of the 11 questionnaires used, the CI-specific CISS V-15 questionnaire was the most frequently employed, having been used in 21 studies8,13–16,19,20,23,25–27,29,32–35,43–46,48, followed by the 19-item College of Optometrists in Vision Development Quality of Life (QOVD-QOL) questionnaire18,22,42,47 (developed for visual abnormalities in general) and the Conlon survey28,32,37 developed for visual disorders in general and the Academic Behaviour Survey13,24,35 (for CI). The remaining questionnaires were used once only.9,41,49,51,55,56,59 Consequently, although in general more studies were based on the use of questionnaires (35 studies), most of them used the CISS V-15 and thus there were actually a higher percentage of articles in which subjects’ symptoms were obtained from their case histories.

As regards psychometric validation, only three of the questionnaires used had been validated, the CISS V-15,48 CIRS symptom questionnaire parent version55 and the Conlon survey.66 The CISS V-15,48 is a CI-specific questionnaire that has proven useful in differentiating subjects with CI from those with normal binocular vision and has been widely used to develop the diagnosis of this disorder in both child and adult populations, and to monitor the effectiveness of different treatments in the various clinical trials conducted to date. However, since it has only been validated for CI, its use cannot be generalised to other dysfunctions unless validating for other anomalies.

In the same way the CIRS symptom questionnaire parent version55 has been proved to be a valid instrument for differentiating children with CI from those with normal binocular vision, although it has only been used on one occasion.

Meanwhile, the Conlon survey,66 validated by RASCH analysis, was developed to analyse the symptoms associated with any type of visual anomaly, including accommodative and binocular dysfunctions, and has shown to be a reliable and valid measure of visual discomfort for adults.

Despite the existence of these three validated questionnaires, our results indicate that there is a lack of specific questionnaires for each of the existing accommodative and binocular dysfunctions. The 11 questionnaires identified were used for different dysfunctions, although the vast majority of them (7) were employed for CI.9,24,48,49,51,55,56 The Russell59 and Sterner41 questionnaires were used to analyse accommodative insufficiency (AI), while the two remaining questionnaires42,66 were employed for accommodative and binocular dysfunctions in general.

The existence of 267 different ways of naming the symptoms that can be grouped into 34 categories indicates a wide disparity in forms of referring to the same symptom. A clear example is the case of the symptom of “blurred vision”, for which 34 different ways of referring to it were found.

An analysis of the 34 symptom categories shows that most of these categories were related to children although the great majority of these symptoms have also been used for adult populations and for the combination of children and adults. This finding is related to the fact that most of the studies are focused in children population. However it is worth noting that there are several symptoms (“head or book tilt”, “inability to estimate distance accurately”, “be distracted” and “extraordinary reading or writing posture”) which have been only reported in children population. The same happens when considering symptoms as “red eye”, “watery eyes”, “dry or gritty eyes” and “eye turn noticed” which have only been reported in adults population, although certainly there are only few studies which have reported them. These findings show that authors do not seem to differentiate symptoms for children and adults.

In addition to that, the vast majority of these categories were associated with binocular dysfunctions compared to symptom categories related to accommodative dysfunctions. In general, it should be noted that symptoms overlap between accommodative and binocular anomalies. No category was associated exclusively with accommodative dysfunctions, although two symptoms in a high number of studies (“feel sleepy” and “pulling eyes”) were only related to binocular anomalies. These findings confirm that it is difficult to disjoin accommodation from vergence system. Due to the link between both systems, a deficiency in one system could cause an abnormality in the other so that symptoms would overlap. For that reason, it should be difficult to determine a very specific question which could only be related to either an accommodative deficiency or a vergence one.

Similarly, it is worth noting that the vast majority of authors associated the symptoms with near vision rather than with far vision. Some categories were associated with both distances, and there were even cases where the authors did not specify the distance associated with the symptoms. No category was exclusively associated with far vision. This finding is clearly related to the fact that CI is the most frequently studied dysfunction67,68 and its symptoms are mainly associated with near vision; thus most categories are related to near vision. It is possible that if other dysfunctions had been analysed, the findings in this respect might have indicated the existence of other symptoms more specific to far vision. Nevertheless, the present analysis indicates that there is a lack of specific questionnaires related to dysfunctions affecting far vision.

Of the symptoms cited most frequently, the category of “headache” appeared in almost all of the 56 articles analysed. The other frequently mentioned symptoms are all mainly related to binocular dysfunctions and are particularly closely associated with near vision. It is also evident that few symptoms were specific to each entity and many overlap. This information may influence clinical management as it is difficult to associate a particular dysfunction with a particular symptom.

When each particular accommodative and binocular dysfunction was considered separately, certain singularities were observed with respect to some symptoms, for example when referring to diplopia in accommodative dysfunctions such as accommodative insufficiency or accommodative excess. CI was associated with the vast majority of symptoms identified; 26 of 34 categories were associated with this dysfunction. This finding highlights the importance given in the scientific literature to CI over and above other dysfunctions. The symptoms most commonly associated with CI are precisely those symptoms which coincide with the questions in the CISS V-15.

The other dysfunctions also had different categories of associated symptoms. However, only a limited number of authors referred to each category for dysfunctions such as convergence excess, accommodative insufficiency, accommodative infacility, accommodative excess or basic exophoria.

In summary, the results of this scoping review demonstrate that gaps exist in our current knowledge. There is a wide range of symptoms related to accommodative and non-strabismic binocular dysfunctions reported in the scientific literature. There is no consensus concerning which symptoms should be considered in the diagnosis of each of these anomalies observing that few symptoms were specific to each entity and many overlap. According to the questionnaires, only the use of three validated symptom questionnaires were reported in the scientific literature, and two of them were specific for CI. However, no specific questionnaires were found for being for the remaining accommodative and binocular dysfunctions when there is the suspicion of an accommodative or binocular anomaly. This coverts the task of identifying the type of symptoms and their frequency and severity in something extremely difficult in spite of being an important aspect for diagnostic purposes. So, future studies should be done in this sense. Further questionnaires might be developed to address symptoms related to accommodative and nonstrabismic binocular dysfunctions other than CI.

Acknowledgements

This work has been supported by “Vicerrectorado de Investigación, Desarrollo e Innovación” of the University of Alicante, Spain (GRE10-06).

References
[1]
J.S. Cooper, C.R. Burns, S.A. Cotter, K.M. Daum, J.R. Griffin, M.M. Scheiman.
Care of the Patient with Accommodative and Vergence Dysfunction.
American Optometric Association, (2006),
[2]
M. Scheiman, B. Wick.
Clinical Management of Binocular Vision.
Lippincott Williams & Wilkins, (2008),
[3]
M. Rosenfield.
Computer vision syndrome: a review of ocular causes and potential treatments.
Ophthalmic Physiol Opt, 31 (2011), pp. 502-515
[4]
K.J. Ciuffreda.
The scientific basis for and efficacy of optometric vision therapy in nonstrabismic accommodative and vergence disorders.
Optometry, 73 (2002), pp. 735-762
[5]
P. Cacho Martinez, A. Garcia Munoz, M.T. Ruiz-Cantero.
Treatment of accommodative and nonstrabismic binocular dysfunctions: a systematic review.
Optometry, 80 (2009), pp. 702-716
[6]
P. Cacho-Martínez, Á. García-Muñoz, M.T. Ruiz-Cantero.
Do we really know the prevalence of accommodative and nonstrabismic binocular dysfunctions?.
J Optom, 3 (2010), pp. 185-197
[7]
S. Abdi, A. Rydberg.
Asthenopia in schoolchildren, orthoptic and ophthalmological findings and treatment.
Doc Ophthalmol, 111 (2005), pp. 65-72
[8]
L.F. Marran, P.N. De Land, A.L. Nguyen.
Accommodative insufficiency is the primary source of symptoms in children diagnosed with convergence insufficiency.
Optom Vis Sci, 83 (2006), pp. 281-289
[9]
E. Borsting, M.W. Rouse, P.N. Deland, et al.
Association of symptoms and convergence and accommodative insufficiency in school-age children.
Optometry, 74 (2003), pp. 25-34
[10]
P. Cacho-Martínez, A. García-Muñoz, M. Ruiz-Cantero.
Is there any evidence for the validity of diagnostic criteria used for accommodative and nonstrabismic binocular dysfunctions?.
[11]
J.E. Sheedy, J.N. Hayes, J. Engle.
Is all asthenopia the same?.
Optom Vis Sci, 80 (2003), pp. 732-739
[12]
P. Cacho-Martínez, A. García-Muñoz.
Evaluación clínica de la visión binocular.
Optometría: Principios básicos y aplicación clínica, pp. 289-317
[13]
E. Borsting, G.L. Mitchell, M.T. Kulp, et al.
Improvement in academic behaviors after successful treatment of convergence insufficiency.
Optom Vis Sci, 89 (2012), pp. 12-18
[14]
C. Barnhardt, S.A. Cotter, G.L. Mitchell, M. Scheiman, M.T. Kulp.
Symptoms in children with convergence insufficiency: before and after treatment.
Optom Vis Sci, 89 (2012), pp. 1512-1520
[15]
T.B. Pang Y, J. Krall.
Factors associated with base-in prism treatment outcomes for convergence insufficiency in symptomatic presbyopes.
Clin Exp Optom, 95 (2012), pp. 192-197
[16]
M. Scheiman, S. Cotter, M.T. Kulp, et al.
Treatment of accommodative dysfunction in children: results from a randomized clinical trial.
Optom Vis Sci, 88 (2011), pp. 1343-1352
[17]
A. Serna, D.L. Rogers, M.L. McGregor, R.P. Golden, D.L. Bremer, G.L. Rogers.
Treatment of symptomatic convergence insufficiency with a home-based computer orthoptic exercise program.
[18]
H.S. Shin, S.C. Park, W.C. Maples.
Effectiveness of vision therapy for convergence dysfunctions and long-term stability after vision therapy.
Ophthalmic Physiol Opt, 31 (2011), pp. 180-189
[19]
T.L. Alvarez, V.R. Vicci, Y. Alkan, et al.
Vision therapy in adults with convergence insufficiency: clinical and functional magnetic resonance imaging measures.
Optom Vis Sci, 87 (2010), pp. 985-1002
[20]
M. Scheiman, M.T. Kulp, S. Cotter, et al.
Vision therapy/orthoptics for symptomatic convergence insufficiency in children: treatment kinetics.
Optom Vis Sci, 87 (2010), pp. 593-603
[21]
M. Wahlberg, S. Abdi, R. Brautaset.
Treatment of accommodative insufficiency with plus lens reading addition: is +1.00D better than +2.00D?.
Strabismus, 18 (2010), pp. 67-71
[22]
H.S. Shin, S.C. Park, C.M. Park.
Relationship between accommodative and vergence dysfunctions and academic achievement for primary school children.
Ophthalmic Physiol Opt, 29 (2009), pp. 615-624
[23]
M. Rouse, E. Borsting, G.L. Mitchell, et al.
Validity of the convergence insufficiency symptom survey: a confirmatory study.
Optom Vis Sci, 86 (2009), pp. 357-363
[24]
M. Rouse, E. Borsting, G. Mitchell, et al.
Academic behaviors in children with convergence insufficiency with and without parent-reported ADHD.
Optom Vis Sci, 86 (2009), pp. 1169-1177
[25]
B. Teitelbaum, Y. Pang, J. Krall.
Effectiveness of base in prism for presbyopes with convergence insufficiency.
Optom Vis Sci, 86 (2009), pp. 153-156
[26]
M. Kulp, G.L. Mitchell, E. Borsting, et al.
Effectiveness of placebo therapy for maintaining masking in a clinical trial of vergence/accommodative therapy.
Invest Ophthalmol Vis Sci, 50 (2009), pp. 2560-2566
[27]
J. Cooper, J. Feldman.
Reduction of symptoms in binocular anomalies using computerized home therapy-HTS.
Optometry, 80 (2009), pp. 481-486
[28]
C. Chase, C. Tosha, E. Borsting, W.H. Ridder 3rd..
Visual discomfort and objective measures of static accommodation.
Optom Vis Sci, 86 (2009), pp. 883-889
[29]
CITT.
Long-term effectiveness of treatments for symptomatic convergence insufficiency in children.
Optom Vis Sci, 86 (2009), pp. 1096-1103
[30]
M. Bartuccio, T.M.J. Kieser.
Accommodative insufficiency: a literature and record review.
Optom Vis Dev, 39 (2008), pp. 35-40
[31]
R. Brautaset, M. Wahlberg, S. Abdi, T. Pansell.
Accommodation insufficiency in children: are exercises better than reading glasses?.
Strabismus, 16 (2008), pp. 65-69
[32]
E. Borsting, C. Chase, C. Tosha, W.H. Ridder 3rd..
Longitudinal study of visual discomfort symptoms in college students.
Optom Vis Sci, 85 (2008), pp. 992-998
[33]
M. Kulp, E. Borsting, G. Mitchell, et al.
Feasibility of using placebo vision therapy in a multicenter clinical trial.
Optom Vis Sci, 85 (2008), pp. 255-261
[34]
CITT.
Randomized clinical trial of treatments for symptomatic convergence insufficiency in children.
Arch Ophthalmol, 126 (2008), pp. 1336-1349
[35]
CITT.
The convergence insufficiency treatment trial: design, methods, and baseline data.
Ophthalmic Epidemiol, 15 (2008), pp. 24-36
[36]
S. Abdi, R. Brautaset, A. Rydberg, T. Pansell.
The influence of accommodative insufficiency on reading.
Clin Exp Optom, 90 (2007), pp. 36-43
[37]
E. Borsting, C.H. Chase, W.H. Ridder 3rd..
Measuring visual discomfort in college students.
Optom Vis Sci, 84 (2007), pp. 745-751
[38]
M.I. Bodack, M. Vricella.
Vision therapy in an adult sample.
J Behav Optom, 18 (2007), pp. 100-105
[39]
S. Aziz, M. Cleary, H.K. Stewart, C.R. Weir.
Are orthoptic exercises an effective treatment for convergence and fusion deficiencies?.
Strabismus, 14 (2006), pp. 183-189
[40]
R.L. Brautaset, A.J. Jennings.
Effects of orthoptic treatment on the CA/C and AC/A ratios in convergence insufficiency.
Invest Ophthalmol Vis Sci, 47 (2006), pp. 2876-2880
[41]
B. Sterner, M. Gellerstedt, A. Sjöström.
Accommodation and the relationship to subjective symptoms with near work for young school children.
Ophthalmic Physiol Opt, 26 (2006), pp. 148-155
[42]
W. Vaughn, W.C. Maples, R. Hoenes.
The association between vision quality of life and academics as measured by the College of Optometrists in Vision Development Quality of Life questionnaire.
Optometry, 77 (2006), pp. 116-123
[43]
M. Scheiman, G.L. Mitchell, S. Cotter, et al.
A randomized clinical trial of treatments for convergence insufficiency in children.
Arch Ophthalmol, 123 (2005), pp. 14-24
[44]
M. Scheiman, G.L. Mitchell, S. Cotter, et al.
A randomized clinical trial of vision therapy/orthoptics versus pencil pushups for the treatment of convergence insufficiency in young adults.
Optom Vis Sci, 82 (2005), pp. 583-595
[45]
M. Scheiman, S. Cotter, M. Rouse, et al.
Randomised clinical trial of the effectiveness of base-in prism reading glasses versus placebo reading glasses for symptomatic convergence insufficiency in children.
Br J Ophthalmol, 89 (2005), pp. 1318-1323
[46]
M.W. Rouse, E.J. Borsting, G.L. Mitchell, et al.
Validity and reliability of the revised convergence insufficiency symptom survey in adults.
Ophthalmic Physiol Opt, 24 (2004), pp. 384-390
[47]
M.A. White T.
A comparison of subjects with convergence insufficiency and subjects with normal binocular vision using a Quality of Life Questionnaire.
J Behav Optom, 15 (2004), pp. 37-41
[48]
E.J. Borsting, M.W. Rouse, G.L. Mitchell, et al.
Validity and reliability of the revised convergence insufficiency symptom survey in children aged 9–18 years.
Optom Vis Sci, 80 (2003), pp. 832-838
[49]
P. Adler.
Efficacy of treatment for convergence insufficiency using vision therapy.
Ophthalmic Physiol Opt, 22 (2002), pp. 565-571
[50]
P. Cacho, A. García, F. Lara, M.M. Segui.
Diagnostic signs of accommodative insufficiency.
Optom Vis Sci, 79 (2002), pp. 614-620
[51]
M. Gallaway, M. Scheiman, K. Malhotra.
The effectiveness of pencil pushups treatment for convergence insufficiency: a pilot study.
Optom Vis Sci, 79 (2002), pp. 265-267
[52]
A. Garcia, P. Cacho, F. Lara.
Evaluating relative accommodations in general binocular dysfunctions.
Optom Vis Sci, 79 (2002), pp. 779-787
[53]
F. Lara, P. Cacho, A. Garcia, R. Megias.
General binocular disorders: prevalence in a clinic population.
Ophthalmic Physiol Opt, 21 (2001), pp. 70-74
[54]
M.W. Rouse, L. Hyman, M. Hussein, H. Solan, Convergence Insufficiency and Reading Study (CIRS) Group.
Frequency of convergence insufficiency in optometry clinic settings.
Optom Vis Sci, 75 (1998), pp. 88-96
[55]
E. Borsting, M.W. Rouse, P.N. De Land, Convergence Insufficiency and Reading Study (CIRS) group.
Prospective comparison of convergence insufficiency and normal binocular children on CIRS symptom surveys.
Optom Vis Sci, 76 (1999), pp. 221-228
[56]
M.H. Birnbaum, R. Soden, A.H. Cohen.
Efficacy of vision therapy for convergence insufficiency in an adult male population.
J Am Optom Assoc, 70 (1999), pp. 225-232
[57]
E. Porcar, A. Martinez-Palomera.
Prevalence of general binocular dysfunctions in a population of university students.
Optom Vis Sci, 74 (1997), pp. 111-113
[58]
M. Gallaway, M. Schieman.
The efficacy of vision therapy for convergence excess.
J Am Optom Assoc, 68 (1997), pp. 81-86
[59]
G.E. Russell, B. Wick.
A prospective study of treatment of accommodative insufficiency.
Optom Vis Sci, 70 (1993), pp. 131-135
[60]
T. Matsuo, H. Ohtsuki.
Follow-up results of a combination of accommodation and convergence insufficiency in school-age children and adolescents.
Graefes Arch Clin Exp Ophthalmol, 230 (1992), pp. 166-170
[61]
P. Dwyer.
The prevalence of vergence accommodation disorders in a school-age population.
Clin Exp Optom, 75 (1992), pp. 10-18
[62]
S.B. Deshpande, R.K. Ghosh.
Study of primary convergence insufficiency.
Indian J Ophthalmol, 39 (1991), pp. 112-114
[63]
M.L. Mazow, T.D. France, S. Finkleman, J. Frank, P. Jenkins.
Acute accommodative and convergence insufficiency.
Trans Am Ophthalmol Soc, 87 (1989), pp. 158-168
[64]
R.P. Rutstein, K.M. Daum, J.F. Amos.
Accommodative spasm: a study of 17 cases.
J Am Optom Assoc, 59 (1988), pp. 527-538
[65]
G.A. Chrousos, J.F. O’Neill, B.D. Lueth, M.M. Parks.
Accommodation deficiency in healthy young individuals.
J Pediatr Ophthalmol Strabismus, 25 (1988), pp. 176-179
[66]
E. Conlon, W. Lovegrove, E. Chekaluk, E.P. Pattison.
Measuring visual discomfort.
Vis Cognit, 6 (1999), pp. 637-663
[67]
P. Cacho-Martínez, A. García-Muñoz, M.T. Ruiz-Cantero.
Diagnostic validity of clinical signs associated with a large exophoria at near.
J Ophthalmol, 2013 (2013), pp. 549435
[68]
J. Cooper, N. Jamal.
Convergence insufficiency-a major review.
Optometry, 83 (2012), pp. 137-158
Journal of Optometry

Subscribe to our newsletter

Article options
Tools

Are you a health professional able to prescribe or dispense drugs?

Cookies policy
To improve our services and products, we use cookies (own or third parties authorized) to show advertising related to client preferences through the analyses of navigation customer behavior. Continuing navigation will be considered as acceptance of this use. You can change the settings or obtain more information by clicking here.