. 2013 Mar 9;7(1):2–21. doi: 10.1016/j.optom.2013.01.004

Table 5.

Conclusions, bias and limitations of the studies.

Year of publication and author	Conclusions	Bias/limitations identified by the authors	Bias/limitations observed in the review
2006, Marran LF³⁷	CI is a separate and unique clinical condition and can occur without a comorbid AI condition. However, CI by itself is not a highly symptomatic condition. Only when the CI is comorbid with AI, do children with CI score higher than children with normal binocular vision, strongly suggesting that the high score is driven by the AI condition.	–	–

2006, Sterner B³⁸	The ROC analysis illustrate that the AA has potential discrimination ability for accommodative insufficiency. Values of 8 D monocular or 11 D binocular are values which could be used as reference values since they clearly imply a high risk of symptoms for children with results below these limits.	Children below 7.5 years with no reported symptoms could have been biased as they tend to give the “correct” reply just to please the interviewer. The population could be described as an invited population. Perhaps children with symptoms were more willing to take part in the study implying that the prevalence is higher than it would be if a true screening was applied. The choice of references values of AA is somewhat arbitrary.	No validated symptom questionnaire used. Binocular accommodative amplitude considered. Accommodative amplitude results interpreted with the knowledge of the results of subjective symptoms of patients.

2004, Rouse MW³⁹	Adults with symptomatic CI have a significantly higher CISS score than adults with NBV. The CISS is a valid and reliable instrument that can be used clinically or as an outcome measure for research studies of adults with CI. A CISS score ≥ 21 distinguish between adults with normal and abnormal levels of symptoms.	–	Clinical population. Conclusions are not representative of general population. Questionnaire results interpreted with the knowledge of the results of diagnosis.

2003, Borsting E J⁴⁰	Children with CI show a significantly higher CISS symptom score than children with normal binocular vision. The CISS is a valid and reliable instrument to use as an outcome measure for children aged 9 to 18 who are enrolled in clinical research concerning CI. A CISS score of ≥16 distinguish between children with normal and abnormal levels of symptoms associated with CI.	–	Clinical population. Conclusions are not representative of general population. Questionnaire results interpreted with the knowledge of the results of diagnosis.

2002, García, A⁴¹	There is no sign strongly associated with the presence of diminished AA. However, failing MAF with −2 D lenses seems to be the sign mostly associated with AI. Authors propose using MAF together with diminished AA for diagnosing AI.	–	No validated symptom questionnaire used. Clinical population. Conclusions are not representative of general population. Diagnosis interpreted with the knowledge of the results of tests.

2002, Cacho P²⁹	Anomalous results of NRA are not clearly associated with any dysfunction. High values of PRA are related to disorders associated with accommodative excess, so that a high value of PRA (≥3.50 D) should be considered as one of the diagnostic signs associated with accommodative excess.	–	No validated symptom questionnaire used. Clinical population. Conclusions are not representative of general population. Diagnosis interpreted with the knowledge of the results of tests (sensitivity and specificity obtained with tests used for diagnosing the anomalies).

1999, Borsting E²⁸	The CIRS symptom survey is useful for identifying the type and frequency of symptoms in children with convergence insufficiency (CI) and also able to differentiate between the CI and normal binocular vision (NBV) groups.	Sample size of 14 subjects relatively small. Results could be explained by experimenter bias in the administration of the survey to the parent and child. Other source of potential bias is that the CI group could have had a co-occurring condition that affected the responses to the survey.	Clinical population. Conclusions are not representative of general population. Normal binocular subjects were recruited through advertisements at the teaching clinic. Questionnaire results interpreted with the knowledge of the results of diagnosis.

1991, Dwyer PS⁴	Measuring binocular function under fused conditions give a more complete measure of the status of binocularity. A system of nomenclature of accommodative and vergence disorders consistent with the concept of vergence-accommodation “adaptability” rather than visual axis deviation is suggested.	–	No validated symptom questionnaire used.

1988, Rutsein RP⁴²	Diagnosis of accommodative excess should be based on dynamic retinoscopy.	–	No validated symptom questionnaire used. It is proposed that diagnosis should be based on dynamic retinoscopy that it has been previously used to diagnose patients with accommodative excess. Clinical population. Conclusions are not representative of general population.

1988, Chrousos GA⁴⁵	The AA of patients with AI is considerably below the normal for the patients’ ages. The range of the deficiency is from 3.5 D to 8 D with an average of 6 D below the minimum normal for their respective ages. The clinical recognition of AI is important to prevent unnecessary frustration in these individuals.	–	No validated symptom questionnaire used. It is not reported the value of the minimal accommodative amplitude used for considering accommodative insufficiency.

1986, Scheiman M⁴³	Divergence insufficiency must be differentiated from divergence paralysis as well as from sixth nerve palsy, convergence excess and basic esophoria, all of which can present with an esodeviation at distance. The differential diagnosis depends very much upon the nature of the patient's symptoms.	–	No validated symptom questionnaire used.

1986, Daum KM⁴⁴	Patients with exodeviations, when divided into three classes on the basis of the relation between the near and distance angles of deviation, show significant differences in various clinical parameters. Patients with equal exodeviations have the largest angles of deviations overall and those with CI generally have smaller angles than the other groups. Differences in the AC/A ratios are to be expected on the basis of the classification criteria.	The data should not be considered exactly representative of the general population because the clinic form which the records were drawn is a referral clinic.	No validated symptom questionnaire used. Clinical population. Conclusions are not representative of general population.

CI: convergence insufficiency, AI: accommodative insufficiency, AA: accommodative amplitude, MAF: monocular accommodative facility, NRA/PRA: negative and positive relative accommodation, D: diopters.