Binocularity (Eye Teaming) Research


Atzmon D, Nemet P, et al "A randomized prospective masked and matched comparative study of orthoptic treatment versus conventional reading tutoring treatment for reading disabilities in 62 children." Binoc Vision & Eye Muscle Surgery Qtrly, (8):91-106, 1993
    Reading improved in children with reading disabilities when they were given vision therapy. The treatment was as effective as reading practice.

 
Blake R, Martens W,  Di Gianfilippo A, " Reaction time as a measure of binocular interaction in human vision." Invest. Ophthalmol. Vis. Sci. 1980 19: 930-941.
    In a series of psychophysical experiments monocular and binocular reaction times (RTs) were measured in response to the presentation of sinusoidal grating patterns. Over a wide range of contrast values, binocular RT was consistently faster than monocular RT, even at high- contrast levels where RT had reached asymptotic levels. For observers with good stereopsis this binocular summation effect was greater than that expected on the basis of probability summation alone, whereas observers with deficient stereopsis performed at the level of probability summation. For normal observers broadband random noise presented to one eye produced an elevation in RT to gratings presented to the other eye; no such dichoptic masking effect was found in a stereoblind observer. These results validate the use of RT as an efficient, reliable measure of binocular interaction in human vision.
 

Cooper J, Feldman J  "Reduction of symptoms in binocular anomalies using computerized home therapy HTS".  Optometry 2009, 80(9): 481-86.
    
Background:  Asthenopic symptoms often are associated with various accommodative/vergence disorders. Recent studies have found that symptoms associated with convergence insufficiency are reduced by in-office vision therapy with supplemental home therapy. No studies have used standardized symptom questionnaires to evaluate the effectiveness of either in-office or home-based vision therapy in binocular anomalies other than convergence insufficiency. This retrospective study was designed to evaluate the changes in symptoms using an automated, home computer vision therapy program (HTS") in accommodative/vergence disorders.
     Methods:  A retrospective study of 43 prepresbyopic patients who completed the HTS was performed. Before and immediately after treatment all patients in this study completed a 15-question symptom questionnaire (Convergence Insufficiency Symptom Survey). Treatment consisted of various accommodative and vergence activities.
     Results:  Initial symptoms scores on the scaled questionnaire were 32.8 (SD = 8.1); after therapy they were 20.6 (SD = 11.5). These changes were both clinically and statistically significant. Forty percent were normalized and 55% improved. Convergence amplitude improved from 22” to 53” after treatment, and divergence amplitudes improved from 15” to 25”. These findings were clinically significant. Lastly, more than 75% of the patients finished the program by 40 sessions (equivalent to 8 weeks).
     Conclusion:  Automated vision therapy delivered by the HTS system improved convergence and divergence amplitudes with a concomitant reduction in symptoms. The HTS system should be used on those patients with symptoms associated with an accommodative/vergence anomaly when in-office vision therapy supplemented with home therapy is not practical.


Dalziel CC. "Effect of vision training on Patients who fail Sheard's criterion."  Am J Optom Physiol Opt, 58:21-3, 1981.
    Abstract: One hundred convergence insufficiency patients who did not meet Sheard's criterion at near were given a program of in-office and at-home training.  The objective was to see if they would meet Sheard's criterion after training.  Results were analyzed in terms of the numbers successfully meeting this criterion as well as other criteria, i.e., Percival's elimination of symptoms, improvement of stereopsis, and elimination of fixation disparity. Of the 100 patients, 84 successfully met Sheard's criterion correlated well with having subjective symptoms.

Daum KM. "Characteristics of exodeviations: II. Changes with treatment with orthoptics." Am J Optom Physiol Opt, 63:244-51, 1986.
    Abstract: This study examines retrospectively the records of 179 patients who had binocular visual dysfunction as a result of an exodeviation (either at distance or neat or both).  The patients were classified as having convergence insufficiency (N=110), equal exodeviations (N=49), or divergence excess (N=18).  The diagnostic groups and the different frequencies of deviation reacted differently to treatment with a standard orthoptic regimen. Nearly al the patients (97%) achieved some improvement in either objective or subjective areas or both. However, fewer were able to satisfy the criteria set for total success. Factors correlated with the success of the treatment were the initial angle of deviation at distance and the initial level of stereopsis. The results and implications of this study are discussed.

Daum KM. "The course and effect of visual training on the vergence system."  Am J Optom Physiol Opt, 59:223-7, 1982.
    Abstract: The effect of a variety of vergence training procedures on the visual system of 35 asymptomatic young adults with normal binocularity was evaluated.  Vergence ranges were measured before the study began and at the end of the 3-week period.  Sub-populations were evaluated at one week and at 6 months to document further the course of the effects.  Positive fusional vergence training significantly increased the vergence ranges after 1 week of training; a greater effect was measured after 3 weeks.  The vergence capability was found to have decreased 6 months later, but the effects of the training were still apparent.  Negative fusional vergence training was less effective; however, significant increases were demonstrable after 3 weeks of training.  The phorias and accommodative amplitude were not affected by the orthoptics.  Relatively short periods of training can provide long-lasting increases in the vergence ability of a group of binocular normals.

Daum K. "Double-blind placebo-controlled examination of timing effects in the training of positive vergences."  Am J Optom Physiol Opt, 63:807-12, 1986.
    Abstract: The purpose of this study was to document the effects of positive fusional vergence therapy and to determine the most effective timing of such training.  Four experimental protocols were selected and five subjects were assigned randomly to each of the four experimental groups.  Each subject in each group spent 120 min (total) over a period of 3 weeks doing positive fusional vergence training.  Group A trained in twelve 10-min sessions;  group B in six 20-min sessions; and group C in three 40min sessions.  Group D was a control group. All the training was in-office and consisted of positive fusional vergence training on the synoptophore.  Each of the test groups showed increases in their positive fusional vergence ability at both distance and near.  Group A (shorter sessions) demonstrated the largest increases overall.  In addition, the group that trained in short 10-min session (group A) was the only one that showed significant increases in the negative fusional vergences and the positive blur finding.  It is best to use short, frequent training sessions to increase the amplitude of positive fusional vergence.

Daum KM, Rutstein RP, Eskridge JB. "Efficacy of computerized vergence therapy."  Am J Optom Physiol Opt, 64:83-9, 1987.
    Abstract: The purpose of this study was to determine the efficacy of computerized fusional vergence therapy and the effect of two different vergence-training velocities.  Six subjects received positive vergence training using a slow vergence training rate (0.75/s) and six subjects received positive vergence training using a fast vergence-training rate (5.00/s).  Six subjects served as controls and did not receive therapy.  The duration of therapy was 80 min over a period of 4 weeks.  All training activities were monitored.  All vergence evaluations were double masked.  Subjects using a slow training rate showed significant increases in positive vergence ranges as measured with the major amblyoscope, whereas subjects training with fast rates did not.  Vergence therapy using computerized video display is an effective technique for increasing the amplitudes of positive fusional vergence and slower rates are more productive than faster rates.

Daum KM, Rutstein RP, et al.  "Horizontal and vertical vergence training and its effect on vergences and fixation disparity curves: I. Horizontal data."  Am J Optom Physiol Opt, 65:1-7, 1988.
    Abstract: The purpose of this study was to assess the effects of horizontal and vertical vergence training on fusional vergencies and the fixation disparity (FD) curve.  Thirty-four subjects were divided into three groups.  One-third served as controls and the other two-thirds underwent 5 hours of supervised horizontal and vertical vergence training, respectively.  Before and after the 4-week training period, vergences and FD curves were measured by a single individual who was intentionally uniformed of each subject's group.  Analysis revealed that the positive vergences increased significantly for those in the horizontal group. No evidence was found to suggest changes in any variable related to the FD curve.

Daum KM. "Negative vergence training in humans."  Am J Optom Physiol Opt, 63:487-96, 1986.
    Abstract: Two healthy subjects (male and female, ages 22 and 25 years) spent 50 hours over a period of 7 consecutive weeks training the negative vergence system.  The training was performed in two 45-min daily sessions, usually immediately before and after the workday.  The training was exclusively negative vergence training using a device such as variable vectograms, the aperture rule, the synoptophore, and loose or bar prisms.  An extensive examination of the visual systems before after, and periodically during the training demonstrated that the negative vergences increased at distance by 5.0 prism diopters and at near by 9.1prism diopters (using hand-held prisms, bar prisms and the synoptophore).  The phorias of both subjects became more exophoric or less esophoric at both distance and near by 3.6 prism diopters.  A haploscope equipped with a coincidence optometer showed only small increases in vergence amplitude but confirmed that the lag of accommodation became more stable after the training than it was before.  Other testing suggested that the negative relative accommodation, the angle of deviation at both distance and near, positive vergences, the associated phoria, and the slope of the fixation disparity curve changed significantly over the period of training. Negative vergence training can increase the negative vergence capabilities and also affect the phoria position of the eyes via feedback into the slow vergence system.

Ficarra AP, Berman J, et al. "Vision training: predictive factors for success in visual therapy for patients with convergence excess."  J Optom Vision Dev, 27:213-9, 1996.
    Abstract: A retrospective study was conducted to analyze predictive factors for success of visual therapy (VT) in patients with convergence excess. The records of 31 patients (mean age = 15.9 years) were reviewed. Each had received at least four VT sessions and full pre and post-training evaluation. The mean number of VT sessions was 19.4. VT produced a significant reduction in symptoms of both distance blur and headaches. Additionally, significant post-therapy changes occurred in distance base-in recovery, near base-in break and recovery, near phoria, and positive relative accommodation. The relative exohoric shift in near phoria was significantly correlated with pre-therapy refractive error, near phoria, and the magnitude of the prescribed near addition. Furthermore, a non-significant reduction in the stimulus accommodative convergence-accommodation ratio was found. Significant changes in quantifiable optometric parameters were observed after VT. The post-therapy change in near phoria was best predicted by the magnitude of the pre-VT near phoria.
 

Frye ML, Jarrard P, Lyon DW. "Visual Information Processing: A Case Study." Optometry - Journal of the American Optometric Association June 2008 (Vol. 79, Issue 6, Pages 299-300).
   Background: Visual information processing is the use of visual perceptual and cognitive skills to organize visual stimuli presented in the environment and to integrate this information to understand what is being viewed. This is a case study of a patient who exhibited deficits with visual information processing skills and the subsequent therapy to improve these deficits.
   Case Summary: A 12-year-old boy was referred by a local optometrist for a visual information processing evaluation.The patients mother stated that he earned As and Bs but struggled with reading and writing and could not keep up with his peers during class. She also commented that he has no time for detail. The patient had the complaint of words jumping around when reading. Before the evaluation a visual efficiency examination was done. At that time it was determined that he had a vertical phoria. He was subsequently prescribed glasses to correct his vertical imbalance.  He returned 6 weeks later to complete the visual information processing evaluation. Data were obtained at both the first and second assessments showing a comparison before and after treatment with the prescribed lenses. The following assessments were administered: Developmental Test of Visual Perception (2nd edition), Tests of Visual Perceptual Skills (nonmotor)-Selected Subtests, Matching Familiar Figures Test, Wold Sentence Copy, Woodcock Johnson III-Selected Subtests, Developmental Eye Movements (DEM), and Visagraph.
    In looking at the comparison of the DEM before and after wearing the prescribed prescription for the vertical phoria, the patient showed a significant improvement with correction in the amount of time that it took for him to complete the horizontal subtest. On the other assessments that the patient completed, he scored in the low-average range overall on both the motor-reduced processing and visual-motor integration. It was determined that the patient appears to have difficulty in the areas of rapid naming automaticity and oculomotor efficiency, which are critical skills required for reading. It was recommended that the patient participate in visual information processing therapy to improve oculomotor skills, increase his reading rate, and enhance his enjoyment of reading. The patient completed 10 in-office sessions as well as daily home therapy. The therapy included saccadic workbook activities using the Michigan Tracking series, sight word repetition using Dolch word lists, and 2 in-office computer programs: the Visual Therapy System and the ACE reader.  During therapy sessions, he also worked on handwriting speed and accuracy. Final evaluation 4 months later demonstrated an improvement in scores from average to above average in all categories except visual matching, which improved from low to low average. Grade level efficiency of eye movements improved on Visagraph testing. He also reported keeping up with peers in reading and writing tasks. His mother reported she noted improved self-esteem.
   Conclusion: This case shows the improvement that can be made in reading and writing through a vision therapy program. This case also demonstrates the importance of treating any misalignment of the eyes before working on visual perceptual skills.

Gallaway M, Scheiman M. "The efficacy of vision therapy for convergence excess."  J Am Optom Assoc, 68:81-6, 1997.
    Abstract: The records of 83 consecutive patients with convergence excess who were treated with vision therapy were reviewed to assess the impact of treatment on clinical findings and patient symptoms.  Statistically and clinically significant changes in direct and indirect measures of negative fusional vergence were seen, with 84% of patients reporting a total elimination of initial symptoms.  Larger increases in negative fusional vergence were found than those previously reported.  This may be a result of the more extensive and better-controlled in-office treatment used in this study.  Optometric vision therapy was successful in enhancing negative fusional vergence and eliminating symptoms in the vast majority of patients with convergence excess and should be considered an effective treatment for this condition.

Griffin JR. "Efficacy of vision therapy for nonstrabismic vergence anomalies." Am J Optom & Physiol Optics, 64 (6): 411-414, 1987.
     A review of the literature published in the past 15 years was carried out to determine the effect of visual training on vergence measurements for nonstrabismic patients. Results of cited studies are summarized.

Grisham JD, Bowman MC, et al. "Vergence orthoptics: validity and persistence of the training effect."  Optom Vis Sci, 68:441-51, 1991.
    Abstract: This study investigated the validity and permanence of orthoptic treatment for vergence deficiencies. The relation between Risley prism vergences, a subjective measure, and vergence-tracking rate, an objective index, was investigated. The course of orthoptics progress was compared in cases of clinical vergence dysfunction. Vergence-deficient control subjects showed no significant change in either index. However, trained subjects demonstrated rapid increases in both indices. The persistence of the training effect was monitored for up to 9 months. No regression was observed in subjects who met all release criteria, but one subject who chose to terminate therapy early showed a slow regression in tracking rate and recurrence of symptoms. These data support the validity of vergence training and increase the plausibility of previous clinical reports of orthoptics success.

Grisham, JD, Powers, MK, Riles, P. "Vision Skills of Poor Readers in High School"   Optometry 78, 542-549, 2007
    Background: Prior findings suggest that poor readers tend to have poor visual skills, but few reports give full frequency distributions of skill variables, and little data are available for adolescents.
     Methods: Visual skills and visual acuity were measured in 461 students (average age 15.4 years) in 4 California high schools within the same school district. Participating students had been identified by their schools as poor readers. Standard optometric tests and published criteria for adequate or weak visual skills were used.
     Results: In this sample, 80% of the students were found to be inadequate or weak in 1 or more of the following visual skills: binocular fusion ranges at near, accommodative facility, and convergence near point. More students were deficient in binocular fusion range than in either accommodative function or near point of convergence. In contrast, only 17% had deficient visual acuity20/40 or worse in 1 eyethe standard model of deficiency for school vision screenings.
     Conclusion: The results support and extend previous studies showing that large numbers of poor readers in high school may be at high risk for visual skills dysfunction.


Grisham, JD, Powers, MK, Riles, P. "Visual Skills Training Improves Reading Performance"  Gemstone Foundation, 400 Capitol Mall, Suite 1540, Sacramento, California 95814-4408
    Abstract:  Many Students in under-performing high schools have clinically deficient visual skills (saccadic tracking, accommodative facility, and /or vergence ranges) that can be improved by a computerized visual skills training program (ARVO 2001).  The same training program also improves scores on standardized reading tests (ARVO 2001).  Here we begin to quantify the relation between visual skills and reading performance.
    Methods:  We examined data from more than 5000 high school students, gathered over the past three academic years from freshmen at low performing schools in California.  Each student's visual skill levels had been measured during school-sponsored screening by optometrists or vision scientists and their trained assistants.  Skills assessed were accommodative near-point and facility, convergence near-point, vergence ranges and Developmental Eye Movement tracking ratios. Distance visual acuity, eye muscle balance, refractive error, and external eye health were also recorded, and referrals to community eye care professionals were made where appropriate. Selected students with deficient visual skills received training via an Internet-based program, administered in school fro up to thirty 20 minute sessions.  Reading efficiency scores were obtained before and after training via the Taylor Visagraph II Reading Eye Movement system, with each measurement taken twice.  Reading scores on standardized tests (STAR and California Achievement Test) before and after visual skills training were made available by the schools for each student.
    Results:  The average reading level for these ninth graders was 6.0.  Students with poor visual skills tended to score lower, but many students with good reading scores had poor visual skills as well. Students with adequate visual skills increased 1.0 grade level in one year (on average) without visual training.  Poor readers with poor visual skills who completed 30 sessions of training also increased 1 grade level, but those who completed fewer than eight sessions increased only 0.35 grade level. A significant (p<0.05) nonparametric correlation existed between improvements in visual skills and improvements in reading scores for all years.  Results were qualitatively consistent across different reading tests as well as the Visagraph.  Students who completed visual skills training and whose visual skills improved continued to show improvements in reading scores in subsequent years over their peers who did not complete visual training.
    Conclusion:  Poor readers tend to have poor visual skills, but some good readers do as well.  Improving visual skills improves reading scores for poor readers and these gains persist in subsequent years.

Hayes GJ, Cohen BE, Rouse MW, De Land PN. "Normative values for the nearpoint of convergence of elementary schoolchildren."  Optom Vis Sci 1998 Jul;75(7):506-12
    Background: Nearpoint of convergence (NPC) values of 8 to 10 cm are widely used to diagnose binocular dysfunctions such as convergence insufficiency.  However, there are no published age-related normative values in the literature to substantiate these values.
    Methods: Subjects were 297 schoolchildren in kindergarten, third grade, and sixth grade who had passed a school-based Modified Clinical Technique vision screening.  Each child had the NPC break and recovery taken three times using a standardized protocol developed by the Convergence Insufficiency and Reading Study group.  The examiners used an Astron International (ACR/21) Accommodative Rule with a movable column of 20/30 letters as the target.
    Results: For each grade, the distribution of NPC break was right skewed, with a concentration of values between 1 and 6 cm.  At least 85% of the subjects in each grade had an NPC break < or = 6 cm.  NPC break values (mean +/- SD) were 3.3 +/- 2.6 cm for kindergartners,  4.1 +/- 2.4 cm for third graders, and 4.3 +/- 3.4 cm for sixth graders, and the means were found to be statistically different (analysis of variance, p = 0.031).  NPC recoveries (mean +/- SD) for the three groups were 7.3 +/- 4.8 cm, 8.7 +/- 4.2 cm, and 7.2 +/- 3.9 cm, respectively, which were also significantly different (analysis of variance, p = 0.027). The recovery distributions were more symmetric and less skewed than those for break.  For each grade level, there was a strong positive relationship between NPC recovery and NPC break, but the difference between NPC recovery and break had a low correlation with the NPC break.
    Summary: Kindergartners had somewhat better NPC breaks than third or sixth graders, whereas no clear age trend was present for NPC recovery.  A supporting study using a random sample of clinic patients (aged 10-12 years) suggests that patients with NPC breaks > 6 cm are more than twice as likely to be symptomatic than patients with NPC breaks < or = 6 cm.  Based on these results and the NPC break distributions in this study, a clinical cutoff value of 6 cm is suggested for patients of elementary school age.  A cutoff value in the 6- to 10-cm range is recommended for children of elementary school age in a screening context. The exact value within this range depends on the level of concern with identifying patients who have visual signs and symptoms associated with a receded NPC.

Hung GK, Ciuffreda KJ, Semmlow JL. "Static vergence and accommodation: population norms and orthoptic effects."  Doc Opthalmologica, 2:165-79, 1986.
    Abstract: This study investigated the effect of orthoptic therapy lasting 8-16 weeks on the accommodative and vergence system function of 22 visually-normal asymptomatic individuals and 21 visually-abnormal symptomatic individuals.  Following therapy, symptomatic individuals experienced reduction of symptoms and improvement in visual parameters toward the normal mean function.

Luu CD, Green JF, Abel L. "Vertical fixation disparity curve and the effects of vergence training in a normal young adult population." Optom Vis Sci, 77: 663-69, 2000.
     Forty-five subjects with normal vision and binocular function underwent vertical vergence training for one week. The control group consisted of 34 subjects. Vertical prism bar training provided a long-term effect, both increasing the vertical fusional amplitude and flattening the slope of the vertical fixation disparity curve.

McKenzie JA, Capo JA, Nusz KJ, Diehl NN, Mohney BG. "Prevalence and Sex Differences of Psychiatric Disorders in Young Adults Who Had Intermittent Exotropia as Children."  Arch Ophthalmol. 127(6):743-747, 2009.

   Objective  To evaluate the prevalence and sex differences of mental disorders diagnosed among young adults who had intermittent exotropia (IXT) as children.

   Methods  The medical records of all children (<19 years) diagnosed as having IXT as residents of Olmsted County, Minnesota, from January 1, 1975, through December 31, 1994, and their randomly selected nonstrabismic birth- and sex-matched controls (1:1) were retrospectively reviewed.

   Results  A mental health disorder was diagnosed in 97 (53.0%) of the 183 patients with childhood IXT followed to a mean age of 22 years compared with 55 (30.1%) controls (P < .001). Patients with IXT were 2.7 (95% confidence interval, 1.7-4.1) times more likely to develop a psychiatric illness than controls. A mental health disorder was diagnosed in 63% (41 of 65) and 47% (56 of 118) of males and females with IXT, respectively, compared with 33% (22 of 66) and 28% (33 of 117) of male and female controls, respectively. Additionally, males with IXT had a greater use of psychotropic medication (P = .003), psychiatric emergency department visits (P < .001), psychiatric hospital admissions (P = .04), suicide attempts (P = .004), and suicidal ideation (P = .002) than controls, and females with IXT had more suicidal ideation (P = .02) than controls.

   Conclusions  Children diagnosed as having IXT, especially males, are more likely to develop mental illness by the third decade of life compared with children without strabismus.


North RV, Henson DB. "The effect of orthoptic treatment upon the vergence adaptation mechanism." Optom Vis Sci, 69:294-9, 1992.
    Abstract: Visual training has an effect on the vertical vergence amplitudes. Three mature symptomatic patients exhibited a significant increase in the vertical vergence that compensates for the vertical heterophoria. Subjects with normal binocularity and have no vertical heterophoria did not exhibit increased vertical vergence amplitudes after training.

Rouse MW, Borsting E, Hyman L, Hussein M, Cotter SA, Flynn M, Scheiman M, Gallaway M, De Land PN, "Frequency of Convergence Insufficiency Among Fifth and Sixth Graders." The Convergence Insufficiency and Reading Study (CIRS) group. Optom Vis Sci 1999 Sep;76(9):643-9.
     PURPOSE: To estimate the frequency of convergence insufficiency (CI) and its related clinical characteristics among 9- to 13-year-old children. 
     METHODS: Fifth and sixth graders were screened in school settings at three different study sites. Eligible children with 20/30 or better visual acuity, minimal refractive error, no strabismus, and exophoria at near were evaluated according to a standardized protocol to determine the presence and severity of CI. These children were classified according to the presence and number of the following clinical signs: (1) exophoria at near > or =4delta than far, (2) insufficient fusional convergence, and (3) receded nearpoint of convergence. Also, children were classified as accommodative insufficient (AI) if they failed Hofstetter's minimum amplitude formula or had greater than a + 1.00 D lag on Monocular Estimate Method retinoscopy. 
     RESULTS: Of 684 children screened, 468 (68%) were eligible for further evaluation. Of these, 453 had complete data on CI measurements and were classified as: no CI (nonexophoric at near or exophoric at near and < 4delta difference between near and far) (78.6%); low suspect CI (exophoric at near and one clinical sign: exophoria at near > or =4delta than far) (8.4%); high suspect CI (exophoric at near and two clinical signs) (8.8%); and definite CI (exophoric at near and three clinical signs) (4.2%). CI status varied according to ethnicity and study site (p < 0.0005), but not gender. The frequency of AI increased with the number of CI-related signs. For CI children with three signs, 78.9% were classified as also having AI.  
     CONCLUSIONS: These findings suggest that CI (defined as high suspect and definite) is frequent (13%) among fifth and sixth grade children. In addition, there is a high percentage of CI children with an associated AI.

Rouse MW, Hyman L, Hussein M, Solan H. "Frequency of convergence insufficiency in optometry clinic settings. Convergence Insufficiency and Reading Study (CIRS) Group." Optom Vis Sci 1998 Feb;75(2):88-96
     PURPOSE: To estimate the frequency of convergence insufficiency (Cl) and its related characteristics among 8- to 12-year-old children randomly selected from 2 optometry clinic populations. 
     METHODS: Clinic records of 620 children were randomly selected and reviewed according to a standard protocol, using a systematic sampling method based on the total number of 8- to 12-year-old children seen over a 1-year period at 2 optometry clinics. Records were reviewed for demographic and clinical data. Data on Cl-related symptoms were obtained at one of the sites. Records that met the eligibility criteria of: good visual acuity (20/30 or better in both eyes); minimal refractive error (-0.50 to +1.00 D and < or = 1.00 D of astigmatism in either eye, and < or = 1.00 D of anisometropia); and no strabismus were evaluated for Cl-related characteristics. Eligible children were classified according to the direction of their near heterophoria and the number of the following clinical signs present: (1) exophoria at near > or = 4 delta than at far; (2) insufficient fusional convergence [i.e., failing Sheard's criterion or minimum normative positive fusional vergence (PFV) of 12 delta base-out (BO) blur/15 delta BO break]; and (3) receded nearpoint of convergence (NPC) of > or = 7.5 cm break or > or = 10.5 cm recovery. Children were then classified as: no Cl (nonexophoric at near or < 4 delta difference between far and near); low suspect (exophoric at near and1 sign); high suspect (exophoric at near and 2 signs); or definite Cl (exophoric at near and 3 signs).
     RESULTS: Sixty-seven percent (415/620) of the records met the eligibility criteria and had complete data on phoria, NPC, and PFV. The age (mean +/- SD) of the study population was 10.2 +/- 1.2 years. Ethnicity data were available for 85% of those eligible; the ethnic distribution was 36% African American, 29% Caucasian, 19% Hispanic, and 1% Asian. About one-half of the 415 children were classified as either low suspect (33%); high suspect (12%); or definite Cl (6%). Clinically significant Cl (high suspect and definite categories) was identified in 17.6% of the children. The percentage of children rated as symptomatic increased with the number of Cl-related clinical signs present. 
     CONCLUSIONS: These findings suggest a high frequency of Cl in optometry clinic populations and a potential correlation between patient symptoms and the number of Cl signs present.


Rouse M, Borsting E, Mitchell GL, Kulp MT, Scheiman M, Amster D, Coulter R, Fecho G, Gallaway M; The CITT Study Group. "Academic Behaviors in children with convergence insufficiency with and without parent-reported ADHD." Optom Vis. Sci. 2009.
*OD, MS, FAAO daggerMPH, FAAO double daggerOD, FAAO section signOD Southern California College of Optometry, Fullerton, California (MR, EB), The Ohio State University College of Optometry, Columbus, Ohio (GLM, MTK), Salus University, College of Optometry, Philadelphia, Pennsylvania (MS, MG), and NOVA Southeastern University, Ft. Lauderdale, Florida (DA, RC, GF). The CITT Study Group members are listed in the Acknowledgments.
     PURPOSE: To determine if children with symptomatic Convergence Insufficiency without the presence of parent-reported Attention Deficit Hyperactivity Disorder (ADHD) have higher scores on the academic behavior survey (ABS). 
     METHODS: The ABS is a 6-item survey that evaluates parent concern about school performance and the parents' perceptions of the frequency of problem behaviors that their child may exhibit when reading or performing schoolwork (such as difficulty completing work, avoidance, and inattention). Each item is scored on an ordinal scale from 0 (Never) to 4 (Always) with a total score ranging from 0 to 24. The survey was administered to the parents of 212 children 9- to 17-year old (mean age 11.8 years.) with symptomatic convergence insufficiency before enrolling into the Convergence Insufficiency Treatment Trial and to 49 children with normal binocular vision (NBV) (mean age 12.5 years). The parents reported whether the child had ADHD, and this information was used to divide the symptomatic convergence insufficiency group into the convergence insufficiency with parent report of ADHD or convergence insufficiency with parent report of no ADHD groups. 
RESULTS: Sixteen percent of the convergence insufficiency group and 6% of the NBV group were classified as ADHD by parental report. An analysis of covariance showed that the total ABS score for the symptomatic convergence insufficiency with parent report of ADHD group (15.6) was significantly higher than the symptomatic convergence insufficiency with parent report of no ADHD group (11.7, p = 0.001) and the NBV group (8.7, p < 0.0001). Children with convergence insufficiency with parent report of no ADHD scored significantly higher on the ABS than the NBV group (p = 0.036).
     CONCLUSIONS: Children with symptomatic convergence insufficiency with parent report of no ADHD scored higher on the ABS, when compared to children with NBV. Children with parent report of ADHD or related learning problems may benefit from comprehensive vision evaluation to assess for the presence of convergence insufficiency.

Scheiman, M; Cotter, S; Rouse, M; Mitchell, G L; Kulp, M; Cooper, J; Borsting, E; and the Convergence Insufficiency Treatment Trial (CITT) Study Group "Randomised clinical trial of treatments for convergence insufficiency in children." Arch. Opthalmol. 2005

Scheiman, M; Cotter, S; Rouse, M; Mitchell, G L; Kulp, M; Cooper, J; Borsting, E; et al.  "A Randomized Clinical Trial of Vision Therapy/Orthoptics versus Pencil Pushups for the Treatment of Convergence Insufficiency in Young Adults."  Optometry and Vision Science. 2005. 
   Purpose: The purpose of this article is to compare vision therapy/orthoptics, pencil pushups, and placebo vision therapy/orthoptics as treatments for symptomatic convergence insufficiency in adults 19 to 30 years of age.
   Methods: In a randomized, multicenter clinical trial, 46 adults 19 to 30 years of age with symptomatic convergence insufficiency were randomly assigned to receive 12 weeks of office-based vision therapy/orthoptics, office-based placebo vision therapy/orthoptics, or home-based pencil pushups. The primary outcome measure was the symptom score on the Convergence Insufficiency Symptom Survey. Secondary outcome measures were the near point of convergence and positive fusional vergence at near.
   Results: Only patients in the vision therapy/orthoptics group demonstrated statistically and clinically significant changes in the near point of convergence (12.8 cm to 5.3 cm, p = 0.002) and positive fusional vergence at near (11.3” to 29.7”, p = 0.001). Patients in all three treatment arms demonstrated statistically significant improvement in symptoms with 42% in office-based vision therapy/orthoptics, 31% in office-based placebo vision therapy/orthoptics, and 20% in home-based pencil pushups achieving a score <21 (our predetermined criteria for elimination of symptoms) at the 12-week visit.
   Discussion: In this study, vision therapy/orthoptics was the only treatment that produced clinically significant improvements in the near point of convergence and positive fusional vergence. However, over half of the patients in this group (58%) were still symptomatic at the end of treatment, although their symptoms were significantly reduced. All three groups demonstrated statistically significant changes in symptoms with 42% in office-based vision therapy/orthoptics, 31% in office-based placebo vision therapy/orthoptics, and 20% in home-based pencil push-ups meeting our criteria for elimination of symptoms.

Shin H, Park S, Park C. "Relationship between accommodative and vergence dysfunctions and academic achievement for primary school children."  Opthamlic and Physiological Optics, 29 (6): 615-24.
   The purpose of this study was to investigate the prevalence and types of non-strabismic accommodative and/or vergence dysfunctions in primary school children, and to determine the relationship of these dysfunctions to academic achievement. A total of 1031 parents and their children aged 9-13 years responded to the College of Optometrists in Vision Development Quality of Life (COVD-QOL) questionnaire. Of these, 258 children whose visual symptom scores were e20 were identified for further evaluation. Comprehensive eye and vision examinations were provided to the children who met the eligibility criteria (114 of 258): eligible symptomatic children were those without amblyopia, strabismus, ocular and systemic pathology, and contact lens wear. Children were also excluded if they had visual acuity poorer than 20/25 in either eye or vertical phoria >1 prism diopter.
   The results showed that 82 of 114 (71.9%) of criteria-eligible symptomatic primary school children had non-strabismic accommodative and/or vergence dysfunctions. In addition, a significant relationship was found between these dysfunctions and academic scores in every academic area (reading, mathematics, social science and science) in the total sample. Therefore, accommodative and vergence functions should be tested for all school children who have visual symptoms and/or academic difficulties. Additional study is needed to determine if improvements of accommodative and vergence functions also improve academic achievement.