YOU ARE NOW CONNECTED TO THE MEDLINE (1995 - 98) FILE. ==CONVERGENCE EXCESS== 1 AUTHOR Gallaway M AUTHOR Schieman M TITLE The efficacy of vision therapy for convergence excess. SOURCE J Am Optom Assoc 1997 Feb;68(2):81-6 ABSTRACT BACKGROUND: Convergence excess is a commonly encountered non-strabismic ocular motility disorder. There are, however, very few research data that evaluate the effect of vision therapy for this condition in a clinical population. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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. 1 AUTHOR Kushner BJ AUTHOR Morton GV TITLE Distance/near differences in intermittent exotropia. SOURCE Arch Ophthalmol 1998 Apr;116(4):478-86 ABSTRACT BACKGROUND: Burian's classification of exotropia based on the difference between the distance deviation and near deviation (distance/near differences) leaves some questions unanswered. Controversy exists concerning whether the divergence excess pattern is caused by an excess of divergence or by excessive accommodative convergence. Much of the literature on this subject has been confusing because investigators did not eliminate tenacious proximal fusion as an artifact in calculating the ratio of accommodative convergence to accommodation (AC/A ratio). Previously, one of us (B.J.K.) proposed a classification system that respected this artifact and subdivided the classification system proposed by Burian. METHODS: A total of 202 consecutive patients with an exotropia underwent a series of measurements to determine the respective role of accommodative convergence and tenacious proximal fusion as a cause for their distance/near differences. In addition, the value obtained by a rapid prism adaptation test as a possible substitute for 1 hour of monocular occlusion was studied. RESULTS: In 98 patients, the initial distance deviation exceeded the near deviation. In 10 patients, the distance/near differences were caused by a high AC/A ratio, which would have been mislabeled by Burian's classification system. Brown's recommendation of using +3.00-diopter lenses at near to diagnose simulated divergence excess would have led to the misdiagnosis of a high AC/A ratio in 61 of these patients. In 26 patients, the near deviation exceeded the distance deviation. Burian's classification would have incorrectly labeled 2 patients as having convergence insufficiency when, in fact, they had pseudoconvergence insufficiency. The new proposed classification system proved 100% sensitive and 100% specific (6 of 6 patients for both parameters) for identifying preoperatively exotropic patients who postoperatively developed an esotropia at near with a high AC/A ratio. Rapid prism adaptation tests at near proved useful for identifying the presence of tenacious proximal fusion, but were not accurate in its quantification. CONCLUSIONS: The validity and utility of the new classification system was confirmed. Identification of exotropic patients with a high AC/A ratio and consideration of nonsurgical treatment is important. The rapid prism adaptation test is qualitatively, but not quantitatively, the same as 1 hour of monocular occlusion. 4 AUTHOR Porcar E AUTHOR Martinez-Palomera A TITLE Prevalence of general binocular dysfunctions in a population of university students. SOURCE Optom Vis Sci 1997 Feb;74(2):111-3 ABSTRACT PURPOSE: Although some authors report that the prevalence of general binocular dysfunctions (nonstrabismic) for nonpresbyopes in the clinical population is greater than any condition except refractive error, limited research is available to support this statement. This clinical study determined the presence and clinical implications of these conditions in a population of university students with heavy near visual demands. METHODS: From a group of second year students who were given a thorough eye examination, 65 students were selected. The criteria for selection were the absence of significant uncorrected refractive error, healthy eyes, and no strabismus or amblyopia. RESULTS: 32.3% of the subjects showed general binocular dysfunctions. In 10.8% of the cases, accommodative excess was present. 7.7% had convergence insufficiency with accommodative excess. 6.2% showed accommodative insufficiency. 3.1% had basic exophoria. Convergence excess with accommodative insufficiency, basic esophoria, and fusional vergence dysfunction all showed the same prevalence of 1.5%. CONCLUSIONS: Accommodative and nonstrabismic binocular vision problems are prevalent in this population. Accommodative excess is the most common condition. Because these dysfunctions may have a negative effect on performance, appropriate vision evaluation for this population is important. 9 AUTHOR van den Berg AV AUTHOR van Rijn LJ AUTHOR de Faber JT TITLE Excess cyclovergence in patients with intermittent exotropia. SOURCE Vision Res 1995 Dec;35(23-24):3265-78 ABSTRACT Recently, we developed a model of binocular fixation. This model predicts the amount of cyclovergence as a function of target elevation and horizontal target vergence. The prediction derives from the assumption that version and vergence add linearly and that the eye positions are constrained in three respects: (1) the foveae of the two eyes are directed towards the target, (2) the version component follows Listing's law, i.e. cycloversion, and horizontal and vertical version are not independent, (3) the vergence component is restricted to a plane approximately perpendicular to Listing's plane, i.e. horizontal, vertical and torsional vergence are not independent. The version and the vergence components are characterized by a common primary direction for the two eyes. We applied this model to data of patients with intermittent exotropia. In two patients with an amblyopic eye we found that the common primary direction rotates towards the amblyopic eye. In the third patient, not suffering from amblyopia, the common primary direction was practically straight ahead. In all three patients, cyclovergence angles were larger than those found in normal subjects. We found that the increased cyclovergence was compatible with our model for normal subjects if an offset on the horizontal vergence was given. This offset represents the additional convergence effort required in these patients to overcome the exodeviation of the eyes. According to our model the increased horizontal vergence effort results in excess cyclovergence. The relation between horizontal vergence and cyclovergence offers a new method for measuring the angle of exotropia.