Some clinical characteristics of V-pattern exotropia and surgical outcome after bilateral recession of the inferior oblique muscle: a retrospective study of 22 consecutive patients and a comparison with V-pattern esotropia.
OBJECTIVE
A V-pattern exotropia (XT) with bilateral overaction of the inferior obliques (IO) and/or underaction of the superior obliques (SO) is a common finding. The clinical characteristics of this condition in a large series are not available in the scientific literature. Also, data is lacking about the surgical outcome of graded bilateral IO recession. Lastly, a comparison of the pre- and postoperative findings of a V-pattern exotropia population with those of a V-pattern esotropia population is also lacking in the literature.


METHODS
Twenty-two consecutive patients without complicating factors were fully evaluated and submitted to bilateral graded recessions of the IO; 19 were also operated for a horizontal binocular alignment imbalance.


RESULTS
Preoperative findings: The distribution of V patterns showed 77.2% in the range of 15 to 25 prism diopters (PD) and 22.8% in the range 26 to 35 PD. An overaction of the IO was present bilaterally in 86.4% of the patients and unilaterally in 4.5%. Bilateral underaction of the SO was observed in 4.5% and unilateral in 13.6%. Bilateral overaction of the SO was seen in 18.2% and unilateral in 31.8%. Elevation in adduction was observed bilaterally in 13.6% and unilaterally in 31.8%. A vertical deviation was seen in 50.0% and a marked tendency of it to vanish or diminish in the up- and down positions, as well as at near, was observed. After surgery, 72.7% had less than 15 PD of V pattern or less than 10 PD of A pattern; 36.4% had the V pattern fully corrected. Surgery eliminated a vertical imbalance in 72.7% of the patients, reduced in 9.1%, left unchanged in 9.1% and increased in 9.1% Of the 11 patients devoid of vertical deviation, 72.7% remained so and in 27.3% a vertical deviation was created. Binocularity: There was an improvement of the fusional status with surgery, (ascertained with the Worth Four Dot Test and the major amblyoscope measurement).


CONCLUSIONS
All cases were in the range of 15-35 PD preop'. Overaction of the IO was a prominent finding. Underaction of the SO was less prevalent as compared with a V-ET population. Overaction of the SO was observed bilaterally in 18.2% and unilaterally in 31.8%, a finding never detected in a V-ET population. A vertical imbalance was observed in one-half of the cases. A good outcome (collapse of the V pattern) was obtained with bilateral graded recession of the IO, This procedure is relatively safe concerning the vertical alignment.
Division of Ophthalmology, School of Medicine, University of São Paulo, São Paulo, Brazil.
Jorger Alberto F
JA
Caldeira
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004948:Esotropia / Q000145:classification / Q000601:surgery*; D005099:Exotropia / Q000145:classification / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D009801:Oculomotor Muscles / Q000601:surgery*; D013508:Ophthalmologic Surgical Procedures; D012189:Retrospective Studies; D016896:Treatment Outcome; D015348:Vision, Binocular