RESUMO
BACKGROUND: Variable exotropia is determined by a series of mechanisms that provide different clinical characteristics to outline individual therapy. There is no specific categorization that can identify such an entity. A clinical classification is proposed that includes different clinical features in accordance with the mechanisms involved in the variability genesis of such exotropias. METHODS: Patients with a diagnosis of variable angle exotropia without previous surgery were included. A complete ophthalmic and strabismus exploration was performed. Variability characteristics were studied and grouped by entries in the classification proposed. RESULTS: Ninety patients were examined from the Pediatric Ophthalmology and Strabismus Unit of the General Hospital of Mexico O.D., with a diagnosis of variable angle exotropia. The following forms of presentations were found: secondary variable angle exotropia due to neurological alteration in 32 cases (35.5%), secondary variable angle exotropia due to monocular bad vision in 19 cases (21.2%), dissociated horizontal deviation in 14 cases (15.5%), mixed variable angle exotropia in 22 cases (4.5%) and primary variable angle exotropia in 3 cases (3.33%). CONCLUSIONS: This classification allows categorization of all patients of variable angle exotropia into proposed categories. The most common mechanism responsible for variability is neurological alteration. Primary variable angle exotropias are rare and are present in a minimum percentage.
Assuntos
Exotropia/classificação , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
BACKGROUND AND PURPOSE: 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. SUBJECTS AND 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). CONCLUSION: 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.