[Clinical classification of variable angle exotrophy].
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.
Arroyo-Yllanes
María Estela
ME
Clínica de Oftalmología Pediátrica y Estrabismo, Servicio de Oftalmología del Hospital General de México, O.D., Cuauhtémoc, 03100 México, Mexico. mearroyo1@prodigy.net.mx
Osorio-González
Déborah Itzel
DI
Pérez-Pérez
José Fernando
JF
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005099:Exotropia / Q000145:classification*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D055815:Young Adult