The effect of surgery on the AC/A ratio.
The accommodative convergence/accommodation (AC/A) ratio is used clinically as a diagnostic tool in the assessment of convergence excess and near esotropia and the differentiation of true and simulated divergence excess. An abnormally high AC/A ratio has been implicated in the aetiology of some forms of strabismus but the evidence for alteration in the ratio following surgery is inconclusive. In a prospective study of 38 patients the effect of routine squint surgery was investigated in concomitant strabismus. The AC/A ratio was found to decrease significantly after surgery in both esotropes and exotropes. Furthermore a trend was demonstrated which suggested an increased risk of overcorrection in esotropes with a high (> or = 7:1) pre-operative AC/A ratio.
Lucas
E
E
St Thomas' Hospital, London, UK.
Bentley
C R
CR
Aclimandos
W A
WA
D000065:Accommodation, Ocular / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D003290:Convergence, Ocular / Q000502:physiology*; D004948:Esotropia / Q000503:physiopathology; D005099:Exotropia / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D013285:Strabismus / Q000601:surgery*; D016896:Treatment Outcome