Simultaneous vs. alternate PCT disparity in XT

1 October 2018 | Fiona Rowe (Prof) | EYE - Paediatrics, EYE - Strabismus

The authors quantified the relationship between simultaneous prism and cover test (SPCT) and alternate prism and cover test (APCT) alignment in patients with measures at the same visit after surgery for exotropia. This was a retrospective study of 955 patients having surgery for exotropia; 274 had both measurements at distance and 319 had both measurements at near at two to six months follow-up. Two hundred and thirty had both measurements at both distances. Of the included patients, median age was 10.6 years for the distance measurement group and 9.5 years for the near measurement group. SPCT and APCT were strongly correlated but significantly different. A positive linear correlation was found for near and distance with a mean difference between measurements of 5.6±5.6PD for near and 4.4±4.7PD for distance. Seventy-six percent had SPCT of 0 at distance and 81% at near. A significant difference between measurements at distance was associated with intermittent versus non-intermittent exotropia, age at the time of surgery as a continuous variable, pattern of deviation, larger preoperative angle, presence of preoperative fusion, surgery without medial rectus resection, postoperative exotropia versus esotropia and postoperative fusion. Significance at near was associated with amblyopia / sensory vision loss, larger preoperative angle, preoperative fusion, surgery without medial rectus resection and postoperative exotropia versus esotropia.