Abstract
Purpose :
To evaluate the applicability of the prism under cover test (PUCT), which doesn't suspend fusion, to quantify misalignment in strabismus with alternate fixation when simultaneous prism and cover test (SPCT) is not feasible.
Methods :
Children aged 4 to 11 years, with alternate fixation horizontal strabismus and alternate prism and cover test (APCT) distance deviation (DD) up to 25 PD were eligible. In group 1 of the study, SPCT was not feasible (n=18), whereas in group 2 it was (n=24). Refraction, PUCT, APCT, central/peripheral fusion, and stereoacuity, were measured. Repeatability of PUCT, agreement between PUCT and SPCT, and correlations between variables were studied.
Results :
In group 1, mean DD was 15.6 and 9.5 PD using APCT and PUCT, respectively (intraclass correlation, ICC: 0.90). Mean stereoacuity was 201.17 arc seconds. PUCT was better correlated with stereoacuity than APCT, but not significantly (p= 0.12). Coefficient of repeatability for PUCT was 3.38 PD. In group 2, mean DD was 17.66, 14.16, and 12.50 PD using APCT, PUCT and SPCT, respectively. Mean stereoacuity was 285.9 arc seconds. Correlations APCT-PUCT (0.87), APCT-SPCT (0.82), and SPCT-PUCT (0.95) were significant. APCT didn't show as good correlation with stereoacuity (0.58) as SPCT and PUCT (0.74 and 0.78, respectively). Concordance correlation coefficient between SPCT and PUCT was 0.91, and Bland Altman agreement between the two variables was also good.
Conclusions :
PUCT is a procedure of interest in children when SPCT is not feasible, in order to estimate manifest deviation, predict stereoacuity, and support the diagnosis of MFS.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.