Central fixation testing in microtropia
Reviewed by Fiona Rowe

This study compared the two assessment methods of the 4D prism test and ocular fixation assessment in order to identify micro strabismus with identity. The study included 112 children; 46 males and 66 females. Anisometropia was present in 108 patients and 90 had at least 1.25D of anisometropia. A central suppression response was obtained in 24 patients by the 4D prism test. Ocular fixation assessment detected 68 patients with eccentric fixation. Agreement for both tests was found in 88 patients. Disagreement was in 24 cases. Potential factors influencing the results included visual acuity of the worse eye, level and degree of anisometropia, are and refractive error. After logistic regression analysis, no association was found for these factors. Given the discrepancy in results for one fifth of cases and the knowledge that fixation pattern can change over time, the author recommends that diagnosis of microtropia should be made over time with regular re-assessment, particularly where treatment is ongoing. Both tests should be viewed as independent and not interchangeable.

The agreement between the Irvine 4D prism test and assessment of ocular fixation in microtropia with identity.
Garretty T.
STRABISMUS
2021;29(2):81-5.