Microtropia is usually secondary to previous squint surgery, anisometropia, or primary monofixation syndrome but can sometimes be caused by an unusual macular abnormality.1- 3
We describe a 12-year-old girl who was referred by the optometrist with reduced visual acuity of 20/30 OD and 20/20 OS. Ocular motility assessment revealed a right microtropia measuring 14 prism diopters for distance and 6 prism diopters for near, right amblyopia with reduced motor fusion, and reduced stereoacuity of 600 seconds/arc on the Frisby test. Anterior segment examination findings were normal. Fundus examination revealed a right congenital, idiopathic epiretinal membrane involving the disc and macula (Figure 1). Subsequent examination revealed the epiretinal membrane to have increased in size, causing macular traction and reducing visual acuity to 20/40 OD (Figure 2).
Salvi SM, Kumar BV, Burke JP. Microtropia Secondary to Presumed Congenital Epiretinal Membrane. Arch Ophthalmol. 2007;125(10):1437. doi:10.1001/archopht.125.10.1437