To the Editor.
—We read with interest the report on "Monofixational Intermittent Exotropia" in the January Archives (97:93-95, 1979) by Baker and Davies and can confirm their observations. We, too, have cared for a number of patients with intermittent exotropia who had, in fact, an ultra-small-angle monofixational exotropia when their eyes were "straight," and who maintained the same level of sensory binocular cooperation after surgical correction of the exotropia.We question, however, the prevalence of monofixation syndrome that Baker and Davies found in one third of their patients. They noted this frequency to be higher than expected according to Parks.1Diagnosing monofixation syndrome in children solely on the basis of Titmus stereo test stereoacuity is difficult, since performance on this test is age related and variable.2 Using this test, a stereoacuity of 60 s of arc is found in only 50% of normal children at the age 4½
Romano PE, Romano JA, Puklin JE. Monofixational Intermittent Exotropia. Arch Ophthalmol. 1979;97(8):1543-1544. doi:10.1001/archopht.1979.01020020193027