decompensated heterophoria

A decompensated heterophoria is a heterophoria that causes symptoms, or that is likely to deteriorate without treatment, because fusion can no longer adequately control the latent deviation.^1,2 Most symptomatic heterophorias were previously compensated, and decompensating factors matter most if they change markedly.¹

Whether a heterophoria stays compensated depends on the size of the deviation, sensory fusion, and motor fusion. Uncorrected hyperopia, incipient presbyopia, astigmatism, anisometropia, low or unbalanced fusional reserves, visual field loss, and poor general health can each contribute to decompensation. A heterophoria that cannot be overcome may also break down into a strabismus, which is a separate outcome from decompensation.¹

Symptoms include blurred vision, diplopia, distorted vision, difficulty with stereopsis, headache, and aching or sore eyes.^1,2 Size alone does not settle the diagnosis, because small phorias are sometimes decompensated and large ones are sometimes compensated. On the cover test, a slow, hesitant, or jerky recovery movement usually accompanies decompensation, and a quick, smooth recovery suggests compensation.¹