Porphoria, or latent squint, describes the situation where the eyes move out of the aligned state when they are dissociated.
Latent squint is a very common finding, and is rarely pathological.
Factors unmasking a latent squint include fatigue, alcohol, sedative drugs, unilateral visual impairment and bright sunlight (1).
A latent squint can be demonstrated by an alternative-cover test (by alternatively covering one eye then the other). If a latent squint is present then a movement will be seen in each as it is uncovered. Visual defects, such a cataract or refractive error, should be remedied and the patient reassured (1).
- (1) GP (28/9/2001), 48.
Last reviewed 01/2018