This site is intended for healthcare professionals
Last reviewed dd mmm yyyy. Last edited dd mmm yyyy
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).