Blue field entoptic test in patients with ocular trauma.

The blue field entoptic test was applied to study macular function in 32 patients with severe ocular trauma and markedly reduced visual acuity (6/60 [20/200] or less) in whom fundus details could not be seen initially. This test is based on the entoptic phenomenon, whereby one can observe one's own leukocytes flowing in the perifoveal retinal capillaries. Twenty of the 21 patients (95%) with normal perception of the corpuscles regained a visual acuity of 6/12 (20/40) or better on follow-up, whereas ten of the 11 patients (91%) with abnormal test responses had, on follow-up, a visual acuity of counting fingers or less. The blue field entoptic test is therefore useful in prognosticating macular function in patients with reduced visual acuity due to media opacities secondary to ocular trauma.