Gaze Evoked Deformations of the Peripapillary Retina in Papilledema and Ischemic Optic Neuropathy.

PURPOSE

To examine the effects of horizontal eye movements on the shape of the peripapillary basement membrane layer (ppBM layer) in patients with papilledema, anterior ischemic optic neuropathy (AION) and normal eyes.

METHODS

Spectral-domain optical coherence tomography (SD-OCT) axial rasters of the optic nerve were used to analyze the shape of the ppBM layer. We compared registered images in two eye positions: 10° to 15° of adduction and 30° to 40° of abduction from 80 patients (45 with papilledema, 15 with AION, and 20 normal eyes).

RESULTS

Horizontal eye movements induce a relative "seesaw-like" shape deformation of the ppBM layer in patients with papilledema. On adduction, there is a relative posterior displacement temporal to the basement membrane opening (BMO) and an anterior displacement nasally (P = 0.001). The pattern reverses in abduction. Normal eyes and AION display similar but smaller changes in shape predominantly affecting the temporal side on adduction. The shape difference was significantly different for normal eyes (P = 0.03) and for AION (P = 0.01).

CONCLUSIONS

Horizontal eye movements affect the shape of the ppBM layer. The deformation in normals and AION, in adduction, causes posterior displacement temporal to the BMO. In contrast, the deformations in papilledema are larger, involving temporal and nasal sides, presumably because of shifts in cerebrospinal fluid pressure against the scleral flange and hydraulic stiffening of the optic nerve sheath. The clinical importance of gaze-induced deformations is unknown but repetitive motion may be a factor in the genesis or progression of a variety of optic neuropathies.