Static and dynamic aspects of accommodation in mild traumatic brain injury: A review

Sensory and motor pathway for monocular blur-driven accommodation.

Examples of accommodative responses to simple sinusoidal blur stimuli at frequencies of 0.1, 0.2, and 0.3 Hz in the patient and a normal control subject. High contrast, black and white target of 3 degrees angular extent. T = target movements; A = accommodative responses.

A, Preoperative accommodative response to a linear ramp stimulus in a patient with a cerebellar cyst. Solid line represents the stimulus for increasing and decreasing accommodation, and the dotted portion represents the actual dynamic accommodative response. B, Preoperative (top) and postoperative (bottom) accommodative responses to repetitive, predictable step stimuli in a patient with a cerebellar cyst.

Monocular and binocular push-up accommodative amplitudes of 12 patients with mild traumatic brain injury plotted on Duane's graph for visually normal individuals over a wide range of ages. Poly. = Polynomial fit to data.

Exponential fit to raw data (accommodative response as a function of time) for a visually normal subject (top) and a mTBI subject manifesting dynamic abnormalities (bottom) for both increasing accommodation. Tau = time constant, Ampl. = response amplitude, and PV = peak velocity.

A, Mean binocular accommodative lens flipper facility rate (cpm) in the mTBI group, before and after the fatigue trials. Plotted as the mean +1 SEM. B, Individual binocular accommodative lens flipper facility rates (cpm) in the mTBI group, before and after the fatigue trials.