Abstract
Purpose: :
To investigate the effects of combined Tenotomy + Anderson procedure on both acquired vertical (downbeat) nystagmus (DBN) and horizontal infantile nystagmus (IN). Tenotomy improved visual acuity and reduced oscillopsia in patients with IN and acquired pendular nystagmus. Its effectiveness combined with other surgeries should also be accessed.
Methods: :
Patient 1 had DBN, oscillopsia, strabismus, and diplopia; he adopted a chin–down (upgaze) position. Asymmetric superior rectus recessions and inferior rectus tenotomies reduced right hypertropia and rotated both eyes downward. Patient 2 had horizontal IN, a 20º left–eye exotropia, and alternating fixation (left eye in left gaze, right eye in right gaze). Eight mm lateral rectus recessions and medial rectus tenotomies were performed. Horizontal and vertical eye movements were recorded pre– and post–surgically using high–speed digital video. The expanded nystagmus acuity function (NAFX), peak–to–peak amplitudes, and frequencies were measured.
Results: :
Patient 1: The NAFX peak was moved from 10º up to primary position; primary–position NAFX values were improved by 17%. Visual acuity increased 20% from 20/25 to 20/20+1. Vertical NAFX values increased across the –10º to +5º vertical range. Right hypertropia was reduced to 3–4º, foveation time per cycle increased from 88 ms to 178ms (102%), vertical–component amplitude was reduced by 46%, and frequency was unchanged at ∼3 Hz. Diplopia and oscillopsia were decreased. Patient 2: The procedure transformed two lateral, narrow NAFX vs. gaze angle curves (due to fixating–eye changes) into one broad curve with a 81.3% increase in primary position where acuity increased from 20/150 to 20/80, with a slight decrement in left–gaze. Diplopia decreased, the ability to converge was regained, and to hold gaze, improved. Right hypertropia was reduced, foveation time per cycle increased from 35.5 ms to 126.9 ms (257.4%), horizontal–component amplitude was reduced by 45.7%, and frequency remained unchanged at ∼4 Hz.
Conclusions: :
Increased NAFX values and visual acuities plus reduced diplopia and oscillopsia demonstrated the effectiveness of combined Tenotomy + Anderson procedure in DBN and IN. Tenotomy should be part of the treatment plan for selected cases of acquired and infantile nystagmus.
Keywords: nystagmus • strabismus • eye movements