Onset of oscillopsia after visual maturation in patients with congenital nystagmus1

Purpose

To describe the clinical and oculographic characteristics of a cohort of five patients with congenital nystagmus (CN) and late-onset oscillopsia caused by a coincidental decline in other visual and/or ocular motor functions.

Design

Retrospective, observational, case series.

Participants

Five visually mature patients with CN and recent-onset oscillopsia were evaluated clinically and with motility recordings.

Intervention

Eye movement analysis was performed off-line by computer analysis of digitized data. Nystagmus was analyzed for null-zone characteristics, waveforms, frequency, amplitudes, and slow-phase drift velocity during foveation. Surgical and medical treatment of associated ocular conditions in four of five patients.

Main outcome measures

Presence of symptomatic oscillopsia and average time during foveation periods of slow-phase drift velocity less than 10°/second.

Results

One of the five patients had associated rod-cone dystrophy, and another had recurrence of childhood head posturing with return of an eccentric null zone. The remaining three patients had decompensated strabismus associated with their oscillopsia. All five patients complained of oscillopsia in primary position that was relieved in the four who received treatment. Treatment included prismatic correction in one patient and surgery in three. Recordings in primary position after treatment showed increased duration during foveation periods of slow-phase drift velocity less than 10°/second and an overall decreased intensity (amplitude/frequency) of the nystagmus.

Conclusions

Symptomatic oscillopsia in patients with CN is unusual. This visually disturbing symptom can be precipitated by new or changing associated visual sensory conditions (e.g., decompensating strabismus, retinal degeneration). If the associated conditions can be treated, then accompanying oscillopsia may be relieved.