Periodic alternating nystagmus clearing after cataract surgery

Area of Science:

• Ophthalmology
• Neuro-ophthalmology

Background:

• Periodic alternating nystagmus (PAN) is an involuntary eye movement disorder often associated with reduced visual acuity.
• The exact mechanisms linking visual loss to PAN are not fully understood but are thought to involve impaired fixation.
• Cataracts significantly impair vision, potentially triggering or exacerbating conditions like PAN.

Observation:

• A 60-year-old male presented with PAN and severe vision loss (hand motion only) secondary to bilateral cataracts.
• The patient underwent extracapsular cataract extraction and intraocular lens implantation in his left eye.

Findings:

• Postoperatively, the patient's left eye vision improved to 20/60.
• Crucially, the periodic alternating nystagmus resolved in the left eye with the improvement in visual function.

Implications:

• This case highlights the critical role of visual fixation in suppressing PAN.
• Surgical intervention to restore visual acuity, such as cataract extraction, can be an effective treatment for PAN associated with visual impairment.
• Further research into the neuro-visual pathways involved in PAN is warranted.