CLINICAL COMMUNICATIONS: Clinical Pearls
This month’s Clinical Communications are under the clinical editorship of Clinical Editor, Andrew B. Mick, OD, FAAO. Following each article in this section, Dr. Mick provides Clinical Pearls in these Clinical Communications, emphasizing the clinical take-home message. This is part of our ongoing effort to enrich the clinical content of OVS and make it relevant and accessible to clinicians, readers, and authors alike.
Patching for Diplopia Contraindicated in Patients with Brain Injury?
Kevin E. Houston and A. M. Barrett
Purpose. Patching for double vision is a common palliative treatment for head-trauma patients with acquired strabismus when prisms are not feasible.
Methods. We review literature on spatial neglect and discuss possible effects of monocular occlusion on spatial attention.
Results. Patching the left eye has been shown to worsen spatial judgments in some brain-injured patients with left neglect by inhibiting the right superior colliculus further impairing contralateral leftward orienting (the Sprague Effect).
Conclusions. Because more peripheral parts of the visual field increasingly project to the contralateral superior colliculus with the temporal crescent being entirely contralateral, avoiding patching of the temporal crescent was advised, and in most cases can be achieved by taping off the spectacle lens and avoiding an elastic eye patch.
Retrograde Degeneration of Retinal Ganglion Cells Secondary to Head Trauma
Lee Vien, Christina DalPorto, and David Yang
Purpose. To discuss the clinical case of a patient with transsynaptic retrograde degeneration (TRD) demonstrated by progressive retinal nerve fiber layer loss documented by serial spectral domain optical coherence tomography secondary to traumatic brain injury after 2 months posttrauma.
Case Report. A 25-year-old Caucasian male patient presented to a polytrauma rehabilitation center (PRC) for evaluation and treatment secondary to a severe traumatic brain injury (TBI) from a motorcycle accident 2 months before. Spectral domain optical coherence tomography (SD-OCT) was completed at intervals that ranged between 8 and 42 days for a duration of 119 days. A comparison to the pre-trauma SD-OCT 10 months before revealed progressive thinning of the retinal nerve fiber layer (RNFL) in both eyes over multiple follow-ups post-trauma. Humphrey visual field (HVF) testing revealed an incomplete congruous right homonymous hemianopsia that gradually improved over the follow-ups. Analysis of the macular ganglion cell–inner plexiform layer (GCIPL) thickness displayed loss that corresponded to the pattern of visual field defect.
Conclusions. TRD can occur as soon as 2 months after severe TBI with damage posterior to the lateral geniculate nucleus. Progressive RNFL loss can be tracked with SD-OCT, and the rate of thinning may slowly stabilize over time. Visual field defects can improve months after the trauma but may not correspond to the progressive RNFL loss detected by SD-OCT.