Selective Unidirectional Horizontal Saccadic Paralysis From Acute Ipsilateral Pontine Stroke: Response

Letters to the Editor Selective Unidirectional Horizontal Saccadic Paralysis From Acute Ipsilateral Pontine Stroke: Response of eye movements should not be limited to pursuit, but must include examination of saccades. Joshua M. Kruger, MD, PhD Juan M. Sanchez, MD Department of Ophthalmology, Hadassah Medical Center, Jerusalem, Israel I n their recent publication, Pham and Trobe present the rare occurrence of a gaze palsy selectively impairing unidirectional horizontal saccades with preserved smooth pursuit (1). They demonstrated, for the first time in humans, radiological evidence of a lesion localizing to the dorsomedial pontine tegmentum, corresponding to the region of the pontine paramedian reticular formation (PPRF). We report a second case with very similar findings. A 67-year-old woman developed a sudden inability to look to her right. She had a history of hypertension, right retinal vein occlusion, and long-standing mild rightsided facial weakness. She had undergone left femur repair 3 weeks previously. Examination revealed impairment of saccades to the right that were associated with abnormal blinking and slow velocity. Smooth pursuit was normal (See Supplemental Digital Content, Video, http://links.lww.com/WNO/A217). Brain MRI revealed a lesion in the right dorsomedial caudal pons consistent with acute ischemia (Fig. 1). These results provide further support that the location of the PPRF in humans is in the dorsomedial pontine tegmentum. This case further reinforces the point made by Pham and Trobe that clinical evaluation Ruth Eliahou, MD Department of Neuroradiology, Hadassah Medical Center, Jerusalem, Israel Marc Gotkine, MBBS Department of Neurology, Hadassah Medical Center, Jerusalem, Israel The authors report no conflicts of interest. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the full text and PDF versions of this article on the journal's Web site (www.jneuro-ophthalmology.com). REFERENCE 1. Pham TD, Trobe JD. Selective unidirectional horizontal saccadic paralysis from acute ipsilateral pontine stroke. J Neuroophthalmol. 2017;37:341-347. FIG. 1. A. Axial diffusion-weighted imaging reveals a hyperintense lesion (arrow) in the right dorsomedial pons. B. Apparent diffusion coefficient map shows corresponding hypointensity (arrow). C. Fluid-attenuated inversion recovery sequence shows faint hyperintensity in the area of interest. Letters to the Editor: J Neuro-Ophthalmol 2017; 37: 347-353 347 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited.