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Show Improvement on Automated Perimetry After Surgery for Idiopathic Intracranial Hypertension: Comment We read with interest the article by Rizzo et al (1) entitled "Perimetry, Retinal Nerve Fiber Layer Thickness and Papilledema Grade After Cerebrospinal Fluid Shunting in Patients With Idiopathic Intracranial Hypertension" (1). We appreciate their efforts to establish better evidence for the efficacy of surgical intervention in the treatment of idiopathic intracranial hypertension (IIH) patients who are refractory to medical management. We were surprised to see them state in the article that "there are no case series of automated perimetry outcomes after cerebrospinal fluid (CSF) shunting in IIH patients." We believe this statement is incorrect; we reported visual out-comes including perimetric mean deviation in a retrospec-tive series of IIH patients who underwent either optic nerve sheath fenestration (ONSF) or CSF diversion (shunt) at our institution (2). Preoperative and postoper-ative visual acuity and perimetric mean deviation (MD) were shown, and we demonstrated that patients in both groups improved. It is quite interesting that the mean improvement of 5.63 dB in the study by Rizzo et al is very similar to the 6.57 dB improvement we found in our series of shunted patients. In fact, although the final peri-metric MD in the ONSF cohort was worse than that in the shunted group, a mean improvement of 6.21 dB was seen for ONSF as well. This finding suggests that there may be a limit to the improvement in visual function that can occur after any surgical intervention for papilledema and vision loss; alternatively, it may mask a bimodal distribution of patients with minimal improvement and those in whom marked recovery occurs. Patient selection bias remains a limiting factor in the interpretation of data in all of our retrospective analyses. We look forward to planned prospective studies that may help us to better serve our patients with this sight-threatening disease. Prem S. Subramanian, MD, PhD Pedro L. Fonseca, MD Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland Daniele Rigamonti, MD Department of Neurosurgery, Johns Hopkins University School, Baltimore, Maryland Neil R. Miller, MD Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland The authors report no conflicts of interest. REFERENCES 1. Rizzo JL, Lam KV, Wall M, Wilson MD, Keltner JL. Perimetry, retinal nerve fiber layer thickness and papilledema grade after cerebrospinal fluid shunting in patients with idiopathic intracranial hypertension. J Neuroophthalmol. 2015;35:22-25. 2. Fonseca PL, Rigamonti D, Miller NR, Subramanian PS. Visual outcomes of surgical intervention for pseudotumour cerebri: optic nerve sheath fenestration versus cerebrospinal fluid diversion. Br J Ophthalmol. 2014;98:1360-1363. Improvement on Automated Perimetry After Surgery for Idiopathic Intracranial Hypertension: Response We thank our colleagues for drawing attention to their experience with cerebrospinal fluid shunting in idiopathic intracranial hypertension patients. When our article was initially submitted to the Journal of Neuro-Ophthalmology, the article by Fonseca et al entitled "Visual outcomes of surgical intervention for pseudotu-mor cerebri: optic nerve sheath fenestration versus cere-brospinal fluid diversion" had not yet been published. We appreciate the authors taking the time to compare and contrast their results with ours. We also look forward to the results of prospective studies on this topic. Jennifer L. Rizzo, MD Department of Ophthalmology and Vision Science, UC Davis Eye Center, University of California, Davis, California The author reports no conflicts of interest. 332 Letters to the Editor: J Neuro-Ophthalmol 2015; 35: 329-332 Letters to the Editor Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. |
