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Jose-Carlos Pastor, Iraxte Zabalza, Ruben Cuadrado, Jose Alberto de Lazaro, Angela Morejon, Yrbani Lantigua, Rosa Coco; Visual alterations in a cohort of young male patients with acute/subacute intoxication with mercury vapor. Invest. Ophthalmol. Vis. Sci. 2016;57(12):300.
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© ARVO (1962-2015); The Authors (2016-present)
Mercury intoxication is a well known condition with several visual and neurological alterations. But there is still a controversy about the existence of two level of involvement: visual pathway and/or retinal structures. By the end of 2012, 47 workers were affected by mercury exposure for 13 days. Blood levels were high (600-1000 mcg/L, normal < 10 mcg/L) and patients were not chelated. The purpose of this work is to describe the visual disturbances encountered in the most severe affected sub-group, correlating the structural and functional findings
A prospective observational study on 23 patients ( range 28-56 years) was approved by Ethical Committee. Functional tests were: visual acuity (ETDRS), color vision (Farnsworth-Munsell, 28 Hue), contrast sensitivity (CSV-1000), visual field (Humphrey 750i), ERG, pERG, mERG and VEP (Metrovision, following ISCEV standard). Additionally autofluorescence, macular thickness by OCT (3D OCT2000, Topcon), and nerve fiber layer thickness (CFNR) (Stratus 3000, Zeiss Meditec) were recorded. Appropriate statistical tests were performed: Spearman, Mann-Whitney, Wilcoxon and t student. Values were compared against normal
Two patients were excluded, as they have pathological unrelated findings: one idiopathic parafoveolar telangiectasias type 2 and one congenital dyscromatopsia. All patients showed loss of contrast sensitivity in all frequencies, alterations in the discrimination of colors (Confusion index: 1.64±1.18) and defaults in the visual field in 14 out of 22 (MD, mean defect: -8.9 dB). Also increase of latency and decrease of the extent of the b wave (ERG), of the p50 wave of the pERG and an increase of the implicit time of the p100 wave of the VEP. No alterations were registered in the structural tests (macular thickness: 246.1 ± 20.9 µ; CFNR: 101.89 ±11.6 µ) or in the mERG.
Most of the found alterations were already described in other series. Alterations in the pERG not described have been found. These patients are being followed to analyze the progression of their pathologic findings. Because of the scarcity in reports of this poisoning any new clinical data is relevant.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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