Visual field losses in workers exposed to mercury vapor

• Published in: Environmental research Vol. 107; no. 1; pp. 124 - 131
• Main Authors: Barboni, Mirella Telles Salgueiro, da Costa, Marcelo Fernandes, Moura, Ana Laura de Araújo, Feitosa-Santana, Cláudia, Gualtieri, Mirella, Lago, Marcos, Medrado-Faria, Marcília de Araújo, Silveira, Luiz Carlos de Lima, Ventura, Dora Fix
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier Inc 01.05.2008; Elsevier
• Subjects: Adult; Air Pollutants, Occupational - toxicity; Automated perimetry; Biological and medical sciences; Case-Control Studies; Chemical and industrial products toxicology. Toxic occupational diseases; Female; Humans; Male; Medical sciences; Mercury - toxicity; Mercury Poisoning - physiopathology; Mercury vapor; Metals and various inorganic compounds; Middle Aged; Neurotoxicology; Occupational Exposure; Toxicology; Vision; Visual field; Visual Fields - physiology; South America; Brazil; America; Mercury vapor; Automated perimetry; Vision; Visual field; Neurotoxicology; Human; Vapor; Nervous system diseases; Toxicity; Vision disorder; Perimetry; Occupational exposure; Heavy metal; Eye disease; Mercury; Occupational medicine
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2007.07.004

Visual field losses associated with mercury (Hg) exposure have only been assessed in patients exposed to methylmercury. Here we evaluate the automated visual field in 35 ex-workers (30 males; 44.20±5.92 years) occupationaly exposed to mercury vapor and 34 controls (21 males; 43.29±8.33 years). Visual fields were analyzed with the Humphrey Field Analyzer II (model 750i) using two tests: the standard automated perimetry (SAP, white-on-white) and the short wavelength automated perimetry (SWAP, blue-on-yellow) at 76 locations within a 27° central visual field. Results were analyzed as the mean of the sensitivities measured at the fovea, and at five successive concentric rings, of increasing eccentricity, within the central field. Compared to controls, visual field sensitivities of the experimental group measured using SAP were lower for the fovea as well as for all five eccentricity rings ( p<0.05). Sensitivities were significantly lower in the SWAP test ( p<0.05) for four of the five extra-foveal eccentricity rings; they were not significant for the fovea ( p=0.584) or for the 15° eccentricity ring ( p=0.965). These results suggest a widespread reduction of sensitivity in both visual field tests. Previous reports in the literature describe moderate to severe concentric constriction of the visual field in subjects with methylmercury intoxication measured manually with the Goldman perimeter. The present results amplify concerns regarding potential medical risks of exposure to environmental mercury sources by demonstrating significant and widespread reductions of visual sensitivity using the more reliable automated perimetry.