Toxic Effects of Chronic Mercury Exposure on the Retinal Nerve Fiber Layer and Macular and Choroidal Thickness in Industrial Mercury Battery Workers
Metin Ekinci, Erdinç Ceylan, Sadullah Keleş, Halil Hüseyin Çağatay, Aytekin Apil, Burak Tanyıldız, Gunay Uludag
Department of Ophthalmology, Kafkas University, Kars, Turkey
Med Sci Monit 2014; 20:1284-1290
The aim of this study was to evaluate the toxic effects of mercury on retinal nerve fiber layer thickness (RNFLT), macular thickness (MT), and choroidal thickness (CT) by using spectral-domain optical coherence tomography (SD-OCT) in battery industry workers who had been chronically exposed to mercury.
Material and Methods: Battery factory workers (n=31) and healthy non-factory employee controls (n=15) participated in the study. Participants were divided into 3 groups: Group 1 (n=15) was factory workers who had worked for more than 5 years in a mercury battery factory; Group 2 (n=16) was factory worker who had worked for less than 5 years in a mercury battery factory; and Group 3 (n=15) was healthy non-employees. Systemic symptoms were recorded. Ophthalmic examination included best-corrected visual acuity test, color vision test, full ophthalmologic examination, and SD-OCT of the RNLF, macula, and choroid. To determine mercury exposure, venous blood samples were collected and mercury levels were assessed.
Results: In our study group the most common systemic symptoms were insomnia (67.7%) and fatigue (67.7%). There were no significant differences between Group 1 and Group 2, but there were significant differences between Group 3 and both Group 1 and Group 2 in best-corrected visual acuity values (1=2<3), color vision scores, blood mercury levels, and duration (mean ±SD, range) of mercury exposure(1>2>3). OCT values of RNFLTs, MTs, and CTs of all 3 groups were statistically different from each another (1<2<3).
Conclusions: SD-OCT can be useful for evaluating the toxic effects of chronic exposure to mercury.
Keywords: Color Vision - drug effects, Choroid - pathology, Macula Lutea - pathology, Manufacturing Industry, Mercury - toxicity, Nerve Fibers - drug effects, Occupational Exposure - adverse effects, Retina - drug effects, Statistics, Nonparametric, Time Factors, Tomography, Optical Coherence - methods, Turkey, Visual Acuity - drug effects