CLINICAL INVESTIGATION Evaluation of iron, zinc, and copper levels in pterygium tissue Hu ¨ seyin Ortak • Helin Deniz Demir • Durali Mendil • Erkan So ¨g ˘u ¨t • Aylin Ardagil • Mu ¨cahit Eg ˘ri Received: 5 August 2011 / Accepted: 22 November 2011 / Published online: 17 February 2012 Ó Japanese Ophthalmological Society 2012 Abstract Purpose To determine the concentration of the trace elements iron, copper, and zinc in pterygium tissue and healthy conjunctiva tissue and to investigate the involve- ment of these elements in pterygium etiopathogenesis. Methods Twenty patients with pterygium were enrolled in the study. The pterygium was excised and a conjunctival rotational flap or autograft inserted. Normal conjunctiva tissue was obtained from the flap or graft. The concentra- tions of iron, zinc, and copper in the pterygium and conjunctiva tissues were determined by atomic absorption spectrometry after microwave digestion. Results Iron, zinc, and copper levels were significantly higher in the pterygium tissue than in the normal con- junctiva (P \ 0.001). The mean iron, zinc, and copper concentrations in the pterygium tissue were 819, 214, and 3.40 lg/g, whereas the mean concentrations of these elements in the control tissue were 491, 148, and 2.19 lg/g, respectively. Conclusions Pterygium is a fibrovascular proliferative disorder and elevated levels of trace elements in pterygium tissue may play a pathogenic role via oxidative damage. Keywords Atomic absorption spectrometry Á Conjunctiva Á Pterygium Á Trace elements Introduction Pterygium is a common ophthalmic problem routinely found during ophthalmic examinations; it is characterized by abnormal fibrovascular tissue that extends on to the corneal surface [1]. In advanced cases, visual acuity can be reduced as a result of irregular corneal astigmatism and loss of corneal transparency [2]. Although several factors, for example sun exposure, dryness, and dust have been reported to contribute to the etiology of pterygia, the exact pathogenic mechanism is not understood. In recent studies, levels of specific growth factors, for example vascular endothelial growth factor (VEGF), and cellular mediators, for example nitric oxide (NO), have been studied [3, 4]. However, to the best of our knowledge, the involvement of trace elements in the etiopathogenesis of pterygium has not been evaluated. The trace elements iron, copper, and zinc are essential in the biochemical processes of human organisms. For instance, iron is important in cell growth, oxygen metabolism, a variety of enzymatic activity, and the immune response. Copper is a cofactor for many enzymes, for example cytochrome C oxidase and super- oxide dismutase. Similar to other trace elements, zinc is present in more than 70 different enzymes that function in H. Ortak (&) Á H. D. Demir Department of Ophthalmology, Faculty of Medicine, Gaziosmanpas ¸a University, Tokat, Turkey e-mail: huseyin.ortak@hotmail.com D. Mendil Faculty of Science and Arts of Chemistry, Gaziosmanpas ¸a University, Tokat, Turkey E. So ¨g ˘u ¨t Department of Biochemistry, Faculty of Medicine, Gaziosmanpas ¸a University, Tokat, Turkey A. Ardagil Department of Ophthalmology, Go ¨ztepe Training Hospital, Istanbul, Turkey M. Eg ˘ri Department of Public Health, Faculty of Medicine, Gaziosmanpas ¸a University, Tokat, Turkey 123 Jpn J Ophthalmol (2012) 56:219–223 DOI 10.1007/s10384-012-0118-7