Clinical Ophthalmology (Jul 2016)
A mathematical approach to human pterygium shape
Abstract
Bojan Pajic,1–4 Iraklis Vastardis,1 Predrag Rajkovic,5 Brigitte Pajic-Eggspuehler,1 Daniel M Aebersold,6 Zeljka Cvejic2 1Eye Clinic ORASIS, Swiss Eye Research Foundation, Reinach AG, Switzerland; 2Department of Physics, Faculty of Sciences, University of Novi Sad, Novi Sad,3Faculty of Medicine of the Military Medical Academy, University of Defence, Belgrade, Serbia; 4Division of Ophthalmology, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland; 5Department of Mathematics, Faculty of Mechanical Engineering, University of Niš, Niš, Serbia; 6Department of Radiation Oncology, Inselspital, Bern University Hospital, Bern, Switzerland Purpose: Pterygium is a common lesion affecting the population in countries with high levels of ultraviolet exposure. The final shape of a pterygium is the result of a growth pattern, which remains poorly understood. This manuscript provides a mathematical analysis as a tool to determine the shape of human pterygia.Materials and methods: Eighteen patients, all affected by nasal unilateral pterygia, were randomly selected from our patient database independently of sex, origin, or race. We included all primary or recurrent pterygia with signs of proliferation, dry eye, and induction of astigmatism. Pseudopterygia were excluded from this study. Pterygia were outlined and analyzed mathematically using a Cartesian coordinate system with two axes (X, Y) and five accurate landmarks of the pterygium.Results: In 13 patients (72%), the shape of the pterygia was hyperbolic and in five patients (28%), the shape was rather elliptical.Conclusion: This analysis gives a highly accurate mathematical description of the shape of human pterygia. This might help to better assess the clinical results and outcome of the great variety of therapeutic approaches concerning these lesions. Keywords: etiology, pterygium, limbal stem cells, stem cells dysfunction, mathematical shape analysis
