Evaluation of depth perception and heterophoria among laboratory sciences students in Mashhad, 2011

Normal stereopsis as the highest level of binocular vision is required for most of clinical works such as working with microscope and some jobs, like piloting and surgery. The aim of this study was to evaluate, depth perception and hetrophoria in Mashhad laboratory sciences students in 2011. In this cross sectional study from 153 Mashhad laboratory sciences students, 42 subjects were selected randomly. Eye examinations including subjective and objective refraction and measurement of hetrophoria by cover test and prism bar were performed. The stereopsis was then determined with the T.N.O stereo test at 40 distance observation. Data were analyzed using SPSS version 11.5 software. Patients with amblyopia, cataract, and other ocular pathology were excluded from the study. Mean stereoacuity of the subjects was 147/14 129/76. Among this population, 14 subjects (%33.3) used microscope monocularly and 28 subjects (% 66.7) used it bionocularly. There was no significant difference between mean stereopsis and hetrophoria and other relative effective factors such as refractive error, way of using microscope, near point of convergence age and sex (p>0.05). Comparison between mean monocular and binocular stereopsis was not significant (p>0.05). There was no statictically significant difference between mean stereopsis and hetrophoria and other relative factors. However due to working too much with microscope, most of the laboratory sciences students had anomaly of binocular vision like intermittent exotropia and abnormal near point of convergence. This indicates the necessity of more research in anomaly of binocular vision in laboratory sciences students.