[ study of the severity of keratoconus in optometric clinic's patients of Mashhad University of medical sciences]

Keratoconus is characterized by thinning and steepening of the central cornea. This study was undertaken to determine the severity of this disease and its relation with age and gender. In a cross sectional study, the data are reviewed from 1485 keratoconic eyes examined at the optometric's clinic of Mashhad University of Medical sciences from 1991 to 2005. The criteria for diagnosis of keratoconus were: Irregular corneal astigmatism, scissors retinoscopy reflex, Vogt's striae, Fleischer's ring or central corneal power higher than 47.2 D. The disease severity based on the central keratometry reading classified into mild, moderate, advanced and severe. SPSS software was used for data analyzes. The patient's mean age in this study was 25.33 +/- 8.39 years. From 1485 eyes, 73.1, 20.7, 5.9 and 0.3 percent had mild, moderate, advanced and severe keratoconus respectively. The highest prevalence of this disease was in 20-29 years [49.02 percent] and the lowest was related to over 40 years of age [6.4 percent]. The prevalence of keratoconus in females was higher than males [P< 0.001]. The majority of patients in this study had mild keratoconus and were in 20-29 years and it's prevalence in females were higher than males

study of the changes in refractive errors of the Participant's students in entrance exam of universities in Mashhad

Some studies reported the relationship between near- work activity and progression of myopia. The objective of this study is to investigate a longitudinal changes in refractive errors of the participant's student in entrance exam of the universities [EEU] in educational zones of Mashhad. In this study, 49 students in the final year of high school were randomly chosen and followed longitudinally study using standard objective and subjective refraction methods. Their refractive errors were determined in two succeeding visits; first: before the EEU [October] and second: after EEU [August of the following year]. The data were then statistically analyzed by SPSS. From 49 students [20 boys and 29 girls] the results of this study indicate that after EEU, the amount of myopia [spherical equivalent] increases from-0.088 to-0.357 dioptres [P=0.001] in boys and from -0.085 to-0.365 dioptres in girls [P=0,008]. Amount and type of astigmatism did not change significantly in boys and girls after EEU. These results support the idea that longtime reading and intensive near vision working in short distance relates with increasng the amount of myopia, but it does not correlate with the amount and type of astigmatism