¡¡¡¡INTRODUCTION

¡¡¡¡Evaluation of corneal shape is an important aspect in the preoperative assessment of refractive surgery candidates. The Orbscan II system combines scanning slit with placido disc technology and has the capacity to provide detailed information regarding curvature and elevation of both anterior and posterior corneal surfaces, global thickness of the cornea[1], and anterior chamber depth[2]. With multiple measurement functions, the Orbscan system is a valuable screening tool to detect abnormal corneal shapes, such as keratoconus and contact lensª²induced corneal thinning[3ª²5]. To detect early abnormal changes in corneal morphologic features, a database of topography in normal human eyes is required to establish baseline indices. The purpose of this study was to analyze the corneal morphologic features of persons with hyperopia using the Orbscan II corneal topography.

¡¡¡¡MATERIALS AND METHODS

¡¡¡¡The Orbscan II corneal topographic maps of 295 eyes in consecutive subjects with hyperopia who enrolled preoperative assessment for LASIK were reviewed retrospectively. Subjects having any type of ocular pathologic features or surgery or a family history of keratoconus were not included in this study. All patients wearing contact lenses before LASIK assessment stopped contact lens wear for at least 2 weeks before examination. In our study, The Orbscan II (Bausch & Lomb, Claremont, CA) topographies were performed by one experienced examiner. Then all data, including demographic information, refraction, and quantitative data from each Orbscan II videokeratography, were entered into a database. One Orbscan II topography measurement from each eye was evaluated. All results were analyzed statistically using SPSS statistics software version 11.5 (SPSS Inc., Chicago, IL). Descriptive analyses including mean values and standard deviation (SD), Oneª²way ANOVA, Pearson correlation coefficient and confidence interval of 95% were performed. A P value of less than 0.05 was considered to be statistically significant.

¡¡¡¡RESULTS

¡¡¡¡In this study, 295 eyes (OS=147, OD=148) with hyperopia were analyzed. They were divided into three age groups; 17ª²29 years old (n=99,33.6%) 30ª² 44 years old (n=93,31.5%) and >45years old (n=103,34.9%). The total mean corneal thickness was 546.4¡À35.5¦Ìm. It was found 547.3¡À38.4¦Ìm in 17ª²29 years old, 553.4¡À38.3¦Ìm in 30ª² 44 years old and 546.2¡À29.3¦Ìm in older than 45 years old (Table 1). That differs significantly between age group of 17ª²29 years old and other age groups. The mean corneal thickness was found in female 551.5¡À35.9¦Ìm, and in male 542.6¡À34.7¦Ìm (Table 2).The mean depth of anterior chamber in 17ª²29 years old patients was 2.82¡À0.39mm, in 30ª² 44 years old patients was 2.49 ¡À 0.39mm and in patients more than 45 years old was 2.37¡À0.40mm (Table 3), the mean depth of anterior chamber was 2.5¡À0.40 in female and 2.6¡À0.40 in male. The depth of anterior chamber had only a mild difference between age groups of 30ª² 44 and patients more than 45 years old.                 
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¡¡¡¡Table 1The corneal thickness according to age£¨ÂÔ£©

¡¡¡¡Table 2The corneal thickness according to sex£¨ÂÔ£©

¡¡¡¡Table 3The anterior chamber depth according to age£¨ÂÔ£©

¡¡¡¡The total mean keratometry was 43.91¡À1.90D. The mean keratometry was 43.61¡À1.70D in 17ª²29 years old patients, 43.45¡À1.80D in age group of 30ª² 44 years old and 44.68¡À1.90D in group more than 45 years old. Mean keratometry results of patients was 43.69 to 44.13 and its comparison between two age groups of 17ª²29 and 30ª² 44 years old showed significant F=0.554, P=0.01.This significance wasn¬ðt been found between other age groups.

ÉÏÒ»Ò³  [1] [2] [3] [4] ÏÂÒ»Ò³