Abstract

Static and dynamic cyclotorsion measurement and evaluation of related factors in patients candidates for PRK

To evaluate the degree of static and dynamic cyclotorsion and related factors in patients candidate for photorefractive keratectomy. In this analytic-descriptive study, 400 patients (aged 18-55 years) who were candidates for photorefractive keratectomy with laser excimer (zyoptix 100 HZ) by a single ophthalmologist in Khatam-al-Anbia Hospital were enrolled. The patients' age, sex, myopic and astigmatism degrees and static and dynamic cyclotorsion degree were measured and registered. Finally, the data was analyzed statistically. 73% of patients (n=146) were female and the mean age of all patients was 29.8±5.7 years (19-49). The mean preoperative sphere and cylinder degree of patients was -3.24±1.72 and -1.06±1.04, respectively. The mean spheric equivalent (SE) was -3.78±1.69, the mean total static excyclotorsion and incyclotorsion were 3.81±2.65 (48.5%) and - 2.99±2.13 (27.8%), respectively and 23.8% had no static cyclotorsion. The mean dynamic excyclotorsion and incyclotorsion were 3.66±2.65 (65.8%) and -2.62±2.13 (27.5%), respectively, and 23% had no dynamic cyclotorsion. There was no significant relationship between static or dynamic cyclotorsion and age and no significant relationship between static cyclotorsion and sex, but women showed higher degrees of dynamic cyclotorsion (P=0.04). Also, sphere and cylinder degree had no significant relationship with cyclotorsion, however, there was a linear significant correlation between static and dynamic cyclotorsion (p=0.05). The amount of dynamic cyclotorsions during photorefractive keratectomy is higher in female and correlate straight with static cyclotorsions.

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