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مقاله
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Abstract
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Title:
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Enantiomorphism and rule similarity in the astigmatism axes of fellow eyes
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Author(s):
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Hassan Hashemi, Amir Asharlous, Abbasali Yekta, Payam Nabovati, Masumeh Mohebi, Mehdi Khabazkhoob
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Presentation Type:
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Poster
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Subject:
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Cornea and Anterior Segment
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Others:
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Presenting Author:
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Name:
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Mehdi Khabaz khob
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Affiliation :(optional)
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Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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E mail:
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khabazkhoob@yahoo.com
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Phone:
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Mobile:
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09120250544
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Purpose:
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To evaluate the relationship patterns between astigmatism axes of fellow eyes (rule similarity and symmetry) and to determine the prevalence of each pattern in the studied population.
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Methods:
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This population-based study was conducted in 2015 in Iran. All participants had tests for visual acuity, objective refraction, subjective refraction (if cooperative), and assessment of eye health at the slit-lamp. Axis symmetry was based on two different patterns: direct (equal axes) and mirror (mirror image symmetry) or enantiomorphism. Bilateral astigmatism was classified as isorule if fellow eyes had the same orientation (e.g. both eyes were with-the-rule) and as anisorule if otherwise.
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Results:
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Of the total cases of bilateral astigmatism, 80% were isorule, and in the studied population, the prevalence of isorule and anisorule astigmatism was 14.89% and 3.53%, respectively. No significant inter-gender difference was observed in the prevalence of isorule (p=0.479) or anisorule (p=0.617) astigmatism. The prevalence of isorule increased with age (p<0.001). The prevalence of both isorule and anisorule increased at higher degrees of spherical ametropia (p<0.001). Median inter-ocular axis difference was 10 degrees in mirror symmetry and 20 degrees in direct symmetry with no significant difference between two genders (p>0.288). Both symmetry patterns reduced with age (p<0.001). Among cases of bilateral astigmatism, 15.5% and 19.8 % had exact direct and mirror symmetry, respectively. Exact symmetry within 15 degrees was observed in 43.4% of cases of direct symmetry and 68.3% of those with mirror symmetry.
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Conclusion:
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The majority of bilateral astigmatism in the population is isorule while anisorule astigmatism is rare. The relation pattern between the axes of fellow eyes tends to be more mirror symmetry than direct symmetry, and enantiomorphism is the most common pattern in a population of bilateral astigmatism.
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Attachment:
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184poster1.pptx
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