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:: Volume 24, Issue 3 (Iranian Journal of Ophthalmology 2012) ::
2012, 24(3): 52-56 Back to browse issues page
Induced Secondary Astigmatism and Horizontal Coma after LASIK for Mixed Astigmatism
S-Farzad Mohammadi Dr., Maryam Tahvildari Dr., Tahereh Abdolahinia *
, tabdolahinia@gmail.com
Abstract:   (7922 Views)

Purpose : To describe a distinctive pattern of induced higher order aberration (HOA) after LASIK for mixed astigmatism

Case reports : Wavefront-guided LASIK with iris recognition and eye tracking (Excimer laser: Technolas 217z APT protocol Microkeratome: Moria CB) was performed in six eyes with moderate to high mixed astigmatism for a nominal optical zone of 6.3 mm. The patients were re-examined beyond 9 months postoperatively.

Results : Postoperative uncorrected distance visual acuities (UDVA) equaled preoperative corrected distance visual acuities (CDVA). The cycloplegic cylinder increased an average of about 2.50 D compared with dry retinoscopy. Significant increases in HOAs were detected with pupils dilated, specially in the amounts of secondary astigmatism (mean change=0.41 µm) and horizontal coma (HC) (mean change=0.29 µm). Large kappa angles were detected in all of the eyes studied (mean=7.45̊).

Conclusion : The bitoric ablation profile of mixed astigmatism LASIK may induce significant secondary astigmatism which causes a remarkable disparity between dry and wet refraction and manifests as an unusual skiascopic reflex during wet retinoscopy. A large kappa angle may cause tilted ablation and induce HC.

  

Iranian Journal of Ophthalmology 201224(3):52-56 © 2012 by the Iranian Society of Ophthalmology
Keywords: Mixed Astigmatism LASIK, Ablation Profile (Bitoric Photoablation), (Induced) Higher Order Aberration, Skiascopic Reflex, Secondary Astigmatism, Horizontal Coma, Kappa Angle
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Type of Study: Original | Subject: Anterior segment
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Mohammadi S, Tahvildari M, Abdolahinia T. Induced Secondary Astigmatism and Horizontal Coma after LASIK for Mixed Astigmatism. Iranian Journal of Ophthalmology. 2012; 24 (3) :52-56
URL: http://irjo.org/article-1-703-en.html


Volume 24, Issue 3 (Iranian Journal of Ophthalmology 2012) Back to browse issues page
مجله چشم پزشکی ایران Iranian Journal of Ophthalmology
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