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Comparison of single-segment and double-segment Intacs® insertion with femtosecond laser for keratoconus. Tiep KHUC, Marc DOAT, Jean-Louis BOURGES, Nicolas ALFONSI, Jean-Marc LEGEAIS, Gilles RENARD Hôtel-Dieu Hospital, Paris, France Authors have no financial interest. Purpose.
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Comparison of single-segment and double-segment Intacs® insertion with femtosecond laser for keratoconus Tiep KHUC, Marc DOAT, Jean-Louis BOURGES, Nicolas ALFONSI, Jean-Marc LEGEAIS, Gilles RENARD Hôtel-Dieu Hospital, Paris, France Authors have no financial interest
Purpose To evaluate the efficacy of single-segment Intacs® using the femtosecond laser (IntraLase®, AMO) for insertion and compare with double-segment Intacs® in subjects with keratoconus
Methods (1/2) • Setting: Hôtel-Dieu, Paris, France • Prospective study • 66 eyes of 59 patients classified into two groups - single-segment group: 38 eyes, 35 patients - double-segment group: 28 eyes, 26 patients • Both groups matched by t test
Methods (2/2) • Implantation procedure Femtosecond IntraLase® FS 2 laser (60 kHz) (IntraLase Corp.) • Parameters - dissection’s depth in the cornea was 80% of the central pachymetry (300 – 400 µ) - channel dissection size: 6.6 x 7.6 mm • Main outcome measure: improvement of visual acuity, refractive error, K values • Follow-up: 6 months • Single or double-segment Intacs® implanted according to keratoconus asymetry and spherical equivalent (SE)
Global results p < 0.05 for each variable.
Single-segment results p < 0.05 for each variable. Improvement of UCVA for 34 eyes (89%).
Double-segment results p < 0.05 for each variable, except cylinder (p=0.18). Improvement of UCVA for 21 eyes (75%).
Comparison double vs single-segment Only 1 eye experienced loss of BSCVA in the single-segment group, versus 5 eyes in the double-segment group.
Complications • No peroperative complication • 8 Intacs® (7.6%) were removed from 5 eyes because of partial extrusion
Discussion (1/2) • Safe and efficient; improvement of UCVA+++ • Trend towards improved outcomes with single-segment Intacs® (more important reshaping of the cornea) • Results consistent with existent data (Sharma, 2005) • Cases of loss of vision may be attributed to an induced irregular astigmatism
Discussion (2/2) Double-segment (preop/postop/differential) Superior and inferior flattening Superior steepening Single-segment (preop/postop/differential) Inferior flattening
Conclusion • Intacs® implantation using IntraLase® FS 2 was safe and effective for treating keratoconus • Better results were achieved with single-segment Intacs® • Colin J, Cochener B, Savary G, Malet F, Holmes-Higgin D. INTACS inserts for treating keratoconus: one-year results. Ophthalmology 2001;108:1409-1414. • Siganos CS, Kymionis GD, Kartakis N, Theodorakis MA, Astyrakakis N, Pallikaris IG. Management of keratoconus with Intacs. Am J Ophthalmol 2003;135:64-70. • Alio JL, Artola A, Hassanein A, Haroun H, Galal A. One or 2 Intacs segments for the correction of keratoconus. J Cataract Refract Surg 2005;31:943-953. • Sharma M, Boxer Wachler BS. Comparison of single-segment and double-segment Intacs for keratoconus and post-LASIK ectasia. Am J Ophthalmol 2006;141:891-895. • Ertan A, Kamburoglu G. Intacs implantation using a femtosecond laser for management of keratoconus: Comparison of 306 cases in different stages. J Cataract Refract Surg 2008;34:1521-1526.