Single-segment and double-segment INTACS for post-LASIK ectasia.

  • Hassan Hashemi Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran.
  • Ali Gholaminejad Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran.
  • Kazem Amanzadeh Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran.
  • Maryam Hashemi Department of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
  • Mehdi Khabazkhoob Department of Epidemiology, Faculty of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Keywords: INTACS ring, LASIK, Ectasia, Myopia

Abstract

The objective of the present study was to compare single segment and double segment INTACS rings in the treatment of post-LASIK ectasia. In this interventional study, 26 eyes with post-LASIK ectasia were assessed. Ectasia was defined as progressive myopia regardless of astigmatism, along with topographic evidence of inferior steepening of the cornea after LASIK. We excluded those with a history of intraocular surgery, certain eye conditions, and immune disorders, as well as monocular, pregnant and lactating patients. A total of 11 eyes had double ring and 15 eyes had single ring implantation. Visual and refractive outcomes were compared with preoperative values based on the number of implanted INTACS rings. Pre and postoperative spherical equivalent were -3.92 and -2.29 diopter (P=0.007). The spherical equivalent decreased by 1 ± 3.2 diopter in the single-segment group and 2.56 ± 1.58 diopter in the double-segment group (P=0.165). Mean preoperative astigmatism was 2.38 ± 1.93 diopter which decreased to 2.14 ± 1.1 diopter after surgery (P=0.508); 0.87 ± 1.98 diopter decrease in the single-segment group and 0.67 ± 1.2 diopter increase in the double-segment group (P=0.025). Nineteen patients (75%) gained one or two lines, and only three, who were all in the double-segment group, lost one or two lines of best corrected visual acuity. The spherical equivalent and vision significantly decreased in all patients. In these post-LASIK ectasia patients, the spherical equivalent was corrected better with two segments compared to single segment implantation; nonetheless, the level of astigmatism in the single-segment group was significantly better than that in the double-segment group.

References

Sharma M, Boxer Wachler BS. Comparison of singlesegment and double-segment Intacs for keratoconus and post-LASIK ectasia. Am J Ophthalmol 2006;141(5):891-5.

Binder PS, Lindstrom RL, Stulting RD, et al. Keratoconus and corneal ectasia after LASIK. J Cataract Refract Surg 2005;31(11):2035-2038.

Geggel HS, Talley AR. Delayed onset keratectasia following laser in situ keratomileusis. J Cataract Refract Surg 1999;25(4):582-6.

Amoils SP, Deist MB, Gous P, et al. Iatrogenic keratectasia after laser in situ keratomileusis for less than - 4.0 to -7.0 diopters of myopia. J Cataract Refract Surg 2000;26(7):967-77.

Randleman JB, Russell B, Ward MA, et al. Risk factors and prognosis for corneal ectasia after LASIK. Ophthalmology 2003;110(2):267-275.

Ertan A, Karacal H. Factors influencing flap and INTACS decentration after femtosecond laser application in normal and keratoconic eyes. J Refract Surg 2008;24(8):797-801.

Twa MD, Nichols JJ, Joslin CE, et al. Characteristics of corneal ectasia after LASIK for myopia. Cornea 2004;23(5):447-57.

Khan MI, Injarie A, Muhtaseb M. Intrastromal corneal ring segments for advanced keratoconus and cases with high keratometric asymmetry. J Cataract Refract Surg 2012;38(1):129-36.

Kubaloglu A, Sari ES, Cinar Y, et al. Intrastromal corneal ring segment implantation for the treatment of keratoconus. Cornea 2011;30(1):11-7.

Sansanayudh W, Bahar I, Kumar NL, et al. Intrastromal corneal ring segment SK implantation for moderate to severe keratoconus. J Cataract Refract Surg 2010;36(1):110-3.

Daxer A, Mahmoud H, Venkateswaran RS. Intracorneal continuous ring implantation for keratoconus: One-year follow-up. J Cataract Refract Surg 2010;36(8):1296-302.

Tunc Z, Helvacioglu F, Sencan S. Evaluation of intrastromal corneal ring segments for treatment of post-mLASIK ectasia patients with a mechanical implantation technique. Indian J Ophthalmol 2011;59(6):437-43.

Tomita M, Inoue N, Tsuru T. Treatment of keratoectasia after LASIK by intrastromal corneal ring segments in two patients who had no preoperative risk factors. Clin Ophthalmol 2010;4(7):785-791.

Pinero DP, Alio JL, Uceda-Montanes A, et al. Intracorneal ring segment implantation in corneas with post-laser in situ keratomileusis keratectasia. Ophthalmology 2009;116(9):1665-74.

Uceda-Montanes A, Tomas JD, Alio JL. Correction of severe ectasia after LASIK with intracorneal ring segments. J Refract Surg 2008;24(4):408-11.

Ramirez-Miranda A, Gomez-Bastar A, Navas A. Keratoconus correction using intrastromal corneal ring segments and posterior chamber phakic intraocular lens implantation. J Cataract Refract Surg 2011;37(7):1373-4.

Khan MI, Muhtaseb M. Intrastromal corneal ring segments for bilateral keratoconus in an 11-year-old boy. J Cataract Refract Surg 2011;37(1):201-5.

Kaya V, Utine CA, Karakus SH, et al. Refractive and visual outcomes after Intacs vs ferrara intrastromal corneal ring segment implantation for keratoconus: a comparative study. J Refract Surg 2011;27(12):907-12.

Alfonso JF, Lisa C, Fernandez-Vega L, Madrid-Costa D, et al. Intrastromal corneal ring segments and posterior chamber phakic intraocular lens implantation for keratoconus correction. J Cataract Refract Surg 2011;37(4):706-13.

Alio J, Salem T, Artola A, et al. Intracorneal rings to correct corneal ectasia after laser in situ keratomileusis. J Cataract Refract Surg 2002;28(9):1568-74.

Kymionis GD, Siganos CS, Kounis G, et al. Management of post-LASIK corneal ectasia with Intacs inserts: one-year results. Arch Ophthalmol 2003;121(3):322-6.

Alio JL, Artola A, Hassanein A, et al. One or 2 Intacs segments for the correction of keratoconus. J Cataract Refract Surg 2005;31(5):943-53.

Pokroy R, Levinger S, Hirsh A. Single Intacs segment for post-laser in situ keratomileusis keratectasia. J Cataract Refract Surg 2004;30(8):1685-95.

Abad JC, Arango J, Tobon C. Comparison of astigmatism correction using shorter arc length 90 degrees /120 degrees asymmetric intacs severe keratoconus versus 150 degrees single-segment intacs severe keratoconus in asymmetric keratoconus. Cornea 2011;30(11):1201-6.

Rabinowitz YS. Intacs for keratoconus. Curr Opin Ophthalmol 2007;18(4):279-83.

How to Cite
1.
Hashemi H, Gholaminejad A, Amanzadeh K, Hashemi M, Khabazkhoob M. Single-segment and double-segment INTACS for post-LASIK ectasia. Acta Med Iran. 52(9):681-686.
Section
Articles