Long-term follow-up results of corneal collagen cross-linking in keratoconus

Abstract

Objective: To evaluate the changes in corneal parameters (keratometry, corneal thickness, topography indices) after corneal collagen cross-linking in keratoconus.

Methods: The medical records of 6 patients who underwent corneal collagen cross-linking treatment for keratoconus and have been followed-up for a minimum of 24 months were recruited. Best corrected visual acuity (BCVA), maximum keratometry (Kmax), central corneal thickness (CCT) values and corneal topography indices: index of surface variance (ISV), index of vertical asymmetry (IVA), keratoconus index (KI), central keratoconus index (CKI), minimum radius of curvature (Rmin), index of height asymmetry (IHA), and index of height decentralisation (IHD) were recorded.

Results: The mean preoperative Kmax value was 46.67±4.15 (43.30-57.10) D and the mean Kmax value at the final postoperative visit was 45.41±2.95 (43.00-53.20) D. Mean preoperative CCT was 494.70±33.69 (438-537) µm and final postoperative mean CCT was 495.60±34.99 (433-539) µm. The deterioration in corneal topography indices stopped during the follow-up period of each case.

Conclusion: Stopping the deterioration of corneal parameters in keratoconus is the desired outcome after cross-linking treatment. Our results found an improvement or at least stabilization in all topography indices in keratoconus patients. J Clin Exp Invest 2015; 6 (4): 343-350

Key words: Keratoconus, corneal collagen cross-linking, corneal topography

Keywords

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Keratokonusta korneal kollajen çapraz-bağlama tedavisinin uzun dönem sonuçları

Öz

Amaç: Keratokonusta kornea kollajen çapraz bağlama sonrası kornea parametreleri (keratometre, kornea kalınlığı, topografi indeksleri) değişikliklerini değerlendirmek.Yöntemler: Keratokonus için korneal kollajen çapraz bağlama tedavisi uygulanan ve en az 24 ay takip edilen 6 hastanın tıbbi kayıtları çalışmaya alındı. En iyi düzeltilmiş görme keskinliği (EİDGK), maksimum keratometri (Kmax), santral kornea kalınlığı (SKK) ve korneal topografi indeksleri: Yüzey Varyans indeksi (ISV), dikey asimetri indeksi (IVA), keratokonus indeksi (Kİ), merkez keratokonus indeksi (CKI), minimum eğrilik yarıçapı (Rmin), yükseklik asimetrisi indeksi (IHA) ve yükseklik desantralizasyon indeksi (İHD) kaydedildi.Bulgular: Ameliyat öncesi Kmax değeri 46,67±4,15 (43.30-57.10) D ve ameliyat sonrası nihai ziyarette ortalama Kmax değeri 45.41±2.95 (43.00-53.20) D. Preoperatif SKK 494,70±33,69 µm idi ve nihai postoperatif ortalama SKK 495,60±34,99 µm idi. Her vakada korneal topografi indekslerindeki bozulma takip süresi boyunca durdu.Sonuç: Keratokonusta kornea parametrelerinin bozulmasını durdurmak çapraz bağlama tedavisinden sonra arzu edilen sonuçtur. Bizim çalışmamızın sonucunda keratokonus hastalarının tüm topografi indekslerinde iyileşme veya en azından stabilite saptanmıştır

Anahtar Kelimeler

• Keratokonus, korneal kollajen çapraz bağlama, kornea topografisi

References

1. Cingu AK, Bez Y, Cinar Y, et al. Impact of collagen cross-linking on psychological distress and vision and health-related quality of life in patients with keratoconus. Eye Contact Lens 2015;41:349-353.
2. Wollensak G. Crosslinking treatment of progressive keratoconus: new hope. Curr Opin Ophthalmol 2006;17:356-360.
3. Arbelaez MC, Sekito MB, Vidal C, Choudhury SA. Collagen
4. cross-linking with riboflavin and ultraviolet-A light in keratoconus: one-year results. Oman J Ophthalmol 2009;2:33-38.
5. Wollensak G, Spoerl E, Reber F, Seiler T. Keratocyte cytotoxicity of riboflavin/UV-A treatment in vitro. Eye 2004;18:718-722.
6. Cingü AK1, Sogutlu-Sari E, Cınar Y, et al. Transient corneal endothelial changes following accelerated collagen cross-linking for the treatment of progressive keratoconus. Cutan Ocul Toxicol 2014;33:127-131.
7. Raiskup-Wolf F, Hoyer A, Spoerl E, Pillunat LE. Collagen crosslinking with riboflavin and ultraviolet-A light in keratoconus: long-term results. J Cataract Refract Surg 2008;34:795-801.
8. Greenstein SA, Fry KL, Hersh PS. Corneal topography indices after corneal collagen crosslinking for keratconus and corneal ectasia: one-year results. J Cataract Refract Surg 2011;37:1282-1290.

9. Hassan Z, Szalai E, Modis L, et al. Assessment of corneal
10. topography indices after collagen crosslinking for keratoconus. Eur J Ophthalmol 2013;23:635-640.
11. WaveLight GmbH. WaveLight® Allegro OculyzerTM 1074 User Manual (English). Erlangen: WaveLight GmbH; 2001.
12. Wollensak G, Spoerl E, Seiler T. Riboflavin/ultravioleta-induced
13. collagen crosslinking for the treatment of keratoconus. Am J Ophthalmol 2003;135:620-627.
14. Spoerl E, Wollensak G, Seiler T. Increased resistance of cross-linked cornea against enzymatic digestion. Curr Eye Res 2004;29:35-40.
15. Wollensak G, Spoerl E, Seiler T. Stress-strain measurements
16. of human and porcine corneas after riboflavin- ultraviolet-A-induced cross-linking. J Cataract Refract Surg 2003;29:1780-1785.
17. Rabinowitz YS. Keratoconus. Surv Ophthalmol 1998;42:297-319.
18. Poli M, Cornut PL, Balmitgere T, et al. Prospective study of corneal collagen cross-linking efficacy and tolerance in the treatment of keratoconus and corneal ectasia: 3-year results. Cornea 2013;32:583-590.
19. Hashemi H, Seyedian MA, Miraftab M, et al. Corneal collagen cross-linking with riboflavin and ultraviolet a irradiation for keratoconus: long-term results. Ophthalmology 2013;120:1515-1520.
20. Caporossi A, Baiocchi S, Mazzotta C, et al. Parasurgical therapy for keratoconus by riboflavin-ultraviolet type A rays induced cross-linking of corneal collagen: preliminary refractive results in an Italian study. J Cataract Refract Surg 2006;32:837-845.
21. Viswanathan D, Males J. Prospective longitudinal study of corneal collagen cross-linking in progressive keratoconus. Clin Experiment Ophthalmol 2013;41:531-536.
22. Wittig-Silva C, Chan E, Islam FM, et al. A randomized,controlled trial of corneal collagen cross-linking in progressive keratoconus: three-year results. Ophthalmology 2014;121:812-821.
23. Cinar Y, Cingu AK, Turkcu FM, et al. Accelerated corneal collagen cross-linking for progressive keratoconus. Cutan Ocul Toxicol. 2014;33:168-171.
24. Cinar Y, Cingu AK, Turkcu FM, et al. Comparison of accelerated and conventional corneal collagen crosslinking for progressive keratoconus. Cutan Ocul Toxicol 2014;33:218-222.
25. Toprak I, Yaylalı V, Yildirim C. Factors affecting outcomes of corneal collagen crosslinking treatment. Eye 2014;28:41-46.
26. Caporossi A, Mazzotta C, Baiocchi S, Caporossi T.Long- term results of riboflavin ultraviolet A corneal collagen cross- linking for keratoconus in Italy: the Siena Eye Cross Study. Am J Ophthalmol 2010;149:585–593.
27. Greenstein SA, Shah VP, Fry KL, Hersh PS. Corneal thickness changes after corneal collagen crosslinking for keratoconus and corneal ectasia: one-year results. J Cataract Refract Surg 2011;37:691-700.
28. Vinciguerra P, Camesasca FI, Albe E, Trazza S. Corneal collagen cross-linking for ectasia after excimer laser refractive surgery: 1-year results. J Refract Surg 2010;26:486–497.
29. Cınar Y, Cingü AK, Sahin A, et al. Intraoperative corneal thickness measurements during corneal collagen cross-linking with isotonic riboflavin solution without dextran in corneal ectasia. Cutan Ocul Toxicol 2014;33:28-31.
30. Sloot F, Soeters N, van der Valk R, Tahzib NG. Effective corneal collagen crosslinking in advanced cases of progressive keratoconus. J Cataract Refract Surg 2013;39:1141-1145.
31. Toprak I, Yildirim C. Effects of corneal collagen crosslinking on corneal topographic indices in patients with keratoconus. Eye Contact Lens 2013;39: 385-387.