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Influence of corneal collagen crosslinking with riboflavin and ultraviolet-a irradiation on excimer laser surgery.
Invest Ophthalmol Vis Sci. 2010 Aug; 51(8):3929-34.IO

Abstract

PURPOSE

Riboflavin/ultraviolet A (UVA) cross-linking (CXL) of corneal collagen is a novel method of stabilizing corneal mechanical properties and preventing progression of keratectasias. This study was conducted to investigate whether CXL influences ablation rate, flap thickness, and refractive results of excimer laser procedures ex vivo.

METHODS

Corneal epithelium was removed from enucleated porcine eyes, and CXL was performed with riboflavin 0.1% and UVA radiation (365 nm, 3 mW/cm(2)) for 30 minutes. Control eyes received epithelial abrasion only. Diffusion of riboflavin through the cornea was assessed by using infrared-excited, two-photon microscopy of riboflavin autofluorescence, combined with second-harmonic generation of fibrillar collagen. During phototherapeutic keratectomy, corneal thickness was measured by optical coherence pachymetry. During LASIK for myopia, the flap thickness of microkeratome cuts was measured and the induced refractive change assessed by Placido topography. Data were analyzed by Shapiro-Wilk test and Student's t-test.

RESULTS

Multiphoton imaging showed a rapid (30-minute) and even distribution of riboflavin throughout the corneal stroma. No difference in ablation rate was measured in treated and untreated corneas (P = 0.90). Mean flap thickness was increased by 44% in cross-linked corneas (P < 0.01). After LASIK for myopia of 4 to 25 D, the mean corneal refractive change was reduced in CXL-treated eyes by 20.1% (P < 0.05). This effect was less pronounced in thinner flaps.

CONCLUSIONS

CXL reduces the amount of refractive change after LASIK for myopia. Although the laser ablation rate is unaffected, CXL results in an increased flap thickness. This study suggests the need for adjustment of microkeratome and laser parameters for LASIK after CXL and indirectly endorses the theory of a direct stiffening effect of CXL.

Authors+Show Affiliations

Department of Ophthalmology, University of Würzburg, Würzburg, Germany.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

20207972

Citation

Kampik, Daniel, et al. "Influence of Corneal Collagen Crosslinking With Riboflavin and Ultraviolet-a Irradiation On Excimer Laser Surgery." Investigative Ophthalmology & Visual Science, vol. 51, no. 8, 2010, pp. 3929-34.
Kampik D, Ralla B, Keller S, et al. Influence of corneal collagen crosslinking with riboflavin and ultraviolet-a irradiation on excimer laser surgery. Invest Ophthalmol Vis Sci. 2010;51(8):3929-34.
Kampik, D., Ralla, B., Keller, S., Hirschberg, M., Friedl, P., & Geerling, G. (2010). Influence of corneal collagen crosslinking with riboflavin and ultraviolet-a irradiation on excimer laser surgery. Investigative Ophthalmology & Visual Science, 51(8), 3929-34. https://doi.org/10.1167/iovs.09-4524
Kampik D, et al. Influence of Corneal Collagen Crosslinking With Riboflavin and Ultraviolet-a Irradiation On Excimer Laser Surgery. Invest Ophthalmol Vis Sci. 2010;51(8):3929-34. PubMed PMID: 20207972.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Influence of corneal collagen crosslinking with riboflavin and ultraviolet-a irradiation on excimer laser surgery. AU - Kampik,Daniel, AU - Ralla,Bernhard, AU - Keller,Sabine, AU - Hirschberg,Markus, AU - Friedl,Peter, AU - Geerling,Gerd, Y1 - 2010/03/05/ PY - 2010/3/9/entrez PY - 2010/3/9/pubmed PY - 2010/8/21/medline SP - 3929 EP - 34 JF - Investigative ophthalmology & visual science JO - Invest Ophthalmol Vis Sci VL - 51 IS - 8 N2 - PURPOSE: Riboflavin/ultraviolet A (UVA) cross-linking (CXL) of corneal collagen is a novel method of stabilizing corneal mechanical properties and preventing progression of keratectasias. This study was conducted to investigate whether CXL influences ablation rate, flap thickness, and refractive results of excimer laser procedures ex vivo. METHODS: Corneal epithelium was removed from enucleated porcine eyes, and CXL was performed with riboflavin 0.1% and UVA radiation (365 nm, 3 mW/cm(2)) for 30 minutes. Control eyes received epithelial abrasion only. Diffusion of riboflavin through the cornea was assessed by using infrared-excited, two-photon microscopy of riboflavin autofluorescence, combined with second-harmonic generation of fibrillar collagen. During phototherapeutic keratectomy, corneal thickness was measured by optical coherence pachymetry. During LASIK for myopia, the flap thickness of microkeratome cuts was measured and the induced refractive change assessed by Placido topography. Data were analyzed by Shapiro-Wilk test and Student's t-test. RESULTS: Multiphoton imaging showed a rapid (30-minute) and even distribution of riboflavin throughout the corneal stroma. No difference in ablation rate was measured in treated and untreated corneas (P = 0.90). Mean flap thickness was increased by 44% in cross-linked corneas (P < 0.01). After LASIK for myopia of 4 to 25 D, the mean corneal refractive change was reduced in CXL-treated eyes by 20.1% (P < 0.05). This effect was less pronounced in thinner flaps. CONCLUSIONS: CXL reduces the amount of refractive change after LASIK for myopia. Although the laser ablation rate is unaffected, CXL results in an increased flap thickness. This study suggests the need for adjustment of microkeratome and laser parameters for LASIK after CXL and indirectly endorses the theory of a direct stiffening effect of CXL. SN - 1552-5783 UR - https://www.unboundmedicine.com/medline/citation/20207972/Influence_of_corneal_collagen_crosslinking_with_riboflavin_and_ultraviolet_a_irradiation_on_excimer_laser_surgery_ L2 - https://iovs.arvojournals.org/article.aspx?doi=10.1167/iovs.09-4524 DB - PRIME DP - Unbound Medicine ER -