Journal of Refractive Surgery

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Original Article 

Contralateral Eye Study of Corneal Collagen Cross-linking With Riboflavin and UVA Irradiation in Patients With Keratoconus

Mirko R. Jankov II, MD, PhD; Efekan Coskunseven, MD; Farhad Hafezi, MD, PhD

Abstract

PURPOSE

To assess the progression of keratoconus in patients treated with collagen cross-linking with riboflavin and ultraviolet A (UVA) irradiation.

METHODS

Thirty-eight eyes of 19 patients with progressive keratoconus were enrolled in a prospective comparative study. Average follow-up was 9±2 months (range: 5 to 12 months). The worse eye was treated with collagen cross-linking, and the fellow eye served as the control. Corneal epithelium was mechanically removed. Riboflavin 0.1% solution in dextran T-500 20% solution was applied every 2 to 3 minutes for 30 minutes throughout the irradiation. Ultraviolet A irradiation (370 nm) was performed using a commercially available UVA lamp for 30 minutes.

RESULTS

The group treated with collagen cross-linking demonstrated a mean decrease (less myopic) in spherical equivalent refraction and cylinder of 1.03±2.22 diopters (D) (range: -5.25 to +3.75 D) and 1.04±1.44 D (range: -2.00 to +4.00 D), respectively ( P<.01), and an increase in uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA) of 0.06 ± 0.05 (range: 0.00 to 0.20) and 0.10±0.14 (range: -0.10 to 0.34), respectively ( P<.01). The maximal curvature decreased by 1.57±1.14 D (range: 0.00 to 3.90 D), and intraocular pressure increased by 2±2 mmHg (range: -1 to 6 mmHg), which was statistically significant. No statistical difference was noted regarding central corneal thickness (P=.06) and endothelial cell count (P=.07). The untreated group showed no statistical difference for any of the clinical parameters, apart from UCVA and BSCVA, which decreased by 0.08±0.12 (range: -0.40 to 0.10) and 0.06±0.09 (range: -0.20 to 0.10), respectively (P<.01).

CONCLUSIONS

Riboflavin/UVA collagen cross-linking appears to be efficacious in inhibiting the progression of keratoconus by reducing the corneal curvature, spherical equivalent refraction, and refractive cylinder in eyes with progressive keratoconus at average 9-month follow-up. [J Refract Surg. 2009;25:371-376.]

AUTHORS

From Dunya Eye Hospital, Istanbul, Turkey (Coskunseven); LaserFocus - Centre for Eye Mircosurgery and Milos Eye Hospital, Medical Academy – US Medical School, Belgrade, Serbia (Jankov); and IROC, Institute for Refractive and Ophthalmic Surgery, Zurich, Switzerland (Hafezi).

Dr Jankov is a clinical consultant for WaveLight Laser Technologie AG, Erlangen, Germany. The remaining authors have no proprietary interest in the materials presented herein.

Correspondence: Mirko R. Jankov II, MD, PhD, Centre for Eye Microsurgery, Cara Nikolaja II #25, 11000 Belgrade, Serbia. Tel/Fax: 381 11 344 6626; E-mail: visioncare@mac.com

Received: September 2, 2007; Accepted: May 8, 2008

Posted online: June 30, 2008

Abstract

PURPOSE

To assess the progression of keratoconus in patients treated with collagen cross-linking with riboflavin and ultraviolet A (UVA) irradiation.

METHODS

Thirty-eight eyes of 19 patients with progressive keratoconus were enrolled in a prospective comparative study. Average follow-up was 9±2 months (range: 5 to 12 months). The worse eye was treated with collagen cross-linking, and the fellow eye served as the control. Corneal epithelium was mechanically removed. Riboflavin 0.1% solution in dextran T-500 20% solution was applied every 2 to 3 minutes for 30 minutes throughout the irradiation. Ultraviolet A irradiation (370 nm) was performed using a commercially available UVA lamp for 30 minutes.

RESULTS

The group treated with collagen cross-linking demonstrated a mean decrease (less myopic) in spherical equivalent refraction and cylinder of 1.03±2.22 diopters (D) (range: -5.25 to +3.75 D) and 1.04±1.44 D (range: -2.00 to +4.00 D), respectively ( P<.01), and an increase in uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA) of 0.06 ± 0.05 (range: 0.00 to 0.20) and 0.10±0.14 (range: -0.10 to 0.34), respectively ( P<.01). The maximal curvature decreased by 1.57±1.14 D (range: 0.00 to 3.90 D), and intraocular pressure increased by 2±2 mmHg (range: -1 to 6 mmHg), which was statistically significant. No statistical difference was noted regarding central corneal thickness (P=.06) and endothelial cell count (P=.07). The untreated group showed no statistical difference for any of the clinical parameters, apart from UCVA and BSCVA, which decreased by 0.08±0.12 (range: -0.40 to 0.10) and 0.06±0.09 (range: -0.20 to 0.10), respectively (P<.01).

CONCLUSIONS

Riboflavin/UVA collagen cross-linking appears to be efficacious in inhibiting the progression of keratoconus by reducing the corneal curvature, spherical equivalent refraction, and refractive cylinder in eyes with progressive keratoconus at average 9-month follow-up. [J Refract Surg. 2009;25:371-376.]

AUTHORS

From Dunya Eye Hospital, Istanbul, Turkey (Coskunseven); LaserFocus - Centre for Eye Mircosurgery and Milos Eye Hospital, Medical Academy – US Medical School, Belgrade, Serbia (Jankov); and IROC, Institute for Refractive and Ophthalmic Surgery, Zurich, Switzerland (Hafezi).

Dr Jankov is a clinical consultant for WaveLight Laser Technologie AG, Erlangen, Germany. The remaining authors have no proprietary interest in the materials presented herein.

Correspondence: Mirko R. Jankov II, MD, PhD, Centre for Eye Microsurgery, Cara Nikolaja II #25, 11000 Belgrade, Serbia. Tel/Fax: 381 11 344 6626; E-mail: visioncare@mac.com

Received: September 2, 2007; Accepted: May 8, 2008

Posted online: June 30, 2008

10.3928/1081597X-20090401-02

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