Riboflavin-Ultraviolet A Corneal Cross-linking for Keratoconus.
OBJECTIVE
To evaluate the safety, efficacy of riboflavin-ultraviolet A irradiation (UVA) corneal cross-linking and present refractive changes induced by the treatment in cases of keratoconus.


METHODS
The study includes 15 eyes of 9 patients with keratoconus with an average keratometric (K) reading less than 54 D and minimal corneal thickness greater than 420 microns. The corneal epithelium was removed manually within the central 8.5 mm diameter area and the cornea was soaked with riboflavin eye drops (0.1% in 20% dextran tau-500) for 30 minutes followed by exposure to UVA radiation (365 nm, 3 mW/cm(2)) for 30 minutes. During the follow-up period, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, slit lamp examination and topographic changes were recorded at the first week, first month, 3 and 6 months.


RESULTS
There was statistically significant improvement of UCVA from a preoperative mean of 0.11 +/- 0.07 (range 0.05-0.3) to a postoperative mean of 0.15 +/- 0.06 (range 0.1-0.3) (P < 0.05). None of the eyes lost lines of preoperative UCVA but 1 eye lost 1 line of preoperative BSCVA. The preoperative mean K of 49.97 +/- 2.81 D (range 47.20-51.75) changed to 48.34 +/- 2.64 D (range 45.75-50.40). This decrease in K readings was statistically significant (P < 0.05). All eyes developed minimal faint stromal haze that cleared in 14 eyes within 1 month. In only 1 eye, this resulted in a very faint corneal scar. Other sight threatening complications were not encountered in this series. Progression of the original disease was not seen in any of the treated eyes within 6 months of follow-up.


CONCLUSIONS
Riboflavin-UVA corneal cross-linking is a safe and promising method for keratoconus. Larger studies with longer follow up are recommended.
El-Raggal
Tamer M
TM
Department of Ophthalmology - Ain Shams University - Cairo, Egypt.
Invest Ophthalmol Vis Sci. 1998 Feb;39(2):220-6
9477978
Cornea. 1997 May;16(3):345-51
9143810
Am J Ophthalmol. 2003 May;135(5):620-7
12719068
J Cataract Refract Surg. 2003 Sep;29(9):1780-5
14522301
Cornea. 2002 Mar;21(2):206-9
11862097
Curr Eye Res. 1997 Aug;16(8):792-801
9255508
J Cataract Refract Surg. 2006 May;32(5):837-45
16765803
Cornea. 1992 Nov;11(6):553-9
1468218
J Cataract Refract Surg. 2003 Sep;29(9):1786-90
14522302
Surv Ophthalmol. 1998 Jan-Feb;42(4):297-319
9493273
Ophthalmic Res. 1998;30(5):327-32
9704337
Invest Ophthalmol Vis Sci. 1998 Mar;39(3):644-8
9501878
J Refract Surg. 1999 Nov-Dec;15(6):711-3
10590015
Curr Opin Ophthalmol. 2006 Aug;17(4):356-60
16900027
Curr Eye Res. 2001 May;22(5):333-40
11600933