Corneal healing after riboflavin ultraviolet-A collagen cross-linking determined by confocal laser scanning microscopy in vivo: early and late modifications.
OBJECTIVE
To assess early and late micromorphological modifications of cross-linked corneas in vivo by means of Heidelberg Retinal Tomography (HRT) II confocal microscopy.


METHODS
Prospective nonrandomized open trial.


METHODS
Micromorphological examination of 44 cross-linked keratoconic corneas was performed in vivo by HRT II confocal laser scanning microscopy. Riboflavin ultraviolet (UV)-A-induced corneal collagen cross-linking (CXL) was performed according to the Siena protocol: pilocarpin 1% drops 30 minutes before, topical anesthesia with lidocaine 4% drops 15 minutes before irradiation, mechanical scraping of epithelium (9-mm-diameter area), preirradiation soaking for 10 minutes in riboflavin solution 0.1% (Ricrolin, Sooft, Italy) applied every 2.5 minutes for 30 minutes, 30 minutes exposure to solid-state UVA illuminator (Caporossi; Baiocchi; Mazzotta, X-linker, CSO, Italy), 8-mm-diameter irradiated area, energy delivered 3 mW/cm(2). All patients were examined by confocal scans preoperatively and at the following times after treatment: one, three, and six months, and one, two, and three years.


RESULTS
No damage to the limbal region was observed. Epithelial regrowth was complete after four days of soft contact lens bandage. The anatomy of the subepithelial plexus was restored one year after the operation with full corneal sensitivity. Increased density of extracellular matrix in late postoperative period indicated cross-linked collagen to a depth of 340 microm expressed by a late demarcation line.


CONCLUSIONS
In vivo confocal microscopy showed early and late modification of corneal microstructure after the treatment. The three-year stability of CXL recorded could be related to increased cross-links formation, synthesis of well-structured collagen and new lamellar interconnections.
Mazzotta
Cosimo
C
Department of Ophthalmology and Neurosurgery, Santa Maria delle Scotte Hospital, Siena University, Siena, Italy. cgmazzotta@libero.it
Traversi
Claudio
C
Baiocchi
Stefano
S
Caporossi
Orsola
O
Bovone
Cristina
C
Sparano
Maria Caterina
MC
Balestrazzi
Angelo
A
Caporossi
Aldo
A
D000328:Adult; D003094:Collagen / Q000378:metabolism*; D003319:Corneal Stroma / Q000294:innervation / Q000378:metabolism / Q000473:pathology* / Q000528:radiation effects; D019573:Epithelium, Corneal / Q000473:pathology; D006801:Humans; D007640:Keratoconus / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism; D016850:Limbus Corneae / Q000473:pathology; D018613:Microscopy, Confocal; D009412:Nerve Fibers / Q000473:pathology; D009882:Ophthalmic Nerve / Q000473:pathology; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D011446:Prospective Studies; D012256:Riboflavin / Q000627:therapeutic use*; D014466:Ultraviolet Rays; D014792:Visual Acuity; D014945:Wound Healing
D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin