Transepithelial corneal collagen cross-linking in keratoconus.
OBJECTIVE
To evaluate the clinical effects of transepithelial corneal cross-linking (CXL) on keratoconic eyes pre-treated with substances enhancing epithelial permeability.


METHODS
Prospective, consecutive, single-masked, paired-eye study on 51 patients. The eye with more severe keratoconus was treated; the fellow eye served as the control. Gentamicin, benzalkonium chloride, and ethylenediaminetetraacetic acid were instilled for 3 hours, then oxybuprocaine for 30 minutes. Riboflavin 0.1% in 20% dextran T500 and oxybuprocaine were instilled for 30 minutes. Finally, ultraviolet A irradiation to the central 7.5 mm of the cornea was applied for 30 minutes, while riboflavin was instilled every 5 minutes.


RESULTS
Mean corrected distance visual acuity improved by 0.036 logMAR after CXL and worsened by 0.039 logMAR in the control eyes (P<.05). Safety index was 1.05 after CXL and 0.96 in the control group. Mean spherical equivalent refraction decreased by 0.35 D (less myopic) after CXL and increased by 0.83 diopters (D) in the control eyes (P<.05). Mean apex curvature on tangential videokeratography increased by 0.51 D after CXL and by 1.61 D in the control eyes (P=.16). Mean average simulated keratometry decreased by 0.10 D after CXL and increased by 0.88 D in the control eyes (P<.05). Mean index of surface variance increased (worsened) by 0.9 after CXL and 5.3 in the control eyes (P<.05). Mean endothelial cell density was unchanged.


CONCLUSIONS
A limited but favorable effect of transepithelial CXL was noted on keratoconic eyes, without complications. The effect appears to be less pronounced than described in the literature after CXL with de-epithelialization.
Leccisotti
Antonio
A
School of Biomedical Sciences, University of Ulster, Coleraine, UK. leccisotti@libero.it
Islam
Tahmina
T
D000293:Adolescent; D000328:Adult; D001548:Benzalkonium Compounds / Q000008:administration & dosage; D002463:Cell Membrane Permeability / Q000187:drug effects; D003094:Collagen / Q000378:metabolism*; D003319:Corneal Stroma / Q000378:metabolism*; D019781:Corneal Topography; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D004492:Edetic Acid / Q000008:administration & dosage; D019573:Epithelium, Corneal / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D005839:Gentamicins / Q000008:administration & dosage; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy* / Q000378:metabolism; D008297:Male; D017319:Photosensitizing Agents / Q000627:therapeutic use; D011343:Procaine / Q000008:administration & dosage / Q000031:analogs & derivatives; D011446:Prospective Studies; D012256:Riboflavin / Q000627:therapeutic use; D016037:Single-Blind Method; D014466:Ultraviolet Rays; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
D001548:Benzalkonium Compounds; D003432:Cross-Linking Reagents; D005839:Gentamicins; D017319:Photosensitizing Agents; D011343:Procaine; D003094:Collagen; D004492:Edetic Acid; C005298:benoxinate; D012256:Riboflavin