title: Can possible toxic effect of ultraviolet-A after corneal cross-linking be prevented? In vitro transmittance study of contact lenses at 370 nm wavelength.
abstract: BACKGROUND
  Corneal collagen cross linking (CCL) with ultraviolet A (UVA) has been proposed as a treatment for the progression of corneal ectasia associated with keratoconus and post-laser-assisted in situ keratomileusis (LASIK) ectasia. Despite the reports about safety of procedure, we consider that UVA of sunlight can effect riboflavin saturated and de-epitelizated cornea early after CCL.
  
  
  OBJECTIVE
  To evaluate the UVA blockage capability of 11 different silicone hydrogel contact lenses which are widely used after CCL treatment.
  
  
  METHODS
  Eleven different silicone hydrogel and daily disposable contact lenses were evaluated. The UVA light at 365 nm wavelength for UVA source and UV light meter to measure UVA radiation were used. 3, 9 and 18 mW/cm(2) power of UV radiance was applied centrally to the each type of contact lenses. The power of UVA transmittance for each radiance and percentage of blockage were evaluated for each brand. Also, protection factor (PF) was calculated.
  
  
  RESULTS
  The senofilcon A and narafilcon A had the highest blockage and lowest transmittance (p = 0.02). PF was significantly higher in the senofilcon A and narafilcon A at 3, 9 and 18 mW/cm(2) (p = 0.0001). And also, the hilafilcon B, filcon IV, nelfilcon A, enfilcon A, lotrafilcon A and lotrafilcon B had the highest UVA transmittance.
  
  
  CONCLUSIONS
  The narafilcon A and the senofilcon A may be a good options for epithelial healing after CCL procedure to protect the cornea from UVA of sunlight. And also, the hilafilcon B, filcon IV, nelfilcon A, enfilcon A, lotrafilcon A and lotrafilcon B contact lenses that have high-UVA transmittance feature can be a treatment choice for contact lens-assisted CCL technique in thin corneas.
authors.affiliation: a Department of Ophthalmology , School of Medicine, Gazi University , Ankara , Turkey and.
authors.forename: Kamil
authors.initials: K
authors.lastname: Bilgihan
authors.affiliation: a Department of Ophthalmology , School of Medicine, Gazi University , Ankara , Turkey and.
authors.forename: Erdem
authors.initials: E
authors.lastname: Yuksel
authors.affiliation: a Department of Ophthalmology , School of Medicine, Gazi University , Ankara , Turkey and.
authors.forename: Nuriye Gokcen
authors.initials: NG
authors.lastname: Deniz
authors.affiliation: b Department of Ophthalmology , Ataturk Training and Research Hospital , Ankara , Turkey.
authors.forename: Nilay
authors.initials: N
authors.lastname: Yuksel
mesh_terms: D003094:Collagen / Q000378:metabolism*; D003263:Contact Lenses, Hydrophilic; D003315:Cornea / Q000378:metabolism / Q000528:radiation effects; D003432:Cross-Linking Reagents; D020100:Hydrogels; D012828:Silicones / Q000737:chemistry*; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D003432:Cross-Linking Reagents; D020100:Hydrogels; D012828:Silicones; D003094:Collagen
keywords: Contact-lens assisted cross-linking; UV block contact lenses; corneal collagen cross-linking