To perform the CXL procedure, and in a manner similar to a previously published epithelium-off study
13 a scleral contact lens reservoir containing riboflavin (vitamin B
2) 0.25%, 1.2% hydroxypropyl methylcellulose, benzalkonium chloride 0.007% (Peschke TE, Peschke Meditrade GmbH, Huenenberg, Switzerland) was placed on the eye for 30 minutes. Owing to concerns of benzalkonium chloride toxicity to the corneal epithelium, the first patient was examined after 20 minutes of riboflavin installation. Slit-lamp examination showed an intact epithelium and stromal riboflavin penetration, but no yellow flare in the anterior chamber. The riboflavin-filled scleral contact lens was reapplied for 10 minutes and then the patient was reexamined to find an intact epithelium with a yellow flare in the anterior chamber. All other patients received a slit-lamp examination after the 30-minute riboflavin soak to confirm presence of a yellow flare in the anterior chamber. After the riboflavin soak, the reservoir lens was removed, corneal saturation was confirmed with slit-lamp examination, and a drop of proparacaine 0.5% (ANESTEARS, Lansier, Lima, Peru) was placed on the eye. A single drop of balanced salt solution (Alcon Laboratories, Inc., Fort Worth, TX) was placed on the scleral haptic surface of the treatment lens to ensure 100% humidity under the lens throughout the 30-minute irradiation. The CXLens UVA light-emitting contact lens device (TECLens LLC, Stamford, CT) shown in
Figure 1 was installed on the eye. The 375-nm UVA light at 4 mW/cm
2 intensity was delivered for 30 minutes for a total dose of 7.2 J/cm
2 to the central region of cornea containing the cone. After placement of the device, patients were allowed to close their eyelids if they desired and find a comfortable position for the remainder of the procedure. Riboflavin was not reapplied during the procedure. About halfway through the 30-minute treatment period, an additional drop of proparacaine was applied over the lens. The post-CXL medication regimen consisted of prednisolone acetate 1% (Pred Forte, Allergan, Bucks, UK), topical moxifloxacin 0.5% (VIGAMOX, Alcon Laboratories, Inc.), and topical lubricating drops (Systane Ultra, Alcon Laboratories Inc.). All medications were given every 2 hours on day 0, every 4 hours on day 1, and then tapered over 4 weeks.