193-nm excimer laser-induced fluorescence detection of fluoroquinolones in rabbit corneas

Roy S. Chuck, Ramez E.N. Shehada, Mehran Taban, Tulaya Tungsiripat, Paula M. Sweet, Hebah N. Mansour, Warren S. Grundfest, Peter J. McDonnell

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Objective: To measure the 193-nm excimer laser-induced fluorescence of fluoroquinolone-treated cadaver rabbit corneas. Methods: Prior to ablation with a commercially available ophthalmic excimer laser (Nidek EC-5000; Nidek Technologies, Pasadena, Calif), 35 cadaver rabbit corneas were treated with topical sterile balanced salt solution, 0.3% tobramycin sulfate, or the fluoroquinolones - 0.3% ofloxacin, 0.5% levofloxacin, 0.3% ciprofloxacin hydrochloride, or 0.3% gatifloxacin. The fluorescence generated from each ablated corneal layer was measured and used to identify the presence of antibiotic. This was achieved by training a partial least-squares model to discriminate between the fluorescence spectra of antibiotic-treated and antibiotic-free (healthy) cornea. Antibiotic concentrations down to 0.06 μg/mL were detected with high accuracy. Assuming a constant ablation rate of 0.3 μm per laser pulse, the number of corneal layers ablated to reach antibiotic-free cornea is used to calculate the penetration depth of the antibiotic. Results: The mean ± SD penetration to a detectable depth was as follows: 0.3% ofloxacin, 7.1±3.0 μ; 0.5% levofloxacin, 6.7±1.4 μm; 0.3% ciprofloxacin, 1.2±0.6 μm; and 0.3% gatifloxacin, 7.0±1.9 μm. The penetration depth of 0.3% tobramycin could not be determined because its fluorescence spectrum overlapped with that of the native cornea. Conclusions: Topical administration of fluoroquinolone-containing solutions results in measurable differences in laser-induced corneal fluorescence. Under these experimental conditions, 0.3% ofloxacin, 0.5% levofloxacin, and 0.3% gatifloxacin all appear to penetrate the epithelium significantly more than 0.3% ciprofloxacin (P<.02). Clinical Relevance: Monitoring of laser-induced fluorescence may be helpful in determining the penetration depths and concentrations of topically applied fluoroquinolones within the cornea.

Original languageEnglish (US)
Pages (from-to)1693-1699
Number of pages7
JournalArchives of ophthalmology
Issue number11
StatePublished - Nov 2004

ASJC Scopus subject areas

  • Ophthalmology


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