Confocal assessment of the effects of fourth-generation fluoroquinolones on the cornea.

PURPOSE: To evaluate the toxicity of fourth-generation fluoroquinolone antibiotic solutions on the rabbit corneal epithelium. METHODS: In vivo confocal microscopy was used to assess epithelial structure in 18 rabbits, and tight junction integrity of superficial epithelial cells was evaluated with ZO-1 labeling in 10 rabbits. Eyes were bathed with commercial solutions of moxifloxacin (Vigamox) or gatifloxacin (Zymar) solution for 3 minutes, rinsed with balanced salt solution, and immediately examined. Balanced salt solution rinsing alone served as the control. RESULTS: A decrease in epithelial cell size was observed after treatment with Zymar (P < 0.05, two-way repeated-measures analysis of variance), but not with Vigamox or the control. Normal ZO-1 organization was observed in controls and eyes treated with Vigamox. ZO-1 staining in eyes treated with Zymar was disrupted, patchy, and generally weaker than that in control eyes. CONCLUSIONS: After short-term, intensive exposure to Vigamox, corneal epithelial integrity and tight junction organization are maintained. Zymar induces a loss of superficial epithelial cells and breakdown of tight junctions under similar conditions.

Evaluation of intrastromal lipid deposits after intacs implantation using in vivo confocal microscopy.

PURPOSE: To assess the structure and location of intrastromal lipid deposits after implantation of Intacs by using in vivo confocal microscopy. METHODS: Seven eyes of six patients were examined by in vivo confocal microscopy 5 years (n = 6) or 2 months (n = 1) after uncomplicated implantation of Intacs for the correction of mild myopia. Selected images from all corneal layers were qualitatively evaluated for structural changes, with special attention paid to areas surrounding the Intacs implants. RESULTS: In the peripheral cornea of eyes examined 5 years after surgery, epithelial and endothelial cell layers appeared normal. Tandem scanning confocal microscopy showed stromal haze surrounding the implants in all eyes examined, but no keratocyte activation was seen. Reflective amorphous or crystalline structures consistent with lipid deposition were detected in all eyes with long-term implantation of Intacs. Deposits were localized to the inner and outer edges of Intacs segments and to the region anterior to the implant. Confocal microscopy did not show any deposits in the eye examined 2 months after surgery, although the region anterior to the implant appeared hazy and edematous. Areas central to the implant appeared normal in all eyes. CONCLUSIONS: The mechanical and physiologic stresses introduced by the implantation of Intacs lead to the accumulation of lipid deposits in the extracellular matrix. By using in vivo confocal microscopy, the location and structure of these deposits can be determined.