Ocular penetration of topically applied 1% tigecycline in a rabbit model.

AIM: To evaluate ocular penetration of topically applied 1% tigecycline. METHODS: Forty-two New Zealand White rabbits were divided into 3 groups. A 50 µL drop of 1% tigecycline was administered in group 1. In groups 2 and 3, the drop was administered every 15min for 60min (keratitis protocol). Aqueous humor samples in groups 1 and 2 were collected under general anesthesia at 15, 30, 45, 60, 120, and 180min after the last drop. All animals in group 3 were euthanatized. Cornea, vitreous and blood samples were collected 60 and 120min after the last drop. Tigecycline concentrations were measured using high performance liquid chromatography-mass spectrometry (LC-MS/MS). RESULTS: The peak aqueous humor tigecycline concentration [mean 0.73±0.14 mg/L (SD) and 2.41±0.14 mg/L, respectively] occurred 45min after topical drug application in groups 1 and 2. Group 3 mean values in the cornea, and vitreous, were 3.27±0.50 µg/g, and 0.17±0.10 mg/L at 60min and 3.17±0.77 µg/g and 0.20±0.07 mg/L at 120min, respectively. Tigecycline serum concentrations were negligible. CONCLUSION: Tigecycline levels in the aqueous humor in groups 1 and 2, and in the cornea in group 3 exceeded the minimum inhibitory concentrations of most gram-positive organisms that cause bacterial keratitis and endophthalmitis.

Peripapillary choroidal thickness in patients with chronic obstructive pulmonary disease.

OBJECTIVE: To evaluate the peripapillary choroidal thickness of patients with chronic obstructive pulmonary disease (COPD) via enhanced depth imaging optical coherence tomography (EDI-OCT). MATERIALS AND METHODS: A total of 80 patients with COPD (80 eyes) and 50 control subjects (50 eyes) were enrolled. Choroidal scans and the retinal nerve fiber layer (RNFL) thickness were obtained for all eyes using OCT. RESULTS: The average peripapillary choroidal thickness measurements of the COPD group (147.58 ± 53.53 µm) were lower than the control group (160.84 ± 44.73 µm) (p = 0.068). Inferior segment thicknesses were significantly thinner than the other segments (p < 0.05). Subfoveal choroidal thickness and RNFL thickness measurements of the COPD group were also lower than those of the control group (p = 0.111). CONCLUSION: Hypoxia in COPD seems to affect the choroidal thickness. Thinning of the choroid may be attributed to increased vascular resistance and reduced blood flow in patients with COPD. The possible effects of the disease to the eye may be clarified through the role of the choroidal vasculature in the blood supply of the anterior optic nerve head.

Effect of nepafenac eye drops on pain associated with pterygium surgery.

OBJECTIVE: To assess the effects of nepafenac ophthalmic suspension 0.1% for control of pain in patients undergoing pterygium surgery. METHODS: This randomized, double-masked placebo-controlled study included 62 adults undergoing pterygium surgery. Patients were randomly assigned to receive nepafenac ophthalmic suspension 0.1% or balanced salt solution placebo. They were asked to assess the level of pain using an 11-point numeric rating scale at 6, 12, 24, 48, and 72 hr after surgery. Patients also were evaluated daily for the progression of corneal epithelial healing until complete closure was observed. RESULTS: Except at 72 hr after surgery, the patients reported significantly less pain in eyes receiving nepafenac than in eyes receiving placebo. There was no statistical difference between the two groups in corneal epithelial healing. CONCLUSIONS: Treatment with nepafenac ophthalmic suspension 0.1% significantly reduced postoperative pain compared with placebo after pterygium surgery.

New therapy option for treatment of methicillin-resistant Staphylococcus aureus keratitis: tigecycline.

PURPOSE: The aim of the present study was to evaluate the effectiveness of topically applied tigecycline for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) in a rabbit model. METHODS: Experimental bacterial keratitis was induced in rabbits by a corneal intrastromal injection of 100 colony-forming units (CFUs) of MRSA bacteria. Sixteen hours after the injection, 28 rabbits were randomly divided into 4 treatment groups of 7 rabbits each. In each group, the rabbits' eyes were treated topically with 19 doses of topical tigecycline (10 or 50 mg/mL), vancomycin (50 mg/mL), or isotonic saline. Slit lamp examinations were performed before and after the inoculation by two observers masked to the study for the determination of clinical severity. Corneas were harvested for bacterial quantitation and histopathologic examination. RESULTS: No significant differences were observed in the clinical scores between pretreatment and posttreatment in the 4 groups (P>0.05). The mean difference between the pretreatment and posttreatment clinical scores from the 4 treatment groups was also not significant (P>0.05). All treatment groups had significantly lower CFUs compared with the control group. There were no significant differences in the bacterial load among the treatment groups. The minimum inhibitory concentration (MIC) for tigecycline was 0.12 µg/mL, whereas the MIC for vancomycin was 2.2 µg/mL. The tigecycline 10 mg/mL group had the lowest mean epithelial erosion values among the treatment groups. CONCLUSIONS: Topical tigecycline significantly reduced the bacterial load in infected rabbit corneas and may be as effective as vancomycin for the topical treatment of MRSA keratitis.

Antiangiogenic effect of itraconazole on corneal neovascularization: a pilot experimental investigation.

PURPOSE: To investigate the antiangiogenic effect of itraconazole for the prevention of experimentally induced corneal neovascularization and whether the efficacy depends on the route of administration. MATERIALS AND METHODS: Thirty-six rats were randomly divided into 6 groups with 6 rats in each group. Chemical cauterization of the cornea was performed using silver nitrate/potassium nitrate sticks, and the rats were subsequently treated daily with topical (10 mg/ml), subconjunctival (10 mg/ml) or intraperitoneal (19 mg/kg) itraconazole for 7 days. Control rats received topical, subconjunctival or intraperitoneal 0.9% saline. On the 8th day of the experiment, the rat corneas were photographed to determine the percentage area of the cornea covered by neovascularization. The maximum density of corneal neovascularization was determined by microscopy. RESULTS: The median percentage of corneal neovascularization for group 1 was 31.5% (95% confidence interval, 27.5-35.5%); in group 3, it was 32% (23.5-39.8%); in group 5, it was 47% (36.3-60.0%). The percentages of corneal neovascularization in groups 2, 4 and 6 (the control groups) were 70% (95% confidence interval, 60.7-77.3%), 69% (63.0-77.7%) and 68% (56.5-78.5%), respectively. The area of neovascularization was smaller after itraconazole treatment as compared to saline treatment. Further, the area of neovascularization was smaller after topical and subconjunctival administration than after intraperitoneal administration. Histological evaluation of the corneas showed the most extensive corneal neovascularization in the control group. No local or systemic adverse effects were seen from either treatment group. CONCLUSION: Itraconazole reduces corneal neovascularization shortly after chemical burn. However, a larger experimental study is necessary to confirm the data of this investigation.

Inhibition of corneal neovascularization by topical and subconjunctival tigecycline.

Objective. To investigate the effects of topical and subconjunctival tigecycline on the prevention of corneal neovascularization. Materials and Methods. Following chemical burn, thirty-two rats were treated daily with topical instillation of 1 mg/mL tigecycline (group 1) or subconjunctival instillation of 1 mg/mL tigecycline (group 3) for 7 days. Control rats received topical (group 2) or subconjunctival (group 4) 0.9% saline. Digital photographs of the cornea were taken on the eighth day after treatment and analyzed to determine the percentage area of the cornea covered by neovascularization. Corneal sections were analyzed histopathologically. Results. The median percentages of corneal neovascularization in groups 1 and 3 were 48% (95% confidence interval (CI), 44.2-55.8%) and 33.5% (95% CI, 26.6-39.2%), respectively. The median percentages of corneal neovascularization of groups 1 and 3 were significantly lower than that of the control group (P = 0.03 and P < 0.001, resp.). Histologic examination of samples from groups 1 and 3 showed lower vascularity than that of control groups. Conclusion. Topical and subconjunctival administration of tigecycline seems to be showing promising therapeutic effects on the prevention of corneal neovascularization. Furthermore, subconjunctival administration of tigecycline is more potent than topical administration in the inhibition of corneal neovascularization.

Choroidal thinning in pseudoexfoliation syndrome detected by enhanced depth imaging optical coherence tomography.

PURPOSE: To measure choroidal thickness in patients with pseudoexfoliation (PEX) syndrome and to compare the values with control eyes using enhanced depth imaging optical coherence tomography (EDI-OCT). METHODS: Thirty-four patients with PEX syndrome and 30 age- and sex-matched healthy subjects were included in this study. Only one eye of each of the patients was included. Choroidal thickness was measured manually from the outer border of the retinal pigment epithelium to the inner scleral border at the subfovea, 3 mm temporal to the fovea, and 3 mm nasal to the fovea using EDI-OCT. RESULTS: A total of 34 eyes from 34 consecutive patients with PEX syndrome (19 women and 15 men; mean age 75.3 ± 6.6 years) were included in the analysis. The mean subfoveal, temporal, and nasal choroidal thickness was significantly thinner in the PEX syndrome group compared with the control group (p<0.05, at all points). The mean choroidal thickness in the PEX syndrome group was as follows: 259 ± 33 µm, 211 ± 29 µm, and 106 ± 24 µm, subfoveal, temporal, and nasal to the fovea, respectively. In comparison, the mean choroidal thickness in the control group was 274 ± 23 µm, 225 ± 17 µm, and 117 ± 17 µm, at the subfovea, 3 mm temporal to the fovea, and nasal to the fovea, respectively. CONCLUSIONS: In PEX syndrome, there is choroidal thinning subfoveal, temporal, and nasal to the fovea on EDI-OCT. Decreased choroidal thickness, probably due to increased vascular resistance, and reduced blood flow, is seen in PEX syndrome.