Advances in rapid laboratory diagnosis of infectious endophthalmitis

Drug delivery to the eye anterior chamber by intraocular lenses: An in vivo concentration estimation model

Drug loaded intraocular lenses have been proposed as an alternative to the conventional post-cataract removal prophylaxis through topical drug administration, since the drug or combination of drugs released from the lenses are delivered directly to the target site. In this work, a mathematical model to estimate the concentration of drug released from such lenses in the eye aqueous humor was developed. To attain these estimated concentration profiles, partition and effective diffusivity coefficients for the specific lens material were obtained from standard in vitro release experiments. The model was validated by comparing the predicted aqueous humor concentrations with those obtained in in vivo studies where hydrophilic acrylic intraocular lens loaded with an antibiotic (moxifloxacin) were implanted in rabbits. Subsequently, other partition and effective diffusivity values were determined for levofloxacin, diclofenac and ketorolac in the same hydrophilic acrylic and in a second material, a silicone hydrogel. Predicted drug concentrations in the aqueous humor allowed an initial screening and evaluation of the most promising system for post-cataract removal prophylaxis, with the hydrophilic acrylic material presenting promising results, especially for moxifloxacin and diclofenac controlled release.

The use of blood culture bottles in endophthalmitis

PURPOSE

To study the use of blood culture bottles for culturing vitreous specimens in acute-onset postoperative infectious endophthalmitis cases.

METHODS

Forty-eight eyes of 48 patients with mean age of 66.4 +/- 14.7 years with postoperative endophthalmitis that occurred within 6 weeks after ocular surgery, presenting from June 2001 to January 2005, were retrospectively studied. Vitreous fluid specimens of these patients were cultured in blood culture bottles. The measured outcome is the yield of positive culture.

RESULTS

Vitreous specimens yielded positive in 34 of 48 (70.8%) eyes with blood culture bottles. The most common organism isolated was Staphylococcus epidermidis in 17.6% (6/34) of cases.

CONCLUSION

The direct inoculation of vitreous specimens into the blood culture bottles is easy to perform, with a high yield positive rate (70.8%). It may be an alternative to conventional culture media for culturing vitreous specimen in infectious endophthalmitis especially in clinics or hospitals that are unable to have adequate microbiology laboratory facilities.