Positive vitreous cultures from eyes without signs of infectious endophthalmitis

BACKGROUND AND OBJECTIVE

There is little information on the rate of false-positive vitreous cultures, because cultures from presumably sterile vitreous are not routinely taken in clinical practice. The objective of this study was to determine the rate of positive vitreous cultures from patients who have no signs of endophthalmitis.

PATIENTS AND METHODS

Aerobic cultures from vitreous biopsies were taken from 36 consecutive eyes in which there was no clinical evidence of endophthalmitis. Effluent collected in cassettes during pars plana vitrectomies was processed and cultured in a standard manner. Balanced salt solution was processed intraoperatively through the vitrector and cultured as a negative control.

RESULTS

Positive cultures were obtained in 8 of 36 eyes (22.2%). Coagulase-negative Staphylococcus and Corynebacteria accounted for 7 of the 9 identified organisms. No organism was grown in more than one medium. None of the patients were treated for endophthalmitis after surgery, and none had signs of intraocular infection.

CONCLUSIONS

A substantial number of vitrectomy cultures from effluent specimens grow low-virulence organisms in the absence of clinical signs of endophthalmitis. The absence of inflammation at the time of surgery suggests that these positive cultures are contaminants.

Glaucoma after surgery on the retina and vitreous

Increased intraocular pressure after retinal detachment or its surgery may be addressed in an effective manner, because the clinical setting invariably suggests an ascertainable etiologic mechanism. Directed, stepwise therapy may then be instituted promptly to minimize lasting or functional impairment from long-standing increased intraocular pressure.

Holmium laser sclerectomy. Success and complications

PURPOSE

To investigate the safety and efficacy of holmium YAG laser sclerectomy, a new laser filtration procedure.

METHODS

The authors performed holmium YAG laser sclerectomy on 49 eyes of 46 patients (mean follow-up, 12.3 +/- 1.1 months).

RESULTS

Mean preoperative intraocular pressure (IOP) was 26.9 +/- 1.3 mmHg; postoperative mean IOP on last follow-up visit was 19.7 +/- 1.6 mmHg. Thirty (61%) of 49 eyes achieved a final IOP of 5 to 22 mmHg, 29 (59%) of 49 had a final IOP of 5 to 19 mmHg, and 21 (43%) of 49 had a final IOP of 5 to 15 mmHg. Sixteen (73%) of 22 eyes treated postoperatively with 5-fluorouracil (5-FU) had a final IOP of 21 mmHg or less. Twenty-seven percent of eyes lost one or more lines of vision, and 36% of eyes gained one or more lines of vision; there was no median change in visual acuity. Complications included suprachoroidal hemorrhage in 7 (14%) of 49 eyes and intraoperative vitreous hemorrhage in 2. Seventeen (35%) of 49 eyes required a second IOP-lowering procedure.

CONCLUSION

Holmium YAG laser sclerectomy is an effective means to perform glaucoma filtration surgery. This is a full-thickness filtering procedure, with all of the risks attendant.

Regression of experimental iris neovascularization with systemic alpha-interferon

BACKGROUND

Intraocular neovascularization leads to visual loss in many eye diseases, including diabetic retinopathy, age-related macular degeneration, and neovascular glaucoma. Current treatment relies on laser photocoagulation, involving the destruction of functional retinal tissue. A pharmacologic treatment directed at the newly growing vessels would represent a major advance.

METHODS

The authors investigated the effect of systemic alpha-interferon in an experimental model of iris neovascularization in cynomolgus monkeys. Alpha-interferon was administered systemically to animals with angiographically documented iris neovascularization.

RESULTS

Animals in the treatment group showed regression of neovascularization angiographically and histologically in eight of eight eyes. Control animals with documented iris neovascularization, followed without drug treatment, showed progression of the neovascularization in three of three eyes.

CONCLUSION

Systemic alpha-interferon led to inhibition of neovascularization and regression of new vessels in an experimental model of iris neovascularization. This represents the first successful, controlled treatment of experimental neovascularization in the eye using a systemic drug directed specifically at the neovascular tissue.

Ophthalmic manifestations of chronic angioedema with necrotizing vasculitis

Anatomic features unique to periocular tissues alter the clinical appearance of angioedema, making it difficult to distinguish from cellulitis and other inflammatory conditions. Two patients had prominent periocular manifestations of chronic angioedema with necrotizing vasculitis, a systemic disease often associated with multiorgan involvement. The diagnosis was established by exclusion of other inflammatory disorders and confirmed by biopsy. The scarcity of reports in the ophthalmic literature on chronic angioedema of the eyelids may be caused by its underrecognition. The distinction between chronic angioedema and typical angioedema or urticaria is important because of differences in their diagnostic evaluation, treatment, and prognosis.

Optical coherence tomography

A technique called optical coherence tomography (OCT) has been developed for noninvasive cross-sectional imaging in biological systems. OCT uses low-coherence interferometry to produce a two-dimensional image of optical scattering from internal tissue microstructures in a way that is analogous to ultrasonic pulse-echo imaging. OCT has longitudinal and lateral spatial resolutions of a few micrometers and can detect reflected signals as small as approximately 10(-10) of the incident optical power. Tomographic imaging is demonstrated in vitro in the peripapillary area of the retina and in the coronary artery, two clinically relevant examples that are representative of transparent and turbid media, respectively.

Phthalocyanine photodynamic therapy of experimental iris neovascularization

Photodynamic therapy using chloroaluminum sulfonated phthalocyanine (CASPc) effectively closed experimental iris neovascularization induced in 6 eyes of cynomolgus monkeys by argon laser retinal vein occlusion. Neovascularization was followed by iris photography, fluorescein angiography, and histopathologic examination by light and electron microscopy. Intravenous injection of CASPc followed by irradiation with 675 nm light damaged endothelial cells and pericytes, leading to exposure of the basal lamina and thrombotic occlusion of the blood vessels. Surrounding tissue appeared preserved without evidence of thermal damage. Resorption of occluded vessels by macrophages began 2 to 3 days after photodynamic therapy. Neovascularization reappeared 7 days after photodynamic therapy, probably representing growth of new vessels. Photodynamic therapy with CASPc may be a useful adjunct in the treatment of iris neovascularization. The model is useful in elucidating the ultrastructural changes observed after photodynamic therapy using phthalocyanines.