A new endolaser probe with aspiration capability can be used as a flute needle for drainage of subretinal fluid and for endolaser treatment of a retinotomy site after vitrectomy. This instrument allows removal of vitreous and subretinal fluid during air-fluid exchange and immediate endolaser photocoagulation without exchange of instruments.

Drainage↗

PubMed1992

Laser-induced experimental vascular occlusion using liposome-encapsulated ADP.

The therapeutic occlusion of retinal vessels is often helpful in treating various pathological conditions. We compared the combined effects of argon laser photocoagulation and adenosine diphosphate (ADP) released from temperature-sensitive liposomes with argon laser photocoagulation alone on occlusion of retinal vessels in pigmented rats. In Group A, 8 eyes were treated with liposome-encapsulated ADP and laser photocoagulation. In Group B, 8 eyes were treated with laser photocoagulation alone. The laser parameters (power, spot size, exposure time) were maintained at the same levels for both groups. The laser was focused on the retinal vessels at the optic nerve head. The treated retinal vessels were observed at time zero, day 1, day 4, and weekly for a period of 3 months. At time zero, 6 of 8 eyes were totally occluded in Group A, with best results obtained at 80 mW. Only 1 of 8 eyes in Group B achieved total occlusion. After 3 months, 4 of 8 eyes in Group A remained totally occluded; no eyes in Group B were occluded. Complete and permanent occlusion of retinal vessels can be achieved by using ADP and laser photocoagulation of lower power density than traditional laser photocoagulation alone.

Adenosine Diphosphate↗

PubMed1992

Retinal toxicity of intravitreal lazaroid (21-aminosteroid U75412E).

The 21-aminosteroids or lazaroids are a novel series of compounds being developed for the acute treatment of traumatic or ischemic injury of the nervous system. These compounds were specifically designed to localize within cell membranes and inhibit lipid peroxidation reactions. In this study, 21-aminosteroid U75412E was injected into the vitreous body of rabbit eyes to evaluate its suitability for intraocular injection and its toxicity on intraocular tissues. Doses ranged from 20 micrograms to 200 micrograms. Retinal toxicity was determined through light and transmission electron microscopy and electroretinography. No retinal toxicity was noted in doses of 30 micrograms and below.

Animals↗

PubMed1992

Internal choroidectomy of posterior uveal melanomas under a retinal flap.

Local excision of uveal melanoma is an intriguing therapeutic modality in selected cases. An internal choroidectomy under a retinal flap has been developed as an alternative to retinochoroidectomy in managing posterior pole melanomas. This technique offers more adequate preservation of retinal architecture, thus potentially enhancing central visual function in patients with tumors located close to the fovea.

Adult↗

PubMed1992

Collagen shields and intraocular drug delivery: concentration of gentamicin in the aqueous and vitreous of a rabbit eye after lensectomy and vitrectomy.

Five albino New Zealand rabbits underwent bilateral lensectomy and vitrectomy. All left eyes were fitted with a collagen shield that had been soaked for 5 min in 2.0 mL of gentamicin solution (40 mg/mL for IV use). Right eyes were treated with fortified gentamicin drops (13.6 mg/mL) every 30 min for 12 hrs. Aqueous and vitreous specimens were obtained at the following time intervals: 1, 2, 4, 8, 12 and 24 hrs. We found the gentamicin concentrations to be higher in the aqueous of all eyes treated with fortified gentamicin drops. Only those eyes treated with fortified gentamicin drops attained a therapeutic drug level (4 micrograms-9 micrograms/mL) in the aqueous. Therapeutic drug levels were not attained in the vitreous of either treatment group.

Administration, Topical↗

PubMed1992

Clearance of microsphere-entrapped 5-fluorouracil and cytosine arabinoside from the vitreous of primates.

Experiments were conducted with biodegradable microspheres containing antimetabolites to assess the release of the drugs from the microspheres into the vitreous cavity of primates. Microspheres containing a mixture of radiolabeled and cold cytosine arabinoside (Ara-C) or 5-fluorouracil (5-FU) were prepared using a solvent evaporation process. The copolymers of poly (lactic) and poly (glycolic) acid (85:15) and drug was dissolved in a mixture of chloroform and acetone. The solutions were then emulsified in an aqueous solution of polyvinyl alcohol and stirred for 24 hours to evaporate the organic solvent. A 0.1 mL aliquot of a suspension of the microspheres was then injected into one eye of eight African Green monkeys. Half received 250 +/- 10 micrograms of Ara-C and the others 375 +/- 15 micrograms of 5-FU. The concentration in the vitreous was then measured by removing a 0.1 mL sample of vitreous at 1, 2, 4 and 11 days after injection. Both drugs released from microspheres were still detectable in the eye 11 days after injection and the clearance kinetics were similar for both drugs. The results indicate that the microspheres appear promising as a slow drug-delivery system for future investigations in conjunction with these and other antimetabolites suitable for the treatment of PVR.

Animals↗

PubMed1992

Use of perfluoroperhydrophenanthrene in the management of suprachoroidal hemorrhages.

BACKGROUND: Suprachoroidal hemorrhage may cause the expulsion of intraocular contents. Generally, cases of nonexpulsive suprachoroidal hemorrhage have a better outcome than their expulsive counterparts. Those cases with massive nonexpulsive suprachoroidal hemorrhage do better with treatment than without. Treatment modalities have included suprachoroidal hemorrhage drainage with or without intraocular volume reformation, and vitrectomy. METHODS: The authors used the liquid perfluorocarbon perfluoroperhydrophenanthrene in the treatment of three patients with nonexpulsive suprachoroidal hemorrhage. The perfluorocarbon was injected into the vitreous cavity while the suprachoroidal blood was drained through anterior sclerotomies. RESULTS: With 5 months of follow-up, complete resolution of the suprachoroidal blood was noted in all patients. All three patients had attached retinas, and postoperative visual acuities were improved over preoperative visual acuities. CONCLUSION: Perfluoroperhydrophenanthrene and other perfluorocarbon liquids may be beneficial in the treatment of certain cases of nonexpulsive suprachoroidal hemorrhages.

Aged↗

PubMed1992

Laser-triggered repetitive fluorescein angiography.

Liposome-encapsulated fluorescent dye has been altered to allow full fundus angiography after a single laser shot. By exposing the retinal arteries to laser energy where they emerge at the optic disc nerve head, dye release is elicited simultaneously in all four quadrants of the retina, without choroidal fluorescence, allowing visualization of the retinal microcirculation. Because the quantity of dye release is limited, recirculation does not increase background fluorescence. The procedure can be repeated many times without delay with consistent results. Increasing the laser spot size to 1.5 mm allows consistent dye release at energy densities from 0.5 J/cm2 to 3.4 J/cm2. This refinement will allow direct comparison in primates of this technique and conventional fluorescein angiography. The laser energy delivered to the retina is below suggested levels that may be tolerated by the optic nerve.

Animals↗

PubMed1992

Intravitreal corticosteroids in the treatment of exogenous fungal endophthalmitis.

A rabbit model of exogenous Candida albicans endophthalmitis was used to determine if intravitreal corticosteroids combined with an efficacious antifungal agent enhanced fungal proliferation and ocular destruction, or if the combination can suppress the inflammatory and immunogenic response that causes retinal and uveal destruction. Exogenous Candida albicans endophthalmitis was experimentally induced in 20 rabbit eyes. Eight eyes received intravitreal amphotericin B alone; eight eyes received amphotericin B plus dexamethasone. Four eyes served as controls. By clinical grading on the fourth day after infection, the vitreous of the eyes in the two drug-treated groups was significantly clearer in comparison to that of eyes in the control group. By the seventh day after infection, the eyes treated with amphotericin B plus dexamethasone had significantly clearer vitreous in comparison to the eyes receiving only amphotericin B (P = 0.0017). Quantitative culture results were negative in both treatment groups, and histopathologic examination confirmed the clinical grading. Contrary to current beliefs, there was no evidence that the addition of corticosteroids impaired antifungal activity or enhanced fungal proliferation.

Amphotericin B↗

PubMed1992

Intravitreal corticosteroids as an adjunct in the treatment of bacterial and fungal endophthalmitis. A review.

The use of intravitreal corticosteroids in the management of endophthalmitis remains controversial. Several clinical and experimental reports are reviewed that suggest that intravitreal corticosteroid therapy, when used in conjunction with antibiotics with and without vitrectomy, reduces the intraocular inflammatory process and secondary complications associated with microbial endophthalmitis.

Animals↗

PubMed1992

Vitreon, a short-term vitreoretinal tamponade.

This investigation of the liquid perfluorocarbon, perfluorophenanthrene (Vitreon), establishes its safety and efficacy as a short-term vitreoretinal tamponade. We utilised Vitreon as an intraoperative tool and postoperative vitreoretinal tamponade in 16 patients. Proliferative vitreoretinopathy (PVR) (six), giant retinal tear (four), rhegmatogenous retinal detachment (three), retinal detachment with keratoprosthesis (two), and submacular and vitreous haemorrhage (one) were successfully repaired. Vitreon was left in the eye and removed 5 days to 4 weeks postoperatively. Complications encountered included proliferative PVR (five), limited peripheral retinal detachment (three), macular pucker (two) cataract (three), hypotony (two), excessive fibrin reaction (one), and elevated intraocular pressure (one). At the latest evaluation, all retinas are attached with a follow-up of 1.25 to 12 months (mean 6.8 months).

Adolescent↗

PubMed1992

Immunohistological study of subretinal membranes in age-related macular degeneration.

An immunohistological study was performed on 6 specimens of subretinal membranes obtained surgically from patients suffering from age-related disciform macular degeneration. using immunoperoxidase procedures, we found in those membranes large amounts of IgG, IgA and IgE as well as C1q, C3c and C3d complement components diffusely distributed in the connective stroma and within the new blood vessel walls. Moreover, subretinal membranes contained numerous isolated HLA-DR- and -DQ-expressing cells, including glial, pigment epithelial and vascular endothelial cells. Monoclonal antibodies to immunocompetent cells disclosed only rare B and natural killer lymphocytes or suppressor-cytotoxic T cells, as well as some monocytes. These results show that immune phenomena are involved in proliferative changes associated with subretinal neovascularization. In addition, they suggest there are interactions between the immune system and peptide growth factors.

Antibodies, Monoclonal↗

PubMed1992

Retinal toxicity of 6-methoxypurine arabinoside (ara-M). A new selective and potent inhibitor of varicella-zoster virus.

The toxicity of a new antiviral agent, 6-methoxypurine arabinoside (ara-M), as a selective and potent inhibitor against varicella-zoster virus, was investigated after intravitreal injection in rabbit eyes. Intravitreal doses of ara-M ranging from 20 micrograms to 400 micrograms produced no retinal toxicity, as assessed by electroretinography and light and transmission electron microscopy. These data suggest a potential role for intravitreal ara-M in the antiviral treatment of varicella-zoster viral retinitis.

Animals↗

PubMed1992

Posterior relaxing retinotomies: analysis of anatomic and visual results.

Fifteen eyes with complicated retinal detachments--11 with proliferative vitreoretinopathy (C3 D3), 2 with posterior segment trauma, and 2 with inflammatory retinopathy--were treated with vitrectomy, membrane peeling, and large posterior retinotomy. All posterior relaxing retinotomies were circumferential, including temporal quadrants in all cases. With a minimum follow up of 6 months, 12 eyes (80%) were attached posterior to the retinotomy. Reproliferation resulted in redetachment in 3 eyes (20%). Visual acuity improved in 53%, remained unchanged in 20%, and decreased in 27%. Of the 11 eyes that achieved stable or improved visual acuity, 5 (45%) achieved 20/400 to 20/25 vision, 5 achieved counts fingers perception, and 1 patient remained stable at hand motion perception. Of all the eyes undergoing surgery, hypotony (intraocular pressure < 5 mm Hg) occurred in 6 eyes (40%); 3 of these were among the 12 eyes with attached retinas.

Adolescent↗