Mandi D Conway

Intravitreal clindamycin and dexamethasone for toxoplasmic retinochoroiditis.

BACKGROUND AND OBJECTIVE To present a new method for the management of toxoplasmic retinochoroiditis (TRC). METHODS The patients were females ranging in age from 10 to 61 years (average 26.5). Four eyes of 4 patients were treated with intravitreal injections of 1.0 mg clindamycin in 0.1 mL and 1.0 mg of dexamethasone in 0.1 mL. The injections were given under general or peribulbar anesthesia. Three patients continued one systemic drug. Follow-up ranged from 11 to 26 months (mean 17.5). RESULTS A favorable response was noted in each eye within two weeks after the intravitreal injections. All patients required 2 to 4 intravitreal injections in the affected eye for the control of TRC. Visual acuity improved in each eye. The disc and macula were preserved in all eyes. Recurrence was noted in one case, which responded to a repeated intravitreal injection of clindamycin and dexamethasone. CONCLUSIONS Intravitreal injections of clindamycin and dexamethasone are well tolerated and may offer an additional strategy to treat TRC in patients who are unable to afford or tolerate systemic therapy, or whose disease progresses despite systemic therapy.

Surgical chorioretinal venous anastomosis for ischemic central retinal vein occlusion

BACKGROUND AND PURPOSE To report results of a pilot study to create chorioretinal venous anastomosis (CRVA) in eyes with ischemic central retinal vein occlusion (CRVO) via a pars plana approach. PATIENTS AND METHODS Five eyes of 5 patients with ischemic CRVO underwent surgical CRVA. Following pars plana vitrectomy, the posterior hyaloid face was removed, and slit-like incisions were made with a microvitreoretinal blade adjacent to a major retinal vein in each quadrant. Small pieces of 50 Mersilene sutures (Ethicon, Somerville, NJ) were positioned over the vein and inserted into these incisions to promote vascularization. Panretinal photocoagulation was applied. RESULTS A functional CRVA site was noted at 10 of 16 attempted sites (4 sites in 1 patient could not be evaluated because of cataract). Minor fibrous proliferation was noted at CRVA sites in all eyes. Optic atrophy developed in 3 eyes. Visual acuity improved in 3 eyes, remained unchanged in 1, and deteriorated in 1 eye after a mean follow up of 13.4 months (range 8-20 months). CONCLUSION Surgically induced CRVA may improve the prognosis in some eyes with ischemic CRVO.

Long-term vitreous replacement in primates with intravitreal Vitreon or Vitreon plus silicone.

Six African green monkeys (six eyes) underwent vitrectomy and vitreous replacement with Vitreon (perfluorophenanthrene) or Vitreon plus silicone. A seventh animal served as a control. Vitreon alone and in combination remained optically clear and allowed fundus examination up to 162 days. No toxic effects to the retina were detectable. Vitreon exhibited some degree of emulsification and formed some globules at 45 days postoperatively. Interestingly, Vitreon emulsification occurred at a later time (80 days) in one of the silicone plus Vitreon eyes. The combination of silicone plus Vitreon may offer the advantage of tamponading the inferior and superior retina in phakic eyes.

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±10μg of Ara-C and the others 375±15μg 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 drugdelivery system for future investigations in conjunction with these and other antimetabolites suitable for the treatment of PVR.

Branch retinal artery occlusion (BRAO) combined with branch retinal vein occlusion (BRVO) and optic disc neovascularization associated with HIV and CMV retinitis

Two vaso-occlusive events, branch retinal artery occlusion (BRAO) and branch retinal vein occlusion (BRVO), were observed in the retina of an HIV-infected patient with cytomegalovirus (CMV) retinitis who developed neovascularization of the disc (NVD). Although BRVO and reversible NVD have been reported in association with CMV retinitis, we have seen no reports of concomitant BRAO. CMV damages endothelial cells and causes an occlusive vasculitis. In HIV-infected individuals, damaged endothelial cells and rheologic problems result in increased blood viscosity. HIV infection has also been associated systemically with elevated levels of cytokines, including tumor necrosis factor alpha (TNF-α). In vitro, TNF-α exerts effects that decrease fibrinolytic potential; this activity in the circulation of a patient with AIDS may lead to vascular occlusive events. In the patient reported here, the retinal changes were not reversed by induction therapy with ganciclovir and the NVD did not regress.

Intravitreal tPA and SF6 promote clearing of premacular subhyaloid hemorrhages in shaken and battered baby syndrome

BACKGROUND AND OBJECTIVE Child abuse is a serious problem in many cultures. The ocular signs of shaken baby include intraretinal, subretinal, and preretinal hemorrhages. The hemorrhages may be unilateral or bilateral and are seen in 50% to 80% of patients. Previous treatment was limited to observation or vitrectomy, but some observed eyes develop amblyopia, and pediatric vitrectomy has many complications. PATIENTS We report 4 eyes in 2 children with shaken baby syndrome in whom we administered intravitreal tissue plasminogen activator (tPA) in an attempt to resolve preretinal hemorrhages earlier than observation alone without the complications of vitrectomy. The tPA dose ranged from 12.5-25 microg per injection. Eyes were injected once weekly for 3 consecutive weeks. Each time 0.25 cc of sulfur hexafluoride gas was also injected. RESULTS Within 1 week following the last tPA administration, complete resolution of the preretinal hemorrhage was seen. There were no associated ophthalmic complications. CONCLUSION Intravitreal tPA with an expansive gas is an alternative method to observation or vitrectomy for resolution of preretinal hemorrhages in battered babies and may allow faster resolution of hemorrhages without the complications of vitrectomy.

Effect of a somatostatin analog (octreotide acetate) on the growth of retinal pigment epithelial cells in culture

PURPOSE Proliferative vitreoretinopathy is a serious complication of retinal detachment surgery in which retinal pigment epithelial cells abnormally proliferate within the vitreous cavity and under the retinal surface. Octreotide acetate, a somatostatin analog, has been shown to inhibit the cellular proliferation of a variety of cell types. The aim of this study was to investigate the effect of octreotide acetate on the growth of rabbit retinal pigment epithelial cells in culture. METHODS Retinal pigment epithelial cells were isolated from rabbits and maintained in culture. Cells were exposed to standard media or media supplemented with octreotide acetate 10(-4) M to 10(-12) M for five days. Each concentration of octreotide acetate was tested in quadruplicate. RESULTS Exposure of rabbit retinal pigment epithelial cells to octreotide acetate significantly inhibited proliferation with a peak effect at 10(-8) M. The effect of octreotide is biphasic with higher and lower concentrations having less effect than 10(-8) M. CONCLUSIONS This study suggests that octreotide acetate may be useful in the treatment of proliferative vitreoretinopathy; however, the optimum therapeutic dose range for this drug may be narrow.

Perfluorooctylbromide (PFOB) as a vitreous substitute in non-human primates

We evaluated the toxicity of perfluorooctylbromide in the primate eye as a short-term postoperative vitreous substitute. Four eyes of 4 African green monkeys underwent complete vitrectomy and vitreous replacement with 1.5–2.0 ml of PFOB. One additional animal received BSS as a control vitreous substitute in one eye. Animals were examined twice weekly for clarity and consistency of the vitreous replacement substance. Anterior segment and lenses remained clear in all eyes, although in the immediate postoperative period one eye became inflamed and had a culture-negative vitritis. The other eyes showed a minimal anticipated postoperative vitreous inflammation. Emulsification of the PFOB began within 3 days of injection and progressed up to 3 weeks, precluding fundus examination and fluorescein angiography after 2 weeks. Eyes were enucleated and light microscopy performed at 2 days, 10 days, 33 days, and 45 days. No toxic effects to the retinal cells were detectable by histological examination, but perivasculitis of retinal vessels was noted at 45 days. Indirect examination was normal up to 10 days; thereafter, the fundus view was obscured by the emulsified PFOB. Because of cellular migration into the vitreous cavity and retinal perivasculitis, observed histologically, PFOB seems most suitable for intraoperative rather than postoperative use.

Ocular Photodynamic Therapy in Choroidal Neovascularization Complicating Idiopathic Central Serous Chorioretinopathy

Two consecutive patients with idiopathic central serous chorioretinopathy and decreased vision subsequent to subfoveal choroidal neovascular membranes were treated with photodynamic therapy applied using the protocol of the Treatment of Age-Related Macular Degeneration with Photodynamic Therapy Study Group. Main outcome measures included best-corrected visual acuity, biomicroscopic appearance, and leakage on fluorescein and indocyanine green angiography. Photodynamic therapy offered anatomical, angiographic, and functional improvement. After an initial complete response, the patients required re-treatment at 3 and 4 months, respectively. Cessation of leakage with improvement in visual acuity occurred, but subretinal fibrosis posed a possible limitation for full functional recovery. Although choroidal neovascular membranes complicating idiopathic central serous chorioretinopathy portend a poor visual prognosis, the overall response to photodynamic therapy was favorable.

Ocular manifestation of simian immunodeficiency syndrome (SAIDS).

The management of opportunistic infections is a significant problem in acquired immunodeficiency syndrome (AIDS) and the development of more effective chemotherapeutic agents is needed. We present the ocular manifestations of an AIDS-like disease in rhesus monkeys experimentally infected with simian immunodeficiency virus (SIV) at the Delta Regional Primate Research Center. These findings consisted of rubeosis in the anterior segment and retinitis, optic neuritis, choroiditis and panophthalmitis in the posterior segment of the eye. Investigation of the retinas by electron microscopy revealed SIV in both eyes of one animal and a herpes virus in two animals. Serology confirmed cytomegalovirus (CMV) as the likely agent. This primate model will prove useful for both further investigations of the possible interaction between immunosuppressive lentiviruses and CMV in ocular disease and antiviral drug testing.