Giant retinal pigment epithelial tears in acute retinal necrosis

We observed large peripheral tears of the retinal pigment epithelium in two patients, a 59-year-old man and a 15-year-old girl, who had acute retinal necrosis. These tears ranged from 90 to 180 degrees of the circumference of the peripheral retinal pigment epithelium and occurred in areas of previous retinal viral infection. Both patients had curled folds of tissue at the posterior edge of the retinal pigment epithelial tear. During vitrectomy at the time of fluid-air exchange, we noted the edge of these tears to sag posteriorly. Because of the area that was denuded of retinal pigment epithelium by the tears, we selected a more posterior location for argon laser endophotocoagulation in both patients. These large retinal pigment epithelial tears did not appear to have an adverse effect on the outcome of surgical treatment of the retinal detachments.

A comparison of 5-fluorouridine and 5-fluorouracil in an experimental model for the treatment of vitreoretinal scarring

5-Fluorouridine (5-FUR), a ribonucleotide metabolite of 5-Fluorouracil (5-FU), is a more potent inhibitor of cellular proliferation and cell-mediated contraction in vitro than 5-FU. We compared the efficacy of these two drugs in a cell injection model of proliferative vitreoretinopathy using New Zealand albino rabbits. Forty-five eyes were divided into three groups and injected intravitreally with homologous fibroblasts. Eyes were examined at the time of injection and 7, 14, 21 and 28 days thereafter. By day 28, 70.5% (12 of 17) of 5-FUR treated eyes demonstrated no appreciable proliferative or tractional activity compared with 41.7% (5 of 12) of 5-FU treated eyes and 10% (1 of 10) of control eyes (p < 0.006). Medullary ray puckers developed in 29.4% (5 of 17) and 25% (3 of 12) of 5-FUR and 5-FU treated eyes respectively. No 5-FUR treated eye developed extensive tractional or combined tractional and rhegmatogenous retinal detachment compared with 33.3% (4 of 12) of 5-FU treated eyes and 80% (8 of 10) of control eyes (p < 0.001). These results suggest that 5-Fluorouridine may be more effective than 5-FU for the treatment of vitreoretinal scarring.

Intraocular extracellular cyclic nucleotide concentrations: the influence of vitreous surgery

Levels of cAMP (23.1 pmol/ml) and cGMP (22.6 pmol/ml) are nearly equal in normal rabbit vitreous, although aqueous cAMP levels (29.9 pmol/ml) are 10 times higher than aqueous cGMP levels (2.6 pmol/ml) (P < 0.01). Intravitreal cAMP values decrease slightly 1 week after vitrectomy and lensectomy and return to normal whether the retina is attached, detached, or surgically removed. In contrast, intravitreal cGMP levels are profoundly depressed at 7 days (approximating normal aqueous levels) and are more than 50% lower than normal 30-42 days after surgery. The presence of these cyclic nucleotides in intraocular fluid and their responsiveness after surgery may signify a potential regulatory role in the physiologic responses of the eye to retinal detachment and its repair.

Liposome suppression of proliferative vitreoretinopathy. Rabbit model using antimetabolite encapsulated liposomes

The effects of the antimetabolites, cytarabine (Ara-C) and 5-fluorouridine 5'-monophosphate (FUMP), encapsulated in multivesicular liposomes on formation of vitreous fibroproliferative membranes in New Zealand white (NZW) rabbits were studied. In pharmacokinetic studies, the drug half-life in the vitreous cavity was 124 hr after intravitreal administration of 1.0 mg of FUMP in liposomes. By contrast, the drug half-life after a single injection in nonliposome-treated controls was only 4.5 hr. In a heterologous dermal fibroblast model of proliferative vitreoretinopathy (PVR), there was a 92% decrease in frequency of tractional retinal detachments in rabbits receiving a single intravitreal injection of liposome-encapsulated 0.1 mg of FUMP compared with controls receiving liposomes without drug. A dose of 1 mg of Ara-C in liposome-treated rabbits was associated with only a 46% reduction in tractional detachment compared with controls. Multivesicular liposome-encapsulated FUMP may be useful for inhibiting formation of fibroproliferative membranes in the vitreous after vitreoretinal surgery.

Vitrectomy for retinal detachment associated with acute retinal necrosis

Six patients with retinal detachment associated with the acute retinal necrosis syndrome were treated by the combination of vitrectomy, gas injection, and laser photocoagulation. The retinas were successfully reattached in each patient with one operation. Five of the patients achieved a visual acuity of 20/200 or better, and three had a visual acuity of 20/40 or better.

Fluorouracil therapy of intraocular Greene melanoma in the rabbit

We evaluated the efficacy of intraocular and periocular fluorouracil treatment in an experimental iris tumor of the rabbit (Greene amelanotic melanoma). Four consecutive intravitreal injections of 1 mg of fluorouracil given twice weekly completely suppressed tumor growth in all treated eyes for six weeks if treatment was initiated 24 hours after tumor implantation. In contrast, all control eyes implanted with an equal number of Greene melanoma cells but treated with intravitreal saline developed massive tumor invasion of the iris within two weeks. Additional subconjunctival therapy following intravitreal therapy for two weeks was only slightly more effective than intravitreal therapy alone. If therapy was delayed for one week, the iris tumors became macroscopically visible and subsequent treatment with intravitreal and subconjunctival fluorouracil was of limited value in suppressing growth.

Malignant melanoma at the site of penetrating ocular trauma

We document clinically and histopathologically the development of a uveal melanocytic tumor at the site of penetrating ocular trauma in a 34-year-old man. A metallic intraocular foreign body was extracted via the inferonasal pars plana with an electromagnet in February 1975. At that time no intraocular tumor was noted and the visual acuity returned to 20/20. The patient developed floaters in January 1981, at which time findings from fundus examination and needle biopsy of the lesion suggested the presence of a spindle-cell melanoma. The diagnosis was confirmed histopathologically following enucleation. The possible association between trauma and ocular melanoma is discussed.

Fluid-gas exchange and photocoagulation after vitrectomy. Indications, technique, and results

We describe the indications, complications, and results of postvitrectomy fluid-gas exchange and laser photocoagulation for management of complicated vitreoretinal disease. Indications include proliferative vitreoretinopathy, vitreous opacities associated with proliferative diabetic retinopathy, giant retinal tear, recurrent rhegmatogenous retinal detachment, and trauma. Eyes treated with 50% sulfur hexafluoride gas rather than sterile air demonstrated a higher intraocular pressure on the first postexchange day, which was not a significant source of disease. There was no statistically significant difference in retinal reattachment between eyes treated with gas and those treated with air. Fluid-gas exchange in eyes with partial or total retinal detachment resulted in total or partial retinal reattachment, with the macula attached in 82% of cases within the first 48 hours following exchange. Final reattachment rate, with a mean follow-up of 8.9 months (range, six to 36 months), was 55%. In eyes with proliferative vitreoretinopathy, the combination of postoperative argon or krypton laser photocoagulation with fluid-gas exchange was associated with a final reattachment rate of 75%. Postoperative fluid-gas exchange and photocoagulation appear to be safe and effective advances in the treatment of complicated vitreoretinal diseases requiring vitrectomy.

Clearance of intravitreal fluorouracil. Normal and aphakic vitrectomized eyes

The ocular pharmacokinetics of 5-fluorouracil (5-FU) after intravitreal administration in the rabbit are described for the first time. Following a 1 mg intravitreal injection of C-14 labeled 5-FU in the phakic nonvitrectomized eye, a peak level of 664 micrograms/ml is achieved which declines to 7.8 micrograms/ml at 24 hours. For the aphakic vitrectomized eye comparable values are 669 micrograms/ml at 0.1 hour and 0.21 micrograms/ml at 24 hours. 5-FU is cleared more than two times more rapidly in aphakic vitrectomized eyes than normal eyes during the first 12 hours following injection. Following this, when the actual concentrations are relatively low, the rate of clearance appears relatively similar for both groups of eyes. Although it is difficult to extrapolate from previous in vitro results, potentially therapeutic vitreous concentrations are present in normal rabbit eyes for up to 72 hours following a single intravitreal injection.

5-fluorouracil: new applications in complicated retinal detachment for an established antimetabolite

Long-term reattachment of the retina following the development of proliferative vitreoretinopathy is often prevented by the occurrence of cellular reproliferation. 5-fluorouracil, a synthetic pyrimidine analog, is a potent inhibitor of fibroblast proliferation in cell culture and an animal model of tractional retinal detachment. Doses of up to 1.0 mg, when administered intravitreally to rabbits, result in no demonstrable retinal toxicity by microscopic and electrophysiologic criteria. The first 22 consecutive patients with advanced forms of proliferative vitreoretinopathy were treated with a combination of periocular and intraocular 5-fluorouracil, in addition to scleral buckling and vitrectomy. Retinal reattachment was achieved in 60% of patients at 6 months postoperatively. No serious systemic or ocular complications were observed although delayed healing of corneal epithelial defects occurred in 18% of cases and subtle subepithelial scarring in 31.8%. In combination with standard vitrectomy techniques, post-operative fluid gas exchange, and photocoagulation, periocular and subconjunctival 5-fluorouracil appears to improve the prognosis for longterm retinal reattachment following the development of proliferative vitreoretinopathy.

Multifocal pigment epithelial detachments by reticulum cell sarcoma. A characteristic funduscopic picture

Patients with systemic reticulum cell sarcoma often develop evidence of ocular involvement months or several years prior to the onset of neurologic symptoms. This neoplasm appears to have proclivity of arising multicentrically within the subpigment epithelial space, as well as in the vitreous. When this occurs it may produce a peculiar ophthalmoscopic picture of multiple large, solid detachments of the pigment epithelium that is rarely duplicated by any other disease. Three patients illustrating this disease are presented.

The acute retinal necrosis syndrome. Part 1: Clinical manifestations

The acute retinal necrosis syndrome is characterized by necrotizing retinitis, vitritis, and retinal vasculitis occurring in otherwise healthy patients. Experience with 11 cases and the review of 30 additional cases in the literature are presented. In this series, 50% of the affected eyes developed retinal detachments, and 64% had a final visual acuity of less than 20/200. The natural history, diagnosis, postulated etiology, and suggestions for management will be discussed.