Pars plana vitrectomy for the treatment of ophthalmomyiasis interna posterior in a dog.

Unilateral chorioretinitis caused by ophthalmomyiasis interna posterior in a 5-month-old, female spayed Dachshund is reported. Larva removal by pars plana vitrectomy was performed after an unsuccessful photocoagulation of the organism. The larva was intact after surgical removal and was identified as a first stage instar Cuterebra spp. larva. The eye remains visual and comfortable with no signs of residual or recurrent inflammation postoperatively. This report describes, for the first time, the successful surgical retrieval of an intravitreal fly larva in a dog using vitrectomy techniques without sacrificing either the globe or vision, and taxonomic identification of the parasite.

The efficacy of octreotide in the therapy of severe nonproliferative and early proliferative diabetic retinopathy: a randomized controlled study.

OBJECTIVE: The pilot study examined the ability of octreotide to retard progression of diabetic retinopathy (DR) and delay the need for panretinal photocoagulation (PRP) in patients with advanced stages of retinal disease. RESEARCH DESIGN AND METHODS: Patients with severe nonproliferative DR (NPDR) or early non-high-risk proliferative DR (PDR) were randomly assigned to conventional diabetes management (control group, 12 patients) or to treatment with maximally tolerated doses of octreotide (200-5,000 microg/day subcutaneously; 11 patients). Ocular changes in each eye were assessed at a minimum of every 3 months for 15 months or until disease progressed to high-risk PDR requiring laser surgery. Endocrine assessments occurred at 3-month intervals during the study RESULTS: Only 1 of 22 eyes from patients treated with octreotide reached high-risk PDR requiring PRP, compared with control patients, in whom 9 of 24 eyes required PRP. The decreased incidence of progression requiring laser surgery was statistically significant if events were considered independently (P < 0.006). The incidence of ocular disease progression was only 27% in patients treated with octreotide compared with 42% in patients with conventional diabetes management. This treatment effect on whether the retina worsened approached statistical significance using repeated measures analysis (P = 0.0605). Endocrine management was similar between treatment groups. Thyroxine replacement therapy was administered to maintain a euthyroid state for all octreotide-treated patients and 7 of 12 control patients. CONCLUSIONS: Our results suggest that octreotide treatment in euthyroid patients may retard progression of advanced DR and may delay the time to laser surgery.

Photoreceptor outer segments in aqueous humor from dogs with rhegmatogenous retinal detachments.

OBJECTIVE: To determine whether photoreceptor outer segments can be found in aqueous humor from dogs with rhegmatogenous retinal detachment (RRD). DESIGN: Case series. ANIMALS: 4 dogs with unilateral RRD, 2 dogs with bilateral RRD, 1 dog with unilateral non-RRD, and 1 dog with glaucoma without retinal detachment. PROCEDURE: Aqueous humor samples were fixed in 2% glutaraldehyde and examined by means of transmission electron microscopy. RESULTS: Outer segments were found in aqueous humor from 7 of 8 eyes with RRD but were not found in aqueous humor from dogs with non-RRD or glaucoma. CLINICAL IMPLICATIONS: Photoreceptor outer segments may move into the anterior chamber of eyes with RRD.

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.

Plasminogen activator inhibitor-1 overexpression in nonproliferative diabetic retinopathy.

Plasminogen activator inhibitor-1 is secreted bidirectionally by endothelial cells, acts as the primary regulator of fibrinolysis and as a key modulator of extracellular matrix proteolysis. Elevated serum levels of plasminogen activator inhibitor-1 are observed in serum of diabetic individuals. We investigated whether plasminogen activator inhibitor-1 is overexpressed in capillaries of diabetic donors with non-proliferative retinopathy compared to non-diabetic donors. We also assessed plasminogen activator inhibitor-1 expression in an animal model of retinopathy induced by exposing rabbit retinas to insulin-like growth factor-I. Colloidal gold immunocytochemistry was used to quantify plasminogen activator-1 antigen in donor retinas from diabetic subjects (n = 10) and control subjects (n = 10). This technique was also used to examine expression of plasminogen activator inhibitor-1 for correlation with retinal changes in the insulin-like growth factor-I-induced retinopathy model (n = 14). Plasminogen activator inhibitor-1 immunoreactivity was significantly increased in the retinas of all diabetic subjects as compared to controls. In the rabbit model, the expression of plasminogen activator inhibitor-1 immunoreactivity correlated with pathological retinal changes. In both the diabetic human and insulin-like growth factor-I-injected rabbit, overproduction of plasminogen activator inhibitor-1 was seen within the lumen of capillaries, within the cytoplasm of endothelial cells and in the basement membrane and extracellular matrix surrounding these capillaries. Minimal plasminogen activator inhibitor-1 was detected in the retinas of non-diabetics and in control rabbits injected with either heat-inactivated insulin-like growth factor-I or balanced salt solution. These studies support the conclusion that plasminogen activator inhibitor-1 is overexpressed in the retinal capillaries of diabetics with non-proliferative diabetic retinopathy and in rabbits with insulin-like growth factor-I-induced retinopathy.

Diabetic iris neovascularization.

PURPOSE: To compare the validity of careful slit-lamp biomicroscopic examination of the pupillary margin to screening gonioscopic examination in the early detection and prevention of neovascular glaucoma in diabetic patients. METHODS: We examined two patients with histories of diabetes mellitus. RESULTS: Angle neovascularization developed before iris neovascularization in both patients. CONCLUSION: We believe screening gonioscopic examination is valuable in patients with diabetes.

Experimental vitreous replacement with perfluorotri-n-propylamine.

OBJECTIVE: To evaluate perfluorotri-n-propylamine, a perfluorocarbon oil, as a temporary vitreous replacement in rabbits. METHODS: After undergoing gas compression vitrectomy, rabbits were injected with perfluorotri-n-propylamine for 24 hours or 2 weeks. The rabbits were evaluated clinically and with electroretinography. The globes were then enucleated and processed for histological evaluation. RESULTS: Clinical results showed droplet dispersion in the 2-week but not in the 24-hour group. Histological evaluation showed no changes in the retinal pigment epithelium or photoreceptor outer segments. Foam cells were seen in the 2-week but not in the 24-hour group. There was a marked dampening of the electroretinographic response that normalized after the removal of the oil. CONCLUSIONS: Perfluorotri-n-propylamine demonstrated no retinal toxic side effects in rabbits and is a promising liquid perfluorocarbon oil.

Endogenous Klebsiella endophthalmitis. Report of two cases and review of the literature.

BACKGROUND: Endogenous endophthalmitis is a rare complication of gram-negative sepsis. The diagnosis often is delayed unless a high index of suspicion exists. Familiarity with the clinical setting in which endogenous Klebsiella endophthalmitis occurs will hasten diagnosis and may improve outcome. METHODS: The authors reviewed the medical literature and describe two patients with diabetes who lost vision from endogenous Klebsiella endophthalmitis. FINDINGS: One patient lost all vision in both eyes before the diagnosis of sepsis was clinically suspected. In the other, endophthalmitis was the only clinical sign of septicemia 8 days after hospital discharge for treatment of a Klebsiella urinary tract infection. Survey of the literature showed an increase in the number of cases of endogenous Klebsiella endophthalmitis reported over the last 12 years. Sixty-one percent of the 44 patients reported in the literature since 1981 had diabetes, 68% had suppurative liver disease, and 16% had urinary tract infection. CONCLUSION: An important implication of these associations is that metastatic Klebsiella endophthalmitis must be considered when vitritis occurs in patients with diabetes, particularly in those with acute liver disease or a urinary tract infection, or in any patient with vitritis and suppurative liver disease.

Diabetic retinopathy. Background, classification, pathophysiology.

Diabetic retinopathy is the leading cause of legal blindness in the working adult population of the United States. The longer the duration of diabetes, the greater the likelihood retinopathy will develop. The proper classification of retinopathy is critical to the appropriate choice of therapeutic intervention and to the frequency of follow-up office visits. Monitoring of the patient must be a cooperative, team approach and requires early referral to an ophthalmologist experienced in the care of diabetics. The mainstay of current treatment is prevention through improved glucose control, early detection and, when necessary, intervention with timely laser photocoagulation and/or vitrectomy surgery. Based upon increased knowledge of the pathophysiology of diabetic retinopathy, the future may hold the ability to treat it with biological interventions at an earlier point in the course of the disease.

Subretinal hemorrhage after grid laser photocoagulation for idiopathic juxtafoveolar retinal telangiectasis.

A 56-year-old man had decreased vision secondary to bilateral idiopathic juxtafoveolar retinal telangiectasis. One month after grid laser photocoagulation for macular edema in the right eye, a subretinal hemorrhage developed. Over the next 2 months, the hemorrhage spontaneously resorbed and vision improved to 20/50. At 2-year follow up, without further treatment, vision was still 20/50.

Insulin-like growth factor I acts as an angiogenic agent in rabbit cornea and retina: comparative studies with basic fibroblast growth factor.

The release of growth factors from ischaemic retina has been hypothesized as the central stimulus for retinal neovascularization in proliferative diabetic retinopathy. Two of the growth factors implicated are insulin-like growth factor-I and basic fibroblast growth factor. We examined the effect of insulin-like growth factor-I on in vivo neovascularization using the established angiogenic model of the rabbit cornea (n = 30), and also compared the effects of insulin-like growth factor-I and basic fibroblast growth factor using two new in vivo systems. Either supraphysiologic concentrations of each growth factor (600 micrograms) were injected intravitreally into pigmented rabbits (n = 21) or porous polyfluorotetraethylene chambers filled with an emulsion containing collagen and growth factor (500 ng) were placed on the retina surface (n = 8). Our results demonstrate that when insulin-like growth factor-I was implanted together with a slow release carrier into the pocket of the normally avascular cornea, insulin-like growth factor-I (10 micrograms/pellet) induced angiogenesis in all rabbits. This degree of angiogenesis was comparable to that previously shown for basic fibroblast growth factor. For the intravitreal studies, the fibrotic component was greater in the basic fibroblast growth factor injected eyes, whereas the vascular component was accentuated in the eyes injected with insulin-like growth factor-I. Light and electron microscopy demonstrated areas of vascular proliferation in both groups. Porous polyfluorotetraethylene chamber studies with insulin-like growth factor-I and basic fibroblast growth factor demonstrated vascular proliferation in the vicinity of the chamber similar to the intravitreal injected eyes, but to a lesser degree than the injected eyes. Our experiments overall support the angiogenic potential of both insulin-like growth factor-I and basic fibroblast growth factor and support distinct but complimentary roles for each growth factor in the pathogenesis of proliferative diabetic retinopathy.

Distribution of the posterior ciliary arteries revealed after vascular occlusions. A case report.

Recognized posterior ciliary artery occlusion combined with central retinal artery occlusion is relatively uncommon. Clinical and experimental evidence of combined occlusions appear to support a nasal and temporal distribution for the posterior ciliary arteries in most cases. A case involving a patient in whom the posterior ciliary arteries divided superiorly and inferiorly to supply the region of the macula is reported. Some of the more common variations in the distribution of the posterior ciliary arteries are discussed. Clinicians should be aware that the territorial divisions of the choroidal perfusion in the macula may be horizontally based.

Eye care guidelines for patients with diabetes mellitus.

Diabetic retinopathy is the leading cause of blindness in adults under age 65 in the United States. Risk is related to the stage of retinopathy. With new treatments available, it is imperative that diabetics be properly screened. Those with retinopathy of more than five years duration should be referred to an ophthalmologist. Since photocoagulation has been shown effective for treatment of macular edema and proliferative retinopathy, it is imperative that these patients be referred for timely evaluation.

Inadvertent penetrating injury to the globe with periocular corticosteroid injection.

We surveyed 488 physicians regarding their experience with inadvertent ocular penetration with steroid injections over a 5-year period. Sixty-six cases of ocular penetration were reported by the 209 physicians who responded. Of the 18 patients whose retinal status was known, 12 (67%) had retinal detachments resulting from the penetration. Final visual acuities in 85% of the 26 cases were worse than 20/100.

Central retinal and posterior ciliary artery occlusion after particle embolization of the external carotid artery system.

A 15-year-old boy underwent neuroradiologic embolization of the left internal maxillary artery with polyvinyl alcohol to stop traumatic epistaxis after failure of surgical clipping and nasal packing. Selective catheterization of the external carotid artery before embolization showed a faint choroidal blush. Although the procedure provided hemostasis, embolization to the central retinal artery and ciliary arteries resulted in loss of vision. The route of the emboli to the eye was via the anastomotic network of the lacrimal artery supplied by the external carotid artery system. Neuroradiologic embolization of the external carotid artery is an effective mode of therapy for dural-cavernous fistulas when fed by the external carotid artery system. Because the blood flow to the brain and eye is predominantly supplied by the internal carotid artery, embolization of the external carotid artery is considered relatively safe. The authors document the importance of recognition of the choroidal blush during selective external carotid artery angiography as a sign of collateral blood flow to the eye. Physicians and patients need to be aware of the risk of blindness as a complication of external carotid artery embolization when this sign is present.

Retinal pigment epithelial tear after treatment of metastatic carcinoma of the choroid.

A 59-year-old woman developed a tear of the retinal pigment epithelium (RPE) shortly after receiving radiation therapy and chemotherapy for metastatic breast carcinoma to the choroid. If the RPE tear had not been observed during the early stage of its evolution, the subsequent coiled mass of RPE could have been easily mistaken for reactive hyperplasia. The location of the RPE tear relative to the choroidal metastasis and its temporal relationship to tumor involution suggest that the RPE tear and therapy for metastatic carcinoma were causally related. This is the first description of an RPE tear overlying a metastatic tumor.