Bilateral intravitreal injection of antivascular endothelial growth factor therapy.

PURPOSE: The purpose of this study was to review adverse events and patient preference after bilateral intravitreal injection of antibodies to vascular endothelial growth factor. METHODS: A retrospective case-control study. Patients with exudative age-related macular degeneration who received intravitreal antivascular endothelial growth factor agent injections in both eyes (bilateral group) on the same day over a 23-month period were compared with patients who received injections in only 1 eye. The occurrence of endophthalmitis, cerebrovascular accident, myocardial infarction, death, patient discomfort, and patient preference was compared between the two groups. RESULTS: One hundred and two patients received an average of 4.43 bilateral injections (range 1-13). A case-control group of 102 patients received an average of 10.2 unilateral injections, (range 2-28). Bevacizumab was injected 45.5%, ranibizumab 45.5%, and a combination of bevacizumab and ranibizumab 9% of the time for bilateral injections. Bevacizumab was used 50.3% and ranubizumab 49.7% of the time in unilateral injections. The follow-up of both groups averaged 18.4 months (range 4.7-36.5 months). There were no cases of endophthalmitis or cerebrovascular accident in either group. There was a single case of myocardial infarction in each group. There were two deaths in the bilateral group and three deaths in the unilateral group. More than 90% strongly preferred bilateral injections to unilateral injections. CONCLUSION: Bilateral injections of antivascular endothelial growth factor agents on the same day did not increase the rate of adverse events and was preferred by the majority of patients.

Vitreous amino acid concentrations in patients with glaucoma undergoing vitrectomy.

OBJECTIVE: To measure vitreous concentrations of glutamate and other amino acids in patients with glaucoma undergoing vitrectomy. METHODS: Undiluted vitreous samples were collected from patients undergoing vitrectomy at the University of Iowa (Iowa City) between 1997 and 1998 (n = 69). Vitreous concentrations of 16 amino acids, including glutamate, were determined using high-pressure liquid chromatography. Patients with a history of diabetes mellitus were excluded from the analysis. The study group consisted of those with a history of glaucoma (n = 8), and the control group included those with an epiretinal membrane and/or macular hole with no history of glaucoma (n = 17). Comparison of amino acid concentrations between the 2 groups was performed using a multifactor main effects model that adjusted for the effect of 10 selected covariates. Power analysis was done to determine the level of significant difference in amino acid concentrations. RESULTS: The glaucoma group comprised vitreal specimens from patients with primary open-angle (n = 3) and angle-closure glaucomas that included aqueous misdirection (n = 2), uveitis with secondary angle-closure (n = 2), and Axenfeld Rieger syndrome (n = 1). Indications for vitrectomy in this group included epiretinal membrane, retinal detachment, aqueous misdirection, and uveitis. The control group included specimens from patients with a macular hole (n = 11) and epiretinal membrane (n = 7), with 1 eye having both. Surgical indications in controls were macular hole, retinal detachment, and epiretinal membrane. The mean +/- SD levels of vitreous glutamate, glycine, gamma-aminobutyric acid, and alanine were 6.1 +/- 2.4, 16.3 +/- 7.5, 0.8 +/- 0.3, and 260.5 +/- 101.9 microM, respectively, in glaucoma and 5.2 +/- 2.3, 8.5 +/- 2.5, 0.6 +/- 0.2, and 159.5 +/- 54.9 microM in controls (P >.05 for all). None of the 16 amino acid concentrations measured showed a statistically significant difference between glaucoma and controls (P values between.06 and >.99). A power analysis indicated that a 1.8-fold elevation in the glutamate level was needed to reach significance. MAIN OUTCOME MEASURES: Vitreous amino acid concentrations. CONCLUSIONS: None of the 16 amino acids measured, including glutamate, were significantly elevated in the vitreous of glaucomatous eyes compared with controls. Our results are not consistent with the simple hypothesis of glutamate excitotoxicity in glaucoma. Instead, our findings indicate the dynamic nature of extracellular glutamate, whose concentration is dependent on complex mechanisms not yet fully understood. Further studies are needed to fully elucidate the role of glutamate in the pathogenesis of glaucoma.

Spectral parameter imaging for detection of prognostically significant histologic features in uveal melanoma.

Specific extracellular matrix patterns in uveal melanoma are associated with metastatic risk. The laminin-rich composition and dimensions (on the order of a wavelength or less) of these structures suggest that acoustic backscatter might be affected by their presence. In this study, 10-MHz radiofrequency (RF) ultrasound (US) data were acquired before surgical removal of 117 eyes with uveal malignant melanoma. Histologic sections were evaluated for the presence of matrix patterns and acoustic backscatter was characterized using calibrated spectrum analysis. Statistical correlations between acoustic and histologic patterns were determined and linear discriminant analysis (LDA) and radial basis networks (RBN) were used to develop classification models for histologically based risk groups. Statistically significant correlations were found between acoustic parameters and the presence of histologic matrix-rich patterns. Retrospective classification accuracies of 74.4% and 78.6% were obtained with LDA and RBN, respectively. Leave-one-out analyses indicated estimated predictive accuracies of 71.8% and 75.0% for LDA and RBN, respectively.

Noninvasive in vivo detection of prognostic indicators for high-risk uveal melanoma: ultrasound parameter imaging.

PURPOSE: Primary malignant melanoma of the choroid and ciliary body has traditionally been treated without histologic staging, using purely clinical indicators. The presence of extravascular matrix patterns (EMP) in histologic sections of uveal melanoma has been shown to be an independent indicator of metastatic risk. These patterns are of a dimension and physical composition that are likely to be detected with ultrasound backscatter analysis. Our aim was to determine whether ultrasound parameter imaging could detect the presence of EMP at a diagnostically significant level for treatment staging and for planning investigational studies of therapeutic modalities. DESIGN: Prospective, masked ultrasound-pathologic correlative study. PARTICIPANTS: One hundred seventeen patients diagnosed with previously untreated choroidal melanoma were scanned within 2 weeks before enucleation. METHODS: Tumors were evaluated histologically and divided into high-risk and low-risk groups on the basis of the presence of 2% or more histologic cross-sectional area composed of EMP patterns. Digital ultrasound data were processed to generate parameter images representing the size and concentration of ultrasound scatterers. Histologic and ultrasound images and data were correlated, and linear and nonlinear statistical methods were used to create multivariate models for noninvasive differentiation of high-risk and low-risk tumors. MAIN OUTCOME MEASURES: Presence or absence of high-risk EMP and associated ultrasound parameter classification models. RESULTS: Of the 117 tumors, 69 were classified as low risk, and 48 were classified as high-risk with histologic analysis. A classification that used ultrasound parameter image features with linear discriminant analysis could correctly identify 79.5% of cases retrospectively and 75.2% of cases by use of cross-validation, an estimate of prospective classification ability. By use of a more powerful classification technique (support vector machine), 93.1% of cases were correctly classified retrospectively. With a cross-validation procedure, 80.10% of cases were correctly classified. CONCLUSIONS: Ultrasound can be used noninvasively to classify tumors into high-risk and low-risk groups by detecting the presence of EMP patterns. By the use of previous studies that compared the histologic presence of EMP patterns with patient survival, estimates of hazard rates associated with ultrasound risk groups can be made. The noninvasive ultrasound classification is potentially useful as a prognostic variable and as a tool for stratification of patient populations for tumor treatment evaluation.