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D.E. Grigera, A. Zambrano; Emulsified Silicone Oil in the Anterior Segment and Intraocular Pressure in the Late Postoperative Period of Vitreoretinal Surgery: An Ultrasound Biomicroscopy Study . Invest. Ophthalmol. Vis. Sci. 2003;44(13):4378.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To study, by means of Ultrasound Biomicroscopy (UBM) and of clinical examination, the presence and location of silicone oil (SO) in the filtration area, the degree of SO emulsification in the anterior chamber and its relationship to intraocular pressure (IOP) in patients who underwent vitreoretinal surgery no less than 30 days prior to the UBM examination. Methods: 29 consecutively referred patients with SO injection (Medical grade, 1000 centistoke viscosity) operated by one of the authors (AZ) were prospectively examined by means of: interview, light biomicroscopy, tonometry, UBM. Main outcome measures: Time of permanence of SO (TSO), tonometry, a numerical UBM estimation of the degree of SO emulsification in the anterior chamber (EDSOE), UBM hyperreflectivity at the filtration area. Comparison between EDSOE and IOP was made with Student's t test and Pearson's correlation coefficient was calculated. Results: Average time of permanence of SO was 404 days (median 253, range: 30-1893), ocular hypertension (OH) prevalence: 28.57% (8 eyes, 5 controlled w/topical medication). 100 % of OH cases had an open angle (3-4 degree). Presumed pathophysiology: a) SO impregnation (6 cases), and b) SO impregnation plus goniosynechiae (2 cases). 85.7% of the eyes and 100% of OH cases had emulsified SO particles in the anterior chamber,100% OH cases had trabecular impregnation. 67.85% of the eyes had hyperreflectivity at the filtration area: 31.57% 1 quadrant, 26.3% 3 quadrants, 36.68% 4 quadrants. More prevalent at the superior quadrant (94.73%) than at the inferior (25%), SO was selectively located at the filtration area in 57.89% (11 eyes). No statistically significant differences were observed between TSO and EDSOE (r =0,36 p =0,057) nor between EDSOE and IOP (r =0,29 p =0,08). Conclusions: All eyes with OH had trabecular impregnation with SO. Our study confirms a higher frequency of hyperreflectivity in the superior area of the angle and shows how SO tends to gather selectively at the filtration area. No relationship was observed between EDSOE and IOP in this series.
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