Vision loss associated with the use and removal of intraocular silicone oil

Patrick D Williams1, Christopher G Fuller1, Ingrid U Scott2, Dwain G Fuller1, Harry W Flynn Jr31Texas Retina Associates, Dallas, TX, USA; 2Departments of Ophthalmology and Health Evaluation Sciences, Penn State College of Medicine, Hershey, PA, USA; 3Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USAPurpose: To describe vision loss associated with the use or removal of silicone oil retinal tamponade.Methods: Records were reviewed of all patients with a decrease in visual acuity of at least 3 Snellen lines from best acuity with 5000 centistoke silicone oil in place or after removal of silicone oil at a single retina-only practice between 1996 and 2006.Results: Nine patients (6 men, 3 women) with a mean age of 48 years (range, 16–61) met study inclusion criteria. Seven patients lost at least three Snellen lines of vision while the silicone oil was in place. Four patients had late modest improvements in acuity when compared to their final recorded Snellen vision before silicone oil removal, however no patients exhibited visual improvement when comparing their final recorded visual acuities after oil removal with best recorded acuities under oil tamponade. Loss of the foveal depression was a consistent feature on optical coherence tomography.Conclusions: Vision loss is a possible complication of silicone oil use and removal. Late visual improvement may occur in some patients. Further research is warranted to elucidate the mechanism(s) of vision loss associated with the use or removal of silicone oil.Keywords: retinal tamponade, visual acuity, snellen vision, silicone oi

False positive acetaminophen concentrations in patients with liver injury

AbstractBackgroundAcetaminophen toxicity is the most common form of acute liver failure in the U.S. After acetaminophen overdoses, quantitation of plasma acetaminophen can aid in predicting severity of injury. However, recent case reports have suggested that acetaminophen concentrations may be falsely increased in the presence of hyperbilirubinemia.MethodsWe tested sera obtained from 43 patients with acute liver failure, mostly unrelated to acetaminophen, utilizing 6 different acetaminophen quantitation systems to determine the significance of this effect. In 36 of the 43 samples with bilirubin concentrations ranging from 1.0–61.5 mg/dl no acetaminophen was detectable by gas chromatography-mass spectroscopy. These 36 samples were then utilized to test the performance characteristics of 2 immunoassay and 4 enzymatic–colorimetric methods.ResultsThree of four colorimetric methods demonstrated ‘detectable’ values for acetaminophen in from 4 to 27 of the 36 negative samples, low concentration positive values being observed when serum bilirubin concentrations exceeded 10 mg/dl. By contrast, the 2 immunoassay methods (EMIT, FPIA) were virtually unaffected. The false positive values obtained were, in general, proportional to the quantity of bilirubin in the sample. However, prepared samples of normal human serum with added bilirubin showed a dose–response curve for only one of the 4 colorimetric assays.ConclusionsFalse positive acetaminophen tests may result when enzymatic–colorimetric assays are used, most commonly with bilirubin concentrations >10 mg/dl, leading to potential clinical errors in this setting. Bilirubin (or possibly other substances in acute liver failure sera) appears to affect the reliable measurement of acetaminophen, particularly with enzymatic–colorimetric assays

Subretinal Hyperreflective Material in the Comparison of Age-Related Macular Degeneration Treatments Trials

PurposeTo evaluate the association of subretinal hyperreflective material (SHRM) with visual acuity (VA), geographic atrophy (GA), and scar in the Comparison of Age-Related Macular Degeneration Treatments Trials (CATT).DesignProspective cohort study within a randomized clinical trial.ParticipantsThe 1185 CATT participants.MethodsMasked readers graded scar and GA on fundus photography and fluorescein angiography and graded SHRM on time-domain and spectral-domain (SD) optical coherence tomography (OCT) throughout 104 weeks. Measurements of SHRM height and width in the fovea, within the center 1 mm(2), or outside the center 1mm(2) were obtained on SD OCT images at 56 (n = 76) and 104 (n = 66) weeks.Main outcome measuresPresence of SHRM, as well as location and size, and associations with VA, scar, and GA.ResultsAmong CATT participants, the percentage with SHRM at enrollment was 77%, decreasing to 68% at 4 weeks after treatment and to 54% at 104 weeks. At 104 weeks, scar was present more often in eyes with persistent SHRM than in eyes with SHRM that resolved (64% vs. 31%; P < 0.0001). Among eyes with detailed evaluation of SHRM at weeks 56 (n = 76) and 104 (n = 66), mean VA letter score was 73.5 (standard error [SE], 2.8), 73.1 (SE, 3.4), 65.3 (SE, 3.5), and 63.9 (SE, 3.7) when SHRM was absent, present outside the central 1 mm(2), present within the central 1 mm(2) but not the foveal center, or present at the foveal center (P = 0.02), respectively. When SHRM was present, the median maximum height under the fovea, within the central 1 mm(2) including the fovea and anywhere within the scan, was 86 μm, 120 μm, and 122 μm, respectively. Visual acuity was decreased with greater SHRM height and width (P < 0.05).ConclusionsIn eyes with neovascular age-related macular degeneration (AMD), SHRM is common and often persists after anti-vascular endothelial growth factor treatment. At 2 years, eyes with scar were more likely to have SHRM than other eyes. Greater SHRM dimensions were associated with worse VA. In eyes with neovascular AMD, SHRM is an important morphologic biomarker