A guide to the removal of heavy silicone oil

Aim: Heavy silicone oil removal can be challenging and differs considerably from conventional oil. Traditionally, strong active aspiration had to be applied through a long 18G needle just above the optic disc. We present a novel technique using a much shorter (7.5 mm) and smaller (20G) needle allowing its removal "from a distance." Method: Active aspiration on a vacuum of 600 mm Hg of the "viscous fluid injector" was applied using the 20G cannula in a polymethylmethacrylate model eye chamber that was surface-modified to mimic the surface properties of the retina. Measurements were taken using still photographs. Results: Under injection the maximum diameter of a silicone oil bubble supported by interfacial tension alone was 5 mm for a steel and 7 mm for a polyurethane cannula. Under suction, the silicone bubble changed shape and became conical, thus further increasing the cannula's reach. This conical shape illustrated "tubeless siphoning," which is a physical property of non-Newtonian fluids. Discussion: The use of shorter and smaller gauge cannula for removal of Densiron obviates the need to enlarge the sclerotomy beyond 20G or to apply suction in close proximity to disc and fovea. This potentially reduces the risk of iatrogenic damage such as entry site tears or postoperative hypotony.published_or_final_versio

Labelling, Deviance and Media

Labelling theory is a perspective that emerged as a distinctive approach to criminology during the 1960s, and was a major seedbed of the radical and critical perspectives that became prominent in the 1970s. It represented the highpoint of an epistemological shift within the social sciences away from positivism – which had dominated criminological enquiry since the late-1800s – and toward an altogether more relativistic stance on the categories and concepts of crime and control. It inspired a huge amount of work throughout the 1960s and 1970s, and still resonates powerfully today. This short chapter maps out some of the ways in which labelling, deviance, media and justice interact at the levels of definition and process. It presents an overview and analysis of key mediatised labelling processes, such as the highly influential concept of moral panics. It discusses how the interconnections between labelling, crime and criminal justice are changing in a context of technological development, cultural change and media proliferation. The conclusion offers an assessment and evaluation of labelling theory’s long-term impact on criminology

The Caravan Rolls On

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68409/2/10.1177_107554707900100103.pd

Perception of tilt following counter-rotation surgery

Background: Macular translocation surgery (MTS) is one of the treatment options for age-related macular degeneration (AMD) followed by counter-rotation surgery (CRS) to correct the resulting tilt. The objective of this paper is to determine the perception of tilt following CRS and identify factors that influence the perception of tilt in the presence of residual cyclorotation following CRS. Methods: Thirty-four AMD patients treated with MTS and CRS were investigated; and all measurements were made preoperatively, and after each surgical procedure. Fundus photographs were analysed with computer software to determine the degree of retinal rotation and reliability was assessed by two independent assessors. The degree of perceptual rotation was measured with Maddox rod and the subjective appreciation of tilt was established by direct questioning. Fixation preference was determined by cover test and convergence. Bagolini glasses were used to determine binocular outcome. Results: Post CRS, 20 of the 34 patients had adapted to tilt. There was a significant difference of 5° ± 7° (95% confidence intervals: 1-8°, t = 2.9, degree of freedom = 19, P = 0.008) between the degree of rotation measured from the fundus photographs and the Maddox rod measurement following CRS. Patients with residual retinal rotation less than or equal to 15° did not appreciate tilt in free space. More importantly, fixation with the operated eye and ignoring the image from the non-operated eye was significantly associated with being free of tilt in natural viewing conditions (P < 0.05). Conclusion: Despite the presence of residual cyclorotation of the macula following CRS of up to 27°, a significant proportion (59%) of patients did not perceive the world as tilted in natural viewing conditions. Differences between retinal rotation and perceptual tilt provide evidence of sensory adaptation. It was patients who fixed with their operated eye and ignored the image from the non-operated eye who did not perceive tilt post CRS. © 2010 The Authors. Journal compilation © 2010 Royal Australian and New Zealand College of Ophthalmologists.link_to_subscribed_fulltex