Duration of intraocular gases following vitreoretinal surgery.

BACKGROUND: Intraocular gas tamponades are an important tool in modern vitreoretinal surgery. However, there is considerable variation in their use and perceptions amongst clinicians regarding these agents. METHODS: An electronic survey of vitreoretinal surgeons in the UK was undertaken to establish the patterns of use and surgeons' estimates of the longevity and expansion timing of gas tamponades. In addition, data were prospectively collected on the longevity of gas tamponades in 114 patients from our unit. An analysis was performed to identify patient or surgery factors affecting gas longevity RESULTS: A wide variation in the patterns of use and estimates of longevity and expansion timing of intraocular tamponades was found in the survey of vitreoretinal surgeons. Data from our unit give informed estimates on the longevity of three commonly used tamponades. For 30 % sulphur hexafluoride (SF6), mean 18.0 days, standard deviation (SD) 2.6 days. For 20 % hexafluoroethane (C2F6), mean 34.5 days, SD 3.3 days. For 15 % perfluoropropane (C3F8), mean 67.7 days SD 5.5 days. In the C2F6 group there was correlation between longer duration of the gas bubble and longer axial length (r = 0.438, p = 0.02) and longer gas duration with male sex (p = 0.002). CONCLUSIONS: We present informed gas tamponade longevity figures in clinical practice and report statistically significant associations between longer gas longevity and increasing axial length and male sex.

Acute serous macular detachment and cystoid macular edema after uncomplicated phacoemulsification using standard dose subconjunctival cefuroxime.

Acute toxic serous macular detachment after cataract surgery is very rare, and has been described previously with the use of high concentrations of intra-cameral cefuroxime. We report a case of serous macular detachment and cystoid macular edema 1 day after uncomplicated phacoemulsification using standard dose subconjunctival cefuroxime at the end of surgery. Our case demonstrates that subconjunctival cefuroxime may cause retinal toxicity in a similar fashion to intra-cameral cefuroxime, possibly due to entry of the drug into the anterior chamber through the section or trans-scleral absorption. To our knowledge, this is the first report of this complication with subconjunctival administration of cefuroxime.

Pars Plana Vitrectomy for Vitreomacular Traction Syndrome: Analysing the Preoperative Prognostic Factors.

PURPOSE: To identify the prognostic factors affecting the surgical outcomes in patients with vitreomacular traction syndrome undergoing pars plana vitrectomy. METHODS: This was a retrospective clinical study of 67 eyes of 67 patients with vitreomacular traction syndrome who underwent pars plana vitrectomy. Demographic, clinical, and optical coherence tomography (OCT) characteristics were collected and analyzed. Univariate and multivariate linear regression analysis were used to examine the effect of parameters on change in best-corrected visual acuity (BCVA). RESULTS: At a mean follow-up period of 15.9±12 months (mean±SD), the BCVA improved from 0.7±0.3 LogMAR (mean±SD) to 0.5±0.3. Seven patients developed full-thickness macular hole intraoperatively and tamponade (air, 20% SF6 or 12% C3F8) was used in 41 patients. Retinal breaks were identified intraoperatively in four patients. Regression analysis demonstrated that the preoperative BCVA was the only parameter affecting the postoperative visual outcome. CONCLUSION: In the present study, the preoperative BCVA plays a predictive role in the surgical outcome of patients with VMT undergoing pars plana vitrectomy. No other preoperative OCT characteristics demonstrated prognostic potential. Further prospective studies are needed in order to examine the role of several factors that could potentially facilitate preoperative patient counselling.

Rate and risk factors for the conversion of fovea-on to fovea-off rhegmatogenous retinal detachment while awaiting surgery.

BACKGROUND/AIMS: Progression of a fovea-on to a fovea-off rhegmatogenous retinal detachment (RRD) while awaiting surgery is rare. METHODS: A retrospective review of patient records to identify patients in whom a fovea-on retinal detachment at presentation was found to be fovea off at surgery. RESULTS: We identified 10 cases over 14 years which converted from fovea-on to fovea-off RRD while awaiting surgery. This represented 1.1% of RRDs that were fovea on at presentation (n=930). Nine out of 10 patients had superotemporal RRDs extending to at least the vascular arcade at presentation and all had superotemporal breaks within detached retina, which was significantly higher than the rate for other retinal detachments (100% vs 63%, p=0.02). There were 2.4 breaks per eye, similar to other retinal detachments. Six of the 10 patients converted to a fovea-off retinal detachment within a few hours and the rest by the following day. Visual outcomes were good, with eight patients maintaining their presenting visual acuity and two losing one Snellen line. CONCLUSIONS: Offering same-day surgery to high-risk fovea-on RRDs may not significantly influence visual outcomes and would only prevent about half of the conversions to fovea off. Superotemporal retinal detachments extending to near the arcades are most at risk and might warrant posturing to limit spread of the detachment in the preoperative period.

Activation of nuclear factor-kappaB via endogenous tumor necrosis factor alpha regulates survival of axotomized adult sensory neurons.

Embryonic dorsal root ganglion (DRG) neurons die after axonal damage in vivo, and cultured embryonic DRG neurons require exogenous neurotrophic factors that activate the neuroprotective transcription factor nuclear factor-kappaB (NF-kappaB) for survival. In contrast, adult DRG neurons survive permanent axotomy in vivo and in defined culture media devoid of exogenous neurotrophic factors in vitro. Peripheral axotomy in adult rats induces local accumulation of the cytokine tumor necrosis factor alpha (TNFalpha), a potent activator of NF-kappaB activity. We tested the hypothesis that activation of NF-kappaB stimulated by endogenous TNFalpha was required for survival of axotomized adult sensory neurons. Peripheral axotomy of lumbar DRG neurons by sciatic nerve crush induced a very rapid (within 2 h) and significant elevation in NF-kappaB-binding activity. This phenomenon was mimicked in cultured neurons in which there was substantial NF-kappaB nuclear translocation and a significant rise in NF-kappaB DNA-binding activity after plating. Inhibitors of NF-kappaB (SN50 or NF-kappaB decoy DNA) resulted in necrotic cell death of medium to large neurons (> or =40 microm) within 24 h (60 and 75%, respectively), whereas inhibition of p38 and mitogen-activated protein/extracellular signal-regulated kinase did not effect survival. ELISA revealed that these cultures contained TNFalpha, and exposure to an anti-TNFalpha antibody inhibited NF-kappaB DNA-binding activity by approximately 35% and killed approximately 40% of medium to large neurons within 24 h. The results show for the first time that cytokine-mediated activation of NF-kappaB is a component of the signaling pathway responsible for maintenance of adult sensory neuron survival after axon damage.

Comparative Analysis of Anterior Chamber Flare Grading between Clinicians with Different Levels of Experience and Semi-automated Laser Flare Photometry.

PURPOSE: To assess correlation for anterior chamber flare grading between clinicians with different levels of experience and with semi-automated flare reading in a cohort of patients with heterogeneous uveitic entities. METHODS: Fifty-nine observations from 36 patients were recorded and analyzed for statistical association. In each patient, flare was assessed objectively using the Kowa FM-700 laser flare photometer, and subjective masked grading by two clinicians was performed. RESULTS: The study demonstrated disparity in flare readings between clinical graders with one step disagreement in clinical grading in 26 (44.06%) eyes (p < 0.001) and concordance between the flare readings by experienced grader and flare photometry. After review of semi-automated flare readings, management was changed in 11% of the patients. CONCLUSION: Laser flare photometry can be a valuable tool to remove the observer bias in grading flare for selected cohort of uveitis patients. It can be further applied to titrate therapy in intraocular inflammation.

Classification of semi-automated flare readings using the Kowa FM 700 laser cell flare meter in patients with uveitis.

PURPOSE: To propose a classification system to grade semi-automated flare readings and assess its correlation with clinical flare grading and also to explore the utility of an additional step in clinical flare assessment between grades 0 and 1. METHODS: Semi-automated flare readings from 103 eyes with uveitis were taken using the Kowa FM 700 laser flare meter and classified into two models (LFCM and LFCM_1), and introduction of a 0.5 step in flare grading was explored. RESULTS: Good correlation was present between the conventional SUN clinical flare and the proposed clinical classification for flare (weighted kappa (WK) = 89.64%, p < 0.001). Semi-automated flare grading (LFCM and LFCM_1) had WK agreement of 82.52% and 79.85% (p < 0.001) with conventional SUN clinical flare grading. CONCLUSIONS: The proposed classification system for semi-automated laser flare readings (LFCM) allows stratification of measurements into grades analogous to clinical flare grades and correlates well with conventional clinical flare grading.

Towards evidence based emergency medicine: best BETs from the Manchester Royal Infirmary. Cervical spine imaging in children under 9 after trauma.

A short cut review was carried out to establish whether the odontoid peg view is useful to radiologically exclude cervical spine injury in children under 9 years of age. Altogether 156 papers were found using the reported search, of which two presented the best evidence to answer the clinical question. In addition recent guidelines are noted. The author, date and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses of these best papers are tabulated. A clinical bottom line is stated.

Towards evidence based emergency medicine: best BETs from the Manchester Royal Infirmary. Need for cervical spine imaging for alert children after trauma.

A short cut review was carried out to establish whether clinical examination can be used to exclude cervical spine injury in alert children. Altogether 298 papers were found using the reported search, of which three presented the best evidence to answer the clinical question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses of these best papers are tabulated. A clinical bottom line is stated.