Macular morphology and visual acuity after macular hole surgery with or without internal limiting membrane peeling.

AIM: To examine postoperative macular morphology and visual outcome after 12 months in relation to internal limiting membrane (ILM) peeling versus no peeling, indocyanine green (ICG) staining and re-operation in eyes that achieved macular hole closure after surgery. METHODS: Seventy-four eyes with closed stage 2 or 3 macular holes were recruited from a randomised clinical trial comparing: (1) vitrectomy without ILM peeling; (2) vitrectomy with 0.05% isotonic ICG-assisted ILM peeling; and (3) vitrectomy with 0.15% trypan blue-assisted ILM peeling. Contrast-enhanced Stratus optical coherence tomography was used to assess central foveal thickness, central photoreceptor layer thickness (CPRT), central photoreceptor layer discontinuity (PRD) and relative reflectivity of the outer nuclear layer. Outcomes were correlated with best corrected visual acuity (BCVA) 12 months after surgery. RESULTS: BCVA was correlated with CPRT and PRD. Regression analysis and receiver operating characteristics curve analysis showed that CPRT >33 microm (OR 12.5) and PRD <177 microm (OR 9.86) were highly predictive for regaining reading vision (> or =69 Early Treatment of Diabetic Retinopathy Study letters) 12 months after surgery. No significant difference was found in postoperative macular morphology between subgroups. CONCLUSIONS: Poor vision after 12 months despite macular hole closure was associated with attenuation and disruption of the foveolar photoreceptor matrix. The extent of attenuation and disruption was independent of peeling and staining. TRIAL REGISTRATION NUMBER: NCT00302328.

Value of internal limiting membrane peeling in surgery for idiopathic macular hole stage 2 and 3: a randomised clinical trial.

AIM: To determine the effect of internal limiting membrane (ILM) peeling on anatomical and functional success rates in stage 2 and 3 idiopathic macular hole surgery (MHS). METHODS: Randomised clinical trial of stage 2 and 3 idiopathic macular hole without visible epiretinal fibrosis and with less than 1 year's duration of symptoms. Eyes were randomised to (1) vitrectomy alone without retinal surface manipulation, (2) vitrectomy plus 0.05% isotonic Indocyanine Green (ICG)-assisted ILM peeling or (3) vitrectomy plus 0.15% Trypan Blue (TB)-assisted ILM peeling. Main outcomes were hole closure after 3 and 12 months and best-corrected visual acuity after 12 months. RESULTS: 78 eyes were enrolled. Primary closure rates were significantly higher with ILM peeling than without peeling for both stage 2 holes (ICG peeling 100%, non-peeling 55%, p = 0.014) and for stage 3 holes (ICG peeling 91%, TB peeling 89%, non-peeling 36%, p<0.001). Visual outcomes in eyes with primary hole closure were not significantly different between the groups. CONCLUSIONS: Dye-assisted ILM peeling was associated with significantly higher closure rates than non-peeling in both stage 2 and 3 MHS. Intraoperative ILM staining with 0.05% isotonic ICG was not associated with a significantly different visual outcome than non-peeling or TB peeling in eyes with primary hole closure. TRIAL REGISTRATION NUMBER: NCT00302328.

Normative data of outer photoreceptor layer thickness obtained by software image enhancing based on Stratus optical coherence tomography images.

AIM: To present normative data of outer photoreceptor layer thickness obtained by a new semiautomatic image analysis algorithm operating on contrast-enhanced optical coherence tomography (OCT) images. METHODS: Eight Stratus OCT3 scans from identical retinal locations from 25 normal eyes were registered and combined to form a contrast-enhanced average image. Utilising the vertical intensity gradients of the enhanced OCT images to demarcate retinal layers, thickness measurements of the outer photoreceptor- and retinal pigment epithelium layer (RPE-OS(complex)) were obtained. Additionally backscattered light within the outer nuclear layer (ONL) in the fovea was registered and compared with backscattered light within the ONL in the peripheral part of the macula (I(ratio)-ONL). RESULTS: The mean RPE-OS(complex) thickness in the foveal centre was 77.2 microm (SD = 3.95). The RPE-OS(complex) thickness in the superior macula 0.5-3 mm of the centre was significantly increased as compared with the corresponding inferior retina. In healthy subjects, the I(ratio)-ONL was 1.06. CONCLUSIONS: Contrast-enhanced OCT images enable quantification of outer photoreceptor layer thickness, and normative values may help understanding better the relationship between functional outcome and photoreceptor morphology in retinal diseases.

How do anaesthesiologists treat malignant hyperthermia in a full-scale anaesthesia simulator?

BACKGROUND: Clinical malignant hyperthermia (MH) is rare and usually occurs unexpectedly. Prompt diagnosis and correct treatment is crucial for survival of the patient developing fulminant MH. The aims of the present study were to investigate whether anaesthesiologists could make a correct diagnosis of MH and to evaluate their treatment of fulminant MH in a simulator. METHODS: Thirty-two teams (one anaesthesiologist/one nurse anaesthetist) were exposed to an event of clinical MH in a full-scale simulator. Their performance was videotaped for retrospective analysis of the treatment on the basis of the recommendations of the Danish Malignant Hyperthermia Register. RESULTS: All 32 teams asked the surgeon to terminate the surgery as fast as possible, switched off the vaporiser and administered 100% oxygen. Although all intended to hyperventilate the patient, only 14 teams actually managed to perform the hyperventilation. Most problems were found in teams that switched to manual ventilation. All teams treated the patient with dantrolene, and symptomatic treatment was initiated by all even though some elements of the full treatment were lacking, possibly due to the limited time available. CONCLUSION: All teams diagnosed MH in the simulator satisfactorily. The surprising negative finding was that more than half of the participants failed to hyperventilate the "patient" although they intended to do so. This investigation shows that the problem in these teams' treatment of MH was more a question of practical management of the resources than lack of theoretical knowledge.