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.

Urinary bladder blood flow. I. Comparison of clearance of locally injected 99mtechnetium pertechnate and radioactive microsphere technique in dogs.

The blood flow of the dog urinary bladder measured by radioactive microsphere technique was compared to the clearance of locally injected 99mTechnetium pertechnate (99mTc) in the bladder wall. In semilogarithmic plots the 99mTc washout curves showed a multiexponential course. From the initial slopes (median 5.7 min) the bladder blood flow was calculated to be only 30-62% of the results obtained from the radioactive microsphere technique (blood flow in the muscular layer 21.7-44.8 ml/100 g/min). These lower values imply that the rate of removal of the hydrophilic tracer 99mTc at these flow rates is limited by the capillary diffusion capacity. The multiexponential curves reflect recirculation and excretion of 99mTc by the kidneys with accumulation of 99mTc in the bladder. It is concluded, that clearance studies of locally injected 99mTc in the bladder wall are unable to evaluate bladder blood flow.