Search

Purpose: To assess the epi- and intra-retinal morphology changes of the tangential tractions following vitreoretinal surgery for epiretinal membranes and to investigate the correlation between the depth of retinal changes and functional macular sensitivity (MS). Methods: This is a prospective cross-sectional interventional study, in which 73 eyes of 73 patients with diagnosis of idiopathic epiretinal membrane (iERM) were evaluated. All patients received complete ophthalmic evaluation, including axial anden-facescanning spectral domain-optical coherence tomography (SD-OCT) analysis and microperimetry. Follow-up examinations were performed preoperatively 1, 3, and 6 months post-vitrectomy for iERM and inner limiting membrane (ILM) peeling. Patients were retrospectively categorized into three groups according to the degree of visual improvement at 6 months postoperatively (“better,” “stable,” “worse”). The main outcome measures were the changes of depth of traction, which is defined as the first layer without visible retinal folds measured with en-face analysis setting the offset on ILM; ganglion cell complex (GCC) thickness; best-corrected visual acuity (BCVA), and MS. Results: The mean reduction of the depth of the first retinal layer free from traction was 70.10 μm (SD 17.78) in the “better” group (p< 0.001) and 66.56 μm (SD 18.90) in the “stable” group (p< 0.001). A correlation was found between the preoperative depth of the first retinal layer free from traction and postoperative MS improvement (R= 0.47;p= 0.034) only in the “better” group. There was no significant difference in the reduction of traction between the “better” and “stable” groups. Conclusion: The study shows a significant correlation betweenen-faceSD-OCT analysis MS. We found that patients that can significantly benefit from the vitrectomy and iERM-ILM peeling are those with preoperative deeper retinal changes and better BCVA and those without intraretinal cysts. In the presence of superficial retinal changes, the patients do not get any significant functional improvement. The main outcome was visual acuity gain. It is not tested whether patients improved in terms of reduction in metamorfopsia or reduction in binocular complaints. [ABSTRACT FROM PUBLISHER]

Aim: We evaluated the influence of intra-aortic balloon size and volume on mesenteric and renal flows. Methods: Thirty healthy swine underwent 120-minute ligation of the left anterior descending coronary artery followed by 6 hours of reperfusion. Then, they were randomly assigned to the following five groups of animals, with six animals in each group: no intra-aortic balloon pump (IABP), a short 35-mL IABP, a short 40-mL IABP, a long 35-mL IABP and a long 40-mL IABP. Superior mesenteric artery (SMA) and renal flows were measured at baseline (t0), at 2-hour ischemia (t¹) and every hour thereafter until 6 hours of reperfusion (from tR1 to tR6). Results: SMA flows increased significantly at tR1 only in the two short IABP groups (p<0.001) and balloon volume did not appear to affect flows which, at any experimental time-point, were comparable using 35 mL or 40 mL balloons (p>0.05). Renal flows appeared to be influenced by balloon length, but not by volume. Indeed, flows in the renal arteries rose during IABP treatment; the increase was significantly higher in the short balloon groups and throughout the whole reperfusion (all, p<0.001). Conclusions: Changes in visceral perfusion during IABP assistance were significantly related to balloon length, but not to its volume. This could be relevant for the evolution of balloon engineering design in order to reduce the incidence of mesenteric ischemia following IABP. Further research is necessary to confirm these findings. [ABSTRACT FROM AUTHOR]

Background: To assess changes in deep and superficial perifoveal capillary plexus after macular peeling in idiopathic and diabetic epiretinal membrane (iERM and dERM, respectively). Methods: Cross-sectional comparative study. We included 40 eyes from 40 patients affected by iERM (20 eyes) and dERM (20 eyes), as well as 34 eyes from 17 healthy, age-matched patients. Patients received a complete ophthalmic evaluation including axial and en-face scanning spectral-domain analysis, optical coherence tomography angiography, and microperimetry. Split-spectrum amplitude-decorrelation angiography images were obtained to quantify the deep and superficial layers of perifoveal capillary-free zone (CFZ). The main outcome measures were: (i) differences at baseline between deep and superficial CFZ in iERM and dERM vs control, and (ii) changes in deep and superficial CFZ plexus after surgery in iERM vs dERM. Results: The deep CFZ only significantly increased in dERM at the end of the follow-up period (6 months). No statistically significant differences were found between preoperative and postoperative superficial vascular plexus in iERM or dERM. At the end of the follow-up, statistically significant differences between preoperative and postoperative ganglion cell complex (GCC) average were found only in the iERM group. Best-corrected visual acuity significantly improved after surgery both in the iERM ( P = 0.0053) and dERM ( P < 0.0001) groups. After 6 months, macular sensitivity increased in the iERM group, but there was no statistically significant change in the dERM group. Conclusions: In dERM, the deep CFZ significantly increases after ILM peeling, whereas postoperative angiography changes were not significant in iERM. This could be because the impaired diabetic perifoveal capillary plexus are more sensitive to the iatrogenic damage to Müller cells, induced by peeling. [ABSTRACT FROM AUTHOR]

Purpose To evaluate the efficacy of optical coherence tomography (OCT) angiography versus fluorescein angiography (FA) in terms of retinal vessel imaging in ischaemic diabetic maculopathy defined according to the Early Treatment Diabetic Retinopathy Study (ETDRS) classification. Methods Twenty patients (31 eyes) with ischaemic diabetic maculopathy and 17 control subjects (27 eyes) were enrolled in this prospective study. Patients and control subjects underwent complete ophthalmic examination, including best-corrected visual acuity (BCVA), intraocular pressure, FA, Fourier domain optical coherence tomography (FD-OCT) and OCT angiography. Fluorescein angiograms and OCT angiography images were graded according to the foveal avascular zone (FAZ) of the ETDRS group. Ganglion cell complex (GCC) thickness was evaluated with FD-OCT. Results Optical coherence tomography (OCT) angiography images closely correlated with FA in terms of FAZ parameters. The correlation was strongest with OCT angiography deep imaging. The average GCC thickness was smaller in patients than in controls. Neither GCC parameters nor FAZ was correlated to BCVA. Conclusions Given the correlation between FA and OCT angiography in terms of FAZ parameters, the newer method can be considered a valid, reliable and easy-to-perform method with which to evaluate ischaemic diabetic maculopathy without contrast injection, and thus to visualize and quantify non-perfusion areas without risks of anaphylactic reactions. [ABSTRACT FROM AUTHOR]

This study aims at assessing the differences between highly myopic eyes and emmetropic eyes in the biomechanical response to ex vivo uniaxial tests of the human sclera. Scleral strips were collected from two enucleated eyes with markedly different axial length (AXL) of 24 and 31 mm, respectively. Static stress measurements under uniaxial loading were carried out with a Zwicki-Line testing machine, specially designed for low load mechanical testing applications. Although all uniaxial stress-strain curves showed an exponential response typical of biological viscoelastic materials loaded within the physiological strain range, the qualitative behavior was ostensibly different between the two eyes. With respect to the 24 mm AXL eye, the 31 mm AXL eye mm showed a lower stiffness at physiological strains and a more evident stiffening at larger strains. It was concluded that the myopic eye is more compliant at low strains and stiffer at strains larger than the physiological ones. An interpretation of this behaviour is that the higher percentage of small diameter collagen in myopic sclera delays the process of fiber recruitment and shifts the tissue stiffening to higher strains. [ABSTRACT FROM AUTHOR]

Background: To determine the correlation between the area of morphological changes on the macular surface, the depth of intraretinal changes and the best-corrected visual acuity (BCVA) in patients with idiopathic epiretinal membrane. Methods: In this prospective cross-sectional study, 38 patients underwent BCVA testing with a Snellen eye chart. The depth of traction, photoreceptor outer segment layer (PROS) thickness, central macular thickness (CMT) and presence of intraretinal cysts were measured using the Avanti RTVue XR and 3D Widefield Enface OCT instruments. Enface sections were performed at the inner limiting membrane (ILM) line level (ILM offset). Patients were categorized into two groups: in group 1 ( n = 21), the depth of traction was within 90 μm from the ILM, and in group 2 ( n = 17) it was beyond 90 μm from the ILM. The main outcome measure was the correlation between area of epiretinal traction and BCVA according to the depth of traction. Results: In group 1, the depth of traction was 55.15 ± 14.28 μm, the area of traction was 38.95 ± 13.63 mm, PROS thickness was 51.20 ± 7.23 μm, and CMT was 362.65 ± 41.08 μm. In group 2, the depth of traction was 112.24 ± 10.89 μm, the area of traction was 25.18 ± 4.07 mm, PROS thickness was 50.24 ± 9.01 μm, and mean CMT was 534.29 ± 126.81 μm. Statistically significant differences in depth of traction, area of traction and CMT were found between the two groups ( P < 0.001). The relationship between structure and function between the area of traction and BCVA was better explained in group 2 ( r = 0.814, P < 0.001). Conclusions: We found that intraretinal changes were induced by the ERM, and varied according to the depth of traction measured with en face analysis. In the case of traction deeper than 90 μm, we found a significant correlation between the inner area of the epiretinal traction and BCVA. We believe that retinal stress induced by epiretinal traction is better characterized by combining information provided by sagittal and transverse OCT scans, thus defining its prognostic significance in ERM. [ABSTRACT FROM AUTHOR]