Search

Purpose: To describe and evaluate the effectiveness of the microscope and lens tilting technique associated with the three-dimensional viewing system for improving the peripheral retinal view in noncontact lens vitreoretinal surgeries., Methods: Prospective, single-center, single-surgeon, consecutive case series of 25 patients undergoing vitrectomy for macular surgeries with three-dimensional visualization system. At the end of each surgery, the microscope and the noncontact lens were rotated by 20° in a direction opposite to the rotation of the eye to extend the peripheral visual field., Results: Microscope and lens tilting technique extended the edge of the peripheral viewing field relative to its position with the microscope untilted, by 1.72 mm (±0.37) for the superior retina and 1.93 mm (±0.42) for the inferior retina (P < 0.0001). The ora serrata was visualized in 33% and 0% of cases for the superior retina and 91% and 36% of cases for the inferior retina, in tilted and nontilted microscope positions, respectively (P < 0.01)., Conclusion: Microscope and lens tilting could be useful to extend the peripheral visual field of view in retinal surgery. The three-dimensional system allowed to maintain surgeon comfort and posture during surgery.

Purpose: The aim of this study was to evaluate the efficacy of digital visualization for enhancing the visualization of iridocorneal structures during surgical gonioscopy. Methods: This was a prospective, single-center study on a series of 26 cases of trabecular stent implantation performed by the same surgeon. Images were recorded during surgical gonioscopy, and before stent implantation, with standard colors and with the optimization of various settings, principally color saturation and temperature and the use of the cyan color filter. Subjective analyses were performed by two glaucoma surgeons, and objective contrast measurements were made on iridocorneal structure images. Results: The surgeons evaluating the images considered the optimized digital settings to produce enhanced tissue visibility for both trabecular meshwork pigmentation and Schlemm's canal in more than 65% of cases. The mean difference in the standard deviation of the pixel intensity values was 37.87 (±4.61) for the optimized filter images and 32.37 (±3.51) for the standard-color images ( p < 0.001). The use of a cyan filter provided a good level of contrast for the visualization of trabecular meshwork pigmentation. Increasing the color temperature highlighted the red appearance of Schlemm's canal. Conclusions: We report here the utility of optimized digital settings including the cyan filter and a warmer color for enhancing the visualization of iridocorneal structures during surgical gonioscopy. These settings could be used in surgical practice to enhance the visualization of the trabecular meshwork and Schlemm's canal during minimally invasive glaucoma surgery.

Purpose: To describe the feasibility of intraoperative digital visualization and its contribution to the enhancement of macular pigmentation visualization in a prospective series of macular surgery interventions., Materials and Methods: A prospective, single-center, single-surgeon study was performed on a series of 21 consecutive cases of vitrectomy for various types of macular surgery using a 3D visualization system. Two optimized filters were applied to enhance the visualization of the macular pigment (MP). For filter 1, cyan, yellow, and magenta color saturations were increased. Filter 2 differed from filter 1 only in having a lower level of magenta saturation for the green-magenta color channel., Results: Optimized digital filters enhanced the visualization of the MP and the pigmented epiretinal tissue associated with the lamellar and macular holes. In vitreomacular traction surgery, the filters facilitated the assessment of MP integrity at the end of surgery. Filter 1 enhanced MP visualization most strongly, with the MP appearing green and slightly fluorescent. Filter 2 enhanced MP visualization less effectively but gave a clearer image of the retinal surface, facilitating safe macular peeling., Conclusion: Optimized digital filters could be used to enhance MP and pigmented epiretinal tissue visualization during macular surgery. These filters open new horizons for future research and should be evaluated in larger series and correlated with intraoperative OCT.

Purpose: To describe the early topography of corneal swelling occurring after cataract surgery and to evaluate the impact of the three-dimensional (3D) digital visualization system in minimizing corneal oedema., Methods: Prospective observational, single-centre, consecutive case series of 134 patients undergoing cataract surgery performed by the same surgeon, with either 3D or conventional visualization systems. Eyes were assigned to two groups based on their anterior chamber depth (group ACD ≤3 mm and group ACD >3 mm). Optical coherence tomography was performed to evaluate postoperative corneal swelling., Results: Three corneal swelling profiles were identified on the first postoperative day type 1, limited corneal oedema near peripheral corneal incisions; type 2, dome-shaped corneal swelling spreading from the principal corneal incision and reaching the paracentral cornea; type 3, continuous oedema spreading from the principal incision to central cornea, with a generalized oedema predominating in the upper part of the cornea. On the first day after surgery, in group ACD ≤3 mm, visual acuity was significantly better in patients undergoing surgery with 3D visualization (0.023 vs 0.072 logMar, p = 0.014) with reduced central corneal thickening 17.3 µm (±3.2) in comparison with conventional visualization 44.0 µm (±9.3) (p = 0.0082). In group ACD >3 mm, no significant association was found between the use of the 3D system and pachymetry changes and early visual rehabilitation. On day 21 after surgery, no significant differences in corneal pachymetry values were observed between the two surgical approaches in both groups., Conclusions: We describe early postoperative corneal map profiles providing insight into the pathogenesis of postoperative corneal swelling and possible prevention strategies. By improving visualization of the narrow surgical space in patients with shallow anterior chambers, the 3D system could help to minimize postoperative corneal oedema., (© 2021 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Purpose: To assess the utility of the 3D viewing system in tilted microscope positions for the performance of cataract surgery in challenging positions, for patients with difficulty remaining supine., Methods: Prospective, single-center, single-surgeon, consecutive case series of patients undergoing surgery in an inclined position., Results: 21 eyes of 15 patients who had undergone surgery at inclined positions at angles of 20° to 80°, with a mean angle of 47.62°. Surgeon comfort was considered to be globally good. The surgeon rated red reflex perception and the impression of depth as good and stable in all cases. The operating time was slightly longer for patients inclined at angles of more than 50°. On the first day after surgery, BSCVA was 20/25 or better in all cases. No ocular complications occurred in any of the interventions., Conclusions: Due to the ocular-free design of the 3D system, the surgical procedure and the positioning of the surgeon remained almost identical to that for patients undergoing surgery in a supine position, maintaining the safety of the standard surgical approach.

Purpose: To describe en face anterior segment optical coherence tomography (EF-OCT) characteristics of pterygia and their correlation with in vivo confocal microscopy (IVCM)., Patients and Methods: In this observational case series, we prospectively included 21 eyes of 17 subjects with pterygium. All subjects underwent detailed ophthalmic examination, anterior segment photography, an ocular surface disease index (OSDI) questionnaire, IVCM, and EF-OCT. Eyes were divided into two groups according to pterygium severity (Modified Pterygium Classification System) and OSDI score. EF-OCT images for both groups were analyzed for surface area of Fuchs Patches (FP). The IVCM activity score was based on the number of inflammatory cells, blood vessels, activated keratocytes and the appearance of the cornea/pterygium at the head of the pterygium. The correlations between EF-OCT and IVCM images were then analyzed and compared in both groups., Results: EF-OCT permits clear visualization and evaluation of FPs and the border between the pterygium and the adjacent cornea. The severe pterygium group was characterized by irregular borders and larger FPs (0.13±0.06 mm 2 versus 0.06±0.02 mm 2 respectively) (P=0.003). The mean IVCM activity score was 2.36±0.81 in the severe pterygium group and 1.2±0.42 in the mild pterygium group (P=0.0013). There was a positive correlation between FP surface area and IVCM activity score. A larger FP surface area was associated with a higher activity score on IVCM., Conclusion: EF-OCT allows good evaluation of pterygium extension, borders and FP surface area. EF-OCT analysis of pterygium could represent a simple, non-invasive and reproducible method to evaluate pterygium severity and activity., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Purpose: To study the effects of breathing techniques for anxiety, perceived pain, and patient satisfaction while receiving intravitreal injections., Method: This prospective, randomized clinical study included patients admitted for intravitreal anti-VEGF injections. They were randomized into two groups: a relaxation group who listened to a prerecorded relaxation breathing session before and during the injection, and a control group who received the injection without a relaxation session. Statistical analysis was then performed to assess the factors influencing satisfaction, anxiety, and perceived pain., Results: We included one-hundred four patients in total: 52 in the relaxation group versus 52 in the control group. The relaxation group had a greater decrease in anxiety than the control group (P=0.03) but similar levels of pain (P=0.86). In total, 80.76% of patients in the relaxation group expressed the wish to have a relaxation session during their next injection. Multivariate analysis showed that the patient's usual level of stress as well as the relaxation session affected the level of anxiety experienced before the injection., Conclusion: Relaxation techniques before and during intravitreal injections decrease anxiety in patients without decreasing pain during IVT. Prerecorded relaxation breathing sessions are non-invasive, inexpensive, easy to set up, and reduce anxiety during intravitreal injections on an outpatient basis., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Phacoemulsification is the most frequently performed surgery in the world. Over the past few years, this surgery seems to have reached a plateau with no further innovative breakthroughs. In this paper, we focus on alternatives techniques, the latest innovations, and the research and development pipeline in this field., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Background: Since the onset of the new coronavirus pandemic, the world is facing a public health emergency. Repositioning hydroxychloroquine (HQ) seems to be a promising option. Many emerging evidences have converged on the effectiveness of HQ in the treatment of Covid-19 infection. In a recent paper, Gautret et al. suggested that further works are needed to determine if HQ antiviral prophylaxis is useful, especially for healthcare workers., Methods: The purpose of this paper is to assess the Covid-19 exposure and risks level among caregivers. For this, we performed research on internet and PubMed by crossing the following keywords: healthcare givers, healthcare workers, doctors, nurses, coronavirus, Covid-19, mortality, infection rate, chloroquine, hydroxychloroquine., Results: Data on healthcare worker's infection and mortality by Covid-19 are partial and are not systematically published. However, it seems that the infection rate varies between 3.8% and 9% depending on the country. Moreover, the mean age of this population is relatively old, especially in the OECD area., Conclusions: Anti-Covid-19 HQ prophylaxis should be urgently accessed, especially for healthcare workers. It is to be hoped that HQ prophylaxis reduces the morbidity and mortality from Covid-19 infection among this population which is particularly exposed and relatively old., (Copyright © 2020. Published by Elsevier Ltd.)

Purpose: To evaluate a possible clinical application of spectral-domain optical coherence tomography (SD-OCT) using en-face module for the imaging of the corneoscleral limbus in normal subjects and dry eye patients., Patients and Methods: Seventy-six subjects were included in this study. Seventy eyes of 35 consecutive patients with dry eye disease and 82 eyes of 41 healthy control subjects were investigated. All subjects were examined with the Avanti RTVue® anterior segment OCT. En-face OCT images of the corneoscleral limbus were acquired in four quadrants (inferior, superior, nasal and temporal) and then were analyzed semi-quantitatively according to whether or not palisades of Vogt (POV) were visible. En-face OCT images were then compared to in vivo confocal microscopy (IVCM) in eleven eyes of 7 healthy and dry eye patients., Results: En-face SD-OCT showed POV as a radially oriented network, located in superficial corneoscleral limbus, with a good correlation with IVCM features. It provided an easy and reproducible identification of POV without any special preparation or any direct contact, with a grading scale from 0 (no visualization) to 3 (high visualization). The POV were found predominantly in superior (P<0.001) and inferior (P<0.001) quadrants when compared to the nasal and temporal quadrants for all subjects examined. The visibility score decreased with age (P<0.001) and was lower in dry eye patients (P<0.01). In addition, the score decreased in accordance with the severity of dry eye disease (P<0.001)., Conclusion: En-face SD-OCT is a non-contact imaging technique that can be used to evaluate the POV, thus providing valuable information about differences in the limbal anatomy of dry eye patients as compared to healthy patients.

Purpose: To compare characteristics of functioning blebs (FBs) and nonfunctioning blebs (NFBs) with en-face spectral-domain optical coherence tomography (OCT)., Methods: We evaluated 41 blebs of 38 patients after a first-time trabeculectomy. Eyes were classified into 2 groups: FBs (22 eyes) and NFBs (19 eyes). En-face OCT images were analyzed semiquantitatively for the density of intraepithelial microcysts (0 to 3), internal fluid-filled cavity (0 to 3), and bleb vascularization (0 to 2). Presence of conjunctival fibrosis and visualization of the scleral flap were also analyzed., Results: FBs showed significantly more intraepithelial microcysts than did NFBs: the mean grading of microcyst density was 1.86 for FBs and 0.11 for NFBs (P<0.0001). None of the FBs were rated 0 and none of the NFBs were rated 2 or 3 for the density of intraepithelial microcysts. NFBs presented more conjunctival fibrosis than FBs (63% vs. 32%, P<0.05). There was no significant difference between FBs and NFBs for bleb vascularization, visualization of the scleral flap, and presence of subepithelial fluid-filled cavities. There was a direct correlation between postoperative intraocular pressure and intraepithelial microcyst density (r=-0.7655, P<0.0001). The long-term administration of preserved eyedrops before surgery was associated with fewer intraepithelial microcysts (r=-0.5436; P=0.0006)., Conclusions: FBs were associated with a higher number of intraepithelial microcysts evaluated with en-face OCT. A higher density of microcysts was associated with a lower intraocular pressure and a shorter duration of preserved topical treatment before surgery. En-face OCT provides a simple, noninvasive, and reproducible method to analyze blebs after filtering surgery.

Purpose: To evaluate the usefulness of en face Optical Coherence Tomography (OCT) for evaluation of corneal dystrophies and to describe correlations with in vivo confocal microscopy (IVCM)., Patients and Methods: Thirty-two eyes of 16 patients with 4 types of corneal dystrophies (epithelial basement membrane dystrophy, Fuchs dystrophy, Reis-Bücklers corneal dystrophy and Crocodile Shagreen dystrophy) were enrolled in this study. Axial and reconstructed en face scans were acquired using OCT. Images were then correlated to IVCM findings., Results: En face OCT provided new insights into the structure, size and depth of corneal tissue alterations in various corneal dystrophies. OCT en face images were well correlated with IVCM features. Despite lower resolution than IVCM, en face OCT offers the advantages of being non-invasive and allowing the analysis of larger corneal areas., Conclusion: En face OCT provides useful new information in corneal dystrophies. This imaging technique will probably increase in popularity in the near future for the assessment of various anterior segment diseases., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

Purpose: To analyze the correlation between photophobia and corneal crystal density in nephropathic cystinosis using in vivo confocal microscopy (IVCM) and anterior-segment optical coherence tomography (AS-OCT)., Methods: Forty eyes of 20 patients with nephropathic cystinosis aged 7 to 37 years were included in this study. Ophthalmologic investigations included clinician-assessed and self-assessed evaluations of photophobia, slit-lamp biomicroscopy analysis, the depth of crystal deposition (DCD) and the central corneal thickness (CCT) in the central cornea measured with AS-OCT, and IVCM analysis of the crystal density score (IVCM-CysS), inflammatory cell density (IVCM-inf), and nerve damage (IVCM-N). Age, sex, intraleukocyte cystine concentrations (ICC), and the need for renal transplantation were also recorded., Results: The average subjective and objective photophobia scores were 2.10 ± 1.28 and 1.70 ± 1.41, respectively. Using AS-OCT, the average percentage of crystal infiltration (OCT-CysP) and was 49.56 ± 27.31% (range, 11.45%-95.81%). The mean IVCM-CysS was 8.84 ± 4.34, the mean density of inflammatory cells (IVCM-inf) was 178.28 ± 173.00 cells/mm2, and the mean IVCM-N score was 3.11 ± 2.11. Clinician- and self-assessed estimations of photophobia were correlated (R2 = 0.61). No significant correlation was observed between clinician- and self-assessed photophobia scores and ICC or sex. There were significant correlations between clinician- and self-assessed photophobia scores and age, OCT-CysP, IVCM-CysS, IVCM-inf, and IVCM-N. The IVCM-CysS was also correlated with OCT-CysP (R2 = 0.27), IVCM-inf (R2 = 0.37), and IVCM-N (R2 = 0.56)., Conclusions: In vivo confocal microscopy and AS-OCT are reliable tools to quantify cystinosis corneal crystals. In patients with nephropathic cystinosis, the intensity of photophobia is associated with the density of crystals, infiltration of inflammatory cells, and nerve damage within the cornea.

Purpose: To study the corneal morphological characteristics of acute hydrops by analyzing anterior segment optical coherence tomography (AS-OCT) "en face" images., Patients and Methods: Four patients presenting with acute hydrops were examined at different stages, respectively after 1 day, 1 week, 3 weeks and 6 months. All patients had a complete ophthalmic evaluation including "en face" AS-OCT examination. In vivo confocal microscopy (IVCM) and histological analysis of the cornea obtained after penetrating keratoplasty were also performed in one patient., Results: The "en face" AS-OCT showed that the early edema in acute hydrops corresponded to multiple epithelial microcysts associated with large intra-stromal lacunae. We also observed that, in association with the disappearance of the microcysts and lacunae, "en face" OCT demonstrated subepithelial scars in the form of weakly reflective, fine, interlaced linear opacities. These opacities subsequently increased in thickness resulting in a dense subepithelial network. These findings were consistent with the results of histological and IVCM studies., Conclusion: "En face" AS-OCT allows for precise study of the tissue changes occurring in acute corneal hydrops. Besides a better understanding of this rare complication of keratoconus, this new imaging technique may help clinicians to identify the corneal structural changes, which place keratoconus patients at risk of corneal hydrops., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Purpose: To explore the potential of spectral-domain optical coherence tomography (SD-OCT) using the en-face technology for the imaging of ocular surface diseases and to correlate the findings with in vivo confocal microscopy (IVCM) images., Patients and Methods: 113 eyes of 75 subjects with various ocular surface diseases were investigated with the RTVue(®) anterior-segment en face OCT. En face OCT images were compared to B-scan OCT and IVCM images., Results: Patients with corneal dystrophies, corneal deposits, keratitis, pterygium, conjunctivochalasis, or ocular surface squamous neoplasia and patients who underwent lamellar corneal surgeries were included. En-face OCT images showed ocular surface tissue changes that were not discernible using conventional B-scan OCT. Nevertheless, there was a good correlation with IVCM analysis. Compared with IVCM, the major advantages of en-face OCT included easy operation and rapid image acquisition, with minimal operator experience required. In addition, the non-contact method avoided patient discomfort and external pressure on the globe, which was especially useful in patients with corneal dystrophies, ulcers, or corneal abscesses. Although the resolution of en-face OCT was lower than that of IVCM, it allowed useful overall visualization of corneal lesions due to the larger areas analyzed., Conclusion: En-face SD-OCT is a novel, valuable tool to assess a wide variety of ocular surface diseases. It can provide additional information and new insight into different ocular surface conditions with no corneal contact., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Introduction: The increased utilization of medical applications for smartphones provides new opportunities for doctors, including ophthalmologists. In this study, we examined the availability of ophthalmological applications in the two largest smartphone app stores (Apple App store and Android Play Store) and then proposed a classification for smartphone ophthalmological applications according to their functionalities., Materials and Methods: In November 2012, we searched the Apple App Store and the Android Play Store for ophthalmological themed applications, using numerous ophthalmological keywords. We excluded applications that were not ophthalmology-related., Results: We identified 342 ophthalmological applications. There were two main categories in ophthalmological applications: those for ophthalmologists, and those for patients., Discussion and Conclusions: There are numerous benefits of smartphone use for ophthalmologists as well as their patients. Ophthalmological applications are turning cell phones into medical devices. In addition, smartphones may play a very important role in patient education, self-monitoring, and low-vision aids via magnifying systems., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

Purpose: To compare the 23-gauge (23-G) sutureless vitrectomy incision architecture in macular and non-macular surgery, using anterior segment spectral-domain optical coherence tomography (SD-OCT), and to evaluated its influence on clinical outcomes., Methods: A prospective, observational case series of 43 patients who underwent primary transconjunctival 23-G pars plana vitrectomy (PPV) for macular and non-macular diseases. All sclerotomy wounds were imaged 1 day after surgery using the anterior segment module of SD-OCT (OCT Spectralis; Heidelberg Engineering, Heidelberg, Germany). Sclerotomy architecture, including good wound apposition, presence of gaping and misalignment of the roof and floor of the incisions were evaluated. Preoperative, intraoperative and postoperative medical record data were also prospectively collected., Results:   Incision gaping and misalignment of the roof and floor occurred more frequently in the superotemporal and superonasal quadrants than in the inferotemporal quadrant (p < 0.05) and was more frequent in the non-macular group than in the macular group (p < 0.05). The incidence of incision gaping increased significantly as the incision angle increased. In the macular group, the mean postoperative intraocular pressure (IOP) did not change from the preoperative value, whereas in the non-macular group, the mean IOP decreased significantly from 15.09 ± 2.58 mmHg preoperatively to 12.18 ± 3.25 mmHg on the first postoperative day (p < 0.005). The mean IOP did not differ significantly between the two groups of surgery at 1 week, and at 1 month postoperatively., Conclusions:   In 23-G PPV, non-macular surgery is associated with a significant postoperative IOP decrease in comparison with macular surgery, which could be explained by the most remodelled wound architecture., (© 2012 The Authors. Acta Ophthalmologica © 2012 Acta Ophthalmologica Scandinavica Foundation.)

Purpose: To evaluate the factors affecting the postoperative intraocular pressure (IOP) decrease in 23-gauge (23-G) sutureless vitrectomy, including incision architecture evaluated by anterior segment spectral-domain optical coherence tomography (SD-OCT)., Methods: A prospective cohort study of 43 patients who underwent primary transconjunctival 23-G pars plana vitrectomy. All sclerotomy wounds were imaged 1 day after surgery using the anterior segment module of SD-OCT (OCT Spectralis, Heidelberg Engineering, Heidelberg, Germany). 23-G sclerotomy architecture, preoperative and postoperative medical data were also prospectively collected., Results: Multivariate logistic regression analysis, with backward elimination, found that surgery duration (adjusted OR = 9.17, p = 0.020) and loss of wound apposition (adjusted OR = 15.12, p = 0.022) were risk factors for significant postoperative IOP decrease (≥3 mmHg) 1 day after surgery; while age, gender, myopia, and gas tamponade were not risk or protective factors for postoperative IOP decrease., Conclusions: In 23-G pars plana vitrectomy, the early postoperative decrease in IOP is mainly influenced by surgery duration and the self-sealing nature of the sclerotomy. The IOP decrease was not influenced by the presence or the absence of gas tamponade.

Introduction: Transconjunctival sutureless vitrectomy is a recent advance in vitreoretinal surgery. Some authors have reported an increased risk of postoperative hypotony and endophthalmitis and recommend the creation of oblique incisions, intended to be self-sealing, so as to reduce these risks. However, there is still a debate about the best architecture for transconjunctival sutureless incisions., Materials and Methods: We report two cases of acute endophthalmitis occurring after 23 and 25 gauge transconjunctival sutureless vitrectomy. We analyzed the scleral incisions using the anterior segment module of the Spectralis(®) OCT. To our knowledge, this is the first direct description of the appearance of sclerotomies associated with endophthalmitis., Results: The anterior segment module of Spectralis(®) OCT permitted a high-resolution evaluation of the architecture of the scleral incisions. We found straight, gaping incisions with misaligned edges and vitreous incarceration., Discussion: By way of these two case reports and a review of the literature, we discuss the contribution of anterior segment OCT in the analysis of scleral incision architecture in sutureless vitrectomy. Our findings are consistent with those reported in the literature. The presence of a direct incision, wound gap or edge misalignment are associated with an increased risk of early leakage and postoperative hypotony., Conclusions: The anterior segment module of the Spectralis(®) OCT is a valuable tool for non-invasive, painless and high-resolution documentation of sutureless vitrectomy incisions. It allows for causal analysis and better understanding of the conditions associated with endophthalmitis after sutureless vitrectomy., (Copyright © 2012 Elsevier Masson SAS. All rights reserved.)

Descemet membrane detachment (DMD) is a rare complication that occurs mainly after cataract surgery. We report the case of a 55-years-old woman who underwent refractive lensectomy. The Day-1 postoperative examination was unremarkable, the Day-7 examination showed corneal oedema related to DMD, which was confirmed by Visante(®) OCT. An intracameral injection of SF6 expansive gas allowed the reapplication of the membrane and the receding of corneal oedema. Through this observation, we discuss the pathogenesis of this uncommon entity and the contribution of Visante(®) OCT., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)