Cost optimisation of hybrid institutional incentives for promoting cooperation in finite populations.

In this paper, we rigorously study the problem of cost optimisation of hybrid (mixed) institutional incentives, which are a plan of actions involving the use of reward and punishment by an external decision-maker, for maximising the level (or guaranteeing at least a certain level) of cooperative behaviour in a well-mixed, finite population of self-regarding individuals who interact via cooperation dilemmas (Donation Game or Public Goods Game). We show that a mixed incentive scheme can offer a more cost-efficient approach for providing incentives while ensuring the same level or standard of cooperation in the long-run. We establish the asymptotic behaviour (namely neutral drift, strong selection, and infinite-population limits). We prove the existence of a phase transition, obtaining the critical threshold of the strength of selection at which the monotonicity of the cost function changes and providing an algorithm for finding the optimal value of the individual incentive cost. Our analytical results are illustrated with numerical investigations. Overall, our analysis provides novel theoretical insights into the design of cost-efficient institutional incentive mechanisms for promoting the evolution of cooperation in stochastic systems.

Iterative Development of Clinician Guides to Support Deprescribing Decisions and Communication for Older Patients in Hospital: A Novel Methodology.

BACKGROUND/OBJECTIVES: Medication review is an important component of the management of older hospital patients. Deprescribing (supervised withdrawal of inappropriate medicines) is one outcome of review. This study aimed to iteratively develop and test the usability of deprescribing guides, which support multidisciplinary clinicians to reduce inappropriate polypharmacy in older inpatients. METHODS: Deprescribing guides for hospital clinicians were developed using a novel mixed-methods, ten-step process. Iterative development and usability testing were applied. This included content development through review of the literature; expert consensus through five rounds of feedback using a modified Delphi approach; and usability testing by 16 multidisciplinary hospital clinicians on hypothetical clinical scenarios involving observations, semi-structured interviews, and administration of the System Usability Scale. RESULTS: This novel process was used to develop deprescribing guides that facilitate implementation of evidence on deprescribing in routine hospital care. The guides present evidence-based information in a format that aligns with workflows of multidisciplinary hospital clinicians. The guides were adapted for various clinical roles to navigate efficiently to suit differing workflow needs. Guides include unique communication support in the form of "preferred language". Clinicians can use the "preferred language" to apply the evidence to the individual patient and relay decisions between health providers and with patients/carers. The total System Usability Scale score was 80.6 ± 2.0 (mean ± standard error of the mean), indicating excellent usability. Guides have been developed using consistent format for nine medication classes that are common targets for deprescribing and are publicly available. CONCLUSION: This study demonstrates a novel approach to the development and implementation of evidence-based recommendations that support deprescribing in routine hospital care.

[Assessment of the nerve fiber layer thickness after LASIK using scanning laser polarimetry with variable corneal compensation]. / Mesure de l'épaisseur des fibres nerveuses rétiniennes après LASIK par laser polarimètre à balayage avec compensation cornéenne variable.

AIM: To evaluate the reliability of scanning laser polarimetry with variable corneal compensation after laser-assisted in-situ keratomileusis (LASIK). METHODS: Thirty-six eyes of 18 consecutive patients who had LASIK where included in the study. For each eye, one scanning laser polarimetry with variable corneal compensation (GDxVCC) was performed before LASIK (GDx no 1). One month after surgery, two other scanning laser polarimetry procedures were performed: one used the corneal compensation measured preoperatively (GDx no 2) and one used a new corneal compensation, measured postoperatively (GDx no 3). The values measured preoperatively were compared first to the values obtained postoperatively with GDx no 2, then to the values obtained postoperatively with GDx no 3 (Wilcoxon test). RESULTS: When corneal compensation was re-measured postoperatively (GDx no 3), the measurements were reliable for 35 eyes (97%). We found no significant differences between the preoperative and postoperative values except for the NFI (p=0.032). When the preoperative corneal compensation value was used in the postoperative measurements (GDx no 2), the exam was not reliable for 13 eyes, and it could not be performed at all for two eyes. For the remaining eyes, the values of four parameters were significantly modified: superior thickness (p=0.03), superior ratio (p=0.0005), inferior ratio (p=0.009), and ellipse modulation (p=0.39). The values of the other parameters (average thickness and inferior average) remained unchanged. CONCLUSION: The use of a preoperative customized corneal compensation for the realization of post-LASIK measurements does not provide reliable results. The GDxTMVCC can be considered a reliable tool after LASIK only when the corneal compensation is re-evaluated postoperatively.

[Corneal asphericity in myopes]. / Etude de l'asphéricité cornéenne chez le sujet myope.

PURPOSE: To study the variations of corneal asphericity in a population of myopic patients. METHODS: One hundred consecutive myopic patients were included in this study. The EyeSys videokeratoscope was used to assess the corneal topography of these patients seeking refractive surgery. We compared the results of cycloplegic refractions with the values of the corneal asphericity and mean central keratometry. RESULTS: Mean corneal asphericity was -0.09. Eighty per cent of the myopic patients had a prolate corneal contour, whereas 20% had an oblate corneal contour. No significant relationship was found between the corneal asphericity value and the mean keratometry value or the mean refractive error. CONCLUSION: The mean corneal asphericity in our myopic population was -0.09. This is slightly more than previously reported data in similar studies. No statistically significant relationship was found between corneal asphericity, mean refractive error, and mean keratometry.

[Laser epithelial keratomileusis for the treatment of low to moderate myopia: preliminary results]. / Résultats préliminaires du Laser Epithelial Keratomileusis pour le traitement de la myopie.

PURPOSE: To analyze the refractive outcome and the postoperative pain and corneal haze following laser epithelial keratomileusis (LASEK) for the treatment of low to moderate myopia. METHODS: A monocentric prospective noncomparative study was started in June 2000, after informed consent was obtained from patients with a spherical equivalent of less than -5 diopters (D). This study actually was part of another prospective comparative study where the contralateral eye underwent photorefractive keratectomy. An epithelial debridement was performed using diluted ethanol, the epithelial flap was lifted, photoablation was performed, the flap was put back in place, and secured by a bandage contact lens. The refractive outcome was assessed, and postoperative pain and haze were graded using an analogical visual scale from 0 to 10 and a scale of 0 to 4, respectively. RESULTS: We included 17 eyes of 16 patients. LASEK was performed successfully in 15 eyes (88.2%). One of these eyes could not be assessed for the refractive outcome and postoperative haze because the epithelial flap was torn during contact lens removal. The mean postoperative pain level during the night following the procedure was 5.7+/-2.0. The mean preoperative spherical equivalent (SE) was -2.5+/-1.0 D, and after a 2-month follow-up, the mean postoperative SE was +0.26+/-0.6 D. Twelve eyes (85.7%) and 10 eyes (71.4%) were within +/-1.0 D and +/-0.5 D from the attempted correction, respectively. The corneal haze grade was less than 1 in 12 eyes (85.7%) and equal to 1 in two eyes (14.3%). No complications and no loss of postoperative best-corrected visual acuity were noted. CONCLUSIONS: LASEK appears to be a reliable and reproducible technique for the treatment of myopia-associated SE of less than -5 D. Postoperative pain is moderate and flap-related complications of LASIK are avoided.

[Bilateral retinitis: early manifestation of subacute sclerosing panencephalitis. A case report]. / Rétinite bilatérale révélatrice d'une panencéphalite sclérosante subaiguë

Subacute sclerosing panencephalitis (SSPE) is a progressive encephalitis caused by persistent measles infection. The disease is almost always fatal and mainly affects children and young adults. Ophthalmological signs are frequently observed and can be the presenting manifestations. We report the case of a 22-year-old young man who presented with bilateral posterior retinal necrosis confirmed by fluorescein angiography and normal laboratory tests. The appearance of peripheral retinal tears and stereotyped myoclonic movements were signs of the evolving condition. Diagnosis of SSPE was confirmed by brain MRI, EEG, and cerebrospinal fluid examination. The patient's neurological condition deteriorated rapidly and he died 2 months following the onset of ophthalmological manifestations.

An unusual complication during central venous catheter placement.

A 31-year-old man with disseminated Coccidioides imitis infection required central catheter placement for access. The patient had an inferior vena cava (IVC) filter placed as a result of previous deep venous thrombosis of the left lower extremity. The guidewire could not be removed following placement of the right internal jugular catheter by the Seldinger technique. Fluoroscopic examination revealed entanglement of the J-tip guidewire in the apex of the IVC filter. The catheter was successfully removed by interventional radiologists using a snare tip catheter through the left femoral vein.

[Lamellar keratoplasty with air or viscoelastic substance injection]. / Kératoplastie lamellaire avec aéro-visco dissection.

PURPOSE: To analyze the results of very deep lamellar keratoplasty using dissection with air and a viscoelastic substance. METHODS: This was a prospective monocentric noncomparative study. Candidates for lamellar keratoplasty were enrolled between November 1998 and July 2000. Deep lamellar dissection was performed following air injection into the cornea to create a white emphysema of the stroma. The dissection was performed to the Descemet membrane. Whenever a large bulla was present in the recipient bed, the dissection of the deepest stromal lamellae was performed by injecting a viscoelastic substance into the bulla. A full-thickness allogenic corneal button was sutured to the recipient bed. RESULTS: Fifteen eyes of 14 patients (mean age, 39.3 years) underwent deep lamellar keratoplasty: keratoconus (11 eyes), atopic keratoconjunctivitis (1 eye), herpes zoster keratitis (1 eye), corneal scar after pterygium surgery (1 eye), and rosacea keratitis (1 eye). Excluded from the analysis of the refractive outcome were patients who underwent intraoperative perforation (n = 3) and the patients with postoperative complications affecting the central visual axis: (n = 2 [hemorrhage in the interface and herpetic simplex keratitis]). The mean preoperative visual acuity was 0.10 (range, 0.05 to 0.3). After a 3.8-month-follow-up, the mean best corrected visual acuity was 0.21 (range, 0.1 to 0.6). The visual results were better in patients with keratoconus (mean best corrected visual acuity: 0.22; range, 0.1 to 0.6). The mean postoperative astigmatism was 4.15 diopters (range, 0 to 8). CONCLUSION: Intrastromal air and viscoelastic substance injection appeared to be very useful for performing a very deep lamellar keratoplasty. The results of the refractive outcome were encouraging. Deep lamellar keratoplasty is an interesting alternative to penetrating keratoplasty, because it cannot induce progressive primary graft failure and allogenic endothelial graft rejection and it obviates the need to perform a lamellar dissection of the donor button.

[Enucleation with on-the-table evisceration. Is it a good technique?]. / L'énucléation avec éviscération sur table. Est-elle une bonne technique?

PURPOSE: To evaluate the surgical technique of enucleation followed by an "on-the-table evisceration" and placement of a hydroxyapatite orbital implant wrapped by the patient's own sclera for the treatment of blind phthisis painful eyes. PATIENTS AND METHODS: In this single-center retrospective study, 50 consecutive patients undergoing an operation using the same surgical technique, between April 1993 and November 1999, were studied. Patients underwent enucleation, then the eyeball was eviscerated "on the table". The patient's own cleaned sclera was used to wrap a hydroxyapatite orbital implant, the posterior pole of the sclera was placed at the anterior pole of the implant. Conjunctival breakdown, sphere size, conjunctival discharge, the first signs of sympathetic ophthalmia motility, and cosmetic results were analysed. RESULTS: After an average follow-up of 13.3 months few complications were encountered: 4 cases (8%) of inclusion cyst and 3 cases (6%) of discharge. The implant placed had a diameter of 18 mm, 20 mm, 22 mm in, respectively, 48%, 48%, and 4% of the eyes. The prosthesis motility was good, medium, and poor in, respectively, 33 (78.6%) cases, 8 (19%) cases, and 1 (2.4%) case. The prosthesis tolerance was good, medium, and poor in respectively 86%, 10%, and 4% of the cases. CONCLUSION: The surgical technique of enucleation followed by an "on-the-table" evisceration and autologous sclera wrapping a hydroxyapatite implant is an easy procedure. It allows, on phthisis eyeballs, the placement of a large orbital implant for good cosmesis results, without major complications.

Unilateral dermatomal superficial telangiectasia.

A new case of unilateral dermatomal superficial telangiectasia (UDST) is described, bringing the number of reported cases to 48. This case is unusual in that there was no underlying systemic disorder and no correlation between the onset of the disease and the physiologic hormonal states that have frequently been reported with the acquired type of UDST. The etiopathogenetic mechanisms of this disorder are discussed.