Ride-hailing and (dis)Advantage: Perspectives from Users and Non-users

The introduction of ride-hailing in cities of Latin America and the Caribbean (LAC) remains a relatively new topic in regional research and a contentious issue in local policy and practice. Evidence regarding users and how do they differ from non-users is scarce, and there is little documented evidence about how user preferences and perceptions may influence the uptake of ride-hailing. This paper uses primary data from a survey collected from users and non-users of ride-hailing in Bogotá during 2019 to develop a Latent Class Analysis Model (LCA) to identify clusters of users and non-users of ride-hailing. The paper builds on results from the LCA to reflect on conditions of advantage and disadvantage that may make ride-hailing attractive and beneficial for particular social groups. The paper identifies four unique clusters: Carless middle-income ride-hailing users, Disadvantaged non-users, Young middle-class non-users, and Advantaged ride-hailing users. The research uses data on such perceptions to draw insights that may inform commercial and policy decisions. Findings suggest that issues such as the perception of legality in ride-hailing and aversion to crime play a significant role in the choice of such a mode in the context of Bogotá, particularly among socially and transport advantaged users

Stromal peeling for deep anterior lamellar keratoplasty in post-penetrating keratoplasty eyes

Background/aims To evaluate the clinical outcomes of deep anterior lamellar keratoplasty performed by stromal peeling in eyes that have previously undergone penetrating keratoplasty (PK) for keratoconus. Methods Standardised stromal exchange included (1) 9 mm trephination of the recipient bed outside the old PK wound, (2) creation of a partial anterior corneal flap through lamellar dissection across the PK wound, (3) opening the stromal component of the old PK wound using blunt-tipped Vannas scissors until a plane of separation is reached, (4) severing the attachment of the PK surgical scar from the recipient host, (5) peeling the stroma of the PK graft from the underlying tissue and (6) suturing the donor anterior corneal lamella prepared by microkeratome dissection (450 μm depth, 9 mm diameter). Main outcome measures were success rate, best spectacle-corrected visual acuity (BSCVA) and endothelial cell loss (ECL). Results Of 21 post-PK eyes, stromal exchange succeeded in all but three cases, which were converted to a two-piece mushroom PK. After complete suture removal, mean BSCVA significantly improved from 0.95±0.39 logMAR preoperatively to 0.23±0.17 logMAR (p<0.001). Mean ECL was 5.4±23.2%. Double anterior chamber formation occurred in eight cases (44%), which all resolved after a single re-bubbling. Conclusion In post-PK eyes, stromal exchange can be performed by means of simple peeling without deep anterior lamellar dissection of the previous PK graft. Large-diameter (9 mm) repeat keratoplasty through stromal peeling yields excellent visual outcomes and minimal ECL. Double anterior chamber formation may complicate the postoperative course, but prompt intervention allows successful management

Deep Trephination Allows High Rates of Successful Pneumatic Dissection for DALK Independent of Surgical Experience

PURPOSE: To evaluate the relationship between surgical experience and the success rate of pneumatic dissection for deep anterior lamellar keratoplasty (DALK) using deep trephination. METHODS: A noncomparative case series evaluating the first 10 consecutive keratoconic eyes without deep stromal scarring, operated by 8 surgeons of 3 different experience levels, was conducted; there were a total of 80 patients. Standardized DALK was performed, including deep trephination 450 to 550 μm in depth and 9 mm in diameter, pneumatic dissection, removal of the stroma, and transplantation of a 9-mm partial-thickness anterior lamellar graft. The success rate of pneumatic dissection correlated with surgical experience. RESULTS: Pneumatic dissection succeeded in 7, 7, 8, and 9 cases of 10 cases in the first group of 4 inexperienced surgeons (under 10 previous keratoplasties of any kind); in 9 and 10 of 10 cases in the second group of 2 relatively experienced surgeons (under 100 keratoplasties); and in 10 and 8 of 10 cases in the third group of 2 very experienced surgeons (more than 1000 previous keratoplasties). No difference between the groups was found to be statistically significant with the χ test (P > 0.05). CONCLUSIONS: The standardized DALK technique using a deep trephination allows high success rates of pneumatic dissection even for surgeons inexperienced in keratoplasty

Reproducibility of Corneal Graft Thickness measurements with COLGATE in patients who have undergone DSAEK (Descemet Stripping Automated Endothelial Keratoplasty)

10.1186/1471-2342-12-25BMC Medical Imaging12-BMIM

Intravitreal dexamethasone implant one month before versus concomitant with cataract surgery in patients with diabetic macular oedema: the dexcat study

Purpose: To report clinical outcomes of two different timings of intravitreal dexamethasone (DEX) implant administration for prevention of diabetic macular oedema (DME) worsening following cataract surgery. Methods: This multicentre, retrospective study included patients with DME who received an intravitreal DEX implant 1 month before cataract surgery, ‘precataract DEX’ group, or at the time of cataract surgery, ‘concomitant treatments’ group. Inclusion criteria were a follow-up ≥3 months and ophthalmological examination with optical coherence tomography (OCT) imaging at baseline (cataract surgery) and throughout follow-up. Anatomical improvement was considered to be a decrease in OCT central subfield (CSF) thickness ≥20% compared to baseline. The primary outcomes were anatomical and functional results at 3 months. Results: Two hundred twenty-one patients were included: 136 in the ‘precataract DEX’ group and 85 in the ‘concomitant treatments’ group. At 3 months, a reduction of CSF thickness ≥ 20% was found in 7.3% of eyes in the ‘precataract DEX group’ and in 83.7% of eyes in the ‘concomitant treatments’ group (p < 0.001), with mean CSF thickness lower in the latter group (371 ± 52 µm versus 325 ± 57 µm, p < 0.001). At 3 months, mean best-corrected visual acuity had improved from baseline in both groups (p < 0.001), with no difference between groups (p = 0. 20). No serious systemic adverse events were reported. Conclusion: Both approaches prevented a worsening of DME, showing a comparable visual outcome. Dexamethasone (DEX) implant given at the same time as cataract surgery provided a better anatomical outcome

Preoperative surgeon evaluation of corneal endothelial status: The Viability Control of Human Endothelial Cells before Keratoplasty (V-CHECK) study protocol

introduction the success of keratoplasty strongly depends on the health status of the transplanted endothelial cells. donor corneal tissues are routinely screened for endothelial damage before shipment; however, surgical teams have currently no means of assessing the overall viability of corneal endothelium immediately prior to transplantation. the aim of this study is to validate a preoperative method of evaluating the endothelial health of donor corneal tissues, to assess the proportion of tissues deemed suitable for transplantation by the surgeons and to prospectively record the clinical outcomes of a cohort of patients undergoing keratoplasty in relation to preoperatively defined endothelial viability. methods and analysis In this multicentre cohort study, consecutive patients undergoing keratoplasty (perforating keratoplasty, descemet stripping automated endothelial keratoplasty (DSAEK), ultra-thin DSAEK (UT-DSAEK) or descemet membrane endothelial keratoplasty) will be enrolled and followed-up for 1 year. Before transplantation, the endothelial viability of the donor corneal tissue will be evaluated preoperatively through trypan blue staining and custom image analysis to estimate the overall percentage of trypan blue-positive areas (TBPAs), a proxy of endothelial damage. functional and structural outcomes at the end of the follow-up will be correlated with preoperatively assessed TBPA values. ethics and dissemination the protocol will be reviewed by the ethical committees of participating centres, with the sponsor centre issuing the final definitive approval. the results will be disseminated on clinical trials.gov, at national and international conferences, by partner patient groups and in open access, peer-reviewed journals. trial registration number NCT05847387

Intravitreal dexamethasone implant one month before versus concomitant with cataract surgery in patients with diabetic macular oedema: the dexcat study

none28Purpose: To report clinical outcomes of two different timings of intravitreal dexamethasone (DEX) implant administration for prevention of diabetic macular oedema (DME) worsening following cataract surgery. Methods: This multicentre, retrospective study included patients with DME who received an intravitreal DEX implant 1 month before cataract surgery, ‘precataract DEX’ group, or at the time of cataract surgery, ‘concomitant treatments’ group. Inclusion criteria were a follow-up ≥3 months and ophthalmological examination with optical coherence tomography (OCT) imaging at baseline (cataract surgery) and throughout follow-up. Anatomical improvement was considered to be a decrease in OCT central subfield (CSF) thickness ≥20% compared to baseline. The primary outcomes were anatomical and functional results at 3 months. Results: Two hundred twenty-one patients were included: 136 in the ‘precataract DEX’ group and 85 in the ‘concomitant treatments’ group. At 3 months, a reduction of CSF thickness ≥ 20% was found in 7.3% of eyes in the ‘precataract DEX group’ and in 83.7% of eyes in the ‘concomitant treatments’ group (p < 0.001), with mean CSF thickness lower in the latter group (371 ± 52 µm versus 325 ± 57 µm, p < 0.001). At 3 months, mean best-corrected visual acuity had improved from baseline in both groups (p < 0.001), with no difference between groups (p = 0. 20). No serious systemic adverse events were reported. Conclusion: Both approaches prevented a worsening of DME, showing a comparable visual outcome. Dexamethasone (DEX) implant given at the same time as cataract surgery provided a better anatomical outcome.mixedFallico M.; Avitabile T.; Castellino N.; Longo A.; Russo A.; Bonfiglio V.; Parisi F.; Furino C.; Panozzo G.; Scorcia V.; Carnevali A.; Bandello F.; Parodi M. B.; Cennamo G.; Cillino S.; Vadala M.; Sunseri Trapani V.; Cagini C.; Fiore T.; Lupidi M.; Parravano M.; Varano M.; Giorno P.; Boscia F.; Giancipoli E.; Eandi C.; Le Mer Y.; Reibaldi M.Fallico, M.; Avitabile, T.; Castellino, N.; Longo, A.; Russo, A.; Bonfiglio, V.; Parisi, F.; Furino, C.; Panozzo, G.; Scorcia, V.; Carnevali, A.; Bandello, F.; Parodi, M. B.; Cennamo, G.; Cillino, S.; Vadala, M.; Sunseri Trapani, V.; Cagini, C.; Fiore, T.; Lupidi, M.; Parravano, M.; Varano, M.; Giorno, P.; Boscia, F.; Giancipoli, E.; Eandi, C.; Le Mer, Y.; Reibaldi, M