Weight-adjusted caffeine and ß-blocker use in novice versus senior retina surgeons: a self-controlled study of simulated performance.

BACKGROUND/OBJECTIVES: Tremor and expertise are potentially influenced variables in vitreoretinal surgery. We investigated whether surgeon experience impacts the association of microsurgical performance with caffeine and ß-blockers weight-adjusted intake. SUBJECTS/METHODS: Novice and senior surgeons (<2 and >10 practice years, respectively) were recruited in this self-controlled, cross-sectional study. A simulator's task sequence was repeated over 2 days, 30 min after the following exposures: day 1, placebo, 2.5 mg/kg caffeine, 5.0 mg/kg caffeine, and 0.6 mg/kg propranolol; and day 2, placebo, 0.2 mg/kg propranolol, 0.6 mg/kg propranolol, and 5.0 mg/kg caffeine. Outcomes were total score (0-700, worst-best), simulation time (minutes), intraocular trajectory (centimeters), and tremor-specific score (0-100, worst-best). RESULTS: We recruited 15 novices (9 men [60%], 1.33 ± 0.49 practice years) and 11 seniors (8 men [72.7%], 16.00 ± 4.24 practice years). Novices performed worse after 2.5 mg/kg caffeine and improved following 0.2 mg/kg propranolol in total score (557 vs. 617, p = 0.009), trajectory (229.86 vs. 208.07, p = 0.048), time (14.9 vs. 12.7, p = 0.048), and tremor-score (55 vs. 75, p = 0.009). Surgical performance improved with propranolol post-caffeine but remained worse than 0.2 mg/kg propranolol in total score (570 vs. 617, p = 0.014), trajectory (226.59 vs. 208.07, p = 0.033), and tremor-score (50 vs. 75, p = 0.029). Seniors' tremor-score was lower after 2.5 mg/kg caffeine compared to 0.2 mg/kg propranolol (8 vs. 37, p = 0.015). Tremor-score following propranolol post-caffeine remained inferior to 0.6 mg/kg propranolol alone (17 vs. 38, p = 0.012). CONCLUSION: While caffeine and propranolol were associated with performance changes among novices, only tremor was affected in seniors, without dexterity changes. The pharmacologic exposure impact on surgical dexterity seems to be offset by increased experience.

An Innovative Surgical Technique for Subretinal Transplantation of Human Embryonic Stem Cell-Derived Retinal Pigmented Epithelium in Yucatan Mini Pigs: Preliminary Results.

BACKGROUND AND OBJECTIVE: To develop a safe and efficient surgical procedure for subretinal implantation into porcine eyes of a human embryonic stem cell-derived retinal pigmented epithelium (hESC-RPE) monolayer seeded onto a Parylene-C scaffold. This implant is referred to as CPCB-RPE1. MATERIALS AND METHODS: Ultrathin Parylene-C scaffolds were seeded with hESC-RPE and surgically implanted into the subretinal space of Yucatan mini pigs (n = 8). The surgery consisted of pars plana vitrectomy, induction of a limited retinal detachment, and peripheral retinotomy for insertion of the monolayer using a novel tissue injector, followed by silicone oil tamponade injection, laser photocoagulation around the retinotomy site, and inferior iridectomy. Oral cyclosporine was administered from day 1 and during the entire follow-up period. Three months later, the animals were euthanized and the eyes and major organs were submitted for histological analysis. Adjacent sections underwent immunohistochemical analysis to detect human cells using anti-TRA-1-85 (human blood group antigen) antibody and DAPI antibodies. RESULTS: The cell monolayer was immunopositive for TRA-1-85 3 months after implantation and migration from the Parylene-C scaffold was not detected. One eye had a mild inflammatory reaction around the implant that was negative for human biomarkers. No intraocular or systemic tumors were detected. CONCLUSION: The hESC-RPE cells survived for 3 months in this animal model. The surgical procedure for subretinal implantation of CPCB-RPE1 is feasible and safe, without cell migration off the scaffold or development of ocular or systemic tumors.

Effect of lens status in the surgical success of 23-gauge primary vitrectomy for the management of rhegmatogenous retinal detachment: the Pan American Collaborative Retina Study (PACORES) group results.

PURPOSE: To determine the effects of lens status on the success rate of primary pars plana vitrectomy (PPV) for rhegmatogenous retinal detachment using either perfluoropropane gas (C3F8) or silicone oil (SO) tamponade. METHODS: A retrospective chart analysis was made of 97 eyes from 92 patients with rhegmatogenous retinal detachment with no proliferative vitreoretinopathy that were treated with primary 23-gauge PPV. Eyes included in this were phakic (n = 28), pseudophakic (n = 41), or phakic eyes subject to simultaneous phacoemulsification, intraocular lens implantation, and PPV during primary rhegmatogenous retinal detachment repair (n = 28). Tamponade at the end of PPV was with either C3F8 (n = 65) or SO (n = 32). Success was defined as retinal reattachment at 1 year follow-up after a single procedure in eyes submitted to C3F8 injection; in eyes treated with SO injection, the success rate was defined as retina reattached 1 year after oil removal. Statistical comparisons were made between groups using chi-square, Fisher's exact test, Kruskal-Wallis, Mann-Whitney, and multivariate analysis. All eyes were operated by 2 experienced retina surgeons and had a minimum follow-up of 12 months. RESULTS: The vitreoretinal redetachment rate in eyes subjected to C3F8 tamponade was significantly higher (28.6%) for phakic eyes (P = 0.011) compared with pseudophakic or phakic eyes that underwent to phacoemulsification and intraocular lens implantation (4.5%). Eyes in which SO was used at the end of the surgical procedure demonstrated a similar trend of higher reoperation rates in phakic eyes (28.6%) compared with pseudophakic or phakic eyes (8%) subjected to phacoemulsification and intraocular lens implantation; however, no statistically significant difference was observed (P = 0.201). No statistically significant differences were found between groups in relation to the number of tears (P = 0.863) and their location (inferior: P = 0.189, superior: P = 0.708, nasal: P = 0.756, and temporal: P = 0.08). CONCLUSION: The success rates of primary 23-gauge PPV with either C3F8 or SO tamponade in pseudophakic eyes with rhegmatogenous retinal detachment was higher than the same procedure performed in phakic eyes. Still, the retrospective and limited data presented is too preliminary to suggest or recommend that practitioners perform simultaneous combined cataract surgery with retinal detachment and requires further studies in a larger and prospective design to confirm these present findings.

Anti-VEGF for the management of diabetic macular edema.

Diabetic retinopathy (DR) is an important cause of vision loss around the world, being the leading cause in the population between 20 and 60 years old. Among patients with DR, diabetic macular edema (DME) is the most frequent cause of vision impairment and represents a significant public health issue. Macular photocoagulation has been the standard treatment for this condition reducing the risk of moderate visual loss by approximately 50%. The role of vascular endothelial growth factor (VEGF) in DR and DME pathogenesis has been demonstrated in recent studies. This review addresses and summarizes data from the clinical trials that investigated anti-VEGF for the management of DME and evaluates their impact on clinical practice. The literature searches were conducted between August and October 2013 in PubMed and Cochrane Library with no date restrictions and went through the most relevant studies on pegaptanib, ranibizumab, bevacizumab, and aflibercept for the management of DME. The efficacy and safety of intravitreal anti-VEGF as therapy for DME have recently been proved by various clinical trials providing significantly positive visual and anatomical results. Regarding clinical practice, those outcomes have placed intravitreal injection of anti-VEGF as an option that must be considered for the treatment of DME.

Anterior chamber depth during hemodialysis.

BACKGROUND: Exacerbation of chronic glaucoma or acute glaucoma is occasionally observed in patients undergoing hemodialysis (HD) because of anterior chamber depth changes during this therapy. PURPOSE: To evaluate anterior chamber depth and axial length in patients during HD sessions. METHODS: A total of 67 eyes of 35 patients were prospectively enrolled. Axial length and anterior chamber depth were measured using ultrasonic biometry, and these measures were evaluated at three different times during HD sessions. Body weight and blood pressure pre- and post-HD were also measured. RESULTS: There was no difference in the axial length between the three measurements (P = 0.241). We observed a significantly decreased anterior chamber depth (P = 0.002) during HD sessions. CONCLUSION: Our results support the idea that there is a change in anterior chamber depth in HD sessions.

Bevacizumab for the management of diabetic macular edema.

Diabetic retinopathy (DR) is a leading cause of vision loss in the working-age population and is relatedto 1%-5% of cases of blindness worldwide. Diabetic macular edema (DME) is the most frequent cause of DR vision loss and is an important public health problem. Recent studies have implicated vascular endothelial growth factor (VEGF) in DR and DME pathogenesis, as well as provided evidence of the benefits of anti-VEGF agents for the management of such conditions. Despite the benefits of intravitreal ranibizumab injection for the management of DME, the cost-effectiveness of intravitreal bevacizumab therapy has gained increasing interest in the scientific community. This review summarizes the studies examining bevacizumab for the management of DME, focusing on the efficacy and duration of the clinical benefits of decreasing DME and the improvement of best-corrected visual acuity (BCVA). There is strong evidence that intravitreal bevacizumab injection therapy has a good cost-effective profile in the management of DME and may be associated with laser photocoagulation; however, its clinical superiority in terms of the duration of DME regression and the improvement of BCVA compared with intravitreal ranibizumab and other intravitreal anti-VEGF therapies remains unclear and deserves further investigation.

Intraocular pressure and ocular perfusion during hemodialysis.

AIM: To evaluate the intraocular pressure and ocular perfusion pressure during a hemodialysis. METHODS: Sixty-seven eyes from thirty-five patients were evaluated at the beggining of hemodialysis, 2 hours and 4 hours after initiation. Intraocular pressure was evaluated using a Tonopen. Systolic and diastolic arterial pressures were measured with a manual sphygmomanometer. The ocular perfusion pressure was estimated by measuring the difference between 2/3 of the mean arterial pressure and the intraocular pressure values. Generalized estimating equations were used to evaluate the difference between the repeated measurements using the appropriate correction for inter-eye dependency. RESULTS: There was no statistically significant difference in ocular perfusion pressure, in intraocular pressure (p=0.93) and in systolic arterial pressure (p=0.92) at the three time points (p=0.69). But, when analyzing the extreme values, some patients exhibited lower diastolic perfusion pressures at all time points. CONCLUSION: Our results did not support the view that significant changes in ocular perfusion pressure and intraocular pressure occur during hemodialysis session. However, we observed that some patients exhibited lower diastolic perfusion pressures, which could be a poor prognostic factor for glaucoma patients.

Intraocular pressure and ocular perfusion during hemodialysis / Pressão intraocular e perfusão ocular durante hemodiálise

AIM: To evaluate the intraocular pressure and ocular perfusion pressure during a hemodialysis. METHODS: Sixty-seven eyes from thirty-five patients were evaluated at the beggining of hemodialysis, 2 hours and 4 hours after initiation. Intraocular pressure was evaluated using a Tonopen. Systolic and diastolic arterial pressures were measured with a manual sphygmomanometer. The ocular perfusion pressure was estimated by mea suring the difference between 2/3 of the mean arterial pressure and the intraocular pressure values. Generalized estimating equations were used to evaluate the difference between the repeated measurements using the appropriate correction for inter-eye dependency. RESULTS: There was no statistically significant difference in ocular perfusion pressure, in intraocular pressure (p=0.93) and in systolic arterial pressure (p=0.92) at the three time points (p=0.69). But, when analyzing the extreme values, some patients exhibited lower diastolic perfusion pressures at all time points. CONCLUSION: Our results did not support the view that significant changes in ocular perfusion pressure and intraocular pressure occur during hemodialysis session. However, we observed that some patients exhibited lower diastolic perfusion pressures, which could be a poor prognostic factor for glaucoma patients.

OBJETIVO: Avaliar a pressão intraocular e a pressão de perfusão ocular durante uma sessão de hemodiálise. MÉTODOS: Sessenta e sete olhos de trinta e cinco pacientes foram avaliados no início, após 2 horas e após 4 horas do início de uma sessão de hemodiálise. A pressão intraocular foi avaliada usando o aparelho Tonopen. Pressões arteriais sistólica e diastólica foram aferidas usando esfigmomanômetro manual. A pressão de perfusão ocular foi estimada por meio do cálculo da diferença entre 2/3 da pressão arterial média e valores da pressão intraocular. Equações de estimação generalizada foram usadas para avaliar a diferença entre medidas repetidas usando correção apropriada para dependência entres olhos. RESULTADOS: Não houve diferença estatisticamente significativa na pressão de perfusão ocular, PIO (p=0,93) e na pressão arterial sistólica (p=0,92) nos três períodos medidos da hemodiálise (p=0,69). Mas, quando analisados valores extremos, alguns pacientes exibiram pressões diastólicas menores em todos os períodos aferidos. CONCLUSÃO: Nossos resultados não apontaram mudanças significativas na pressão de perfusão ocular e pressão intraocular durante a hemodiálise. No entanto, foi observado que alguns pacientes exibiram pressões diastólicas menores, o que pode ser um fator de prognóstico ruim para pacientes com glaucoma.