[Atypical presentation of ruptured aneurysmal right sinus of Valsalva with severe aortic insufficiency]. / Presentación atípica de rotura de seno de Valsalva derecho aneurismático con insuficiencia aortica severa.

Aneurysm of the Sinus of Valsalva (ASV) is a rare abnormality and affects less than 0.1% of the general population. We describe the case of a 37-year-old woman with a clinical picture characterized by dyspnea, palpitations, and syncope of 6 years of evolution. The echocardiographic study revealed a right ASV with a sub pulmonary interventricular perforation of 8mm and producing a regurgitant jet into the right ventricle, causing dilatation of the right ventricular outflow tract, pulmonary artery, and severe aortic insufficiency Carpentier DI. The patient underwent successful repair of the defect and interventricular perforation, and valve replacement was not necessary. Timely echocardiographic diagnosis and early surgery are the main predictors that make the difference between an excellent outcome and certain death.

May Measurement Month 2019: an analysis of blood pressure screening results from Mexico.

May Measurement Month 2019 (MMM19) in Mexico was an opportunistic survey, aimed to improve blood pressure (BP) awareness at the individual and population levels. This survey followed the methodology of MMM19, previously published. The total number of participants screened was 39 700, 56.7% female, 36.6% were of mixed ethnicity, mean age [standard deviation (SD)] was 46.9 (17.4) years, and mean body mass index was 27.2 (SD: 4.4) kg/m2. Seven per cent of the participants reported having diabetes, 2.4% reported having a myocardial infarction in the past, 1.1% stroke, 2.0% were pregnant at the time of the survey, 3.7% of women had suffered from hypertension in a previous pregnancy, 11.4% declared that they were smokers, and 47.0% drank alcohol at least once a week. After multiple imputations, of all 39 700 participants, 10 140 (25.5%) had hypertension; of all participants with hypertension, 43.8% were aware of their diagnosis, 41.7% were on antihypertensive medication, and 27.8% had controlled BP (systolic BP <140 mmHg and diastolic BP <90 mmHg). Of those on antihypertensive medication, 27.8% had controlled BP. In Mexico, MMM is the largest hypertension survey ever done, it provides complementary data to the existing information on arterial hypertension in the country and helps to increase the visibility of hypertension: a priority health problem.

Entrenamiento vascular intensivo para el cirujano no vascular.

INTRODUCCIÓN: En la mayoría de los servicios de emergencia del Perú no se cuenta con un cirujano vascular, teniendo que resolver los problemas vasculares el cirujano general. Es necesario que los cirujanos generales estén entrenados en el manejo vascular, sobre todo de aquellas condiciones que pueden comprometer la vida. OBJETIVO: Compartir los resultados del primer curso de cirugía vascular para el cirujano no vascular y el nivel de satisfacción de los alumnos participantes. MÉTODO: El curso de entrenamiento utilizó cinco modelos de simulación distribuidos en cinco sesiones prácticas. Al final del curso se evaluó a los alumnos usando la escala OSATS (Objetive Structured Assesment of Technical Skills) y se midió el tiempo de anastomosis arterial; adicionalmente se evaluó el nivel de satisfacción del curso. RESULTADOS: Participaron 12 alumnos, de los cuales ocho cumplieron los criterios de inclusión. La edad media fue de 39.9 años. La calificación OSATS fue de 19 (± 2.1). El tiempo de anastomosis fue de 17.6 (± 7.9) minutos. El nivel de satisfacción global de curso fue de 31.05; no hubo diferencias significativas entre la satisfacción de las diferentes sesiones prácticas (p = 0.85). El alfa de Cronbach de la encuesta fue de 0,96 (excelente). CONCLUSIONES: El curso intensivo de entrenamiento vascular combina diferentes escenarios quirúrgicos basados en la simulación. El nivel de satisfacción del curso y la fiabilidad de la encuesta para «percepción de las prácticas de simulación¼ fueron excelentes. INTRODUCTION: In most emergency services in Peru there is no vascular surgeon, the general surgeon having to solve the vascular problems. General surgeons need to be trained in vascular management, especially those life-threatening conditions. OBJECTIVE: To share the results of the first course of vascular surgery for the non-vascular surgeon and the level of satisfaction of the participating students. METHOD: The training course used five simulation models distributed in five practical sessions. At the end of the course, the students were evaluated using the OSATS (Objective Structured Assessment of Technical Skills) scale and the arterial anastomosis time was measured; Additionally, the level of satisfaction of the course was evaluated. RESULTS: 12 students participated, 8 met the inclusion criteria, the mean age was 39.9 years, the OSATS score was 19 (± 2.1) and the anastomosis time 17.6 (± 7.9) minutes. The level of overall course satisfaction was 31.05, there were no significant differences between the satisfaction of the different practical sessions (p = 0.85). The Cronbach's alpha for the survey was 0.96 (Excellent). CONCLUSIONS: The intensive vascular training course combines different surgical scenarios based on simulation. The level of satisfaction of the course and the reliability of the survey "perception of simulation practices" were excellent.

Micromechanics modelling for mineral volume fraction determination: application on a terrigenous formation.

This work presents a non-linear Self-Consistent (SC) micromechanics method to model the observed physical elastic properties of a terrigenous formation with the purpose to obtain its depth mineral volume fractions profile. In this approach, it is first assumed that the observed physical elastic properties obtained from well logs, such as the density [Formula: see text] and the elastic compressional [Formula: see text] and shear [Formula: see text] velocities, are a non-linear relationship of the unknown mineral volume fractions [Formula: see text]. Then, a gradient descent algorithm is implemented to seek for those volume fractions [Formula: see text] for which differences between modelled and observed physical elastic properties are minimum. It is assumed that quartz, calcite and clay are the main comprising minerals of the formation. Obtained volume fractions profile follow the same general trends to those estimated by implementing the Linear Least-Squares Inversion LLSI method which is widely used in petrophysical analysis to obtain mineral concentrations from density [Formula: see text], photoelectric effect [Formula: see text] and compressional slowness [Formula: see text] well logs. Results also show that calcite and clay volume fractions from these two methods are highly correlated while quartz volume fractions show low correlation. Further comparison between clay concentrations from SC method with clay concentrations calculated from direct measurements of gamma ray GR well logs used as a guideline also exhibits high correlation. These results suggest that the SC method is better suited to obtain clay and calcite volume fractions rather than quartz volume fractions. However, SC method can provide with insights about the general distribution of quartz along the borehole.

Artificial neural network to guide intracorneal ring segments implantation for keratoconus treatment: a pilot study.

BACKGROUND: To analyze the clinical results of an artificial neural network (ANN) that has been processed in order to improve the predictability of intracorneal ring segments (ICRS) implantation in keratoconus. METHODS: This retrospective, comparative, nonrandomized, pilot, clinical study included a cohort of 20 keratoconic eyes implanted with intracorneal ring segments KeraRing (Mediphacos, Belo Horizonte, Brazil) using the ANN (ANN group) and 20 keratoconic eyes implanted with KeraRing using the manufacturer's nomograms (nomogram group). Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA) (visual acuity is expressed in decimal value and in LogMAR value in brackets), manifest refraction, corneal topography, tomography, aberrometry, pachymetry and volume analysis (Sirius System. CSO, Firenze, Italy) were performed during the preoperative visit; and the two groups, ANN group and nomogram group, did not differ significantly preoperatively in all of the parameters evaluated. These preoperative values were compared with the results obtained at the third-month visit. Mann-Whitney test and Wilcoxon test were used for the statistical analyses. RESULTS: The spherical equivalent and the keratometric values decreased significantly in both groups. The CDVA improved from 0.60 ± 0.23 (0.22 LogMAR) pre-operatively to 0.73 ± 0.21 (0.14 LogMAR) post-operatively in the ANN group (p < 0.005), and from 0.54 ± 0.19 (0.27 LogMAR) pre-operatively to 0.62 ± 0.19 (0.21 LogMAR) post-operatively in the nomogram group (p < 0.01), with statistically significant difference between the two groups (p < 0.05), being better in the ANN group. Coma-like aberrations decreased significantly in the ANN group, while in the nomogram group they did not change significantly, but no statistically significant difference was found between the two groups. CONCLUSIONS: ANN to guide ICRS provides an increase in the visual acuity, reduction in the spherical equivalent and improvement in the optical quality of keratoconus patients. ANN gives better results when compared with the manufacturer's nomograms in terms of better corrected vision and reduction of the coma-like aberrations. The constant inclusion of new cases will make the predictability of ANN increasingly better as the software finetunes its learning.

Posterior corneal features in patients with Down syndrome and their relation with keratoconus.

AIMS: To characterise posterior corneal surface features in patients with Down syndrome (DS) and to compare them with healthy and mild keratoconus corneas. METHODS: This restrospective, comparative, non-randomised, clinical study included 123 eyes, divided into three groups (37 eyes of patients with DS, 46 with mild keratoconus and 40 controls), and took place at Vissum Alicante. Only patients with no previous ocular surgery, no corneal scars and no active ocular disease other than keratoconus were included. The Sirius System topographer (CSO, Firenze, Italy) was used in order to analyse posterior corneal surface keratometry, shape and keratoconus screening indices, posterior corneal aberrations, corneal volume and pachymetry. RESULTS: Patients with DS, when compared with healthy controls, have a steeper (mean keratometry 7 mm (KM): -6.30±0.44 vs -6.15±0.22; p<0.05) and more irregular (root mean square per unit of area: 4.5 mm 0.22±0.22 vs 0.09±0.03, p<0.001; posterior vertex of the ectatic area: 33.22±44.29 vs 10.63±2.88, p<0.001) posterior corneal surface, with higher aberrations (high-order aberrations (HOAs): 1.07±1.43 vs 0.15±0.06, p<0.001; coma-like: 0.88±1.09 vs 0.13±0.07, p<0.001) and thinnest pachymetry (497.68±26.88 vs 538.95±31.67, p<0.001). At the same time, no statistically significant difference was found between patients with DS and patients with mild keratoconus (p>0.05) in KM (-6.38±0.34), HOA (0.56±0.36), coma-like (0.51±0.34) and pachymetry (500.56±36.83). CONCLUSIONS: Posterior corneal surface of patients with DS is steeper, more irregular and shows more higher order aberrations, as well as reduced volume and thinner pachymetry than patients with healthy corneas. Additionally, posterior corneal surface in patients with DS shows similar characteristics to those found in mild keratoconus.

Femtosecond-assisted laser in situ keratomileusis for high myopia correction: Long-term follow-up outcomes.

OBJECTIVE: Report the outcomes of laser in situ keratomileusis (LASIK) for high myopia correction after long-term follow-up. METHODS: Retrospective, consecutive, clinical study including 70 eyes that underwent LASIK using a 500 Hertz (Hz) repetition rate excimer laser and femtosecond technology for flap creation. Visual, refractive, corneal aberrations, and correlation among the variables were evaluated during 3 years. In addition, 34 eyes were followed during 5 years. RESULTS: Significant improvement of 17 logMAR lines was observed in uncorrected vision at 5 years (p < 0.01). This was consistent with spherical equivalent reduction that came from mean preoperative -7.79 diopters (D) to 5 years postoperative -0.24 D (p < 0.01). Significant induction of primary spherical aberration and coma aberration was also found (p < 0.01) at 3 months with levels of 0.61 µm and 0.47 µm, respectively, with no further changes at 5 years (p > 0.05). Pearson correlation showed that the amount of high-order aberrations at 3 months postoperativeley was significantly correlated with the changes in the keratometry throughout the 5 years (delta K) (R2 0.242 p = 0.05). Finally, preoperative corneal asphericity showed an inverse correlation with the delta K (R2 -308 p = 0.01). CONCLUSIONS: Results from this study suggests that LASIK for high myopia correction using 500 Hz repetition rate excimer laser provides stable visual, refractive and aberrometric results after 5 years of follow-up. A more prolate cornea and the amount of higher-order aberrations induced after LASIK are factors that negatively impact in the long-term stability of the procedure.

Laser flap enhancement 5 to 9 years and 10 or more years after laser in situ keratomileusis: Safety and efficacy.

PURPOSE: To study the safety and efficacy of refractive enhancement by flap lifting 5 and 10 years after laser in situ keratomileusis (LASIK). SETTING: Vissum Alicante, Spain. DESIGN: Retrospective case series. METHODS: Eyes with a flap lift at least 5 years after primary LASIK with a 3-month follow-up were evaluated. The primary outcome measures were safety and the complication rate. Moderate epithelial ingrowth was managed with Nd:YAG laser treatment. RESULTS: The primary LASIK procedure was myopic in 45 eyes, hyperopic in 22 eyes, and presbyopic in 3 eyes. The mean time from primary LASIK to the flap lift was 12.3 years ± 3.45 (SD). In 57 eyes, the primary LASIK flap was created at least 10 years before the enhancement. The mean pre-lift spherical equivalent was -1.29 ± 1.23 diopters (D) in the myopia group and +0.65 ± 1.72 D in the hyperopia group. Three months later, 88% of eyes and 74% of eyes, respectively, had an uncorrected distance visual acuity of 20/20 or better; 100% achieved at least 20/25. No eye lost 2 lines or more of corrected distance visual acuity. In the myopia group, the efficacy index was 0.94 and the safety index was 0.98 at 6 months. Mild epithelial ingrowth developed in 31.43% of eyes and clinically significant epithelial ingrowth in 11.42% of eyes; 4.28% required a relift for severe epithelial ingrowth. CONCLUSIONS: Late flap lift for refractive enhancement 10 years or more after LASIK provided good efficacy and safety with fast visual recovery. The rate of surgical intervention for significant postoperative epithelial ingrowth was low.

Invasive Pharmacology Outcomes with Different Corneal Cross-Linking Protocols: A Review.

Collagen corneal cross-linking (CXL) is an invasive pharmacological treatment strategy used for corneal ectatic disorders and is currently the only treatment capable of halting the progression of the disease. In the past 20 years, the conservative management of progressive corneal ectasia has changed, thanks to this procedure that produces strengthening of the corneal tissue through the photochemical reaction generated by the combined action of riboflavin and ultraviolet A radiation. Many modified protocols have been implemented to halt the progression of the disease and to delay or prevent visual loss and surgical procedures such as corneal transplantation. Because of the variety of different protocols that are currently used, the results that are being reported are very variable, and could generate some confusion in relation to the true efficacy of the procedure. The aim of this review was to provide an overview of the aforementioned protocols that are designed to maintain the efficacy of CXL in halting the progression of the disease but avoiding the major limitations of the procedure.

Clinical Outcomes of a New Asymmetric Intracorneal Ring Segment for the Treatment of Keratoconus.

PURPOSE: To report visual, refractive, and corneal aberrations after implantation of a new asymmetric intracorneal ring segment (ICRS). METHODS: This was a prospective, multicenter clinical study including 30 eyes of 26 patients with keratoconus. All cases were implanted with an ICRS, named the VISUMRING (VR), which had an arc length of 353 degrees and 2 asymmetric sections that can be customized in base width, length, and thickness. Ophthalmic evaluation included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction, topography, and anterior corneal aberrations using the Sirius System (CSO, Firenze, Italy). Mean follow-up period was 14.7 ± 7.9 months. RESULTS: Significant improvement of both UDVA and CDVA was observed after 1 year. UDVA improved from 0.08 ± 0.22 to 0.22 ± 0.16 and CDVA from 0.24 ± 0.29 to 0.43 ± 0.18 (P = 0.01). A significant reduction of more than 7 D in the spherical equivalent from -12.38 ± 3.77 D to -5.00 ± 3.26 D (P < 0.05) was noted 1 year after the procedure. In terms of higher-order aberrations, a slight reduction that was not statistically significant in the higher-order and coma-like aberrations was noted at 1 year from 4.32 and 3.82, to 4.12 and 3.55, respectively. Regarding complications, 5 of the 30 cases needed to have the VR explanted throughout the follow-up period due to severe corneal melting. CONCLUSIONS: VR ICRS improves vision and refraction and induces major corneal flattening in patients with keratoconus. Further design enhancement is needed to increase the reduction of the asymmetric corneal aberrations and reduce the extrusion rate.

Keratoconus Corneal Posterior Surface Characterization According to the Degree of Visual Limitation.

PURPOSE: To characterize posterior corneal surface features in patients with keratoconus and healthy controls and correlate them with the severity of the disease according to visual limitation. METHODS: Retrospective, comparative, clinical study including 477 cases, 374 keratoconic eyes and 103 healthy corneas. Patients were classified according to the degree of visual limitation. The corneal posterior surface including shape indices and keratoconus screening indices was evaluated using the rotating Scheimpflug camera and Placido disc topographer. RESULTS: Dioptric power of the posterior corneal surface increases linearly as corrected distance visual acuity deteriorates (r > 0.700; P < 0.001). A significant correlation was also observed between shape indices root mean square per unit of area (RMS/A) (posterior surface irregularity) and corrected distance visual acuity (r = -0.750; P < 0.001). In addition, keratoconus screening indices such as posterior corneal aberrations and posterior ectasia vertex (KVb) also showed significant correlation with the degree of visual limitation (r = -0.687; P < 0.001 and r = -0.789; P < 0.001, respectively). Receiver operating characteristic curves demonstrate that RMS/A and KVb showed highest discriminating capabilities between normal and mild keratoconus cases with an area under the curve of 0.96 and 0.97, respectively, with a sensitivity and specificity of more than 93% for the RMS/A and 89% and 84% for the KVb. CONCLUSIONS: Posterior corneal surface characteristics correlate with the degree of visual impairment and can be used for classifying patients with keratoconus. RMS/A, KVb, and posterior corneal aberrations are the most representative variables of visual function deterioration and are also useful to differentiate normal from mild keratoconus cases.

Corneal Epithelial Thickness Intrasubject Repeatability and its Relation With Visual Limitation in Keratoconus.

PURPOSE: To evaluate intra-subject repeatability of anterior segment optical coherence tomography (AS-OCT) combined with placido disc MS-39 (CSO, Firenze, Italy) and correlate epithelial thickness measurements and the degree of visual limitation in keratoconus patients. DESIGN: Reliability analysis and cross-sectional study. METHODS: Setting: Vissum, Alicante, Spain. SUBJECTS: Total of 167 eyes, of which 107 were from keratoconus patients and 60 were healthy. PROCEDURES: Three repeated consecutive epithelial thickness measurements were taken: central 3.0 mm and the nasal, temporal, superior, and inferior regions at 3.0-6.0 mm and 6.0-8.0 mm. MAIN OUTCOME MEASURES: Intrasubject repeatability of epithelial indices was assessed and correlated to the degree of best-corrected visual acuity (BCVA). RESULTS: The intraclass correlation coefficient was ≥0.90, indicating highly repeatable measurements for both keratoconus and healthy eyes. In multivariate analysis, epithelial indices associated with worse BCVA were as follows: thinner 3 mm central (P = .04), thicker 8 mm superior (P < .001), and thinner 8 mm inferior (P < .001). Thickness central 3 mm decreased as keratoconus grading increased (P = .002). The superior-inferior ratio at 8 mm significantly increased as keratoconus grading increased (P < .001). In multivariate analysis thinner 3 mm central (R2 = 6.19%, P = .04), greater superior-inferior 8 mm ratio (R2 = 8.37%, P = .004), greater superior-inferior 6mm ratio (R2 = 2.67%, P = .02), and steeper K2 (R2 = 21.51%, P < .001) were associated with keratoconus with a combined area under the curve of 0.92. CONCLUSION: High repeatability of epithelial thickness measurements may be achieved in both keratoconus and healthy eyes with the MS-39. There is a significant correlation between epithelial thickness measurements and BCVA. These measurements may be of additional value in discriminating between keratoconus and healthy eyes.

Metal-Organic Frameworks as Drug Delivery Platforms for Ocular Therapeutics.

Metal-organic frameworks (MOFs) have been evaluated as potential nanocarriers for intraocular incorporation of brimonidine tartrate to treat chronic glaucoma. Experimental results show that UiO-67 and MIL-100 (Fe) exhibit the highest loading capacity with values up to 50-60 wt %, whereas the performance is quite limited for MOFs with narrow cavities (below 0.8 nm, for example, UiO-66 and HKUST-1). The large loading capacity in UiO-67 is accompanied by an irreversible structural amorphization in aqueous and physiological media that promotes extended release kinetics above 12 days. Compared to the traditional drawbacks associated with the sudden release of the commercial drugs (e.g., ALPHAGAN), these results anticipate UiO-67 as a potential nanocarrier for drug delivery in intraocular therapeutics. These promising results are further supported by cytotoxicity tests using retinal photoreceptor cells (661W). Toxicity of these structures (including the metal nodes and organic ligands) for retinal cells is rather low for all samples evaluated, except for HKUST-1.

Corneal Morphologic Characteristics in Patients With Down Syndrome.

Importance: Literature suggests corneal morphologic characteristics compatible with keratoconus are present in a high percentage of patients with Down syndrome (DS), suggesting the need to perform a detailed examination of the anterior segment to try to avoid serious visual impairment in this group of patients. Objective: To characterize the abnormal features of the cornea in patients with DS and compare these with a control group. Design, Setting, and Participants: Multicenter case-control study at Vissum Alicante, Alicante, Spain, and the Ophthalmology and Pediatric Department, Cairo University, Cairo, Egypt. Data collection took place between May 2013 and May 2016. Data were analyzed between June 2016 and August 2016. The study included 321 eyes of 217 participants from 2 groups: 112 participants in the DS group and 105 healthy participants in the control group. Interventions: Patients were evaluated using Placido disc/Scheimpflug camera topographer (Sirius, CSO). Visual, refractive and anterior, and posterior corneal characteristics were assessed and compared in both groups. Main Outcomes and Measures: Keratoconus diagnosis. Incidence of corneal morphologic irregularities similar to keratoconus in patients with DS. Results: In the DS group, mean (SD) age was 14.88 (15.76) years, 54 (48%) were women, 66 (59%) were white, and 46 (41%) were Arab. In the control group, mean (SD) age was 40.29 (14.66) years, 54 (51%) were women, and all were white. Clinical assessment of corneal topography showed that 71.3% (95% CI, 45.2-97.4) of patients in the DS group showed characteristics compatible with keratoconus. Differences were found in steepest keratometry of 47.35 diopters (D) in patients with DS vs 43.70 D in control individuals (difference, 3.65 D; 95% CI, 3.23-4.35 D; P <.001) and in corneal pachymetry of 503 µm in patients with DS vs 545 µm in control individuals (difference, 42 µm; 95% CI, 38.8-56.7 µm; P <.001). Conclusions and Relevance: Patients with DS have steeper and thinner corneas and more corneal aberrations than those without genetic alterations and normal corneas. The findings suggest a detailed corneal study should be considered in such patients to detect keratoconus and implement treatment as appropriate to try to avoid serious visual impairment in this group of patients.

Clinical outcomes with a diffractive trifocal intraocular lens.

PURPOSE: To evaluate clinical and visual outcomes, quality of near vision, and intraocular optical quality of patients bilaterally implanted with a trifocal PanOptix intraocular lens. METHODS: In this prospective consecutive case-series study, 52 eyes of 26 bilateral patients (mean age, 60.2 ± 7.4 years) were implanted with the AcrySof IQ Panoptix intraocular lens. Visual acuity, defocus curve, contrast sensitivity (Pelli-Robson test), near activity visual questionnaire, and internal aberrations with Osiris were evaluated. A prototype light-distortion analyzer was used to quantify the postoperative light-distortion indices. The follow-up was 6 months after surgery. RESULTS: Uncorrected, corrected distance, and uncorrected near visual acuities improved with the surgery (p ≤ 0.02). Distance corrected near visual acuity was 0.13 ± 0.10, 0.13 ± 0.13, and 0.13 ± 0.08 at 1, 3, and 6 months after surgery, respectively (p = 0.82). Distance corrected intermediate visual acuities were 0.09 ± 0.13, 0.13 ± 0.15, and 0.12 ± 0.12 at 1, 3, and 6 months, postoperatively. Binocular contrast sensitivity was 1.86 ± 0.15 Log Units. Defocus curve provided a visual acuity equal or better to 0.30 LogMAR between defocus levels of +0.50 to -3.00 D. The near activity visual questionnaire scores improved significantly with the surgery (p < 0.01). CONCLUSION: The AcrySof IQ Panoptix intraocular lens is able to restore visual function with an acceptable intermediate and near vision after cataract surgery with good contrast sensitivity and an improvement in the near activity visual questionnaire.

Descemet Membrane Endothelial Keratoplasty (DMEK) Under Previous DMEK for Secondary Endothelial Graft Failure.

PURPOSE: To describe an alternative treatment option for secondary Descemet membrane endothelial keratoplasty (DMEK) graft failure, using a second DMEK graft without primary graft removal ("DMEK under DMEK"). METHODS: A 72-year-old patient with pseudophakic bullous keratopathy in the left eye underwent an 8.25-mm second DMEK under an 8.5-mm failed DMEK because of previous graft rejection and subsequent secondary failure. RESULTS: Corrected distance visual acuity improved from 0.2 (decimal scale) before surgery to 0.56 (best visual potential due to concomitant preexisting macular damage) from the first month after surgery and up to sixth-month follow-up. Complete corneal transparency was achieved from the first postoperative day and remained until the end of the follow-up. Pachymetry returned to normal values within the first month. No intraoperative or postoperative complications were observed. CONCLUSIONS: A second DMEK graft without peeling or removing the first DMEK graft is an alternative treatment option for DMEK graft secondary failure. This approach is able to achieve full anatomical and functional restoration of the prefailure status. This technique allows a second graft surgery to be easier, faster, and with less intraoperative risks (as a result of a potential difficult host descemetorhexis). Future studies with larger samples and a longer follow-up are necessary to confirm the short and long-term outcomes of this new DMEK under DMEK approach.

Accommodative intraocular lenses: where are we and where we are going.

Presbyopia still remains the last frontier of refractive surgery. Its surgical management is under constant evolution due to the limitations that exist today with respect to its management, which is probably in relation with the multifactorial basis in which presbyopia is clinically developed in the human. Until currently, virtually all surgical techniques that have been proposed for its correction are based on the induction of pseudoaccommodation in the presbyopic eye, including multifocality. However, the real restoration of accommodation is more complex, and it has been tried by the use of different, so called, "accommodative" pseudophakic intraocular lenses (AIOL). Overall, the reported results with these lenses by independent authors have been modest in relation with the restoration of the accommodative power of the eye and these modest benefits are usually lost with time due to the long term changes in the capsular bag. This fact made these lenses to be almost abandoned in the last few years, but there are currently other AIOL models being used with innovative mechanisms of action and different anatomical support outside the capsular bag that offer encouraging preliminary results that could bring a new potential of application to these types of lenses. In this article, we will update the modern refractive surgeon about the fundamentals and provide updated information about the outcomes of AIOLs by reviewing the concept of accommodation, the different attempts that have been accomplished in the past, their demonstrated published results in human clinical trials, and the future alternatives that may arrive in the near future.

The use of intracorneal ring segments in keratoconus.

Keratoconus is a corneal degeneration that usually appears during puberty and may seriously deteriorate the quality of life of the patients. This corneal disease is today the first indication of corneal transplantation in young patients. Until the last decade of the XX century, keratoplasty procedures were the only alternative to treat this pathological condition. In the beginning of the XXI century, intracorneal ring segments implantation was proposed as a therapeutic choice for treating keratoconus patients. Since then, several published articles have reported the benefits of this surgical procedure in treating this type of corneal ectatic disorder. The purpose of the present investigative work is to summarize the characteristic of the intracorneal ring segments and also to review the different features published in the literature in relation to this surgical technique for the treatment of keratoconus patients.

Biocompatibility and Biomechanical Effect of Single Wall Carbon Nanotubes Implanted in the Corneal Stroma: A Proof of Concept Investigation.

Corneal ectatic disorders are characterized by a progressive weakening of the tissue due to biomechanical alterations of the corneal collagen fibers. Carbon nanostructures, mainly carbon nanotubes (CNTs) and graphene, are nanomaterials that offer extraordinary mechanical properties and are used to increase the rigidity of different materials and biomolecules such as collagen fibers. We conducted an experimental investigation where New Zealand rabbits were treated with a composition of CNTs suspended in balanced saline solution which was applied in the corneal tissue. Biocompatibility of the composition was assessed by means of histopathology analysis and mechanical properties by stress-strain measurements. Histopathology samples stained with blue Alcian showed that there were no fibrous scaring and no alterations in the mucopolysaccharides of the stroma. It also showed that there were no signs of active inflammation. These were confirmed when Masson trichrome staining was performed. Biomechanical evaluation assessed by means of tensile test showed that there is a trend to obtain higher levels of rigidity in those corneas implanted with CNTs, although these changes are not statistically significant (p > 0.05). Implanting CNTs is biocompatible and safe procedure for the corneal stroma which can lead to an increase in the rigidity of the collagen fibers.

Clinical outcomes with a new microincisional diffractive multifocal IOL.

BACKGROUND: To evaluate the refractive outcomes and the optical performance as well as the quality of life in patients implanted with a new diffractive multifocal intraocular lens (IOL). METHODS: Prospective, clinical study including 41 cases of patients who underwent cataract surgery and were divided in two groups: group 1, including 20 eyes implanted with the multifocal IOL SeeLens MF (Hanita Lenses, Israel); group 2, 21 eyes implanted with the Acrysof SA60AT IOL. Visual acuity, defocus curve, intraocular aberrations, contrast sensitivity function and quality of life were assessed during a follow up period of 6 months. RESULTS: Significant improvement was observed in the uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) in both groups (p < 0.02). The multifocal group showed better results in terms of uncorrected near visual acuity (UNVA) and distance-corrected near visual acuity (DCNVA) (p < 0.01). Comparison of both groups showed better visual acuities for the multifocal IOL group in defocus levels from -3.0 D to -1.50 D (p ≤ 0.01). At 6 months, there was a significant reduction of the internal higher order aberrations (p ≤ 0.04). A significant increase in scotopic contrast sensitivity was detected for 6 cycles/° spatial frequency during follow up (p = 0.04), but no significant changes were observed for the rest of spatial frequencies (p ≥ 0.06). Visual Functioning Index (VF-14) questionnaire showed that patients reported high levels of satisfaction when performing daily tasks. CONCLUSIONS: The SeeLens MF IOL is able to successfully restore distance, near and intermediate visions after cataract surgery. It also provides functional intermediate vision with optimal intraocular optical quality.