Flexible probe for in vivo quantification of corneal epithelium permeability through non-invasive tetrapolar impedance measurements.

Studies concerning the functional status of the corneal epithelium are of special interest due to its key role in preventing ocular surface disease and corneal infections. In particular, quantitative measurements of the epithelium permeability translayer electrical resistance (TER) have been proven as a sensitive in vitro test for evaluation of the corneal barrier function. In a recent work from the authors (Guimera et al. Biosens. Bioelectron. 31:55-61, 2012), a novel method to non-invasively assess the corneal epithelial permeability by using tetrapolar impedance measurements, based on the same TER theoretical principles, was presented and validated using a rigid sensing device. In this work, the usability of this method has been dramatically improved by using SU-8 photoresist as a substrate material. The flexibility of this novel sensing device makes no need to apply pressure on the cornea to ensure the electrical contact between the electrodes and the corneal surface. The feasibility of this flexible sensor has been evaluated in vivo by increasing the permeability of rabbit corneal epithelium. For that, different concentrations of benzalkonium chloride (BAC) solution were instilled on different rabbit corneas. The obtained results have been compared with measurements of the permeability to sodium fluorescein of different excised corneas, a well-known method used to evaluate the corneal barrier function, to demonstrate the feasibility of this novel flexible sensor for quantifying the corneal epithelium permeability in vivo in a non-invasive way.

Immediate bilateral sequential cataract surgery.

PURPOSE: There is a constant controversy between performing cataract surgery for one eye or for both eyes in the same surgical session. The objective of this study is to review the scientific evidence on the efficacy and safety, determine the reduction of costs of sequential bilateral cataract surgery on the same day compared to unilateral cataract surgery, as well as to compare the rate of associated complications. METHODS: A comprehensive search of the PubMed and Web of Science databases has been conducted to identify relevant articles on sequential bilateral cataract surgery from 2000 to 31 of December of 2020. RESULTS: Literature shows that there is strong evidence demonstrating the efficacy and safety of same-day sequential bilateral cataract surgery. Studies have not found a higher rate of postoperative complications compared to unilateral cataract surgery. CONCLUSIONS: Same-day sequential bilateral cataract surgery is a good surgical option for the resolution of the cataract, provides rapid visual rehabilitation and without greater risks than unilateral surgery. It also provides a reduction in sanitary costs. There is a psychological fear of performing bilateral surgery due to the potential risk of complications that would affect both operated eyes. In this article we discuss the efficacy, safety, complications rate and associated costs in sequential bilateral cataract surgery in the same surgical act.

Study of the clinical profiles of patients with eating disorders in specific units.

OBJECTIVE: The purpose of this study is to describe the clinical profiles of patients diagnosed of a specific Eating Behavior Disorder (EBD) who come to a specialized outpatient unit for patients over 18 years old with this disorder. METHOD: This is an observational, cross-sectional and descriptive study in which 101 medical records of patients with an eating disorder diagnosis have been analyzed retrospectively. RESULTS: The clinical profiles observed showed 93.9% women, medium age 29.9%, in which 33% of the patients had an illness course of 2 to 5 years. Purgative forms were more frequently observed. A total of 19.8% had substance abuse disorders and 54.4% anxiety disorders. CONCLUSIONS: Specific units for Eating Disorders should be included in the combined resources that not only allow for treatment of the eating behavior disorders but also for their psychopathological comorbidities, the prognosis and evolution of the disease depending on the latter.

Evaluation of femtosecond laser-assisted cataract surgery after 10 years of clinical application. / Evaluación de la cirugía de la catarata asistida con láser femtosegundo tras 10 años de aplicación clínica.

INTRODUCTION: Femtosecond laser-assisted cataract surgery (FLACS) has been considered a technological advance in modern cataract surgery. After years of experience, it has been observed that clinical outcomes had more complications than expected at the beginning. The aim of this study is to compare the benefits and disadvantages of the FLACS technique with conventional cataract surgery. METHOD: The PubMed and Web of Science platforms were used to search for scientific literature. RESULTS: The FLACS has currently improved the surgical technique in terms of the shorter ultrasound time used and the lower loss of endothelial cells. Likewise, the centration of capsulotomy and the correction of astigmatism with arcuate incisions have also been improved. As disadvantages, are the high cost of the laser, the intraoperative capsular complications, the induction of intraoperative myosis, and the learning curve of the technique. CONCLUSIONS: The FLACS technique is considered beneficial for specific cases, such as patients with scheduled premium surgery, or with low endothelial cell count. However, it is believed that given the technological cost it is not a cost effective technique for most standard cases in our daily clinical practice.

Phakic intraocular lenses: Recent advances and innovations. / Lentes intraoculares fáquicas: recientes avances e innovaciones.

Phakic intraocular lenses (pIOL) are recommended when counselling refractive surgery candidates presenting with high ametropia or ocular surface and/or corneal conditions that contraindicate corneal refractive surgery. This review aims to present the state-of-the-art regarding pIOL models currently available in Europe, addressing their newer indications and recent design innovations. These include, in the case of posterior chamber pIOLs, the addition of a central hole to improve aqueous humour circulation, the availability of larger optical zones, and multifocal optics for the compensation of presbyopia. The review also highlights their good safety and efficacy results, as well as the role of patient education to ensure adequate outcomes in the medium-long term. The indications of pIOLs in special situations, as well as bi-lensectomy, a procedure that most pIOL patients may eventually require as they age and develop cataracts, are also addressed.

Alkalithermophilic actinomycetes in a subtropical area of Jujuy, Argentina.

The objective of this study was to examine the alkalithermophilic actinomycete communities in the subtropical environment of Jujuy, Argentina, characterized by sugarcane crops. Laceyella putida, Laceyella sacchari, Thermoactinomyces intermedius, Thermoactinomyces vulgaris and Thermoflavimicrobium dichotomicum were isolated on the media with novobiocin, from sugar cane plants and renewal rhizospheres, and grass and wood soils. Soil pH was almost neutral or lightly alkaline, except for grass soil acidified by lactic liquor. A smaller number of actinomycetes was found on the living plants and bagasse (recently obtained or stored according to the Ritter method) with respect to decomposed leaves on the soil. Thermophilic species of Laceyella, Thermoactinomyces, Thermoflavimicrobium, Saccharomonospora, Streptomyces and Thermononospora were isolated on the media without novobiocin, from composted sugar cane residues. Air captured near composted bagasse piles, contained alkalithermophilic actinomycete spores.

Corneal collagen cross-linking. A review of its clinical applications. / Entrecruzamiento del colágeno corneal. Revisión de sus aplicaciones clínicas.

OBJECTIVE: To perform a literature review of the current clinical applications of corneal collagen cross-linking. METHODS: An exhaustive literature search was made, including the main biomedical databases, and encompassing all years since the introduction of cross-linking in ophthalmology practice. RESULTS: Corneal collagen cross-linking using UVA irradiation and riboflavin is a surgical technique that is currently being optimised, and is supported by a good amount of pre-clinical and clinical studies. These papers found show the beneficial effect of the surgery on preventing the progression of corneal ectasia, especially keratoconus, but also on pellucid marginal degeneration and keratectasia after refractive surgery. The effect of cross-linking on avoiding the occurrence of iatrogenic keratectasia when combined with a photo-ablative procedure is less clear to date. Additionally, it appears that cross-linking may have a considerable beneficial effect on controlling corneal infection caused by fungi, bacteria and amoebae. However, its effect on viral keratitis can be detrimental. The benefit on bullous keratopathy seems to be rather transient. CONCLUSIONS: Corneal collagen cross-linking may be used with relative safety and efficacy in patients with progressive keratoconus. Its use could also be considered in patients with other corneal ectasias or with corneal infections of non-viral origin. Currently, there is still a need for more studies as regards its effect on preventing iatrogenic keratectasia.

Optical coherence tomography to monitor photodynamic therapy in pathological myopia.

AIM: To evaluate the role of optical coherence tomography (OCT) in determining choroidal neovascularisation (CNV) activity before and after photodynamic therapy (PDT) in patients with pathological myopia. METHODS: 33 patients (33 eyes) with pathological myopia and being treated with PDT were included. Every 3 months all patients were evaluated and presence or absence of leakage on fluorescein angiography, presence of intraretinal or subretinal fluid on OCT, and macular and choroidal neovascular complex thickness on OCT, were determined at each examination. RESULTS: The macular thickness decreased significantly after PDT at 6 months (p = 0.001) and at 12 months follow up (p = 0.01). However, no significant changes in CNV thickness were measured after PDT at 6 months of follow up (p = 0.418) and at 12 months of follow up (p = 0.521). Once the diagnosis of CNV associated with pathological myopia was established, before treatment, OCT had a sensitivity of 96.96% for detecting CNV activity. After treatment, OCT had a good sensitivity (95.23%) and a moderate specificity (69,69%) in determining CNV activity, which resulted in a diagnostic efficiency (proportion of correct results) of 79.62%. CONCLUSIONS: OCT appears to be useful for indicating CNV activity. Therefore, it may serve as a complementary technique for deciding the need for PDT and re-treatment in patients with pathological myopia.

Cataract surgery on the previous corneal refractive surgery patient.

Cataract surgery in cases with previous corneal refractive surgery may be a major challenge for the ophthalmologist. The refractive outcome of the case deserves special attention in the preoperative planning process, which should be tailored for the type of prior refractive procedure: incisional, ablative under a flap, or on the corneal surface. Avoiding refractive surprise after cataract surgery in these cases is principally dependent on the accuracy of the intraocular lens calculation, together with the selection of the appropriate biometric formula for each case. Modern techniques for cataract surgery help surgeons to move toward the goal of cataract surgery as a refractive procedure free from refractive error. We give practical guidelines for the cataract surgeon in the management of these challenging cases.

Analysis of the promoter region of the murine complement factor H gene.

We have used the luciferase system to assay basal promoter activity of the murine factor H gene. Based on the results from luciferase assays with clones of 13 nested deletions, a 242-bp region that appeared to contain an enhancer element was subcloned upstream of a heterologous promoter and was shown to enhance transcription. A 26-bp fragment from this region was shifted in electrophoretic mobility assays, and this fragment contains a consensus sequence for the adenovirus major late transcription factor/upstream stimulatory factor (MLTF/USF). This fragment had enhancing activity in a minimal factor H promoter construct, demonstrating that it is a major enhancer of the factor H gene in murine liver cells.

Reproducibility of digital image analysis for measuring corneal haze after myopic photorefractive keratectomy.

PURPOSE: To evaluate the usefulness of digital image analysis for quantifying corneal haze by determining the reproducibility of its measurements at the corneal plane. METHODS: In a prospective study, 20 randomly selected eyes that had undergone myopic photorefractive keratectomy were photographed focusing the slit beam on their anterior corneal surface. Each photograph was examined using computer image analysis techniques that detect the edge of the reticular pattern of the image. Quantification of the difference between two areas, treated and adjacent untreated cornea, each containing 3,750 pixels with a resolution of 256 gray levels, was performed. Intra-analyzer variation was determined by evaluating the photographs obtained by two analyzers under standard conditions on four separate visits. Interanalyzer variation was calculated using one measurement and the mean of the four measurements. RESULTS: The pooled standard deviation of the measurements for the analyzers was 0.63 and 0.62 gray levels (coefficient of variation, 4.1% and 3.3%). An association between less severe haze measurements and higher reproducibility scores was found (r = .42; P = .007). The mean interanalyzer variation was smaller for the average of four measurements, 0.55 +/- 0.37 gray levels, than for one measurement, 0.94 +/- 0.73 gray levels (P = .014). CONCLUSIONS: Good reproducibility for haze measurements by digital image analysis of the differences between the treated and adjacent untreated corneal areas was obtained. When the average of four measurements was used instead of a single measurement, interanalyzer reproducibility increased significantly. This new technique may be used to quantify and analyze corneal haze after myopic photorefractive keratectomy.

Digital system measurement of decentration of Worst-Fechner iris claw myopia intraocular lens.

BACKGROUND: Topography measures the centration in refractive and corneal refractive surgery, but until recently there was no effective method to measure decentration in intraocular lens (IOL) implantation. PATIENTS AND METHODS: We measured the decentration of 22 phakic eyes, in 14 high myopic patients, based upon photographs of the anterior segment using a digital analysis system (IMAGEnet Topcon Corporation 1988, Tokyo, Japan). These eyes had undergone IOL implantation for the correction of myopia with Worst-Fechner iris claw lenses. Decentration was measured with respect to the centers of both the cornea and pupil. RESULTS: Mean decentration of the IOL center from the cornea center was 0.51 +/- 0.25 mm (range, 0 to 0.8374 mm). When measured with respect to the center of the pupil, the average decentration was 0.47 +/- 0.29 mm (range, 0.182 to 0.9341 mm). A positive correlation between the decentration measurements of the two methods was found (p < .01 indicated statistical significance). CONCLUSIONS: This digital imaging system (IMAGEnet) accurately measured decentration of IOLs in myopic eyes.

Comparison of intersecting trapezoidal keratotomy and arcuate transverse keratotomy in the correction of high astigmatism.

BACKGROUND: High astigmatism can be corrected using trapezoidal or arcuate transverse keratotomies. Videokeratography enables qualitative evaluation of the corneal topography. METHODS: Fifty-five eyes of 41 patients presenting with high astigmatism after penetrating keratoplasty or naturally occurring astigmatism (mean, 6.29 diopters [D]; range, 3.00 to 16.00 D) underwent correction using either intersecting trapezoidal or arcuate transverse keratotomies. Corneal topographic maps were analyzed and classified into keratographic patterns. Mean follow up was 3 years (range, 1 to 6 years). RESULTS: The mean net decrease in refractive astigmatism was 3.60 D (52.7% reduction). The flattening/steepening ratio was on average higher for intersecting trapezoidal keratotomy (7.26 for astigmatism after penetrating keratoplasty and 8.31 for naturally occurring astigmatism) than for arcuate transverse keratotomy (.98 in astigmatism after penetrating keratoplasty and 1.76 in naturally occurring astigmatism). Accordingly, intersecting trapezoidal keratotomy tended to produce a hyperopic shift in the spherical equivalent refraction (mean hyperopic shift, 2.65 and .56 D, respectively). The mean vector-corrected change of refractive astigmatism after intersecting trapezoidal keratotomy was 88.8% in naturally occurring (n = 21 eyes) and 70.3% in penetrating keratoplasty astigmatism (n = 13). Arcuate transverse incisions corrected on average 79.9% of naturally occurring (n = 13) and 60.8% of penetrating keratoplasty astigmatism (n = 8). Videokeratography showed the asymmetric bowtie pattern as the most frequent pattern for both procedures. Intersecting trapezoidal keratotomy was characterized by relatively higher incidences of polygonal and irregular patterns. Arcuate transverse incisions caused less wound healing defects and glare than intersecting trapezoidal keratotomy. CONCLUSIONS: Both intersecting trapezoidal keratotomy and arcuate transverse incisions effectively reduced high naturally occurring astigmatism and astigmatism after penetrating keratoplasty. However, greater corneal surface irregularity and more complications were seen following intersecting trapezoidal keratotomy. Trapezoidal keratotomy should not be used unless a large decrease of myopia is needed, and then a nonintersecting technique is preferable.

Prospective trial of intraoperative mitomycin C in the treatment of primary pterygium.

AIMS: A prospective, randomised, double blind, placebo controlled study of intraoperative mitomycin C as adjunctive treatment of primary pterygium was conducted. METHODS: A total of 66 eyes of 54 patients with primary pterygium were treated with excision, with or without a single intraoperative application of mitomycin C (0.1 mg/ml for 5 minutes) to evaluate the efficacy and toxicity of this adjunctive treatment. The mean follow up was 14.1 months (range 12-23 months). RESULTS: Of the 36 eyes that underwent simple excision, 14 (38.8%) exhibited recurrences whereas only one of 30 eyes (3.33%) treated with excision and intraoperative application of mitomycin C had recurrence (p = 0.0006). Neither serious ocular complications nor systemic toxicity were noted in the mitomycin C treated group. CONCLUSION: Intraoperative mitomycin C appears to be an effective and safe adjunctive treatment of primary pterygium.

Combined procedure for glaucoma and cataract: a retrospective study.

To ascertain the long-term effects of a triple procedure in the case of coexisting cataract and glaucoma, we did a retrospective study of 93 eyes that had cataract extraction, IOL implantation, and trabeculectomy within a ten-year period. Mean follow-up was 32.4 +/- 21.9 months. Mean postoperative intraocular pressure (IOP) was significantly lower than preoperatively, even though fewer medications were being used. One year after surgery, 60% of eyes had a best corrected visual acuity of 20/40 or better with an average improvement of 3.8 Snellen lines. Patients who had had surgery four or more years before the study had the highest percentage of eyes with an IOP exceeding 22 mm Hg. This group also had the poorest IOP control when no medications were used and when the patient took fewer medications than before surgery. The finding that IOP control decreases with postoperative time raises questions about the long-term success of the triple procedure in controlling IOP.

Cataract surgery in a patient with Brown-McLean syndrome.

The Brown-McLean syndrome is defined by corneal edema that involves the peripheral 2.0 to 3.0 mm of cornea, sparing the central cornea. This syndrome is usually associated with previous cataract surgery but has been reported rarely in patients with other predisposing factors such as angle-closure glaucoma or spontaneous lens absorption with iridodonesis. We describe the clinical course of a 50-year-old man with myotonic dystrophy who had Brown-McLean syndrome with no identifiable predisposition for peripheral corneal edema. Although this syndrome appears to be the result of peripheral endothelial dysfunction, this patient was able to tolerate cataract extraction without developing central corneal edema.

Final clear corneal incision size for AcrySof intraocular lenses.

PURPOSE: To evaluate clear corneal incision size variation in phacoemulsification surgery after the implantation of 2 models of AcrySof intraocular lenses (IOLs). SETTING: Departamento de Oftalmología, Clínica Universitaria de Navarra, Universidad de Navarra, Pamplona, Spain. METHODS: This prospective study comprised 108 eyes that had phacoemulsification and implantation of an Acrysof IOL model MA60BM (56 eyes) or MA30BA (52 eyes). Wound incision size was quantified using the Nordan incision size measurer. The incision size for each IOL model was evaluated before and after implantation and its relationship with the complications during implantation analyzed. RESULTS: Mean incision size varied from 3.7 mm +/- 0.14 (SD) before implantation to 3.9 +/- 0.11 mm after implantation for the MA60BM model (P = .001) and from 3.3 +/- 0.15 mm to 3.4 +/- 0.13 mm for the MA30BA model (P = .001). Intraoperative complications occurred in 14 eyes, and difficulty during IOL implantation, in 23 eyes. There was no association between final incision size and complications. CONCLUSIONS: Incision size increased after the implantation of the 2 AcrySof IOL models used in this study. Modifications to model MA30BA have led to an average decrease in wound size of 0.5 mm with respect to the MA60BM model. Most difficulties encountered were attributable to improper IOL unfolding.

[Effect of growth hormone and parenteral nutrition on the catabolic phase following major digestive surgery]. / Efecto de la hormona del crecimiento y la nutrición parenteral sobre la fase catabólica tras cirugía digestiva mayor.

The purpose of the present study was to determine if the administration of a biosynthetic human growth hormone (bGH) was able to enhance the efficacy of total parenteral nutrition (PN). Patients (n = 38) who had undergone major gastrointestinal surgery were randomly divided in two groups. Group I (n = 20) treated only with PN and Group II (n = 18) treated as in Group I plus bGH (4 UI/daily). Our study shows that the administration of bGH produces a significant increase in serum levels of growth hormone and Somatomedin-C. It also caused a positive nitrogen balance from the first 24 hours on (p less than 0.01). In Group II on day 12 after operation a statistically significant increase in transferrin (p less than 0.05), albumin (p less than 0.01) and total proteins (p less than 0.02) was observed. Our study suggest that the administration of bGH produces, perhaps through Somatomedin-C as mediator, an increase in protein synthesis.

Anterior chamber contamination following uncomplicated cataract surgery: comparative results using intravenous imipenem.

BACKGROUND AND OBJECTIVE: An attempt was made to establish the effect of an intravenous antibiotic on anterior chamber (AC) fluid contamination when administered before surgery. PATIENTS AND METHODS: A prospective study of AC contamination was conducted in 60 patients undergoing extracapsular cataract extraction (ECCE)/intraocular lens (IOL) implantation. The final 20 patients received 1 g of intravenous imipenem 1 hour before surgery. RESULTS: There were 4 positive AC cultures from the 20 patients in the imipenem group, and 13 positive AC cultures from the 40 control patients (P = .4, chi-square test). Of the 60 eyes, 17 had positive AC aspirate cultures and 23 had positive conjunctival smears. Only in one instance was the microorganism isolated from each case the same (1.7%). CONCLUSIONS: An insignificant decrease in AC contamination was observed when intravenous imipenem was used before surgery. The results also suggest that conjunctiva might not be the main source of contamination during surgery.

Permanent pacing in patients with congenital atrio-ventricular block--experience of 33 cases.

OBJECTIVES: The authors review permanent pacing in patients with congenital atrioventricular block (CAVB) and present their experience in permanent pacing in this pathology. STUDY POPULATION AND METHODS: In a population of 4,355 patients submitted to implantation of permanent pacing between January 1980 and January 1998, 33 (0.75%) had CAVB. The mean age of the patient population with CAVB was 16.7 years (aged from eleven days to 35 years); 33% were below 10 years of age; 16 patients were male. The majority of the patients had symptoms of brain hypoperfusion; two patients had concomitant malignant ventricular tachyarrythmias (one of these with Torsade de Pointes due to congenital long QT syndrome). Transvenous (endocardial) pacing was used in 32 patients (two with previous epicardial pacing and exit block) and epicardial pacing in one. The mode of stimulation used was VVI in three patients, DDD in eight patients, VVIR in 14 patients, DDDR in four patients and VDD in four. Smaller pulse generators were used in children of lower weight. In recent years single lead VDD systems have been preferred whenever technically possible. Vascular access was the left cephalic vein in 17 patients; the left subclavian vein in 14 patients and the right jugular vein in one patient. During a mean follow-up of 6.9 years, two patients with ventricular stimulation systems developed "Pacemaker Syndrome" and required a change of mode of stimulation. Lead fracture and posterior cutaneous necroses were observed in two other patients, who were accordingly submitted to surgical revision. It was deemed necessary, one year later, to increase the lead loop in a child with a permanent pacemaker implanted at eleven days of age. No other complications occurred with the other patients; replacement of the pulse generators was performed in an elective manner. CONCLUSIONS: CAVB is a rare indication for the implantation of a permanent pacemaker. In children, in the majority of cases, endocardial stimulation is possible in spite of the obvious technical difficulties due to low weight. Sequential, more physiological, stimulation systems should be preferred. However, VVIR stimulation systems of smaller dimensions can be the first choice of mode of stimulation in smaller children, mainly due to anatomical and technical limitations.