Corneal dioptric power and astigmatism: A comparison between colour light-emitting diode based (CassiniTM) and Scheimpgflug technology (PentacamTM) topography. / Comparación de medidas de poder dióptrico corneal y astigmatismo entre un topógrafo basado en tecnología de diodo-emisor de luz a color (Cassini®) y un topógrafo basado en tecnología Scheimpflug (Pentacam®).

AIM: To determine the agreement and to compare the measurements obtained from a colour light-emitting diode based (CassiniTM) and Scheimpflug (PentacamTM) based topography in the evaluation of the anterior, posterior, and total corneal power and astigmatism. METHODS: A total of 30 eyes from 30 healthy patients were consecutively measured using PentacamTM and CassiniTM. The main evaluated parameters were the anterior, posterior, and total dioptric power, and a power vector analysis of the astigmatism. The agreement between both devices was analysed using the intraclass correlation coefficient (ICC) and performing Bland-Altman plots. The comparison of means was performed using paired Student t-test. RESULTS: The agreement between both devices when comparing the anterior and total corneal dioptric power was very high (ICC>0.85), but not when studying the posterior cornea (ICC<0.5). In the astigmatism analysis, measurements from the anterior cornea also showed an excellent agreement (ICC>0.78), but was poor for the corneal posterior surface (ICC<0.31). When studying the corneal dioptric power, no statistically significant differences were found for the anterior surface (P>.05), but PentacamTM obtained higher values for posterior and total surfaces (P<.001). As regards the magnitude of the astigmatism, no significant differences were found between both devices. CONCLUSION: Both devices were highly comparable when studying the anterior cornea, but the agreement was poor-moderate when measuring posterior cornea. Therefore, the data obtained by both topographers are not interchangeable.

Corneal toxicity after Ozurdex(®) migration into anterior chamber. / Toxicidad corneal tras migración de Ozurdex(®) a cámara anterior.

OBJECTIVE: To describe a case of corneal toxicity after migration of a dexamethasone implant into the anterior chamber. CASE REPORT: A 62-year-old man with aphakia and a history of vitrectomy received a dexamethasone implant for a refractory Irvine-Gass syndrome. Thirty days later, the implant migrated into the anterior chamber causing endothelial contact with secondary corneal oedema that justified the removal of the implant without resolution of the oedema. DISCUSSION: Clinical tolerability to dislocated implant is poor in cases with pre-existing corneal oedema, and because of this, it must be removed early. In cases of aphakia and vitrectomy, the increased risk of Ozurdex(®) dislocation justifies performing a prior endothelial count.

[The use of digitalis: a prospective study on the posology of digoxin with weekly interruption]. / El uso de la digital: estudio prospectivo de la pauta posológica de digoxina con descanso semanal.

The dixogin dosage with an interruption of two consecutive days a week is frequently used in our country. We decided to compare this kind of digoxin dosage with an uninterrupted one by means of describing in each case the serum digoxin level, by determining whether it is in the so-called therapeutic range (0.8-2.0 ng/ml) or not, and by correlating the serum level to the clinical response (the control of heart rate in patients with atrial fibrillation). We designed a crossover clinical trial on 14 patients taking digoxin, having normal renal function and suffering from atrial fibrillation. The serum digoxin concentration found in the weekly interruption digoxin dosage (1.02 +/- 0.23 ng/ml before and 0.66 +/- 0.15 ng/ml after) was lower than one found in the continuous dosage (1.09 +/- 0.23 ng/ml). The 25% of the patients (before the interruption) and 75% (after the interruption) had plasma levels lower than 0.8 ng/ml, in opposition to the 8.3% found in the uninterrupted dosage. No patient on the continuous dosage showed clinical and/or electrocardiographic signs of digoxin toxicity. The mean heart rate was higher in the weekly interruption dosage (74.4 +/- 11.6 beats/min before and 83.9 +/- 6.4 beats/min after) than in the continuous dosage (72.9 +/- 10.5 beats/min). In terms of achieving serum digoxin levels within the so-called therapeutic range, the uninterrupted dosage proved to be better than the discontinuous one as well as to control the heart rate.

Development and validation of the Spanish Hazard Perception Test.

OBJECTIVE: The aim of the current study is to develop and obtain valid evidence for a hazard perception test suitable for the Spanish driving population. To obtain valid evidence to support the use of the test, the effect of hazardous and quasi-hazardous situations on the participants' hazard prediction is analyzed and the pattern of results for drivers with different driving experience--that is, learner, novice, and expert drivers and reoffender vs. nonoffender drivers--is compared. Potentially hazardous situations are those that develop without involving any real hazard (i.e., the driver did not actually have to decelerate or make any evasive maneuver to avoid a potential collision). The current study analyzed repeat offender drivers attending compulsory reeducation programs as a result of reaching the maximum number of penalty points on their driving license due to repeated violations of traffic laws. METHOD: A new video-based hazard perception test was developed, using a total of 20 hazardous situation videos plus 8 quasi-hazardous situation videos. They were selected from 167 recordings of natural hazards in real Spanish driving settings. RESULTS: The test showed adequate psychometric properties and evidence of validity, distinguishing between different types of drivers. Psychometric results confirm a final version of the hazard perception test composed of 11 video clips of hazards and 6 video clips of quasi-hazards, for which an overall Cronbach's alpha coefficient of.77 was obtained. A lack of ability to detect quasi-hazards and distinguish them from hazardous situations was also found for learner, novice, and reoffender drivers. Learner drivers obtained lower average scores than novice and experienced drivers with the hazardous situation videos, and learner drivers obtained lower average scores than experienced drivers with the quasi-hazardous situation videos, suggesting that the ability to correctly identify hazardous traffic situations may develop early by accumulating initial driving experience. However, the ability to correctly identify quasi-hazardous situations may develop later with the accumulation of further driving experience. Developing this ability is also difficult for reoffender drivers. CONCLUSION: The test has adequate psychometric properties and is useful in distinguishing between learner, novice, and expert drivers. In addition, it is useful in that it analyzes the performance of both safe and unsafe drivers (reoffenders who have already lost their driving license).

Inheritance of the general shell color in the scallop Argopecten purpuratus (Bivalvia: Pectinidae).

Although some external coloration and pigmentation patterns in molluscan shells may be attributable to environmental factors, most variation in these phenotypic characters depends on uncomplicated genetic mechanisms. Genetic research on inheritance of color variations in the north-Chilean scallop (Argopecten purpuratus) has now been expanded to analyze color segregation in juvenile scallops produced under controlled conditions employing self- and cross-fertilization. Calculations from the results were used for comparison with different numerical models based on Mendelian inheritance, and results were also obtained on the inheritance of a dorsoventral white line often observed on the left (upper) valve in this species. The results confirmed the hereditary basis for color variation in the shell of this scallop, suggesting a simple, dominant model of epistasis to explain the distribution of the different color variants observed (purple, brown, orange, yellow, and white). The presence of the white line may be controlled by a recessive allele with simple Mendelian traits on a locus distinct from those that control color variation.