Corneal densitometry with Galilei dual Scheimpflug analyzer

This study aims to apply the densitometry distribution analysis (DDA) method to study corneal densitometry depending on age and corneal region from Galilei Dual Scheimpflug Analyzer tomography. A total of 83 healthy participants aged 39.02 ± 18.34 years (range 9–81 years) were screened using a Ziemer Galilei G2. Images were analysed using the DDA, and two parameters, α (corneal transparency) and β (corneal homogeneity), were estimated. A two-way ANOVA analysis was performed to investigate whether α and β are influenced by age, corneal región (four concentric areas were considered), and their interaction. The parameters α and β statistically change with age and corneal region. A statistically significant interaction effect of 13% (α) and 11% (β) exists between age and corneal region. However, the corneal region plays a more significant role than aging in corneal densitometry; 31% (α) and 51% (β) of the variance can be attributed to the corneal region, while 28% (α) and 5% (β) can be attributed solely to aging. Corneal densitometry can be objectively assessed from Galilei G2 images using the DDA method. The corneal region plays a more significant role than aging in corneal densitometry. Consequently, general results on corneal densitometry and aging should be taken cautiously

Divulgación científica y orientación laboral para fomentar el interés en la asignatura de Física en grados de ingeniería

[EN] Physics, a first-year course in Engineering degrees, is often failed by students. Furthermore, students do not seem to recognize the usefulness of the subject as part of their training. To improve the perception that undergraduate students have of Physics courses, as well as to increase their interest in the subject, a couple of special lectures were held within the Physics II course. These special lectures consisted of science outreach and job guidance, both in business and academia. During the talks, the speakers emphasized their personal experiences during and after their university studies. Participating students (35 students from various engineering degrees) were asked to answer an anonymous feedback survey after attending the special lectures. All the students who answered the survey were satisfied with the experience carried out. They also affirmed that they considered the special lectures useful for their training, and a vast majority said they had improved their perception of the subject.[ES] Las asignaturas de Física en el primer curso en los grados de ingeniería cuentan con un elevado número de suspensos. Además, los alumnos parecen no reconocer la utilidad de la asignatura como parte de su formación. Para mejorar la percepción que los alumnos tienen de la asignatura, así como para aumentar su interés por la misma se celebraron un par de clases magistrales especiales en el seno de la asignatura Física II, consistentes en orientación laboral sobre el mundo empresarial y el académico. Durante las charlas las ponentes hicieron hincapié en su experiencia personal durante y después de su etapa universitaria. Se pidió a los alumnos participantes (35 estudiantes de diferentes ingenierías) que contestasen una encuesta anónima de retroalimentación después de atender a las clases magistrales especiales. La totalidad de los alumnos que contestaron a la encuesta quedaron satisfechos con la experiencia realizada, afirmaron que les había parecido útil para su formación y una inmensa mayoría aseveró haber mejorado su percepción de la asignatura.Esta innovación pudo llevarse a cabo gracias al programa EXPERTIA 2020-21 y al National Science Centre (Poland) under the OPUS 19 funding scheme; project no. 2020/37/B/ST7/00559.Consejo, A. (2021). Divulgación científica y orientación laboral para fomentar el interés en la asignatura de Física en grados de ingeniería. En IN-RED 2021: VII Congreso de Innovación Edicativa y Docencia en Red. Editorial Universitat Politècnica de València. 1327-1336. https://doi.org/10.4995/INRED2021.2021.13700OCS1327133

Corneal tissue changes following short-term soft contact lens wear of different materials

Purpose: To study the effect of different soft contact lens (CL) materials during short-term wear on corneal tissue. Methods: Twenty-two healthy participants wore both silicone hydrogel (MyDay, CooperVision) and hydrogel soft CLs (Biomedics 1 day extra, CooperVision) for 8 h per lens. In each session, Scheimpflug images were captured before and immediately after CL removal. Images were analysed using the densitometry distribution analysis, a technique from which two parameters, α (corneal transparency) and β (corneal homogeneity), were estimated. In addition, the central corneal thickness changes after CL wear and the influence of the CL material on corneal transparency were evaluated. Results: The β parameter (homogeneity) increased by 5% after wearing both CL materials (paired t-test, p < 0.001). However, the α parameter (transparency) only increased in half of the participants. No material was found to be more determinant in causing the corneal densitometry changes. Statistically significant but not clinically relevant changes in corneal thickness were observed. Conclusions: Biomarkers of corneal tissue integrity (α and β) were affected by short-term soft contact lens wear. The observed changes in corneal transparency and homogeneity were not clinically relevant but support the importance of participant-material biocompatibility

OCT based corneal densitometry: the confounding effect of epithelial speckle

Corneal densitometry is a clinically validated method for objectively assessing the transparency of stroma. The technique is currently dominated by Scheimpflug technology. Still, optical coherence tomography (OCT), in which examination of the statistical properties of corneal speckle is undertaken, has also been considered to assess corneal densitometry. In-vivo, the stroma is observed via the epithelium. However, the effect of this external layer on stromal densitometry has not been considered as yet. This study aims to quantify the influence of epithelium integrity on corneal OCT densitometry. OCT images from eleven freshly enucleated porcine eyes before and after epithelial debridement were used. OCT densitometry was investigated at different stromal depths using four metrics of speckle statistics. Results indicate that there exist statistically significant differences in speckle statistics for a given stromal depth depending on the presence or absence of the epithelium. The estimation error in speckle statistics can reach over 20% depending on the stromal depth. The anterior stroma densitometry values are the ones most affected by epithelial integrity. In conclusion, if OCT densitometry stromal parameters are to be considered in absolute terms, it is essential to consider the confounding effect of the epithelial layer in the analysis

Assessing and compensating for the confounding factors in Scheimpflug-based corneal densitometry

Scheimpflug-based corneal densitometry is a clinically verified method for assessing corneal transparency. Nevertheless, the estimates of corneal densitometry appear to be correlated with age and eye biometry parameters, such as the anterior chamber depth or the pupil size, and that ensues a convoluted conditional estimation problem, where it is difficult to interpret the results. This study aims at devising a methodology for compensating for such confounding factors by using, as a research platform, a commercially available Scheimpflug camera that allows exporting images in a dynamic fashion, allowing averaging the results from multiple acquisitions. Two approaches are considered, one based on appropriately normalizing the line densitometry signal and one based on image histogram equalization. Then, three parameters for describing corneal densitometry are derived including the mean value of backscatter and the scale and shape parameters of the Weibull distribution estimated in regions of interest encompassing parts of corneal stroma. The results show that, unlike the non-normalized measures, the proposed approaches lead to parameters that are not correlated with age nor the eye biometry

Relationship between corneal tissue and shape in short-term soft contact lens wear

AbstractPurposeTo investigate which morphometric and ocular surface tissue parameters are affected by short‐term soft contact lens (CL) wear and to assess whether they carry related or independent information.MethodsTwenty‐two healthy participants wore silicone hydrogel (SiHy; MyDay, CooperVision) soft CLs for 8 h in their left eye. Corneal tomography and corneoscleral topography were captured before and immediately after CL wear. Central corneal thickness (CCT), corneoscleral parameters (limbus position and corneoscleral junction [CSJ] angle) and corneal tissue parameters (corneal transparency and homogeneity) were evaluated.ResultsCorneoscleral parameters (limbus position and CSJ angle) were independent of corneal tissue parameters (transparency and homogeneity) at baseline and after CL wear. CCT was independent of all the other parameters examined at baseline, but baseline values of corneal tissue parameters were moderately correlated with CCT change (transparency: r = −0.51; p = 0.007), homogeneity: r = −0.46; p = 0.02).ConclusionsA complete characterisation of ocular surface changes following CL wear should consider corneoscleral topography and corneal densitometry simultaneously, since they carry complementary information

Evaluación continua de la labor docente universitaria

[EN] The vast majority of universities apply Student Evaluation of Teaching (SET) through anonymous surveys, answered by students at the end of a given course. This method prevents the lecturer from the possibility to improve or adapt their teaching resources to the specific group of students enrolled in the course. In this innovation, we incorporate, in addition to the official university survey, a questionnaire at the beginning of the course and a follow-up questionnaire for undergraduate engineering students enrolled not for the first time in Physics II. In the initial questionnaire, the students demanded clear theoretical explanations and solving more exercises in class. The teaching style was adapted under these two premises. In the follow-up questionnaire, the students declared their satisfaction with the didactic method followed and asked to resolve more exam-type exercises in class, a resource that was implemented. In the final official survey, the students valued teaching activity with 4.76 out of 5.00, a higher rating than the average of Physics II 4.20 out of 5.00. Carrying out questionnaires for the evaluation of teaching at the beginning and in the middle of the semester is an easy and effective method to support students.[ES] La gran mayoría de universidades evalúan la actividad docente por medio de encuestas anónimas, respondidas por los estudiantes al finalizar la docencia de una determinada asignatura. Este método no da margen de actuación al docente para mejorar o adaptar sus recursos didácticos al grupo concreto de alumnos matriculados en la asignatura. En esta innovación incorporamos, además de la encuesta oficial de la universidad, un cuestionario al comienzo del curso y un cuestionario de seguimiento para los alumnos de diversas ingenierías matriculados no por primera vez en la asignatura Física II. En el cuestionario inicial los estudiantes demandaron explicaciones teóricas claras y la resolución de más ejercicios en clase. La docencia de la asignatura se adaptó bajo estas dos premisas. En el cuestionario de seguimiento los estudiantes declararon su agrado con el método didáctico y pidieron que se realizasen más ejercicios tipo examen en clase, recurso que se implementó. En la encuesta final oficial los estudiantes valoraron la actividad docente con un 4.76 sobre 5.00, calificación más alta que la media de la asignatura 4.20 sobre 5.00. Realizar cuestionarios para la evaluación de la docencia a principio y a mitad de cuatrimestre es un método de fácil implantación y efectivo para apoyar a los estudiantes.Consejo, A.; Sevillano, P. (2021). Evaluación continua de la labor docente universitaria. En IN-RED 2021: VII Congreso de Innovación Edicativa y Docencia en Red. Editorial Universitat Politècnica de València. 724-735. https://doi.org/10.4995/INRED2021.2021.13701OCS72473

Corneoscleral junction angle in healthy eyes assessed objectively

Purpose: To introduce a fully objective method to measure corneoscleral junction (CSJ) angle and evaluate the CSJ angle in healthy eyes. Methods: Corneoscleral topography (Eye Surface Profiler, ESP) was acquired from the right eye of 105 healthy Caucasian subjects, ranging from 18 to 59 years old. From the raw anterior eye height data, the topographic limbus was automatically demarcated in 360 semi-meridians. Further, in limbal location, the CSJ angle was automatically calculated from corneoscleral height data using neighbouring auxiliary points for angle calculation. Additionally, CSJ angle was statistically analysed regionally. Results: The mean CSJ angle was 177.5 ± 1.1°. There is a mean difference of 7.7 ± 3.7° between the steepest (smallest) and flattest (largest) CSJ angle within the same eye. There exist statistically significant differences between temporal (178.2 ± 1.4°) and nasal (176.4 ± 1.1°) regions (paired t-test, p < 0.001), and between superior (178.1 ± 1.1°) and inferior (177.9 ± 1.1°) regions (p = 0.038). CSJ angle is correlated with limbus position (r = 0.43, p < 0.001). Conclusion: CSJ angle is rotationally asymmetric. CSJ varies regionally, being the smallest (steepest) in the nasal region. Significant rough changes in CSJ angle were observed for some healthy individuals

Outcomes of human leukocyte antigen-matched allogeneic cultivated limbal epithelial transplantation in aniridia-associated keratopathy - a single-center retrospective analysis

To assess the efficacy and safety of human leukocyte antigen-matched allogeneic cultivated limbal epithelial stem cell grafts in the treatment of aniridia-associated keratopathy (AAK). Methods: Six eyes of 6 patients with severe AAK received an allogeneic stem cell graft between January 2010 and March 2017. Anatomical and functional results were assessed at 6 months, 1 year, 2 years, and the final follow-up visit available. Safety analysis was performed by considering all perioperative and postoperative adverse events and additional surgeries required during the follow-up period.Results:The mean follow-up was 53.6 months (range 24-104 months). In most patients (80%), there was an early improvement of the keratopathy postoperatively, which slowly regressed during longer follow-up. At the final follow-up, 4 of the eyes were graded as failure and 1 eye was graded as partial success. Grading the sixth eye was not possible because of an adverse event. None of the patients maintained a total anatomical success in the long-term. Only 1 patient maintained a modest improvement in best-corrected visual acuity from hand motion to counting fingers. Four serious adverse events were recorded in 2 patients.Conclusions:Severe AAK remains a challenging condition to manage. Transplantation of allogenic ex vivo cultivated limbal stem cells may provide a temporary improvement in ocular surface stability, but anatomical and functional results are poor in the long-term. The eyes are prone to adverse events, and any surgical treatment should take this into consideration