What biomarkers explain about pterygium OCT pattern.

BACKGROUND: Optical coherence tomography (OCT) has become a very useful tool to study in vivo different ocular structures and to improve differential diagnosis and management of many ocular pathologies. This study aims to identify pterygium alterations that trigger characteristic OCT images, and analyze if this pattern correctly demarcates lesion boundary. METHODS: Thirty-two patients, 22 men, and ten women, aged between 26 and 56 (mean age 40.5 ± 6.9) with symptomatic primary pterygium were recruited. After excision, lesion images were obtained by high-definition OCT. Specimens were stained with hematoxylin­eosin (H&E), antivimentin for all mesenchymal origin cells and altered limbal basal cells, CD45 for lymphocyte and macrophage cells, CD1a for Langerhans cells, and S100 for melanocyte and Langerhans cells. RESULTS: The typical OCT wedge-shape hyperreflective mass was evident only by vimentin antibody and included, mainly, fibroblasts but also immune cells (verified by CD45) in a rich network of collagen fibers. The mass apex, often extended centripetally as a thin subepithelial line, hyperreflective by OCT, was formed by a row of fibroblasts under an apparently intact Bowman's layer, as vimentin samples revealed. Hyperreflective epithelium overlying the mass showed a great number of vimentin-positive infiltrated cells such as melanocytes, Langerhans cells, and lymphocytes (identified by the other biomarkers). H&E staining revealed the presence of goblet cells. Nevertheless, only vimentin staining revealed the presence of altered basal cells above partially dissolved or apparently intact Bowman's layer, coinciding in this last case with the fibroblast subepithelial line. In most of the cases (72 %), the altered cells occupied a basal segment shorter than the fibroblast subepithelial line but in some specimens, these cells exceeded the fibroblast line length. CONCLUSIONS: This study demonstrated the great visual accordance between pterygium OCT images and vimentin staining. Alteration in collagen arrangement, infiltration of inflammatory cells, and fibroblast subepithelial line in the lesion apex were the main histological changes responsible for the anomalous hyperreflectivity of the OCT pattern. By contrast, altered basal cells located in the basal epithelial layer of the pterygium head could not be detected by OCT, which might generate lesion size underestimation.

Ocular discomfort in pterygium patients.

PURPOSE: To evaluate the relationship between ocular discomfort and pterygium clinical characteristics. METHODS: The ocular comfort index test was self-completed by 25 men and 15 women (age [mean ± SD], 43 ± 11 years) with primary pterygium. Pterygium corneal area (PCA) and limbal perimeter, course and bilaterality of the lesion, visibility of episcleral vessels, conjunctival hyperemia, and exposure to dry or dusty environments were assessed. Spearman correlation and multiple linear regression were performed to evaluate the relationship between ocular discomfort and pterygium clinical characteristics. RESULTS: Ocular discomfort was inversely correlated with PCA (ρ = -0.447, p < 0.01) and directly correlated with the exposure to dry or dusty environments (ρ = 0.324, p < 0.05). The other studied factors did not show any significant relationship with discomfort symptoms. The linear regression analysis identified PCA as the only factor that significantly influenced ocular discomfort (R = -0.404, p < 0.01). CONCLUSIONS: The findings confirm an inverse linear relationship between ocular discomfort and PCA, providing evidence of corneal sensitivity loss in these patients.

Tear osmolarity and ocular changes in pterygium.

PURPOSE: To determine abnormalities in tear osmolarity (TO), tear function, and impression cytology in patients with pterygium and to assess the relationship between the variables. METHODS: Thirty eyes from 30 patients with primary nasal pterygium and 30 eyes from 30 volunteers without ocular pathologies or dry eye symptoms were enrolled in the present study. TO test, tear ferning test, fluorescein tear breakup time, Schirmer test, and impression cytology of the conjunctiva were performed. Analysis of variance was applied for intergroup comparisons, and Pearson correlation was used to calculate the strength of relationships between the variables. A statistical significance level of P<0.05 was considered. RESULTS: Pterygium patients had significantly higher TO, lower crystallization percentage, and lower goblet cell density (GCD) than control patients. A weak but significant negative correlation seems to exist between TO and crystallization percentage (r=-0.425, P<0.01) and between TO and GCD (r=-0.295, P<0.05). CONCLUSION: There is evidence to suggest that pterygium appears to induce unfavorable conditions of increasing TO that could trigger alterations in tear crystallization and GCD. Being aware of TO changes seems essential to understand the complex relationship among pterygium, tear film functions, and ocular surface changes.

Item by item analysis strategy of the relationship between symptoms and signs in early dry eye.

PURPOSE: The present study aimed at analyzing the relationship between several particular symptoms, risk factors or global questionnaire scores and some tear clinical signs in early dry eye patients. MATERIAL AND METHODS: A total of 77 volunteers were enrolled in the study without any prior classification, although patients with severe dry eye were excluded. Two questionnaires were used to assess ocular symptoms and risk factors, and clinical tear signs were evaluated with four tests (osmolarity, ferning, break-up time and the phenol red thread test). Multiple linear regression analysis was performed to determine the relative predictive value of each particular ocular symptom and risk factor, for each clinical sign. This analysis was repeated using symptoms and risk factors global scores. RESULTS: The symptom "eyes stuck shut in the morning" was the only predictor variable for the sign "ferning crystallization" (R = 0.228, p < 0.05) and "dryness" for "break-up time" (R = -0.315, p < 0.01). "Burning sensation" and "computer use for more than 3 h" were predictor variables for "tear osmolarity" (R = 0.342, p < 0.01), while "itching" and "female gender" were found to predict the outcomes of the "phenol red thread test" (R = -0.462, p < 0.05). Global questionnaire scores were not found to predict any tear clinical sign. CONCLUSIONS: The present findings support the informative value of exploring the associations between clinical signs, ocular symptoms and risk factors by following an item by item strategy rather than opting for global questionnaire scores.

Una tarea para evaluar la agudeza visual dinámica y una valoración de la estabilidad de sus mediciones / No disponible

Apenas existen instrumentos de medición adecuados de la capacidad paradiscriminar estímulos en movimiento, cuya aplicación resulte fácil y cuyasvaloraciones sean estables a través del tiempo. También se constata laausencia de un paradigma de evaluación que se muestre sensible anteaquellos factores que, en estudios previos, han sido relacionados con lavisión dinámica. En consecuencia, nos proponemos como objetivo diseñaruna tarea que permita la valoración de la agudeza visual dinámica (AVD),definida como la capacidad de discriminar detalles en condiciones demovimiento relativo entre sujeto y objeto. Para ello, hemos realizado dosestudios psicofísicos. El primero muestra que la AVD resulta modulada portres factores: velocidad, contraste y trayectoria del estímulo móvil,interaccionando significativamente los dos primeros. En el segundo estudio,hemos averiguado la correlación entre la AVD obtenida por los sujetos entres momentos separados, al menos, una semana (t1 y t2) y entre, al menos,dos semanas (t2 y t3). Estas oscilaron entre 0,78-0,92, para una velocidad de14,1º/seg. y entre 0,72-0,85 para una velocidad de 1,4º/seg. Finalmente,comparamos las valoraciones de AVD en esos tres momentos, noencontrando diferencias significativas en el factor temporal. Concluimosque, nuestra tarea constituye una herramienta objetiva, y de fácil aplicacióntanto clínica como experimental, muy útil para valorar la AVD(AU)

Image processing techniques in a preliminary morphometric characterization of corneal epithelium by scanning electron microscopy.

Several processing techniques of digital images allowed us to quantify the percentage of cell surface covered by microprojections (microvilli or microplicae) (SCM), the adhesion between epithelial cells by the parameter intercellular junctions (IJ), the size (cell area), shape (cell shape) and shade (cell shade) of cells on the corneal epithelium of nine rabbits. The data were analyzed and the epithelial cells were classified into three groups by cluster analysis. Assuming the representativeness of the sample, our findings suggest that for a normal corneal epithelium, 80% of the cells could show SCM >41%, and IJ >0.98 (being one a cell to cell junction without disruptions). Standard deviations of cell shade lower than 21 gray levels could indicate a tendency to lose the cell shade mosaic. Normal corneas could show a majority of cells (54-69%) included in group 2 with smaller mean size (80% of cells with cell area <242 µm(2)), higher SCM (80% of cells with SCM >44.83%), polygonal mean shape and brighter shade. Group 1 (15-30% of cells) could show a larger mean size (80% of cells with cell area >494 µm(2)), lower SCM (although 80% of cells with SCM >32.61%), circular mean shape and darker electron reflex. Group 3 could display a medium mean size, higher SCM (similar to group 2), circular mean shape (similar to group 1), and brighter shade. These analyses could possibly be used to further assess the corneal response to ocular drugs, contact lens, and surgical procedures or to discriminate between pathology stages.