[Heterogeneity of costs and performance for penetrating eye injuries and suturing amniotic membranes under DRG conditions : Analysis of case constellations of the G-DRG C01B of the Regensburg University eye clinic]

Patients with penetrating eye injuries are a very heterogeneous group both medically and economically. Since 2009, treatment involving sutures for open eye injuries and cases requiring amniotic membrane transplantation (AMT) were allocated to DRG C01B of the German diagnosis-related group system. However, given the significant clinical differences between these treatments, an inhomogeneity of costs to performance is postulated. This analysis describes case allocation problems within the G-DRG C01B category and presents solutions.

Impact of corneal cross-linking on drug penetration in an ex vivo porcine eye model

To analyze the influence of corneal cross-linking (CXL) using ultraviolet-A and riboflavin on corneal drug penetration of topically applied drugs.

Stress free configuration of the human eye

Numerical simulations of eye globes often rely on topographies that have been measured in vivo using devices such as the Pentacam or OCT. The topographies, which represent the form of the already stressed eye under the existing intraocular pressure, introduce approximations in the analysis. The accuracy of the simulations could be improved if either the stress state of the eye under the effect of intraocular pressure is determined, or the stress-free form of the eye estimated prior to conducting the analysis. This study reviews earlier attempts to address this problem and assesses the performance of an iterative technique proposed by Pandolfi and Holzapfel [1], which is both simple to implement and promises high accuracy in estimating the eye's stress-free form. A parametric study has been conducted and demonstrated reliance of the error level on the level of flexibility of the eye model, especially in the cornea region. However, in all cases considered 3-4 analysis iterations were sufficient to produce a stress-free form with average errors in node location <10(-6)mm and a maximal error <10(-4)mm. This error level, which is similar to what has been achieved with other methods and orders of magnitude lower than the accuracy of current clinical topography systems, justifies the use of the technique as a pre-processing step in ocular numerical simulations.

Preschool children's eye-movements during pictorial recall

We investigated eye-movements during preschool children’s pictorial recall of seen objects. Thirteen 3- to 4-year-old children completed a perceptual encoding and a pictorial recall task. First, they were exposed to 16 pictorial objects, which were positioned in one of four distinct areas on the computer screen. Subsequently, they had to recall these pictorial objects from memory in order to respond to specific questions about visual details. We found that children spent more time fixating the areas in which the pictorial objects were previously displayed.We conclude that as early as age 3–4 years old, children show specific eye-movements when they recall pictorial contents of previously seen objects.

What was I thinking? Eye-tracking experiments underscore the bias that architecture exerts on nuclear grading in prostate cancer

We previously reported that nuclear grade assignment of prostate carcinomas is subject to a cognitive bias induced by the tumor architecture. Here, we asked whether this bias is mediated by the non-conscious selection of nuclei that "match the expectation" induced by the inadvertent glance at the tumor architecture. 20 pathologists were asked to grade nuclei in high power fields of 20 prostate carcinomas displayed on a computer screen. Unknown to the pathologists, each carcinoma was shown twice, once before a background of a low grade, tubule-rich carcinoma and once before the background of a high grade, solid carcinoma. Eye tracking allowed to identify which nuclei the pathologists fixated during the 8 second projection period. For all 20 pathologists, nuclear grade assignment was significantly biased by tumor architecture. Pathologists tended to fixate on bigger, darker, and more irregular nuclei when those were projected before kigh grade, solid carcinomas than before low grade, tubule-rich carcinomas (and vice versa). However, the morphometric differences of the selected nuclei accounted for only 11% of the architecture-induced bias, suggesting that it can only to a small part be explained by the unconscious fixation on nuclei that "match the expectation". In conclusion, selection of « matching nuclei » represents an unconscious effort to vindicate the gravitation of nuclear grades towards the tumor architecture.