Assessment of endothelial cell density and corneal thickness in corneal grafts an average of 5 years after penetrating keratoplasty

BACKGROUND Corneal transparency is a useful indicator for corneal function. Our aim was to investigate central corneal endothelial cells and corneal thickness in transplanted corneas at an average of 5.4 years after penetrating keratoplasty PATIENTS AND METHODS The study involved 68 perforated keratoplasty patients with at least a 1 year follow-up. Post-operatively, the central corneal endothelial layer was observed using a contact specular microscope. Central endothelial cell density, corneal thickness and the coefficient of variation of endothelial size were statistically analysed. RESULTS The post-operative follow-up time was ranging from 12 months to 23 years. Endothelial cell density (ECD) was 1,501 ± 249 cell/mm(2). The average cell size was 673.6 ± 98.3 μm(2), and the coefficient of variation of cell size was 0.61 ± 0.11. No difference in ECD was detected between diagnostic groups. Corneal thickness was 0.56 ± 0.06 mm. Correlation between ECD and post-operative time was not significant (r = 0.02; p = 0.85). CONCLUSION Our study concluded that ECD showed a higher rate of decrease after penetrating keratoplasty with no relation to pre-operative diagnosis

A survey of corneal changes caused by daily wear silicone hydrogel contact lenses

Purpose: The examination of the effects of second generation lotrafilcon B silicone hydrogel (SiH) lenses on the cornea when worn for three years of daily wear. Material and Methods: 55 healthy patients were divided into two groups: current hydrogel contact lens wearers refitted with lotrafilcon B lenses (Group 1; 28 patients) and neophyte contact lens wearers (Group 2; 27 patients). Each patient's subjective eye comfort was measured with a self-administered questionnaire. The corneas were analyzed using contact specular microscope to measure corneal thickness and the endothelium before the SiH lenses were fitted after four weeks, one month, six months, one year, two years, and three years of lens wear. Results: Subjective complaints of patients in Group 1 were reduced; however patients in Group 2 experienced discomfort during the first two to four weeks of use. In Group 1, objective examinations identified a decrease in endothelial cell density. In Group 2, the endothelial cell density increased slightly in the first two years but decreased after three years. The results indicate that lotrafilcon B slows down the deleterious effects of contact lenses. The coefficient of variation significantly decreased after six months in Group 1 (0.47 vs 0.44; p = 0.049), whereas, in Group 2, the hexagonal cells improved significantly after one month (27.78 vs 28.25; p = 0.025). Conclusion: Based on the subjects involved and the period of time under examination, it can be concluded that high-Dk SiH lenses support the physiological metabolism and functions of the cornea by improving oxygen provision

Optimal color primaries for three- and multiprimary wide gamut displays

We present a collection of principles to compare two sets of color primaries for wide gamut displays. A new, algorithmic three-dimensional method to find optimal color primaries both for three-primary and multiprimary displays is described. The method was implemented in a computer program. The resulting optimal color primary sets are discussed. We show that two-dimensional methods to find optimal color primaries by using a chromaticity diagram are inferior to three-dimensional optimization techniques that include luminance information.close

Auditory temporal grouping in newborn infants

Adults normally perceive auditory scenes in terms of sound patterns emitted by concurrently active sources. Thus pattern formation is an important process of auditory object perception. The aim of the present study was to determine whether neonates group sounds by repeating pitch patterns. Standard ("S"; p = 80%) and deviant tones ("D", p = 20%) differing only in pitch were delivered either in a randomized order (random condition) or in a repeating SSSSD pattern (grouped condition). Both event-related brain potentials and gamma-band activity differed between the S and D tones in the random condition but not in the grouped condition. These results suggest that in the grouped condition, the S and D tones were processed as part of the same higher order regularity by the neonate auditory system. Also, for the first time, we observed oscillatory gamma-band activity in neonates, which was sensitive to infrequent pitch changes

Miocene to Quaternary deformation, stratigraphy and paleogeography in Northeastern Slovenia and Southwestern Hungary

The Mura-Zala basin was formed due to ENE-WSW trending crustal extension in the late early and middle Miocene (19 – 11 Ma). Marine sedimentation occurred in several more or less confined depressions (half grabens), then in a unified basin. The rifting phasewas probably connected to uplift and brittle-ductile deformation of metamorphic basement at the eastern part of the Pohorje and Kozjak hills. During the late Miocene thermal subsidence, deltaic to fluvial sediments were deposited.After sedimentation, the southernmost Haloze-Budafa sub-basin was inverted. Mapscale folds, reverse and strike-slip faults were originated by NNW-SSE compression during the latest Miocene(?)–Pliocene. After this folding, Karpatian sediments of theHaloze acquired magnetization. During the late(?)Pliocene to Quaternary(?), the whole Mura-Zala basin, including the folded Haloze, suffered 30° counterclockwise rotation as a relatively rigid block. This rotation affected a wider area from Slovenia to western Hungary and northern Croatia