ABSTRACT
BACKGROUND: Ablation experiments and preclinical studies have shown increased thermal damage and surface roughness after photorefractive keratectomy (PRK) with the erbium: YAG laser. MATERIALS AND METHODS: In this study, the thermal damage was investigated on enucleated pig corneas for various laser pulse durations (80 ns to 1 ms) and radiant exposures (0.2-5 J/cm2). The "scanning-spot" method and the fundamental mode photo-ablation were used for spherical corrections. SEM pictures and surface roughness measurements enabled comparison with the morphology after ArF-excimer laser treatment. The surface roughness is one order of magnitude higher compared to the ArF-excimer laser ablation. The surface of the tissue after ablation looks melted. RESULTS: The thermal damage reduces with increased intensity, and at high intensities the thermal damage results in a constant thickness of > 5 microns. CONCLUSIONS: Laser-induced melting processes might be the main reason for the high thermal damage and the increased surface roughness after erbium: YAG laser treatment. This leads to the conclusion that the erbium: YAG laser is not a real alternative to the ArF-excimer laser in PRK.
Subject(s)
Cornea/surgery , Light Coagulation/instrumentation , Photorefractive Keratectomy/instrumentation , Animals , Cornea/pathology , Equipment Safety , Lasers, Excimer , Microscopy, Electron, Scanning , SwineABSTRACT
The patients' data of 156 children hospitalized on account of social indication were analysed at the Clinic for Pediatrics of Magdeburg District Hospital. Reasons for socially indicated hospitalization were: proved or imminent neglecting of children (49%), insufficient nursing of sick children (31%), suspected ill-treatment (8%), serious family troubles temporarily preventing nursing and safety of children (12%). Neglected hygienic condition of the body, improper nutrition of malnutrition, physical and mental lagging behind might be evidence for the social sufferings of children. Mothers of children obtaining in-patient treatment as a result of social indication predominantly lack lasting partnerships. They are Less qualified concerning vocational training or gave birth to their first child at a comparatively early age. There is an urgent necessity of closely cooperating between the Clinic for Pediatrics, the Maternity Advisory Centre, the Youth Well-Fare Service and the Department of Youth-Well-Fare in order to detect the children concerned in time to be able to find the best possible solution for the future life of the children without delay.
