RESUMO
For patients with keratoconus, rigid gas-permeable contact lenses are the first line correction method and allow good visual acuity for quite some time. In severe stages of the disease with major cone-shaped protrusion of the cornea, even specially designed keratoconus contact lenses are no longer tolerated. If there are contraindications for intrastromal ring segments, corneal transplantation typically has a very good prognosis. In patients with advanced keratoconus - especially after corneal hydrops due to rupture of Descemet's membrane - penetrating keratoplasty (PKP) is still the first line surgical method. Non-contact excimer laser trephination seems to be especially beneficial for eyes with iatrogenic keratectasia after LASIK and for patients with repeat grafts due to "keratoconus recurrences" due to small grafts with thin host cornea. For donor trephination from the epithelial side, an artificial chamber is used. Wound closure is achieved with a double running cross-stitch suture according to Hoffmann. Graft size is adapted individually, depending on corneal size ("as large as possible - as small as necessary"). Limbal centration is preferred intraoperatively, due to optical displacement of the pupil. During the last 10 years, femtosecond laser trephination has been introduced from the USA as a potentially advantageous approach. Prospective clinical studies have shown that the technique of non-contact excimer laser PKP improves donor and recipient centration, reduces "vertical tilt" and "horizontal torsion" of the graft in the recipient bed, and thus results in significantly less "all-sutures-out" keratometric astigmatism (2.8 vs. 5.7 D), more regular topography (surface regularity index [SRI] 0.80 vs. 1.0) and better visual acuity (0.80 vs. 0.60), in comparison to the motor trephine. The stage of the disease does not influence functional outcome after excimer laser PKP. However, the refractive outcome of femtosecond laser keratoplasty resembles that with motor trephine. In contrast to the undisputed clinical advantages of excimer laser keratoplasty with orientation teeth/notches in keratoconus, the major disadvantage of femtosecond laser application is still the necessity of suction and applanation of the cone during trephination, with intraoperative disadvantages and high postoperative astigmatism.
Assuntos
Ceratocone/diagnóstico , Ceratocone/cirurgia , Ceratoplastia Penetrante/métodos , Lasers de Excimer/uso terapêutico , Trepanação/métodos , Terapia Combinada/métodos , Medicina Baseada em Evidências , Humanos , Resultado do TratamentoRESUMO
PURPOSE: Crosslinking/riboflavin-UVA photodynamic therapy is a potential treatment alternative in antibiotic resistant infectious keratitis. For photodynamic therapy a specific (against bacteria) conjugated antibody may be used in order to increase the effect of the treatment. In our present study we analysed the impact of photodynamic inactivation using riboflavin-conjugated antibody or riboflavin alone on Staphylococcus aureus, in vitro. METHODS: Staphylococcus aureus (S. aureus) was incubated in 1â:â100 diluted riboflavin-conjugated antibody (R-AB) for 30 minutes in darkness. Following UVA-light illumination (375 nm) with an energy dose of 2, 3, 4 and 8 J/cm(2), bacteria were brought to blood agar Plates for 24 hours before colony-forming unit (CFU) counting. In an additional group, we incubated bacteria to 0, 0.05 or 0.1â% riboflavin 5-phosphate as described above followed by illumination using UVA light (375 nm) with an energy dose of 2 J/cm(2), before CFU counting. RESULTS: The number of CFU decreased significantly (inactivation of 36â%, p = 0.022) using 1â:â100 diluted riboflavin-conjugated antibody and 2 J/cm(2) UVA-light illumination, compared to untreated controls. The use of 3, 4 und 8 J/cm(2) energy dose and R-AB in 1â:â100 dilution did not further change the decrease of CFU (inactivation of 39, 39 and 40â%; p = 0.016; p = 0.016; p = 0.015). The use of 0.05â% or 0.1â% riboflavin 5-phosphate alone and UVA-light illumination reduced the CFU count significantly (inactivation of 73 and 55â%; p = 0.002; p = 0.005), compared to untreated controls. CONCLUSIONS: The use of riboflavin-conjugated antibody or 0.05â% or 0.1â% riboflavin 5-phosphate and UVA-light illumination reduces the number of CFU of S. aureus. However, none of these photodynamic therapies reached the necessary 99â% killing rate of these bacteria. Further work is needed to increase the efficacy of riboflavin-conjugated antibodies against antibiotic resistant bacteria.
Assuntos
Desinfecção/métodos , Fotoquimioterapia/métodos , Riboflavina/administração & dosagem , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/fisiologia , Terapia por Ultrassom/métodos , Anticorpos Monoclonais/química , Anticorpos Monoclonais/uso terapêutico , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Reagentes de Ligações Cruzadas/química , Fármacos Fotossensibilizantes/administração & dosagem , Fármacos Fotossensibilizantes/química , Riboflavina/química , Staphylococcus aureus/efeitos da radiaçãoRESUMO
Optical radiation emitted from a metal-coated fiber tip apex when it emerges from a liquid into the air was measured. A strong enhancement of the output radiation and its strong dependence on the relative position of the tip to a liquid surface were observed. This phenomenon permits in situ recording of nanometric vibrations of the liquid and provides a basis for development of various ultrasensitive vibration detecting sensors.