Chirurgie réfractive, chirurgie laser de l’oeil / Refractive surgery, eye laser surgery
Sylviane von Gunten
Docteure en médecine
Spécialiste FMH en ophtalmologie et ophtalmochirurgie
Diplôme inter-universitaire de chirugie réfractive
Dre Sylviane von Gunten
Ancien Cheffe de clinique durant trois ans à la Clinique d’Ophtalmologie de l’Hôpital Universitaire de Genève, la Dre Sylviane von Gunten est médecin indépendant depuis octobre 1998. Parallèlement à l’exercice de sa pratique privée, la Dre von Gunten poursuit de l’an 2000 à 2002 une formation en chirurgie réfractive auprès du Dr Korol aux HUG.
À relever qu’en cours de spécialisation, la Dre von Gunten a étudié à Boston à la Harvard Medical School, Massachusetts Eye and Ear Infirmary Hospital. Elle a aussi obtenu un DIU (Diplôme Inter Universitaire) en chirurgie réfractive et phaco-émulsification en juin 2004 à l’université de Bordeaux (France).
Sélection de publications / Selected publications
OBJECTIVE: To determine whether intravitreal dexamethasone administration can alter the elimination of intravitreal vancomycin hydrochloride in rabbit eyes with experimental Streptococcus pneumoniae endophthalmitis. METHODS: Albino rabbits were infected with an intravitreal inoculum of S pneumoniae (2 x 10(3) colony-forming units) and randomized after 24 hours to treatment with intravitreal vancomycin hydrochloride (1 mg), alone or in combination with intravitreal dexamethasone (400 microg). For comparison, uninfected eyes were similarly treated. All eyes were enucleated 24, 48, or 72 hours after treatment, and vitreous levels of vancomycin were quantitated using a fluorescence polarizing immunoassay. RESULTS: The half-life of intravitreal vancomycin in infected eyes was prolonged from 48 to 84 hours when eyes were treated with dexamethasone. Conversely, such treatment shortened the half-life in uninfected eyes from 56 to 42 hours. CONCLUSIONS: Intravitreal dexamethasone administration reduces the elimination of intravitreal vancomycin in rabbit eyes with pneumococcal endophthalmitis, whereas an opposite effect is noted in uninfected eyes. CLINICAL RELEVANCE: In patients with eyes having endophthalmitis caused by virulent organisms, the elimination of intravitreal vancomycin may be reduced when intraocular inflammation is minimized with corticosteroid therapy. This may enhance the efficacy of intravitreal vancomycin therapy in treating the infection.
PURPOSE: To investigate the ocular pharmacokinetics and efficacy of oral trovafloxacin, a novel fluoroquinolone antibiotic, in Staphylococcus epidermidis endophthalmitis. METHODS: Albino rabbits (n = 20) were infected with an intravitreal inoculum of S epidermidis (1.0 x 10(8) colony-forming units [CFU/0.1 ml) and 24 hours later received a single oral dose of trovafloxacin (250 mg/kg). Serum and intraocular samples from infected and control (noninfected) eyes were obtained up to 24 hours after antibiotic administration for measurement of trovafloxacin levels. A second group of rabbits (n = 72) was infected intraocularly and randomized 24 hours later to oral trovafloxacin (250 mg/kg twice a day) for 6 days or no treatment (control). Treatment efficacy was assessed by vitreous culture, clinical examination, and histopathology. RESULTS: Following a single dose of trovafloxacin, maximal vitreous levels were achieved at 8 hours in infected eyes, with a penetration ratio of 36%. Vitreous levels were greater than 15 times the minimum inhibitory concentration of the strain employed. In animals with established endophthalmitis, treated eyes were sterilized after 5 days (P = .0495) compared with control eyes, which autosterilized at 14 days. Clinical and histologic examination revealed significant amelioration of anterior segment inflammation in treated eyes, although severe destruction of posterior segment structures occurred in both groups after 6 days of therapy. CONCLUSIONS: These data support trovafloxacin as a potential oral agent for treatment or prophylaxis of S epidermidis endophthalmitis, although retinal alterations that occur over the period required for vitreous sterilization suggest that it will not replace intravitreal therapy in established endophthalmitis.
BACKGROUND: Macular epiretinal membranes, whether idiopathic or secondary to vitreo-retinal pathology may result in a lowering of central vision and/or metamorphopsia following a distortion of retinal tissue. Although an adequate surgical peeling procedure is known to result in a functional improvement, the criteria for patient selection for such intervention are, as yet not clearly established. METHODS AND RESULTS: In order to establish prognostic indicators of a good visual recovery, we studied 25 cases of epiretinal membrane. Our results showed an improvement in visual acuity of 2 or more Snellen lines among 34% of our patients, regardless of their initial visual acuity. The duration of symptoms prior to intervention was found to be a prognostic factor whereas the presence of macular edema detected preoperatively on fluorescein angiography had no effect on the final visual outcome. CONCLUSION: A common post-operative complication came to our attention: secondary opacification of the crystalline lens.
We studied the aqueous humor penetration of ofloxacin after topical, oral, and intravenous administration in 51 consecutive patients undergoing cataract surgery. Aqueous humor concentration (mean +/- SD) was 0.53 +/- 0.35 mg/l when ofloxacin 0.3% eyedrops were instilled topically six times, one drop every three hours, until 90 minutes preoperatively, and 0.63 +/- 0.29 mg/l (P = .45) when two additional instillations were made, one drop every 30 minutes, until 30 minutes before aqueous humor aspiration. Aqueous humor concentration two hours after a single 200-mg oral dose (0.38 +/- 0.15 mg/l) was significantly lower (P = .048) than that 12 hours after the same oral dose (0.58 +/- 0.24 mg/l). Two hours following an intravenous infusion of 200 mg of ofloxacin, aqueous humor concentration was 0.33 +/- 0.19 mg/l. Our results suggest that therapeutic levels above the minimum inhibitory concentration for many bacteria cultured in endophthalmitis can be achieved in aqueous humor after either topical or oral administration, which indicates that this antibiotic passes easily through the corneal and the blood aqueous barriers.
Présentations en ligne / Online presentations
Comparaison des résultats visuels et réfractifs des traitements myopiques Zyoptix Asphérique® versus Zyoptix Tissue Saving® : une étude rétrospective - Pilly B, Farpour B, Von Gunten S, Desmangles P, Parendeau P