E.-M. Haller-Schober

Microwave treatment of contact lens cases contaminated with acanthamoeba.

Purpose. Microbially contaminated contact lens cases are a predisposing risk factor for Acanthamoeba keratitis. Several findings have shown that microwave irradiation kills the six Food and Drug Administration test challenge microorganisms. We aimed to determine what effect microwave irradiation has on Acanthamoeba trophozoites and cysts. Methods. Different types of contact lens cases were contaminated with trophozoites and cysts of three different Acanthamoeba species (A. comandoni, A. castellanii, A. hatchetti) and were exposed to microwave irradiation for 3, 5, and 8 minutes, respectively. Results. Trophozoites, as well as cysts of the different Acanthamoeba strains, were effectively killed, even by only 3 minutes of microwave irradiation, and there were no negative effects of irradiation on the contact lens cases themselves. Conclusion. We demonstrate that microwave treatment is a very effective, easy, and cheap method to keep contact lens cases free of Acanthamoeba, thus considerably reducing the risk of an Acanthamoeba keratitis.

One- and two-step hydrogen peroxide contact lens disinfection solutions against Acanthamoeba : How effective are they?

PurposeEffective contact lens disinfection solutions are important to keep the storage case free of acanthamoebaeand thus prevent an infection of the eye. The aim of our study was to evaluate the effectivity of two new one-step hydrogen peroxide disinfecting solutions against Acanthamoebaspp. and compare it to the effectivity of other commercially available systems.MethodsNine one-step 3% hydrogen peroxide systems including the new systems Silver Sept (platinum and silver disk for intensifying disinfection) and Blue Vision (newly composed catalytic tablet) and 2 two-step systems (0.6 and 3.0% H2O2) were tested for their effectivity against cysts of two Acanthamoebakeratitis isolates at different concentrations.ResultsAfter a soaking time of 8 h (overnight soaking of contact lenses) the 2 two-step systems completely destroyed the cysts of both Acanthamoebastrains, even at the highest concentration of cysts tested. The nine tested one-step systems showed weaker effects. The new Blue Vision system was able to eradicate the cysts of one strain at the low concentration of cysts.ConclusionsOne-step hydrogen peroxide systems do not have sufficient effects on Acanthamoebacysts and therefore may not protect the contact lens user from a possible infection of the eye. Further development of tablets like the ones used in the Blue Vision system may result in better cysticidal effects for one-step systems.

Twenty Years of Acanthamoeba Diagnostics in Austria

Acanthamoebae are the causative agents of an often seriously progressing keratitis (AK) occurring predominantly in contact lens wearers and can cause several disseminating infections potentially resulting in granulomatous amoebic encephalitis (GAE) in the immunocompromised host. Our institution is the Austrian reference laboratory for Acanthamoeba diagnostics and the aim of this study was to give an overview of proven cases of Acanthamoeba infections in Austria during the past 20 yr. All samples of patients with suspected AK or GAE were screened for Acanthamoeba spp. by culture and/or PCR and the detected amoebae were genotyped. Altogether, 154 cases of AK and three cases of GAE were diagnosed. Age of the AK patients ranged from 8 to 82 yr (mean 37.8) and 58% of the patients were female. Approximately 89% of the AK patients were contact lens wearers, almost all cases were unilateral and 19% of the patients required a keratoplasty. Age of the GAE patients ranged from 2 to 25 yr (mean 14.7), all were HIV‐negative, but two were severely immunosuppressed at the time of diagnosis. The predominant genotype in the AK cases was T4, other genotypes found were T3, T5, T6, T10 and T11. The three GAE cases involved genotypes T2, T4 and T5.

Long-term Follow-up of Punctal and Proximal Canalicular Stenoses After Silicone Punctal Plug Treatment in Dry Eye Patients

PURPOSE To determine the clinical value and relevance of punctal and proximal canalicular stenoses after punctal plug therapy in moderate to severe dry eye syndrome. DESIGN Retrospective, observational case series. METHODS Seventeen eyes were determined to have punctum or proximal canalicular stenoses after spontaneous loss of a collared silicone punctal plug. After initial diagnosis all patients had 12 months or more of follow-up (mean, 39; range, 12 to 87 months). The clinical data collected included gender and age of patients, localization of the stenosis, plug size, duration of punctal occlusion, subjective symptoms, objective ocular surface disease parameters, and occurrence of complications. RESULTS A statistically significant correlation between localization of the stenosis and plug size, and localization of the stenosis and duration of punctal occlusion could not be found. At follow-up, subjective symptoms (P < .01) and frequency of artificial tear application (P < .001) were significantly reduced compared to data before plug insertion. Schirmer I test results (P < .001), corneal fluorescein staining (P < .01), and rose bengal staining (P < .001) improved significantly, whereas tear break-up time (P < .2) and impression cytology scores of the conjunctival surface (P = .2) remained almost unchanged. Complications could not be found. CONCLUSION Within the observation period of up to seven years, all stenoses remained asymptomatic. Additionally, subjective symptoms and most dry eye parameters in our study population improved.

Evaluation of ocular surface and tear film function following modified Hughes tarsoconjunctival flap procedure

Purpose:  To evaluate ocular surface characteristics and tear film function following modified Hughes flap for eyelid reconstruction.

Influence of single-fraction Gamma-Knife radiosurgery on ocular surface and tear function in choroidal melanoma patients

Aim To evaluate ocular surface and tear function in patients with choroidal melanoma treated with single-fraction radiosurgery. Methods 36 patients (median age 62 years; range 26–84 years) were enrolled between 2001 and 2006 at a single institution. They were treated with the Leksell Gamma Knife in one fraction with a median dose of 30 Gy (range 25–35 Gy). In both eyes of all patients treated subjective symptom score (visual analogue scale) was evaluated, central corneal sensitivity testing, Schirmer test without local anaesthesia, and corneal and conjunctival staining were performed before therapy and 3, 6, 12, 24 and 36 months thereafter. The respective untreated fellow eye served as control. Results Three months after radiosurgery, the subjective dry eye symptom score and lissamine green staining score of the ocular surface were significantly higher in the treated eyes compared with the fellow eyes (p<0.001, p=0.028, respectively). After 12 months, a significant difference between the treated and the fellow eyes in corneal sensitivity (p=0.041) and corneal fluorescein staining (p=0.002) was found when compared with pretreatment values. After 24 months Schirmer test values without local anaesthesia were significantly reduced in the treated eyes vis-à-vis untreated fellow eyes and pretreatment values (p=0.004). The dose applied to the lacrimal gland was significantly correlated to ocular surface staining scores (p=0.001) and Schirmer test values (p=0.026) at 24 months after irradiation. Conclusions Stereotactic single-fraction Gamma-Knife radiotherapy of choroidal melanoma with a median dose of 30 Gy significantly affected ocular surface and tear function and increased dry eye symptoms and signs.

Wirkung von Mikrowellenbestrahlung auf Akanthamöben: eine geeignete Möglichkeit zur Kontaktlinsenbehältersterilisation?

ZusammenfassungHintergrundMitAkanthamöben kontaminierte Kontaktlinsenbehälter gelten als Hauptrisikofaktor für eine mögliche Infektion des Auges. Führt die Mikrowellenbestrahlung mit handelsüblichen Geräten zur Abtötung vonAkanthamöbenzysten und-trophozoiten, und kann sie vom Kontaktlinsenträger zur Behälterhygiene eingesetzt werden?Material und MethodeKontaktlinsenbehälter zur Aufbewahrung weicher und harter Kontaktlinsen wurden mit Zysten und Trophozoiten der SpeziesA. hatchetti, A. castellanii undA. comandoni beimpft. Eine der Testserien wurde mit dehydrierten Zysten durchgeführt. Die Bestrahlungsdauer betrug 3, 5 und 8 Minuten.ErgebnisseBereits nach einer Bestrahlungsdauer von 3 Minuten im feuchten Milieu kam es zur vollständigen Abtötung der Zysten und Trophozoiten aller drei Spezies. Bei der Bestrahlung dehydrierter Zysten konnten die Zysten der SpeziesA. hatchetti undA. castellanii auch nach einer Bestrahlungsdauer von 8 Minuten nicht vollständig zerstört werden. Die verwendeten Kontaktlinsenbehälter zeigten keine Beeinträchtigung durch die Bestrahlung.SchlussfolgerungenDie Mikrowellenbestrahlung von Kontaktlinsenaufbewahrungsbehältern im feuchten Milieu (Behälterbefüllung mit Leitungswasser) stellt für den Kontaktlinsenträger eine sichere und leicht zu bewerkstelligende Maßnahme in der Kontaktlinsenhygiene dar, um einer möglichenAkanthamöbeninfektion des Auges vorzubeugen.SummaryBackgroundMicrobially contaminated contact lens storage cases are considered to be a predisposing risk factor forAcanthamoeba keratitis. What kind of effect does microwave irradiation have on contact lens cases contaminated withAcanthamoeba cysts and trophozoites?Material and methodsDifferent types of contact lens cases were contaminated with trophozoites and cysts of three differentAcanthamoeba species(A. hatchetti, A. castellanii, A. comandoni) and exposed to microwave irradiation for 3, 5 and 8 minutes respectively. One of the three test series was run with dehydrated cysts.ResultsAfter an irradiation period of 3 minutes under humid conditions cysts and trophozoites of all three strains were completely destroyed. Dehydrated cysts ofA. hatchetti andA. castellanii were not killed by irradiation. There were no negative effects of irradiation on the contact lens cases themselves.ConclusionAcanthamoeba cysts and trophozoites are effectively killed by microwave irradiation on condition that irradiation takes place in humid conditions. This can be easily achieved by filling the contact lens storage cases with tap water. We recommend microwave irradiation as a cheap and save method for the sterilization of contact lens cases in order to avoid a possibleAcanthamoeba infection of the eye.

Histopathologische Befunde nach Leksell®-Gamma-Knife-Radiochirurgie

ZusammenfassungDie klinische Wirksamkeit des Leksell® Gamma Knife wurde bereits belegt, bislang fehlt jedoch der histopathologische Nachweis der Wirksamkeit der Radiochirurgie.Material und MethodikDie histopathologischen Untersuchungen an 8 enukleierten Augen wurden einer Kontrollgruppe von 10 Aderhautmelanomen, die mittels alleiniger Enukleation behandelt wurden, gegenübergestellt. Enukleationsgründe waren bei 5 Patienten eine ungenügende Rückbildung, bei weiteren 3 Komplikationen wie Neovaskularisationsglaukom bzw. persistierende Netzhautabhebung.ErgebnisseDie mit dem Leksell® Gamma Knife behandelten Tumoren wiesen im Vergleich zur Kontrollgruppe ein größeres Ausmaß an Nekrosen (> 50% eine totale Tumornekrose), mehr Ballonzellen sowie weniger Mitosen auf, Gefäßveränderungen (Einengung bis Thrombosierung) waren in allen mit dem Gamma Knife behandelten Tumoren zu finden.DiskussionDas Leksell® Gamma Knife verursacht Nekrosen sowie alle Formen des Kernuntergangs (Nekrobiosen), eine verminderte Reproduktivität sowie Gefäßveränderungen in den bestrahlten Tumoren. Die Gefäßveränderungen scheinen eine entscheidende Rolle bei der Tumorregression zu spielen.SummaryRadiosurgery for uveal melanoma can achieve tumor contrail according to clinical studies, yet histopathological proof has not been described.Material and method8 eyes after radiosurgery which had to be removed either to regression failure (5) or severe complications like neovascular glaucoma or persisting retinal detachment (3) were investigated histopathologically and compared to 10 uveal melanomas that were treated by enucleation alone.ResultsUveal melanomas treated with the Gamma Knife showed tumor necrosis (in more than 50% total necrosis), a higher number of balloon cells, less number of mitoses and vascular changes (thickening of the vessel’s walls, obliteration, thrombosis) which could not be demonstrated in enucleated eyes without irradiation.ConclusionLeksell® Gamma Knife can cause tumor necrosis and varying degrees of cell death and reduced reproducibility. Vascular changes seem to play a major role in tumor regression.