Comparison of modern high-speed vitrectomy systems and the advantages of using dual-bladed probes.

PURPOSE: This study analyzes the efficiency of different vitrectomy systems and compares single with double-bladed cutters. METHODS: The systems EVA™ (DORC), Constellation® Vision System (ALCON), megaTRON S4HPS (Geuder) and Stellaris® PC (Bausch and Lomb) were used. We chose 20G and 23G probes, since not all systems had switched to a smaller G at the time the study was conducted in 2016. Cut rates were varied in increments of 1000 cuts/min from 500 cpm to the system's maximum and vacuum pressures were varied in increments of 100 mmHg, from 100 to 600 mmHg up to the individual system's maximum. In this study water, egg white, Pluronic®-F127 gel and isolated porcine vitreous were used as models of human vitreous. The vitrectomy efficiency was calculated from the aspirated mass (g) within 30 s. The aperture of the different vitrectomy probes was filmed with a high-speed camera. RESULTS: The area under the curve analysis showed differences in efficiency between vitrectomy systems. For water, a reverse relationship between the aspirated mass and cut rate was shown. By contrast, for most systems aspirated egg white and porcine vitreous showed a non-linear increase or decrease for 4000 cpm and above. For all vitreous surrogates, EVA™'s double-bladed probe aspirated significantly (p < 0.001) more vitreous than its mono-bladed probe. Video recordings showed less vitreous traction for double- in contrast to single-bladed probes. CONCLUSION: We can demonstrate differences in the efficiency of vitrectomy depending on the vitrectomy system used. Double-bladed probes were more efficient and probably safer than single-bladed probes.

Irrigation with phosphate-buffered saline causes corneal calcification during treatment of ocular burns.

Corneal calcification is a vision-threatening manifestation of calcium containing agents in ocular burn. As we previously reported, our interest was sparked by a particular discrepancy of a case: A patient treated for a non-calcium containing agent in eye burn from exposure to an alkaline mixture of NaOH and KOH, who unexpectedly developed corneal calcification. This current study aims to elucidate whether the 2min lasting irrigation with a phosphate-buffered saline itself, regardless of rinsing regimen, triggers corneal calcification. The Ex Vivo Eye Irritation Test (EVEIT) system was used on rabbit corneas to replicate the very same phosphate-buffered saline solution the patient was treated with. The rabbit corneas were first burned with 1 M NaOH, rinsed with 4.9% phosphate-buffered saline for 2 min, and were then moisturized with an artificial tear solution for 48 h. All corneas were fluorescein-stained for photo documentation, snap-frozen, lyophilizated, and the electrolyte content was analyzed by Energy-Dispersive X-ray spectroscopy (EDX). The EDX analysis revealed pathological phosphorous in corneal stroma after a single rinsing with phosphate-buffered saline. Ongoing application of artificial tears containing physiological 14.581 mmol Ca2+ /l led to macroscopically visible calcification, but only in areas of induced corneal erosion. Regardless of the rinsing protocol neither 2 or 15 min of eye rinsing with phosphate containing rinsing solutions, we have given proof that corneal calcification is a foreseeable effect of the phosphate-buffered saline rinsing of mechanically epithelial damaged and chemically burnt eyes. Thus, it is crucial to legally restrict the formulations of phosphate-buffered salines in the medical treatment of eye burns, corneal erosions or chemical splashes of the eye.

First aid therapy for corrosive chemical eye burns: results of a 30-year longitudinal study with two different decontamination concepts.

PURPOSE: There is currently uncertainty about the most efficacious decontamination solution for corrosive chemical eye burns. This 30-year longitudinal study evaluated the relative efficacy of two different decontamination methods. Passive decontamination consists of rinsing with tap water, 0.9% normal saline, isotonic buffered phosphate solution, or Ringer's lactate. Active decontamination adds an amphoteric, polyvalent, and chelating component with Previn® (Diphoterine®) solution (Laboratoire Prevor, Valmondois, France). METHODS: A prospective evaluation of patients treated in two specialized eye clinics for eye burns was begun in 1988. Recorded data included exposure circumstances, type of corrosive, different types of first therapy, and clinical treatment and outcome. Patients were treated from clinic admission and up to 24 h after the corrosive chemical burn with rinsing for 15 min using two different protocols. From 1988 to 2005, sterile 0.9% normal saline or Ringer's lactate was used. Since 2006, sterile, hypertonic, amphoteric Previn® solution was used. Comparative statistical analysis was done with the Fisher contingency tables and Wilcoxon tests. RESULTS: There were a total of 1495 patients with 2194 chemically burned eyes. In 1988-2005, the annual incidence was 66.1/year; in 2006-2017, it was 65.5/year. Similar incidences were noted when initial rinsing was with tap water or isotonic buffered phosphate solutions. There was a significantly more severe outcome of corrosive chemical eye burns with any first aid rinsing solutions other than Previn® solution or tap water was used (p < 0.001). Previn® solution or tap water rinsing in the pre-hospital setting and secondary rinsing with Previn® solution in the hospital decreased lesion severity in comparison with all other rinsing solutions (p < 0.001). CONCLUSION: The frequency of corrosive chemical eye burns was comparatively high despite tightening of occupational health and safety regulations over the past 30 years. The severity of corrosive chemical eye burns has been dramatically decreased since the introduction of Previn® solution for initial and secondary rinsing. A new protocol for immediate Previn® solution use by the Cologne Fire Brigade and secondary Previn® solution rinsing in hospital has reduced the frequency of severe corrosive chemical eye burns to less than 60% as compared to the period of 1988-2005 when other rinsing solutions were utilized.

[Retinovascular Findings in Susac's Syndrome]. / Retinovaskuläre Zeichen des Susac-Syndroms.

BACKGROUND: Susac syndrome is a vasculopathy affecting the central nervous system, retina and cochlea leading to the triad encephalopathy, branch retinal artery occlusions and hearing loss. To date, about 300 cases have been described in the literature. PATIENTS/METHODS: Three patients with confirmed Susac syndrome were evaluated for disease-specific retinal pathologies. In addition, the overall history of the disease is presented to put the ophthalmological pathology into context. RESULTS: All three cases showed a retinal occlusive microangiopathy with branch retinal artery occlusions. MRI imaging revealed snowball-like lesions of the corpus callosum in two of three cases. At the initial presentation not all criteria of the disease-specific triad encephalopathy, branch retinal artery occlusions, and hearing loss were fulfilled in the three patients. CONCLUSION: Interdisciplinary collaboration between neurologists, otorhinolaryngologists and ophthalmologists is mandatory to establish the diagnosis of the disease. The occurrence of the characteristic retinal pathology with small artery occlusions and a segmental vasculopathy should always lead to the differential diagnosis of Susac syndrome.

[Atypical genesis of anterior ischemic optic neuropathy]. / Atypische Genese einer anterioren ischämischen Optikusneuropathie.

BACKGROUND: This article presents a case of arteritic anterior ischemic optic neuropathy as a manifestation of granulomatosis with polyangiitis (GPA). CASE REPORT: A 52-year-old woman suffered acute unilateral vision loss. Besides a unilateral papillary edema, serological investigations revealed elevated inflammation parameters with a positive (cytoplasmic) anti-neutrophil cytoplasmic autoantibodies (c-ANCA) titer. In addition to the occurrence of pulmonary nodules and cavitary lesions this is indicative for the diagnosis of GPA. RESULTS: Treatment with cyclophosphamide and prednisolone led to a rapid regression of inflammation parameters but no visual improvement occurred.

Semifluorinated alkanes as a liquid drug carrier system for topical ocular drug delivery.

Semifluorinated alkanes (SFA, e.g. perfluorobutylpentane F4H5, perfluorohexyloctane F6H8) are inert, non-toxic fluids capable of dissolving lipophilic drugs. The aim of this study to assess the bioavailability and safety of SFAs as drug solvents for the topical ocular application of Cyclosporin A (CsA). A commercially available CsA formulation (Restasis, 0.05% CsA in castor oil) was tested against two novel formulations of 0.05% CSA in (a) F4H5 containing Ethanol (0.5 w/w%) and (b) F6H8 containing Ethanol (0.5 w/w%) with 0.05% CsA. Formulations were tested on rabbit corneas cultured on an artificial anterior chamber with a constant flow of an aqueous humour supplement (Ex Vivo Eye Irritation Test (EVEIT) system). Anterior chamber fluids were sampled at multiple time points to analyse the CsA concentration following single and repeated application regimes by HPLC. Photographs of fluorescein sodium-stained corneas were recorded for corneal toxicity evaluation. The impact of the formulations on the integrity of the corneal barrier function was tested after drug application by fluorescein sodium corneal diffusion experiments. The influence on the corneal metabolism was evaluated by analysis of the metabolic markers glucose and lactate. Restasis did not pass the corneal barrier after short term application, CsA in ethanolic F4H6 reached a maximum of 152.95 ng/ml in anterior chamber fluid samples whilst CsA in ethanolic F6H8 reached a maximum of 15.12 ng/ml. After repeated applications for 8h, Restasis reached 21.07 ng/ml compared to 247.62 ng/ml and 174.5 ng/ml for F4H5 and F6H8, respectively. No corneal toxicity was observed in following application of any of the formulations. In contrast to the commercially available castor oil-based formulation, CsA dissolved in SFAs reached therapeutic inner ocular concentrations after topical administration, possibly leading to the replacement of systemic applications of CsA for inflammatory ocular disease.

[Retinovascular findings in Susac's syndrome]. / Retinovaskuläre Zeichen des Susac-Syndroms.

BACKGROUND: Susac syndrome is a vasculopathy affecting the central nervous system, retina and cochlea leading to the triad encephalopathy, branch retinal artery occlusions and hearing loss. To date, about 300 cases have been described in the literature. PATIENTS/METHODS: Three patients with confirmed Susac syndrome were evaluated for disease-specific retinal pathologies. In addition, the overall history of the disease is presented to put the ophthalmological pathology into context. RESULTS: All three cases showed a retinal occlusive microangiopathy with branch retinal artery occlusions. MRI imaging revealed snowball-like lesions of the corpus callosum in two of three cases. At the initial presentation not all criteria of the disease-specific triad encephalopathy, branch retinal artery occlusions, and hearing loss were fulfilled in the three patients. CONCLUSION: Interdisciplinary collaboration between neurologists, otorhinolaryngologists and ophthalmologists is mandatory to establish the diagnosis of the disease. The occurrence of the characteristic retinal pathology with small artery occlusions and a segmental vasculopathy should always lead to the differential diagnosis of Susac syndrome.