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.

[Complications in the treatment of ocular surface squamous neoplasia with interferon α­2b in rheumatoid arthritis]. / Komplikationen der Behandlung von Neoplasien des konjunktivalen Plattenepithels mit Interferon-α-2b bei rheumatoider Arthritis.

BACKGROUND: Interferon α­2b (IFN α­2b) is an established and well-tolerated treatment for ocular surface squamous neoplasia (OSSN). METHOD: Report of complications in two patients with OSSN and rheumatoid arthritis treated with adjuvant topical IFN α­2b. RESULTS: One patient developed a scleral melt and the other one severe keratitis. After discontinuing treatment with IFN α­2b both patients showed considerable improvement. CONCLUSION: Immunosuppressed patients with OSSN under topical IFN α­2b should be closely monitored for early detection of complications.

[Current treatment options with artificial corneas: Boston Kpro, Osteo-odontokeratoprosthesis, Miro Cornea® and KeraKlear®]. / Aktuelle Versorgungsmöglichkeiten mit Keratoprothesen : Boston-Keratoprothese, Osteoodontokeratoprothese, Miro Cornea® und KeraKlear®

BACKGROUND: Although corneal transplant surgery in avascular normal risk eyes is becoming even more minimally invasive and successful, treatment options for difficult to treat patients with high risk eyes are still limited. In these cases HLA typed allogeneic transplants and artificial corneas (keratoprostheses) can be used. METHODS: This article combines a review of the literature in PubMed and own clinical experiences on the use of artificial corneas in high risk eyes. Osteo-odontokeratoprosthesis (OOKP), Boston Kpro, Miro Cornea® and KeraKlear® corneas were used as clinical keratoprostheses. RESULTS: Worldwide, the most experience exists for the use of Boston Kpro and OOKP in high risk eyes. Miro Cornea® and KeraKlear® are new procedures where only preliminary results are available and further evaluation is necessary. The longest experience and best anatomical long-term results have been achieved with OOKPs. Comparable cohorts are available for the Boston Kpro. The function of all keratoprostheses is threatened by secondary glaucoma. Implantation of the KeraKlear® prosthesis remains difficult. The Miro Cornea® shows an initially stable integration behavior. CONCLUSION: Keratoprostheses, such as the Boston Kpro and OOKP are valid treatment options for eyes which are not open to therapy with allogeneic corneal transplantation. Modern implants such as KeraKlear® prosthesis and Miro Cornea® need further prospective clinical evaluation.

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.

[In vitro and in vivo investigations of a modified textile keratoprosthesis. ACTO TexKPRO]. / In-vitro- und In-vivo-Untersuchung einer modifizierten textilen Keratoprothese. ACTO TexKPRO.

BACKGROUND: Clinical application of a keratoprosthesis (KPRO) is still a challenging task. Recent developments reflect the concepts of nut and bolt, intrastromal implantation or an osteoodontokeratoprosthesis (OOKP). A new concept of a textile KPRO has been evaluated in a limited human study with considerable difficulties which after termination of the study and considerable improvements was restarted using animal experiments. MATERIALS: The ACTO TexKPRO is made from polyvinylidene difluoride (PVDF) fibers and transparent silicone. The first and second developmental stages differed in density and size of fibers and furthermore in surface modifications of the fibers and optics which were improved for the second prototype. METHODS: Implantation of the prosthesis was performed in four patients with corneal blindness and in two cases retinal disease which required surgery. In the later animal experiments surgery was performed on three rabbits. Surgery was performed by redressing the conjunctiva, opening of the eyeball with a central 6.5 mm trephination, removal of the lens and iris and implantation and suturing of the TexKPRO. If required a silicone oil endotamponade was placed. RESULTS: All eyes were stable with the keratoprosthesis. The first prototype showed conjunctival recession on the textile haptics with highly susceptible endopthalmitis risk due to infection of the PVDF so that we decided to remove the prosthesis from all eyes after one case of severe endophthalmitis occurred. The longest time of placement was 40 months and the shortest time 6 months. All eyes were restored by keratoplasty. In animals with the new haptic we found better conjunctivalization and stable implantation of the KPRO. DISCUSSION: The textile KPRO provides a stable implantation procedure and safe connection of fibers to the scleral wound bed. The optical and mechanical implantation is safe and stable. Surface epithelialization is improved with the new surface modifications and different PVDF fiber density but beforel new implantations are planned further conceptual changes will be introduced.

[Presentation of software for collation of inpatient diurnal pressure profiles in glaucoma patients]. / Vorstellung einer Software zur Erfassung von stationären Tagesdruckprofilen bei Glaukompatienten.

The aim of diurnal pressure profiles is clarification of therapy safety and the diagnosis of glaucoma. The evaluation of intraocular pressure curves is part of the running assessment. In order to support this evaluation software has been developed which, in addition to the digital presentation of intraocular pressure curves corrected for corneal thickness also allows immediate statistical assessment. After specifying a target pressure it also allows deduction of possible therapy recommendations based on the resulting intraocular pressure values, the cup/disc ratio and the number of antiglaucoma agents given. In this study two collectives were investigated: in the first collective, in addition to the previously determined diagnoses, the intraocular pressure, number and time of measurements, predetermined target pressure, cup/disc ratio and corneal thickness-dependent correction values were evaluated. After completing a scoring system with respect to agreement of the clinical therapy suggestions with those suggestions calculated by the software, the second collective was compared after termination of the diurnal pressure profile. Concordance was found in 73 out of 88 eyes. The digital collation system for profile measurement was found to be very well suited for graphical and clinical documentation of diurnal pressure profile curves. Therapy decisions can be deduced from the available data and supported by the software.

The Ex Vivo Eye Irritation Test (EVEIT) in evaluation of artificial tears: Purite-preserved versus unpreserved eye drops.

OBJECTIVE: Preservatives in artificial tears cause controversy. New developments such as the Purite system have been introduced into the market, with the promise of little damage to the corneal surface. We wanted to give insight into the differences in the effect of preserved and unpreserved artifical tears on rabbit corneas cultured with the Ex Vivo Eye Irritation Test (EVEIT) system. MATERIALS: We compared the two artifical tears products Hylo Comod and Optive being dropped for 72 hours each hour one drop onto the corneal surface. METHODS: Each cornea was mechanically wounded with four epithelial defects on each cornea with a size of 3 to 4.5 mm(2). With n = 4 corneas in the Hylo-Comod and n = 4 corneas in the Optive group, we exposed the corneal surfaces to repeated doses of these artificial tears for 3 days. We observed healing of corneal erosions and surface epithelial integrity with sodium-fluoresceine staining under cobalt blue light illumination. RESULTS: We found nearly complete healing of epithelial defects with both artificial tears. The Hylo-Comod group healed significantly faster. After 72 hours, the vast majority of epithelial defects were closed. All corneas exposed to Purite showed superficial stippling, whereas the HyloComod group did not show any stippling of the cornea; this difference was significant. DISCUSSION: Epithelial healing and recovery in the EVEIT system is observed in both groups, confirming the concept of artificial tears as a supporting factor of corneal health and healing. The superficial stippling of the corneal epithelium was observed only in the Optive group. This effect is considered as a marker of dry eye syndrome, and should be prevented by the application of artificial tears. Preservative-free eye drops such as HyloComod improve healing, and prevent symptoms of dry eye syndrome in the EVEITsystem. Compared to EVEIT results of former experiments with benzalconium chloride-preserved eye drops, Optive promoted healing of corneal erosions.

[Spectral transmission in blue filter intraocular lenses]. / Spektrale Durchlässigkeit bei Blaufilter-Intraokularlinsen.

There is uncertainty in ophthalmology concerning the quality and spectral transmission of light of so-called blue filter intraocular lenses (IOL). Clinical users have noticed that such IOL's appear to have different color intensities. The discussion on medical changes by means of such IOL's is dependent on the real light transmission of these IOL's. To add some objective data we compared these IOL's by systematic transmission measurements and observed technical differences of diffraction and geometry as well as transmission differences. The result gives objective indications that differences between blue filter IOL's from different manufacturers are important and are detailed in this paper.

[Recommendations for acute treatment for chemical and thermal burns of eyes and lids]. / Empfehlungen zur Akutbehandlung von Verätzungen und Verbrennungen der Augen und Lider.

With these recommendations the authors want to improve the acute therapy of eye burns based on the literature and clinical experience. Due to the lack of studies with high evidential value we base these recommendations on the results of experimental work and reports of successfully treated eye burns. A development of this document by systematic research is necessary. Despite the limited knowledge, the collated facts are the current state of the art of treatment according to the knowledge and research of the authors. The most important clinical recommendation is to rinse a chemically or thermally burnt eye as soon and as extensively as possible. Any delay worsens the prognosis. Substances on the market for first aid have different levels of clinical evidence. Thus saline and amphoteric diphoterine have been evaluated in a prospective clinical study showing an advantage for the amphoter. Water, borate buffer, phosphate buffers and derivatives have never been proven to work in clinical applications. Nevertheless, they are recommended. Within experimental work in vitro we could show the value of polyvalent decontamination. Side-effects of phosphate buffers have been demonstrated in retrospective clinical and prospective experimental studies so that even in cases of beneficial effects on pH we cannot recommend these substances which propagate corneal calcification. Special types of burns, such as hydrofluoric acid need special treatment but as clinical studies are lacking only experimental data can offer suitable recommendations.

[Chemical and thermal eye burns. Conservatíve and surgical options of a stage-dependent therapy]. / Verätzungen und Verbrennungen des Auges. Konservative und chirurgische Optionen einer stadiengerechten Therapie.

The basic principles of first aid for chemical and thermal burns are discussed. In the acute phase the primary goal of all measurements is the prevention or limitation of tissue destruction. The further therapeutic care is focused on the modulation of the inflammatory response, the prevention of a bacterial infection and secondary glaucoma and the stimulation of wound healing. The individual concept of measures to be taken is recruited from the careful identification of necrotic tissue, the eye burn classification of severity and on the basis of all described medical and surgical therapy options. In the case of severe and very severe ocular burns a comprehensive surgical reconstruction is included. All outpatient departments and eye clinics taking part on the treatment have to ensure a standardized complete and scientifically valid therapy regime to restore vision.

[Eye irritation and chemical eye burns. Review of experimental and clinical studies]. / Augenirritation und Augenverätzung. Experimentelle und klinische Übersicht.

Chemical burns of the eye are becoming rare due to improvements in occupational protection. Effective decontamination is the foundation for good clinical results of this ophthalmological emergency. The toxicological aspect focuses on classifying the specific toxicity of a chemical substance by evaluating the degree of eye irritation and eye burns. Chemical substances are classified into defined risk levels by specific tests. The traditional ophthalmological approach is based on the clinical presentation of eye burns as a result of contact with a specific toxic substance. In an integral approach it is shown that substance-specific characteristics, such as concentration and specific reactivity as well as individual features, such as mode and duration of exposition have an influence on the clinical appearance of the tissue damage. The decontamination is dependent on the mode of action and the effectiveness of the decontamination solution. Amphoteric substances have the best effectiveness for decontamination of the eye due to their specific characteristics.

[The 2009 performance report of the German cornea banks]. / Leistungsbericht der Deutschen Hornhautbanken 2009.

BACKGROUND: In Germany, human tissue for corneal and amniotic transplantation is supplied by 27 cornea banks. METHODS: The Section for Tissue Transplantation and Biotechnology of the German Ophthalmological Society records the cornea banks' activities by means of an annual questionnaire. RESULTS: In 2009, a total of 4,818 corneal grafts were processed by 21 responding cornea banks, and 57% were deemed suitable for transplantation. This ratio is slightly higher than the European average. In addition, German cornea banks released 1,257 amniotic grafts in 2009. DISCUSSION: German cornea banks are currently facing new regulatory issues due to updated legislation regarding tissue transplantation. Recent updates in European law have limited the cutoff time for postmortem blood sampling to 24 h, and this regulation may lead to a significant reduction in potential donors.

[Visual self-assessment with the ACTO test during follow-up of AMD patients after intravitreal injections]. / Eigenerhebung der Leseleistung mit dem ACTO-Selbsttest bei AMD-Patienten nach intravitrealen Injektionen.

INTRODUCTION: Monthly controls are necessary after injections of vascular endothelial growth factor (VEGF) to enable timely recognition of a renewed decrease in vision. However, these monthly control intervals are not realistic for many older patients with age-related macular degeneration (AMD), and outpatient clinics often reach their logistical limits because of inadequate funding for the additional medical work. Against this background, we conceived the ACTO self-test as a novel screening method for patients to discover unnoticed visual changes outside the routinely scheduled ophthalmic examination. MATERIAL AND METHODS: The paper version of the ACTO self-test consists of a reading chart gradated in decimal steps as well as six questions regarding the quality of the Amsler grid. The patient uses a self-screening test to examine each eye separately and then transfers the results to a table. Along with the self-examination, the Action Eyesight Service Center is available to the patient by phone to motivate the patient and schedule a new appointment if improved test results occur. If decreased values or suspected decreased visual function occur, these are verified immediately by the referring physician. RESULTS: There is a good correlation between the steps of the ACTO self-test and standard visual acuity at 4 m (r(2)=0.9). Altogether, 1,444 patients were followed by phone and 745 participated in repeated regular audits, for a total of 3,003 phone contacts. The treating physician was informed about decreased visual acuity or increased Amsler distortion in the ACTO test in 137 cases, and immediate verification was done. We had 699 dropouts; the reasons were decreased visual acuity below the limits of the ACTO test in 39%, additional monthly examinations by the local ophthalmologist in 29%, and a desire for no more telephone follow-up (despite initial written consent) in 32%. Decreased vision when reading or an increased score on the Amsler test within the ACTO screening test was observed in 18% of AMD patients during the maintenance phase. CONCLUSION: Monthly screening by the ACTO screening test in combination with phone audits offers a new way to test visual acuity, with the Amsler score helping to detect changes in visual function. For patients with visual changes, confirmation by the ophthalmic physician can be achieved in time. Self-assessment cannot replace qualified ophthalmologic examination, but monthly self-controls enhance safety, reduce the number of physician contacts, and improve the detection of visual changes, with the option of immediate ophthalmic retreatment.

[Ocular burns]. / Brûlures oculaires.

Ocular or thermal burns account for 7.7%-18% of ocular trauma. The majority of victims are young. The burns occur in the setting of accidents at work or in the home, or during a physical attack. Chemical burns by strong acids or bases are responsible for the most serious injuries. Associated with the destruction of limbal stem cells, they present as recurrent epithelial ulcerations, chronic stromal ulcers, deep stromal revascularization, conjunctival overlap, or even corneal perforation. The initial clinical exam is sometimes difficult to perform in the presence of burning symptoms. Nevertheless, it enables the physician to classify the injury, establish a prognosis, and most importantly, guide the therapeutic management. The Roper-Hall modification of the Hughes classification system is the most widely utilized, broken down into stages based on the size of the stromal opacity and the extent of possible limbal ischemia. This classification is now favorably supplemented by those proposed by Dua and Wagoner, which are based on the extent of the limbal stem cell deficiency. The prognosis of the more serious forms of ocular burns has markedly improved over the last decade because of a better understanding of the physiology of the corneal epithelium. Surgical techniques aimed at restoring the destroyed limbal stem cells have altered the prognosis of severe corneal burns. In order to decrease the incidence of burns, prevention, particularly in industry, is essential.

[Intravitreal bevacizumab for chronic central serous chorioretinopathy]. / Intravitreales Bevacizumab bei chronischer Retinopathia centralis serosa.

Central serous chorioretinopathy (CSCR) can lead to permanent visual loss in chronic cases. We report on a 57-year-old female patient with persistent findings over 6 months despite conservative therapy. A single intravitreal injection of bevacizumab led to a rapid morphologic and functional restitution without relapse or complication during the 19 weeks period after injection. Intravitreal injection of bevacizumab could be a therapeutic option for the treatment of chronic CSCR, however the results of appropriate studies must be awaited before it can be introduced into routine use.