Ralf Krott

Hyperbaric oxygen therapy in retinal artery occlusion

ZusammenfassungDer akute Verschluss retinaler Arterien ist ein ophthalmologischer Notfall. Er führt in vielen Fällen zu einem massiven, irreversiblen Funktionsverlust. Wir untersuchten den Effekt einer adjuvanten hyperbaren Sauerstofftherapie (HBO) auf den Visusverlauf in einer Pilotstudie. Patienten und Methodik. Patienten mit Zentralarterienverschluss (ZAV) oder Arterienastverschluss (AAV), die sich konsekutiv in unserer Klinik vorstellten, wurde neben einer Bulbusmassage, Vorderkammerpunktion und i.v. Azetazolamid eine HBO angeboten. Die HBO (3-mal 30 min bei 2,4 bar) wurde am 1. Tag 3-mal, am 2. und 3. Tag 2-mal und für mindestens 4 Tage je 1-mal angewendet. Patienten, die eine HBO ablehnten oder Kontraindikationen aufwiesen, wurden als Kontrollgruppe betrachtet. Die Visusbestimmung erfolgte mit ETDRS-Tafeln. Der Beobachtungszeitraum betrug 3 Monate. Ergebnisse. HBO: 8 Patienten mit ZAV hatten einen mittleren Visusanstieg von 1 Stufe, dabei zeigten 4 von 8 Patienten einen Anstieg von 2 und mehr Stufen, 3 von 8 Patienten blieben unverändert, und 1 Patient erlebte einen Abfall von 6 Stufen. Einen mittleren Visusanstieg von 8 Stufen hatten 10 Patienten mit AAV, dabei wiesen 8 von 10 Patienten einen Anstieg von 2 Stufen und mehr auf, 2 von 10 Patienten blieben unverändert. Standardgruppe: 8 Patienten mit ZAV hatten einen mittleren Visusanstieg von 2 Stufen, 3 von 8 Patienten zeigten einen Anstieg von 2 und mehr Stufen, 5 von 8 Patienten blieben unverändert. Einen mittleren Visusanstieg von 4 Stufen hatten 6 Patienten mit AAV, 3 von 6 Patienten wiesen einen Anstieg von 2 Stufen auf, 1 Patient verlor 3 Stufen, bei 2 Patienten blieb der Visus unverändert. Die Ergebnisse werden mit der Literatur verglichen. Schlussfolgerung. Die HBO scheint den Visus bei AAV positiv zu beeinflussen. Weitere Untersuchungen sind notwendig, um die Relevanz der Ergebnisse zu prüfen.AbstractRetinal artery occlusion (RAO) is an ophthalmological emergency that causes a major decrease of visual parameters in most of the cases. Purpose of this pilot study was to evaluate the effect of adjunctive hyperbaric oxygen therapy (HBO) on visual acuity (VA). Patients and Methods. Patients with acute central or branch artery occlusion (CRAO/ BRAO) consecutively admitted to our hospital were offered adjunctive HBO. Standard therapy consisted of ocular massage for 3 minutes, paracentesis and intravenous acetazolamide. HBO (3×30 minutes at 240 kPa) was applied t. i. d. on the first day, b. i. d. on day 2 and 3 and o. d. for at least another 4 days. Patients who refused HBO or had contraindications served as controls. VA was measured according to the guidelines of ETDRS. The follow up was 3 months. Results. HBO: 8 patients with CRAO showed a mean increase in VA of 1 line, 4 of 8 patients had an increase of 2 lines and more, in 3 of 8 patients VA was unchanged and one patient suffered a decrease of 6 lines. 10 patients with BRAO showed a mean increase in VA of 8 lines, 8 of 10 patients showed an mean increase of 2 and more lines, in 2 of 10 patients VA was unchanged. Controls: 8 Patients with CRAO had a mean increase of 2 lines during follow up, 3 of 8 patients showed an increase of 2 lines and more, in 5 of 8 patients VA was unchanged. 6 patients with BRAO had a mean increase of VA of 4 lines, 3 of 6 patients had an increase of 2 lines and more, one patient lost 3 lines and in 2 patients VA was unchanged. The results are compared to the literature. Conclusions. HBO seems to be beneficial for VA in eyes with BRAO. Further investigations are necessary to prove this observation.

External beam radiation in patients suffering from exudative age-related macular degeneration

Abstract · Background: The aim of this prospective study was to ascertain whether external beam irradiation is effective in patients with subretinal neovascularization (SRN) due to age-related macular degeneration (AMD). · Methods: All patients had subfoveal SRN due to AMD as verified by fluoresceinangiography. Two hundred and eighty-seven patient-eyes were treated by external beam irradiation (total dose of 16 Gy in 2-Gy fractions, 5 times a week) from January 1996. The analysis was restricted to those 73 patients with a minimum follow-up of 11 months. Eighteen patients with subfoveal SRN who refused treatment served as control group (CG). 18 patients of the treatment group (TG) were matched for visual acuity, refraction and extent of SRN. The statistical analysis was performed with the unpaired t-test. · Results: The mean age of the CG was 73.9 years (range 66.9–81.3 years) and of the TG 75.6 years (range: 65.7–80.6 years). The median follow-up was 13.5 months (range 11.9–18.4 months) in the CG and 12.9 months (range 11–13.9 months) in the TG. The initial visual acuity (VA) was 20/80 in both groups. After 7 months the follow-up revealed median VA of 20/400 in the CG and 20/160 in the TG (P=0.0335). The final median VA was 20/400 in both groups, with a range from 20/40 to 20/1000 in the CG and from 20/63 to 20/500 in the TG (P=0.2433). The SRN doubled in size during this time in both groups. · Conclusion: These results suggest that external beam irradiation applied in 2-Gy fractions 5 times a week slows down the visual loss in exudative AMD for a short time. Nevertheless, the patients’ reading vision could not be saved in the long term.

Plasminogen in proliferative vitreoretinal disorders

OBJECTIVE Intravitreal fibrin formation is a frequent observation after vitrectomy performed for a variety of vitreoretinal disorders including proliferative vitreoretinopathy (PVR), proliferative diabetic retinopathy (PDR), and endophthalmitis. Plasminogen activators (PA) have been used for the management of this postoperative complication. This approach requires the presence of plasminogen, the substrate for PA mediated fibrinolysis, in the vitreal cavity. METHODS Quantification of plasminogen in the vitreous of 60 patients with PVR, PDR, and macular pucker was performed by streptokinase mediated activation using a chromogenic substrate. The presence of immunoreactive plasminogen was confirmed by immunoblot analysis of vitreal proteins and immunocytochemistry of surgically removed epiretinal membranes. RESULTS Plasminogen levels were dramatically increased in the vitreous of PVR and PDR patients compared with macular pucker patients and normal controls. Staining for plasminogen in epiretinal membranes was confined to the extracellular matrix. Predominant staining of perivascular areas in PDR specimens indicated that breakdown of the blood-retinal barrier is an important source of intravitreal plasminogen in that condition. CONCLUSION Plasminogen may play a role in traction membrane formation in PVR and PDR. Our biochemical analysis of presurgical vitreous indicates that there may be abundant substrate for PA mediated fibrinolysis in the vitreous cavity after vitrectomy.

Long-term fluctuations of the normalised rim/disc area ratio quotient in normal eyes

Abstract · Background. The assessment of the cup of the optic disc in follow-up of glaucomatous optic nerve heads depends on the variability of the cup area over time. We examined the variability of topographic measurements depending on scan focus settings and evaluated the long-term fluctuations of the normalised rim/disc area ratio quotient of normal subjects for 1 year. · Methods. Part 1. Evaluation of the influence of scan focus and corneal curvature on the number of pixels per millimetre in one emmetropic volunteer. The scan focus was varied using contact lenses of different refraction. Part 2. HRT examinations of the optic nerve head of five eyes of five volunteers were repeatedly recorded during a 12-month period. The contour line from the first mean topographic image was transferred into the following seven mean topographic images of each subject. · Results. Part 1. The size of pixels depends on the adjusted scan focus for mean corneal curvature radius between 6 and 9 mm. However, after image to image scaling the size of pixels is nearly independent to the scan focus. Part 2. We found the highest variation of normalised rim/disc area ratio for the location of the temporal horizontal sectors, followed by the temporal inferior and the temporal superior sectors. Variation was smallest in the nasal sectors. Mean fluctuation of the normalised rim/disc area ratio quotient of the 95th percentile was 0.09 following image to image scaling compared to 0.16 when using individual image scaling. · Conclusion. Scan focus variation during HRT follow-up examinations can influence optic disc parameters, especially when image to image scaling has not been performed. A confidence area of an individual optic disc could now be calculated. These confidence bands could help to distinguish more easily between progress of glaucomatous optic nerve head damage and physiological intertopographic variation of optic cup measurements. A decrease of more than 43% in the fluctuations of the normalised rim/disc area ratio could be achieved using image to image scaling techniques. For that reason follow-up of glaucomatous optic nerve heads should only be performed using this software application.

Laceration of the eye with a fishing hook

Editor,—Perforation of the eye is a challenging emergency in ophthalmology and requires immediate treatment. Visual outcome after penetrating injuries with and without intraocular foreign bodies depends on the visual acuity after injury, age of patient, and the severity of the ocular trauma.1 2 We report a case of globe laceration following an accident with a fishing hook which was successfully treated without surgery. ### CASE REPORT A 12 year old boy presented with visual disturbance and a small lid wound on the left eye at our emergency department. He had been playing with a fishing rod while sitting on a tree, and was trying to hook fruit on the ground. …

The nonradioisotopic representation of differentially expressed mRNA by a combination of RNA fingerprinting and differential display

In many applications, an understanding of differentially expressed genes in different tissues, or owing to an applied stimulus is important. However, the wide use of two rather similar polymerase chain reaction (PCR)-based techniques for the identification of differentially expressed mRNAs (RNA fingerprinting by arbitrarily primed PCR [RAP-PCR] and differential, display [DDR-PCR] has shown, that reproducibility is still a problem. By combining features of both RAP-PCR and DDRT-PCR a technique has recently been developed that avoids some of the disadvantages, but the use of radioisotopes for band detection still limits its application. We have improved this technique for analyzing differentially expressed mRNA by resolving the amplified products on nondenaturing polyacrylamide gels and subsequently staining the gels with silver nitrate. Our modification allows the identification of differentially expressed bands with a very high accuracy. Therefore these bands can be very easily reamplified and sequenced directly. Subsequently the differential expression can be verified by semiquantitative RT-PCR with specific primers derived from sequence data. These improvements, together with nonradioactive sequencing techniques, make it possible to do DD analysis completely without a health hazardous owing to radioactivity. The nonradioisotopic differentially expressed mRNA-PCR (DEmRNA-PCR) is a reliable and useful modification of available differential expression methods.

Zur Dosis-Wirkungs-Beziehung der transskleralen Kontaktzyklophotokoagulation

Die Kontaktzyklophotokoagulation hat im Vergleich zur Kryokoagulation des Ziliarkörpers bei der Behandlung von therapierefraktären Glaukomen an Bedeutung gewonnen. Bezüglich der optimalen Dosis-Wirkungs-Beziehung bestehen divergierende Meinungen; dies wurde in der vorliegenden Studie retrospektiv analysiert.Patienten: In 124 Augen von 113 Patienten (Altersverteilung 49,9±26,5 Jahre) wurden entsprechend der Diagnose die Laserparameter mit dem intraokularen Druck (IOD) vor der Therapie, bei der Entlassung und am Ende des Beobachtungszeitraums (Mittelwert: 186 Tage postoperativ) untersucht.Ergebnisse: Von 124 Augen waren nach dem Beobachtungszeitraum 56 Augen (45,2%) unter Therapie druckreguliert (IOD <22 mmHg). 32 Augen (25,8%) wurden bis zu 5mal gelasert. Die Korrelation von Laserenergie und Drucksenkung betrug prs = 0,08 und ist somit nicht signifikant (Rangkorrelation Spearman). Der IOD wurde im Mittel um 9,5 mmHg, von 35,8±10,5 mmHg auf 26,3±10,5 mmHg, signifikant gesenkt (p≅0, Wilcoxon-Test). Aufgrund dieser IOD-Senkung konnte die medikamentöse Therapie postoperativ im Durchschnitt um 3 Antiglaukomatosa je Patient gesenkt werden.Schlußfolgerung: Die vorliegenden Daten deuten an, daß eine Senkung des IOD um etwa 10 mmHg durch die Kontaktzyklophotokoagulation möglich ist. Eine Dosis-Wirkungs-Beziehung zwischen Laserenergie und IOD-Senkung konnte nicht nachgewiesen werden.Purpose: In recent years, transscleral contact-cyclophotocoagulation has increasingly been used for the treatment of therapy-refractive glaucomas. The dose-effect correlation varies according to different authors. In this retrospective study, we tried to determine whether there is a dose-effect correlation of transscleral contact-cyclophotocoagulation.Methods: Following diagnosis, 124 eyes of 113 patients (age range 49.9±26.5 years) were included in the study. The laser parameters used were reviewed along with the intraocular pressure (IOP) before treatment, after treatment and during the follow-up (mean 6 months).Results: The IOP of 45.2% (56) of 124 eyes was <22 mmHg. In 25.8% (32 eyes) a retreatment was necessary. No correlation between energy and decrease of IOP was found (Prs = 0.08 nonsignificant, Spearmann rank correlation). The IOP was reduced from 35.8±10.5 mmHg preoperatively to 26.3±10.5 mmHg at the end of follow-up (P≈0, Wilcoxon test). Therapy could be reduced by up to three antiglaucomatous drugs in therapy-refractive eyes.Conclusions: These data show that a decrease of about 10 mmHg of the IOP is possible using transscleral contact-cyclophotocoagulation. In therapy-refractive eyes, fewer drugs were needed to reach an IOP <22 mmHg. Regardless of the diagnosis, a dose-effect correlation between the decrease of IOP and laser energy was not found.

Antiproliferative Wirkung von Genistein auf kultivierte retinale Pigmentepithelzellen vom Schwein

The isoflavonoid genistein is known as a potent inhibitor of proliferation in endothelial cells and in some tumor cell lines in vitro and in vivo. Cell growth arrest is mediated by inhbitor of the tyrosine-kinase receptor, a target for many growth factors such as fibroblast growth factor, platelet-derived growth factor, epidermal growth-factor and vascular endothelial growth factor, which may play a role in the development of proliferative vitreoretinopathy (PVR). In this study we report on the antiproliferative effect of genistein on retinal pigment epithelial cells (RPE), which is the major cell type involved in PVR. Methods: Cell culture experiments using porcine RPE treated with different concentrations (5 up to 100 μg/ml) of genistein in minimum essential medium +10% fetal calf serum. Inhibition of proliferation was demonstrated by two different methods: (1) uptake of 5-bromo-2-deoxyuridin (BrdU) in S phase after different exposure times (2) expression of proliferating cell nuclear antigen 72 h after scratching confluent RPE. Results: Exposure of RPE to genistein resulted in a concentration-dependent inhibition of cell proliferation at concentrations over 25 μg/ml geinistein. BrdU incorporation was reduced to 65% after 24- and 48-hour treatment with 100 μg/ml genistein in comparison with the untreated cells. Proliferation of RPE growing into the artificial wound was inhibited when cells were exposed for 72 h to more than 25 μg/ml genistein. Conclusions: Genistein at concentrations over 25 μg/ml inhibits RPE proliferation. Further studies will be required to determine the applicability of genistein or other phytoestrogens in order to prevent uncontrolled wound healing processes such as PVR.

Safety Profile Of A Taurine Containing Irrigation Solution (acriprotect) In Pars Plana Vitrectomy

Purpose: To evaluate the clinical safety of a taurine containing irrigation solution (AcriProTect) before its routine application in pars plana vitrectomy (PPV). Methods: Twenty-five patients who underwent PPV were included in this prospective interventional clinical study. Standard irrigation solution containing the addendum 3 mmol/L taurine was used during PPV. Postoperative follow-up visits included a standard eye examination, corneal thickness measurements, endothelial cell counts, determination of the foveal thickness by optical coherence tomography (OCT), and an electrophysiologic examination. For statistical analysis Wilcoxon test was used. Results: Significant improvement of visual acuity (VA) was observed at the 3- and 6-month controls (P = 0.024; P = 0.002 for 3 and 6 months, respectively). Endothelial cell counts and corneal thickness at 3 and 6 months were not significantly different from preoperative values (P = 0.204; P = 0.126 for endothelial cell count and P = 0.475; P = 0.095 for corneal thickness at 3 and 6 months, respectively). Both scotopic and photopic Ganzfeld electroretinography and electro-oculography did not show significant changes during the follow-up. No increase in complication rate was detected. Conclusions: The investigation demonstrates a good biocompatibility of taurine-containing irrigation solution developed for vitrectomy in humans concomitant with habitually observed good functional outcome.

Experimental Implantation of Devices for Electrical Retinal Stimulation In Rabbits

In the treatment of progressive receptor degenerations of the human retina e.g. in retinitis pigmentosa (RP) the electrical stimulation of nerve fibers of retinal ganglion cells is discussed as one possible option. It was reported that blind patients suffering from a massive photoreceptor dysfunction had a kind of visual perception when a stimulating current was applied to the inner retinal surface1. With an implanted array of microcontacts it should be possible to evoke a visual response featuring a minimum of spatial resolution in these patients. One prerequisite for this kind of treatment is the existance of a sufficient number of intact ganglion cell fibers which was shown by Stone and coworkers’. Another prerequisite for this concept of a future RP treatment is that the stimulator could be implanted into the eye and onto the inner surface of the retina. The device has to be biocompatible and it should not change its position on the retina once being implanted.