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Biomedical subjects

G Grabner

Publications and source records attributed to G Grabner.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Intrastromal corneal ring segments (ICRS, KeraVision Ring, Intacs): clinical outcome after 2 years].

BACKGROUND: Since 1996 Intrastromal Corneal Ring Segments (Intacs, KeraVision, Inc., Fremont, CA, USA) have been used for the correction of mild to moderate myopia at the Salzburg Eye Clinic. Aim of this study was to evaluate the stability, reversibility and adjustability of this new method. PATIENTS AND METHODS: Our experiences and final results of 54 surgeries--30 eyes with a minimum follow-up of 2 years--, as well as the potential reversibility (3 explanations, 2 of them followed by PRK) and adjustability (3 exchanges) are reported in detail. RESULTS: None of the eyes lost more than one line in BSCVA (in 14 of 30 eyes the BSCVA improved, "Safety-Index": 1.13). 73% (22/30) reached an UCVA of 1.0 or better, 47% (14/30) of 1.25 or better ("Efficacy-Index": 0.79). After two years 47% (14/30) were within +/- 0.5 D of the attempted correction. We observed no significant intra- or postoperative complications. After ICRS removal the refractive data returned to within +/- 0.75 D (MRSE) and +/- 0.5 D (mean keratometry) of preoperative values, respectively. Patients with an ICRS exchange obtained an improved UCVA between 0.8 and 1.0, gaining between 2 to 4 lines. CONCLUSIONS: Within the follow-up period of 2 years the ICRS seem to provide a very stable correction of low to moderate myopia. The procedure is reversible to a large extent, potentially adjustable (within certain limits) and carries a minimal risk only. After explantation PRK can be performed with good visual results.

Adult↗
PubMed2000

Penetration of cefpirome into the anterior chamber of the human eye after intravenous application.

The penetration of intravenously administered cefpirome into the anterior chamber of the non-inflamed human eye was investigated in this study. A total of 42 patients, all hospitalized for cataract extraction, received a dosage of 1 g or 2 g of cefpirome by iv infusion 1, 2 or 6 h preoperatively. An aqueous humour sample was collected immediately after paracentesis and a blood specimen was simultaneously obtained from each patient. All samples were analysed for cefpirome concentrations using high-pressure liquid chromatography. Mean aqueous humour levels of cefpirome in patients receiving a dosage of 1 g were 1.33 mg/L (1 h), 1.67 mg/L (2 h) and 1.29 mg/L (6 h after application), respectively. When patients received a dosage of 2 g cefpirome the resulting mean aqueous humour concentrations were 1.60 mg/L (1 h), 2.27 mg/L (2 h) and 2.39 mg/L (6 h after application), respectively. A statistically significant difference in aqueous humour concentrations between patients receiving 1 g or 2 g of cefpirome could not be proven. In conclusion, cefpirome penetrates well into the anterior chamber of the non-inflamed human eye in concentrations that are therapeutic for many gram-positive and gram-negative organisms, frequently responsible for anterior segment eye infections.

Aged↗
PubMed2000

Recurrent keratoconus in a patient with Leber congenital amaurosis.

PURPOSE: Clinical history of a 17-year-old patient with Leber congenital amaurosis (LCA) with histologically proven recurrent keratoconus (KC) two years after corneal transplantation in one eye and a recurrence-like appearance with a more global contour on the other eye four years after corneal grafting is reported. The possible mechanisms for this recurrence are discussed in light of the fact that this is, to the best of our knowledge, the first penetrating keratoplasty reported in LCA. METHODS: Computerized videokeratography (CVKG) and specular microscopy were performed preoperatively. The patient underwent regrafting, and the excised corneal button was examined by light microscopy and transmission electron microscopy. RESULTS: Analysis of CVKG showed a keratoconus-like pattern on the right eye, with the left eye demonstrating the aspects usually seen in keratoglobus. Histologic examination revealed the features usually observed in progressed keratoconus. CONCLUSION: Recurrence of keratoconus in a graft has not yet been described after such a short time until now. A "true" recurrence of the disease is postulated; it could be caused by an "aggressive" genetic factor that also leads to the frequent KC in patients with LCA. This mechanism also could explain the high incidence and rapid progress of KC in this disease.

Adolescent↗
PubMed1999

Dodick laser phacolysis: thermal effects.

PURPOSE: To gather experimental data on whether Dodick laser phacolysis leads to corneal or scleral burns. SETTING: The Eye Department, County Hospital Salzburg, Salzburg, Austria. METHODS: The study was done using a pulsed neodymium:YAG (Nd:YAG) laser with a wavelength of 1064 nm; energy, 10 mJ; and duration of pulses, 14 ns. The light pulse is carried by a 400 microns quartz fiber to the laser phacolysis probe. The laser light hits a titanium target inside the tip, causing an optical breakdown and thus a shock wave. The generation of both plasma and the shock disrupt the nuclear material. The temperature at the ultrasonic phaco and laser phacolysis tip was measured under air and balanced salt solution (BSS) in a test chamber and in the anterior chambers of eye-bank eyes. RESULTS: Ultrasonic phacoemulsification led to a difference in temperature up to 55.3 degrees C under air, 12 degrees C in BSS, and 10.9 degrees C in the anterior chamber. There was no clinical significant heat generated by the laser phacolysis tip. CONCLUSION: This initial in vitro study demonstrates that the well-known risk of the tissue heating (i.e., phaco burn) does not occur with Dodick laser phacolysis, even when the irrigation flow is slow or discontinued.

Anterior Chamber↗
PubMed1999

Ocular involvement in IgA-epidermolysis bullosa acquisita.

Epidermolysis bullosa acquisita (EBA) is an autoimmune bullous disease with frequent ocular involvement, but visual loss is rare. In contrast, EBA patients with predominant IgA autoantibodies more frequently develop severe ocular involvement, which tends to be refractory to therapy. We report two patients with 'IgA-EBA' with ocular involvement. Both initially presented with a generalized bullous disease, and direct immunofluorescence microscopy demonstrated IgA in the basement membrane zone of the skin, and in the conjunctiva and cornea of patient 1. On salt-split patient skin, IgA was found predominantly on the dermal side of the artificial split in both patients. Direct immunoelectron microscopy demonstrated IgA below the lamina densa in close association with the anchoring fibrils in both patients. In patient 1, who had a prolonged course of the disease, the skin disorder responded well to treatment with cyclosporin, but the ocular involvement ended in bilateral blindness despite repeated surgical treatment. In patient 2, the blister formation and scarring conjunctivitis was stopped by a combination of prednisolone and colchicine. These patients show that in subepithelial blistering diseases, early delineation of disease nosology is critical to detect subtypes with severe ocular involvement such as 'IgA-EBA'. In addition, colchicine may be a valuable alternative in the treatment of EBA with ocular involvement.

Adult↗
PubMed1999

Laser shaping of corneal transplants in vitro: area ablation with small overlapping laser spots produced by a pulsed scanning laser beam using an optimizing ablation algorithm.

Area laser lathing and trephination of donor corneas is used to produce different types of grafts for human transplantation. 193 nm (ArF excimer) laser radiation is used, since this is known to give a non-thermal laser-tissue interaction with a minimal zone of tissue damage. To guarantee the highest degree of flexibility concerning the overall shape of the grafts as well as their thickness profiles, we use a small (compared with the area to be ablated) scanning laser spot. For area lathing of the tissue we have developed a new ablation algorithm (optimized scanning laser ablation, OSLA) that can be applied to lathe and perforate any tissue--with concave (as in this application), convex or plane surface geometry--where surface precision and smoothness are key issues. Using OSLA with the Excimer Laser Corneal Shaping System (a tool for in vitro fabrication of all kinds of corneal transplants like donor buttons for keratoplasty, lamellar grafts for epikeratoplasty and refractive lenticules) enabled us to produce all types of corneal grafts with very high precision. This is considered to be a major improvement towards the production of refractive lenticules.

Algorithms↗
PubMed1998

[Driving behavior of patients before cataract operation--is an unlimited driver's license justifiable? Results of an analysis of 1,124 patients of the ophthalmology department of a central hospital].

BACKGROUND: The aim of the study was to evaluate the driving habits and patterns of those patients, who underwent cataract-surgery during a one year period at the Landesaugenklinik Salzburg and to compare the preoperative visual acuity with the legal requirements in effect in Austria. MATERIALS AND METHODS: The best-corrected visual acuity prior to surgery and the individual driving customs were noted on a detailed questionnaire. RESULTS: A minimum of 5.6% of the overall number of patients with cataract (not taking visual field defects into account) were driving a motor vehicle with a visual acuity not sufficient to meet current legal requirements. Considering only those drivers licence holders that admitted to still driving a motor vehicle it can be concluded that 26% have a legally unsatisfactory visual acuity. As between 28,000 and 31,000 cataract-operations are performed yearly in Austria, this study seems to clearly indicate that at least 1,600 of these persons--regardless of an additional visual field defect--are illegally driving a motor vehicle. It can be additionally concluded that the number of undetected cases is significantly higher. CONCLUSIONS: It therefore seems appropriate to call for a mandatory eye exam by a qualified ophthalmologist of all persons holding a driving licence, possibly beginning at the age of 60. The license issued thereafter should be valid for an age-related period of time only.

Accidents, Traffic↗
PubMed1998

[Intrastromal corneal ring segments (ICRS, Kera Vision Ring). One year outcome of the first 25 interventions].

BACKGROUND: The advantages of the Intrastromal Corneal Ring Segments (ICRS) as compared to the frequently used methods for the correction of low to moderate myopia (RK, PRK, LASIK) are the intact optical zone and nearly complete reversibility. PATIENTS AND METHODS: Two ICR-Segments, made of PMMA (with an arc length of 150 degrees each) are placed in the deep stromal layers via a small radial incision. At the Landesaugenklinik Salzburg 25 continuous surgeries were performed as part of the European "MECCA-trial". RESULTS: Refractive results, intra- and postoperative complications with a follow-up of 12 months are presented. There was no visual loss after one year. In 40% (10/25) the best corrected visual acuity remained unchanged. In 56% (14/25) one line was gained, once two lines were gained. The spherical equivalent was slightly in the range of undercorrection--as wanted. The refractive astigmatism increased (0.5 dpt). The keratoscopy image showed positive aspheric appearance. CONCLUSION: The ICRS (Kera Vision Ring) seems to offer a precise and stable method to correct low myopia. The procedure is reversible to a large extent, potentially adjustable within certain limits and carries a minimal risk only. Although long-term follow-up is not available yet, initial results of the technique seem very promising.

Adult↗
PubMed1997

Anterior chamber contamination during cataract surgery with intraocular lens implantation.

PURPOSE: To measure anterior chamber bacterial and fungal contamination at the beginning and end of cataract surgery with intraocular lens (IOL) implantation in a large series of patients and to determine the influence of preoperative treatment and operative technique on contamination. SETTING: Department of Ophthalmology, County Hospital of Salzburg, Austria. METHODS: This prospective study comprised 700 consecutive patients having planned cataract extraction (511 phacoemulsification, 189 extracapsular cataract extraction [ECCE]). Thirty-four patients required an anterior vitrectomy; 8 myopic patients did not receive an IOL. A preoperative smear and two intraoperative (at the beginning and end of surgery) anterior chamber aspirates were obtained from each patient. Postoperative smears were obtained at discharge. Three preoperative treatments were evaluated: no lacrimal system irrigation, no topical antibiotic (n = 282); lacrimal system irrigation with balanced saline solution, no topical antibiotic (n = 243); lacrimal system irrigation, antibiotic (neomycin) eyedrops (n = 175). All patients received topical indomethacin twice a day preoperatively. RESULTS: Preoperative conjunctival smears showed bacterial growth in 76.6% of eyes, with coagulase-negative staphylococci (75%) the most common bacteria. Anterior chamber aspirates were culture positive in 14.1% at the beginning and in 13.7% at the end of surgery, with coagulase-negative staphylococci and corynebacteria the most common. Contamination rates of conjunctival smears taken at discharge were significantly lower (35%) than those taken preoperatively. There was no statistically significantly higher risk of anterior chamber contamination in eyes having ECCE than in those having phacoemulsification. Preoperative treatment did not statistically significantly influence intraoperative aqueous humor contamination rates. There were no cases of acute postoperative endophthalmitis. CONCLUSION: Bacteria entered the anterior chamber during cataract extraction and remained there at the end of surgery in a significant percentage of patients. Surgical technique, preoperative antibiotics, and preoperative lacrimal system irrigation had no statistically significant effect on contamination.

Adolescent↗
PubMed1997

[The intrastromal corneal ring (KeraVision Ring, ICR, ICRS). A modern method for correcting minor myopia].

For the correction of low myopia several competing surgical methods have been developed over the last two decades: radial keratotomy (RK) and photorefractive keratectomy (PRK) are used clinically on a very large scale. Both techniques are basically irreversible. RK does structurally weaken the cornea and PRK has to be applied directly at the optical center. Both disadvantages can to a large extent be avoided by the recently introduced Intrastromal Corneal Ring (ICR) that is now implanted worldwide following a long experimental and clinical development phase. The device is manufactured from PMMA and is effective by volume addition in the corneal periphery, shortening of the central arc length and thereby flattening the central optical zone. The latest development uses two ICR-Segments (with an arc length of 150 degrees each) that are placed in the deep stromal layers via a small radial incision. The surgical details, refractive results and intra- and postoperative complications of both, several international studies (with up to 5 years of follow-up), and our own experiences (25 eyes, follow-up 9 months) are presented. The ICRS (KeraVision Ring) seems to offer a precise and stable method to correct low myopia. The procedure is reversible to a large extent, potentially adjustable within certain limits and carries a minimal risk only. A short comparison with RK and PRK is attempted. Although long-term follow-up is not available yet, initial results of the technique seem very promising.

Adult↗
PubMed1995

Expression of MHC class II antigens on rat bone marrow cells and macrophages, and their modulation during culture with murine GM-CSF or M-CSF.

Flow cytometric analysis employing MRC OX 6 and MRC OX17 monoclonal antibodies recognizing determinants on RT1.B or RT1.D molecules, equivalent to murine I-A and I-E, respectively, was used to detect rat MHC class II antigen (Ag) expression. Approximately 5% of freshly isolated rat bone marrow cells (BMC) expressed RT1.B and over 30% displayed RT1.D molecules. The RT1.D+ cells were W3/13+, OX 7+, OX 19- and OX 22-. After one week culture of BMC with murine recombinant granulocyte/macrophage colony-stimulating factor (GM-CSF), regardless of concentrations, 90 to 95% of the cells were scored as bone marrow-derived macrophages (BMDM phi), and over 30% expressed both RT1.B and RT1.D Ag. GM-CSF increases the percentage of BMDM phi bearing MHC class II Ag in a concentration-dependent manner. This effect seems to be specific because antibodies to interferon-gamma, tumor necrosis factor-alpha or interleukin-4 did not reduce the number of cells expressing RT1.B and RT1.D Ag. Furthermore, GM-CSF was able to trigger expression of class II molecules on rat peritoneal macrophages (M phi) and BMDM phi resulted from cultures of BMC with mouse M phi-CSF (M-CSF), and the RT1.B and RT1.D inducing effect of GM-CSF was opposed by M-CSF, and by anti-GM-CSF antibodies. The induction of MHC class II Ag synthesis by GM-CSF on rat BMDM phi was confirmed at the mRNA level by Northern blot analysis employing cDNA probes encoding the RT1.B alpha.

Animals↗
PubMed1994

Different techniques of extracapsular cataract extraction: bacterial contamination during surgery. Prospective study on 230 consecutive patients.

This study was performed to investigate the correlation between the contamination of the anterior chamber and the technique of extracapsular cataract extraction (ECCE). Three different methods were used: uncomplicated planned ECCE, phacoemulsification involving suturing method, and sutureless technique. All patients had posterior chamber intraocular lenses implanted. Two hundred and thirty consecutive patients were included in this prospective study, and preoperative smears of the conjunctiva and intraoperative aspirates of the anterior chamber were investigated. Samples of the aqueous humor were taken at the beginning and at the end of the operation. Cultures were incubated and held for 14 days. More than 71% of the preoperative smears were contaminated by coagulase-negative staphylococci, the most commonly isolated bacteria. However, 27% of the patients had culture-positive anterior chamber aspirates intraoperatively, also with coagulase-negative staphylococci as the most frequent organisms. In no case did postoperative endophthalmitis develop. Preliminary results in a small population show that the contamination of the aqueous humor is statistically significantly less frequent if the cataract extraction is performed by phacoemulsification than if it is done without phacoemulsification. Another interesting finding is that anterior chamber contamination is not significantly more frequent, if a sutureless technique is used for cataract surgery.

Adult↗
PubMed1994

Bacterial contamination during extracapsular cataract extraction. Prospective study on 200 consecutive patients.

Postoperative endophthalmitis remains one of the most devastating complications of eye surgery. In recent years infections with so called 'nonpathogenic' organisms like Propionibacterium acnes or coagulase-negative staphylococci have gained in importance. 200 patients were included in this study, from whom preoperative smears of the conjunctiva and intraoperative aspirates of the anterior chamber (at the start and at the end of the operation) had been taken. All samples were investigated for aerobe and anaerobe microorganisms and fungi. 75% of the preoperative smears had been contaminated, with coagulase-negative staphylococci the most commonly isolated bacteria. But, in addition, 28% of the patients had culture-positive anterior chamber aspirates, also with coagulase-negative staphylococci as the most frequent organisms. In all cases inoculum sizes were extremely small (10-20 c.f.u./ml). Probably because of this small inoculum, but also due to the bacteriocidal qualities of the aqueous humor and the integrity of the posterior capsule sac, in no case had postoperative endophthalmitis developed. For the first time, our study tried to correlate the contamination of the anterior chamber aspirate to the used operation technique: first results show that the contamination of the aqueous humor is significantly lower (p < 0.03) if the cataract extraction is performed by phacoemulsification than if done without.

Adult↗
PubMed1993

Automated digital image analysis of organ culture preserved donor corneas.

The present study reports the application of a modified commercially available automated digital image analysis system (DIA) for the evaluation of organ culture preserved donor corneas. The central corneal endothelium was viewed and photographed under an inverted phase-contrast microscope. The images were then analyzed with the help of DIA. The results of DIA were compared to the findings obtained with a conventional 'fixed-frame analysis' for the same corneas. 100 human donor corneas have been evaluated. DIA, with interactive picture enhancement, was found to be practicable, and to yield reproducible results. The mean number of cells analyzed per photograph was 250 (range 95-395); this, on the average, was four times higher than with conventional fixed-frame analysis (mean 54, range 37-70). The correlation of the cell densities obtained with both methods was highly significant (p < 0.0001). Since additional information, like variation in cell size and shape (circularity form factor), was automatically computed by the program, more data on the homogeneity of the donor endothelial cell pattern were available. Furthermore, this computerized technique does not require an experienced investigator and thereby helps to eliminate bias.

Cell Count↗
PubMed1992

[Corneal ulcer. Current analysis from specialized ambulatory care of a clinic].

A review of 115 cases of ulcerative keratitis that were diagnosed and treated at the specialized ambulatory care center for infectious eye diseases at the 2. Department of Ophthalmology over a period of eight years (January 1983-April 1991) is presented. In the analysis of the etiology nearly half (47.7%) were observed following a trauma to the epithelium, 38 (= 33.0%) were associated with contact lens wear and the third largest group (10.4%) was associated with lid problems. It is apparent that over the course of the last years the spectrum of microorganisms associated with this localized inflammation has shifted: the prevalence of Staphylococci (1983-1986 = 65%) has decreased, whereas the incidence of gram-negative rods increased (1987-1990 = 49%). In 19% Pseudomonas aeruginosa could be isolated, mostly associated with soft contact lens wear. A total of 37.5% of the staphylococci isolates were found to be resistant to gentamicin, most probably as a consequence of the widespread, indiscriminate use of this antibiotic. An updated treatment schedule is presented.

Ambulatory Care↗
PubMed1992

[Corneal sensibility following epikeratophakia].

The postoperative rate of reinnervation following corneal surgery is widely considered to be a useful indicator of the healing process. This study reports the corneal sensitivity of 14 patients following epikeratophakia for different indications (myopia, aphakia and keratoconus) after time periods ranging from 7 to 104 weeks. All transplants were clear at the time of measurement. A newly developed aesthesiometer (using a low electric current for stimulation) was employed. Nine positions on the operated eye were chosen for the measurements, five locations of the non-operated fellow eye served as controls. On the operated eye the corneal sensitivity peripheral to the trephination were significantly reduced at the 9 and 12 o'clock positions as compared to the other eye. The 3 and 6 o'clock locations showed no significant difference. On the epikeratophakia lenticule the sensitivity was significantly reduced at all points, the center showing the largest difference (p less than 0.001). No correlation with age, sex or the indication for the procedure was observed. Although there was a trend of a positive correlation between the postoperative time period and the central corneal sensitivity, the follow-up was too short to reach significant levels. The nearly complete lack of corneal sensitivity, particularly in the center of the transplant is therefore well compatible with its long-time survival, even when the lenticule has been prepared with the cryolathe and lyophilized for transportation.

Adult↗
PubMed1992

[Taenia crassiceps in the anterior chamber of the human eye. A case report].

An otherwise healthy 15-year-old girl developed an iridocyclitis in her right eye. A contractable living parasite measuring two millimeter could be detected in the anterior chamber, the other parts of the eye remained uninvolved. The patient had close contact with the young dog of the family. By using a viscoelastic substance the parasite could be removed alive without any complications. The tapeworm was found to be too young for having developed the characteristic scolex. Western-immunoblotting gave indirect evidence for infection with Taenia crassiceps, a dog's tapeworm. During an observation period of two years no evidence for any other ocular or general Taenia crassiceps infestations could be found.

Adolescent↗