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Günther Grabner

Publications and source records attributed to Günther Grabner.

12 recordsLinked to original sources
PubMed2006

AlphaCor: Clinical outcomes.

PURPOSE: To study the outcomes of AlphaCor implantation. METHODS: : The AlphaCor artificial cornea is indicated for corneal blindness not treatable by donor grafting. Prospective preoperative and follow-up data were collected. Data were evaluated using SPSS for statistical analysis of outcomes, trends, and associations. RESULTS: This report includes data returned through February 28, 2006, for all 322 devices implanted, with mean follow-up in situ of 15.5 months and a maximum of 7.4 years. The probability of AlphaCor retention at 6 months and 1 and 2 years for protocol cases was 92%, 80%, and 62%, respectively, and off-label cases were at higher risk (P = 0.010), as were cases not prescribed medroxyprogesterone (MPG; P = 0.001). Currently, the most common complications were stromal melting, fibrous reclosure of the posterior lamellar opening, and white intraoptic deposits, with incidences in 2005 of 11.4%, 5.1%, and 2.6%, respectively. MPG seems to protect against melts, and eyes with a history of herpetic keratitis were not at increased risk. A history of glaucoma or the presence of tubes did not affect device retention. Complications culminated in loss of an eye in 1.3%. Mean preoperative visual acuity (VA) was hand movements. The VA achieved postoperatively (light perception to 20/20) was affected by previous pathology and postoperative course, with a mean improvement of 2 lines. CONCLUSION: AlphaCor provides a treatment option where a donor tissue graft would not succeed in severe corneal conditions, while being reversible to a donor graft in the event of complications for anatomic integrity. Surgical technique and adjunctive therapies are evolving with experience. Continued data collection is important for a fuller understanding of AlphaCor's role.

Adult↗
PubMed2005

Dynamic corneal imaging.

PURPOSE: To determine the clinical practicability of in vivo dynamic corneal imaging (DCI) to assess the individual elastic properties of normal human eyes, eyes with abnormal findings, and eyes after refractive surgery. SETTING: University Eye Clinic, Paracelsus Private Medical University, Salzburg, Austria. METHODS: The DCI method uses sagittal, stepwise, central indentation of the cornea with electronically controlled microprecision motors and sequential registration of videotopography images. The indentation steps are preselected and range from 50 to 800 mum. The computerized analysis of the videotopography images captured during the process uses Zernike polynomials to establish a newly defined flexing curve for normal eyes and eyes with abnormal findings. RESULTS: Dynamic corneal imaging was done in 187 eyes of 103 patients who had clinically healthy corneas, distinct keratoconus, or previous refractive surgery. The method rapidly evaluated artificially and reversibly induced changes in corneal topography in a clinical setting using a modified Placido disk-based computer-assisted videokeratography system with a small cone. In early analysis, the flexing curve showed a significant correlation with the applied indentation depth. Factors influencing the shape of the curve were central corneal thickness, intraocular pressure, and patient age. The DCI method also allowed easy examination of keratoconic corneas and corneas after refractive surgery. CONCLUSIONS: Dynamic corneal imaging induced a reproducible and reversible change in corneal topography corresponding to the different indentation depths. The results indicate that several clinical parameters are correlated with corneal elastic behavior in vivo and that the technology could increase the predictability of refractive corneal surgery and help in the early diagnosis of corneal diseases and with newly developed therapies.

Adult↗
PubMed2005

Standards for modified osteoodontokeratoprosthesis (OOKP) surgery according to Strampelli and Falcinelli: the Rome-Vienna Protocol.

PURPOSE: To establish a time-proven "gold standard" in modified osteoodontokeratoprosthesis (OOKP) surgery. METHODS: The OOKP is the procedure of choice for restoring sight in patients with corneal blindness caused by end-stage ocular surface disease not amenable to penetrating keratoplasty. Members of the OOKP Study Group met in Rome, Italy in 2001 and Vienna, Austria in 2002 to discuss indications and contraindications, patient selection, surgical technique, postoperative care, and recognition and management of complications of OOKP surgery according to Strampelli and modified by Falcinelli. RESULTS: Falcinelli's modification of Strampelli's technique of OOKP surgery remains the gold standard as far as visual and keratoprosthesis-retention results are concerned. The agreement on indications and contraindications, patient selection, surgical technique, postoperative care, and recognition and management of complications of this technique of OOKP surgery is summarized in the text of this manuscript. CONCLUSION: This standard technique of modified OOKP surgery, where adequately performed, is capable of providing excellent anatomic and functional results even in the long term. In patients with corneal blindness untreatable by other approaches, we strongly recommend this technique for visual rehabilitation. Students of OOKP surgery should become familiar with the protocol described in this paper before subjecting the technique to further modifications.

Alveolar Process↗
PubMed2004

Anterior chamber angle biometry with ultrasound biomicroscopy after diode laser thermal keratoplasty.

PURPOSE: To evaluate the effect of diode laser thermal keratoplasty (DTK) on the geometry of the anterior chamber angle with ultrasound biomicroscopy (UBM). SETTING: Department of Ophthalmology and Optometry, Paracelsus Private Medical University, Salzburg, Austria. METHODS: In 9 eyes, a Rodenstock DTK (ProLaser Medical Systems) was used to correct hyperopia (n = 6) or hyperopic astigmatism (n = 3). Hyperopia was treated with a single- or double-ring pattern and hyperopic astigmatism, with additional spots in each of the flat half meridians. Ultrasound biomicroscopy measurements of the chamber angle were obtained preoperatively and 3 months postoperatively using a Humphrey UBM 840 system with a 50 MHz transducer. Quantitative measurements were performed at 3-, 6-, 9-, and 12-o'clock positions using a standardized method. RESULTS: No statistically significant differences between the preoperative and postoperative chamber angle measurements were detected. CONCLUSIONS: The results of the UMB measurements were surprising given the flattening of the corneal periphery found by computerized topography, a finding that suggests narrowing of the chamber angle. Shortening of the corneal tissue may result in centripetal traction that affects the trabecular meshwork and results in a relative opening of the chamber angle structures.

Adult↗
PubMed2003

Correction of astigmatism with short arc-length intrastromal corneal ring segments: preliminary results.

OBJECTIVE: To evaluate the refractive effect of 130 degrees short arc length intrastromal corneal ring segments (ICRS) designed to correct myopia concurrent with astigmatism. DESIGN: Prospective, nonrandomized, comparative (self-controlled) trial. PARTICIPANTS: Ten eyes of 6 patients from one surgical center with manifest refraction spherical equivalent between -1.00 and -6.00 diopters (D), manifest cylinder correction between 1.00 and 6.00 D, and best spectacle-corrected visual acuity of 20/20 or better. INTERVENTION: The patients were assigned to receive 1 of 6 ICRS thicknesses, ranging from 0.25 to 0.50 mm by 0.05 mm increments, with an arc length of 130 degrees. MAIN OUTCOME MEASURES: Vector analysis of astigmatic correction. Efficacy was assessed by uncorrected visual acuity and by deviation of postoperative spherical and cylindrical refractive error from predicted correction. Safety was assessed by maintenance or loss of preoperative best spectacle-corrected visual acuity. Measurements were made before surgery and after surgery at days 1 and 7 and months 1, 2, 3, and 6. RESULTS: At 6 months, uncorrected visual acuity was 20/20 or better in 80% of eyes (8/10) and 20/40 or better in all eyes. Eight of 10 eyes (80%) were within +/-0.25 D of plano spherical equivalent manifest refraction. There was no loss of best spectacle-corrected visual acuity, and 6 of 10 eyes (60%) gained a line. Reduction of keratometric cylinder by ICRS thickness was statistically significant (P = 0.039). CONCLUSIONS: Preliminary results of visual and refractive performance after correction of compound myopic astigmatism using short arc length ICRS are promising.

Adult↗
PubMed2003

Ten-year follow-up of epikeratophakia for the correction of high myopia.

OBJECTIVE: To determine the long-term functional results of epikeratophakia for myopic patients. DESIGN: Retrospective, noncomparative, interventional case series. PARTICIPANTS: Twenty-two patients (32 eyes; average age, 43+/-6 years) who underwent epikeratophakia surgery for high myopia. Mean preoperative myopia was -18.74+/-9.16 diopters (D; range, -7 D to -49 D). Follow-up was 12+/-2 years. MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), change in mean keratometry, visual acuity under glare conditions, BCVA versus potential acuity meter reading, and patient satisfaction with the visual outcome. RESULTS: Mean preoperative UCVA increased from 20/800+/-20/400 (range, counting fingers-20/400) to 20/80+/-20/200 (range, 20/250-20/32) in 24 eyes. Mean preoperative BCVA of 20/32+/-20/64 increased only in five eyes, whereas six eyes had no change and 18 eyes had a more than one line loss of Snellen BCVA. Mean preoperative keratometry reading decreased from 43.67+/-0.90 D (range, 41.0-46.25 D) to 37.40+/-2.92 D (range, 29.43-47.68 D). In the presence of glare, mean BCVA decreased to 20/100+/-20/100 (range, counting fingers-20/32). Potential acuity meter (PAM) readings were significantly (P<0.05) higher than BCVA. Mean PAM reading was 20/25+/-20/100 (range, 20/100-20/16). Seven patients (11 eyes) were extremely satisfied with the operative result more than 10 years after the operation, whereas four patients (four eyes) were not satisfied at all. CONCLUSIONS: Epikeratophakia for the correction of myopia improved UCVA significantly, but BCVA decreased. The removal of the lenticules in patients who were not satisfied with their visual acuity was uncomplicated, and acceptable vision could be achieved with either contact lenses or intraocular lens implantation.

Adult↗
PubMed2003

Evaluation of bone reduction in osteo-odontokeratoprosthesis (OOKP) by three-dimensional computed tomography.

PURPOSE: To study the stability and preservation of the osteodental lamina in osteo-odontokeratoprosthesis (OOKP) according to Strampelli with spiral computed tomography (CT). METHODS: Computed tomography of the orbit was performed in nine patients after successful OOKP surgery. Indications for surgery included ocular pemphigoid (three patients), Lyell's syndrome (two patients), graft versus host disease (one patient), and severe chemical burns (three patients). In four eyes, the osteodental lamina was covered with a buccal mucosa graft; in five eyes, a "transpalpebral" approach with the placement of the optical cylinder through the patient's own lid skin was used. The mean time from surgery to examination was 4 years. The age of the patients ranged from 32 to 75 years (mean, 52). Spiral CT in the transaxial plane was performed, followed by three-dimensional (3D) surface reconstruction of the OOKP. The dimensions of the osteodental lamina were measured and compared with measurements taken at the time of surgery. RESULTS: A minor reduction of the lamina, mainly in the anterior and inferior part, could be found in all the patients without loss of stability and integrity of the lamina cylinder complex in seven patients. One patient showed complete resorption of the inferior half of the osteodental lamina, and another patient demonstrated "moth-eaten" dissolution of dentine and bone tissue. No correlation between the degree of reduction in the dimensions and patient age, diagnosis, or length of follow-up could be found. CONCLUSION: Osteo-odontokeratoprosthesis shows good results in patients with corneal blindness not amenable to keratoplasty. Nevertheless, the surgeon must be aware of eventual signs of dissolution of the osteodental lamina, making close follow-up mandatory. Because ultrasound biomicroscopy cannot be used in these cases, spiral CT with 3D reconstruction seems to be a good diagnostic alternative.

Adult↗
PubMed2002

Vitreoretinal morphology of plasmin-treated human eyes.

PURPOSE: To investigate the ultrastructure of the vitreoretinal interface following an intravitreal injection of plasmin. METHODS: Plasmin (2 U/0.1 ml) was injected into the vitreous cavity of five postmortem human eyes. The five fellow eyes received phosphate-buffered saline and served as controls. After incubation at 37 degrees C for 30 minutes, the globes were placed in fixative and hemisected. Specimens for scanning and transmission electron microscopy were obtained using a corneal trephine. RESULTS: All plasmin-treated eyes showed complete vitreoretinal separation with sparse collagen fibrils covering the inner limiting membrane. All control eyes showed an attached cortical vitreous. At the vitreous base, there was no cleaving effect. The retinal morphology of plasmin-treated eyes was unchanged. CONCLUSIONS: Plasmin induces a cleavage between the vitreous cortex and the inner limiting membrane without morphologic alteration of the retina.

Aged↗
PubMed2002

Histopathologic findings in explanted osteo-odontokeratoprosthesis.

PURPOSE: To report the histologic findings in three explanted osteo-odontokeratoprosthesis (OOKP) laminae. METHODS: The osteodental lamina of patient 1 with linear IgA bullous dermatosis had to be explanted 15 months after OOKP surgery because of permanent leakage after the resorption of the inferior half of the bone/dentin complex. Patient 2 underwent surgery because of corneal blindness caused by ocular pemphigoid. The remnants of the osteodental lamina were removed after a spontaneous loss of the optic cylinder 30 months after surgery. Patient 3 showed decentration of the optic cylinder 14 years after OOKP surgery was performed because of severe bilateral chemical burn. After intraoperative detachment of the optical cylinder from the broken lamina, the keratoprosthesis had to be completely removed. All specimens were fixed, decalcified using electrolysis, sectioned, and stained with hematoxylin and eosin. RESULTS: All three laminae showed some degree of transformation and resorption of dentin and bone tissue. An inflammatory reaction could be observed in the laminae of patient 1 and 2. Downgrowth of keratinizing squamous epithelium and a reduction of bone tissue and dentin was found in patient 1. Most of the osteodental lamina of patient 2 had been replaced by connective tissue. No signs of acute or chronic inflammation could be found in patient 3. The optical cylinder was surrounded by a thin layer of connective tissue that was enclosed by a layer of woven bone. Dentine was found in just one half of the specimen, adjacent to a partly preserved alveolar-dental ligament. CONCLUSION: No conclusive explanation for the dissolution of the osteodental lamina in some of the patients can be offered at this time, although a few different mechanisms such as epithelial downgrowth and/or localized inflammation seem to play a pivotal role. Conversely, the preservation of the alveolar-dental ligament seems to be essential for the maintenance of the integrity of the OOKP.

Aged↗
PubMed2002

Histopathology of human corneas after amniotic membrane and limbal stem cell transplantation for severe chemical burn.

PURPOSE: To describe the histopathologic changes in the cornea following amniotic membrane transplantation (AMT) combined with limbal transplantation. METHODS: Four eyes with complete limbal stem cell deficiency after severe chemical burn underwent AMT with either a living-related conjunctival limbal allograft (lr-CLAL) (three eyes) or a conjunctival limbal autograft (CLAU) (one eye) for ocular surface reconstruction. Penetrating keratoplasty was performed several months after the initial procedure for further visual rehabilitation. Mean follow up time was 20 months. Light and transmission electron microscopy (TEM) and indirect immunofluorescence microscopy of the excised corneal buttons were performed. RESULTS: All specimens displayed a multilayered epithelium without conjunctival goblet cells over the entire corneal surface. Basal epithelial cells demonstrated a firm connection to the remnants of the transplanted amniotic membrane (AM), which at some places appeared to be in a state of "modification" or "remodeling" in the collagen layers. The basement membrane zone displayed a positive staining when using antibodies against collagen IV and VII, integrin alpha6 and beta4, laminin 5, and bullous pemphigoid antigen 2. Remnants of the AM in the specimen showed staining of collagen IV, which was found also in cross-sections of cryopreserved AM. The recipients Bowman's membranes that were only partially present after the initial trauma were significantly disturbed. CONCLUSION: Within the time frame studied, the transplanted AM apparently survives and integrates into the host tissue being modified or remodeled by recipient cells. AMT in combination with a CLAU or lr-CLAL is a useful technique in promoting a rapid and stable reepithelialization of a corneal surface following severe chemical or thermal damage.

Adolescent↗
PubMedDate not supplied

Corneal sensitivity 10 years after epikeratoplasty.

PURPOSE: To assess corneal sensitivity in patients 10 or more years after epikeratoplasty for myopia, aphakia, hyperopia, and keratoconus. METHODS: A total of 45 eyes of 33 patients (age range at examination 33 to 55 yr) were included in the study. Corneal sensitivity thresholds using an electromagnetic aesthesiometer (Draeger) were measured at various locations on the lenticule and the recipient cornea. Measurements were evaluated regarding the corrective purpose, surgical technique, age, and gender of the patients and the area of measurements. RESULTS: The mean corneal sensitivity threshold in the center of the epikeratoplasty lenticule was significantly lower than on the peripheral recipient cornea (320.0 +/- 365.1 x 10(-5) N versus 0.1 +/- 0.5 x 10(-5) N). Corneal sensitivity at the 3 and 9 o'clock positions was significantly higher compared to the values at the 6 and 12 o'clock positions on the lenticule. No correlations of these values with age, gender, type, and primary indications for the surgery were observed. CONCLUSIONS: These results indicate a relative hypesthesia of the epikeratoplasty lenticule as compared to the peripheral host cornea, even 10 years after surgery. In our patients no clinically significant changes were observed that could be attributed to the reduced sensitivity over this follow-up period.

Adult↗