Biomedical subjects

Christoph Hirneiss

Publications and source records attributed to Christoph Hirneiss.

6 recordsLinked to original sources

PubMed2007

Endothelial cell density in donor corneas: a comparison of automatic software programs with manual counting.

PURPOSE: Several automated systems have become available to determine endothelial cell density (ECD) of donor corneas. The purpose of this study was the comparison of 2 systems, the Endothelial Analysis System EAT V1.4 (Rhinetec, Duesseldorf, Germany) and the NAVIS Cell Count Version 3.4.1 (Nidek Technologies, Erlangen, Germany), against manual ECD counts. METHODS: During organ culture, the endothelium of 50 human corneas was photographed on both conventional film and digitally. Manual fixed-frame counting was performed on 2 photographs by 3 experienced ophthalmologists. Three digital pictures of each cornea were analyzed semiautomatically on the Rhinetec EAT system V1.4. Images were imported and analyzed by the fully automatic mode of the NAVIS system V3.4.1 (which also offers a semiautomatic counting mode). In an additional experiment on 11 corneas, the NAVIS counts on the microscopy system previously used only for manual cell counts were directly compared with manual counts. RESULTS: Mean endothelial cell density obtained by manual counting of all observers was 2679 +/- 313 (SD) cells/mm. Values obtained by digital analysis with EAT were a mean of 1.3% higher (2713 +/- 286 cells/mm), which is not a significant difference. In contrast, analysis of the digital pictures with the fully automated NAVIS software mode showed a mean of 7.0% higher measurements (2867 +/- 111 cells/ mm), a significant difference (P = 0.0001). Altman-Bland analysis revealed that the fully automated NAVIS counts gave too low results for high ECDs and too high results for low ECDs. This result was confirmed by the direct comparison with manual counting. CONCLUSIONS: Fully automated analysis of ECD remains problematic. Validation of any computer-assisted system against manual counting is of importance.

Adolescent↗

PubMed2006

Visual quality of life after macular hole surgery: outcome and predictive factors.

BACKGROUND: In the present study we evaluated the functional success after macular hole surgery in correlation to visual quality of life and looked for predictive factors determining surgical success. METHODS: Fifty-nine patients that underwent pars plana vitrectomy for idiopathic macular hole were included. Follow-up visits were performed in regular intervals after surgery and included a clinical examination, optical coherence tomography (OCT) and measurement of visual acuity. To assess the visual quality of life patients filled out the National Eye Institute 25-item Visual Function Questionnaire (VFQ-25) before and three months and one year after surgery. RESULTS: Macular hole closure was achieved in 57 of 59 patients (97%). Mean visual acuity increased from 20/100 preoperatively to 20/34 one year after surgery (p = 0.02). Despite good visual acuity (20/27) in the fellow eye, visual quality of life (VFQ composite score) rose from 75.9 +/- 14.4 (SD) to 81.5 +/- 14.2 one year after surgery (p<0.001). Although there was no correlation between the increase in visual quality of life and visual acuity, the increase in VFQ-25 could be well predicted: low visual acuity and significant impairment on VFQ-25 testing preoperatively made patients most likely to benefit from macular hole surgery. A relatively high retinal thickness measurement at the hole border measured on OCT further increases the predictive value. CONCLUSION: Macular hole surgery is associated with an increase in visual quality of life despite good visual acuity of the fellow eye. Preoperative visual acuity, VFQ-25 value and partly OCT may help to predict the increase in patients' vision related quality of life after surgery.

Aged↗

PubMed2005

Age effect on retina and optic disc normal values.

PURPOSE: To investigate retinal thickness and optic disc parameters by the Retinal Thickness Analyzer (RTA) glaucoma program in older normal subjects and to determine any age effect. METHODS: Subjects over 40 years of age without any prior history of eye diseases were recruited. Only subjects completely normal on clinical ophthalmologic examination and on visual field testing by Humphrey Field Analyzer (HFA) using the SITA 24-2 program were included. A total of 74 eyes from 74 subjects with even age distribution over the decades were enrolled and underwent topographic measurements of the posterior pole and of the optic disc by RTA. The 'glaucoma full' program in software version 4.11B was applied. RESULTS: Mean patient age was 59.9 +/- 10.3 years with a range from 40 to 80 years. The only parameter intraocular pressure (IOP) correlated with was retinal posterior pole asymmetry (r = 0.27, p = 0.02). IOP itself increased significantly with age (r = 0.341, p = 0.003). Mean defect and pattern standard deviation of the HFA did not correlate with any of the retinal or optic disc measurements. Increasing age correlated significantly with some of the morphologic measurements of the RTA: decreasing perifoveal minimum thickness (r = -0.258, p = 0.026), increased cup-to-disc area ratio (r = 0.302, p = 0.016) and increased cup area (r = 0.338 p = 0.007). CONCLUSIONS: An age effect exists for some of the retina and optic disc measurements obtained by the RTA.

Adult↗

PubMed2005

Comparison of prednisolone 1%, rimexolone 1% and ketorolac tromethamine 0.5% after cataract extraction: a prospective, randomized, double-masked study.

PURPOSE: To compare the efficacy, safety and patient comfort of two topical steroids (prednisolone 1% and rimexolone 1%) and a topical non-steroidal anti-inflammatory agent (ketorolac tromethamine 0.5%) after extracapsular cataract extraction. METHODS: Forty-five patients were enrolled in this prospective, randomized, double-blind study. They were assigned to receive topical treatment with either prednisolone, rimexolone or ketorolac tromethamine ophthalmic solution after phacoemulsification for cataract extraction. On postoperative days 1, 3, 5, 14 and 28 best-corrected visual acuity, intraocular pressure (IOP), slit-lamp examination of the anterior segment and report of the patients' comfort were assessed and compared by Friedman rank time analysis. RESULTS: Regarding the primary outcome efficacy of inflammation control the assessment of cells did not differ (p=0.165), while flare in the anterior chamber was lowest (p=0.008) in the non-steroidal anti-inflammatory drug (NSAID) group. Surface inflammation was lowest with prednisolone (p=0.002). Regarding safety, visual acuity did not differ among the groups. In the prednisolone group one patient, however, responded to steroid treatment with elevated IOP and had to be excluded. In the remaining patients IOP was even lower in the two steroidal treatment groups than with ketorolac (p=0.030). One patient receiving ketorolac had to be excluded because a corneal erosion developed. Patient comfort was highest with prednisolone (p=0.041). CONCLUSIONS: Ketorolac tromethamine provides good control of intraocular inflammation after cataract extraction without the risk of a steroidal IOP increase, which was also not observed under rimexolone therapy. The best surface inflammation control and patient comfort was observed with prednisolone, which remains a good choice.

Administration, Topical↗

PubMed2004

TGF-beta2-induced cell surface tissue transglutaminase increases adhesion and migration of RPE cells on fibronectin through the gelatin-binding domain.

PURPOSE: Migration and adhesion of dislocated retinal pigment epithelial (RPE) cells to a fibronectin-rich extracellular matrix is an initial step in proliferative vitreoretinopathy (PVR). In the present study, the functional role of cell surface tissue transglutaminase (tTG) in adhesion and migration of RPE cells on fibronectin (Fn) and collagen type I (Col I) after stimulation with TGF-beta2 was investigated. METHODS: Cultured human RPE cells were treated with 1.0 ng/mL TGF-beta2 for 24 hours. Cell surface tTG expression was determined by cell fraction analysis. Attachment on Col I, full-length Fn, and its 45-kDa gelatin-binding and 110-kDa cell-binding fragment was measured with an MTT assay. Migration of RPE cells was measured by a Boyden chamber assay, and cell spreading was determined. Experiments were performed in the presence or absence of anti-tTG antibodies and anti-integrin alpha5 and beta1 antibodies. RESULTS: TGF-beta2 markedly induced expression of cell-surface tTG on RPE cells and increased attachment and migration on Fn and Col I. Blocking cell surface tTG inhibited attachment, migration, and spreading on Fn and its 45-kDa gelatin-binding fragment, whereas no effect was seen on Col I and the 110-kDa cell-binding Fn fragment. In contrast, blocking of integrin alpha5 and beta1 suppressed adhesion and migration on full-length Fn and the 110-kDa Fn fragment. CONCLUSIONS: These data demonstrate that TGF-beta2 increases expression of cell surface tTG, which in turn strengthens adhesion, migration, and spreading of RPE cells on Fn through the 45-kDa gelatin-binding Fn fragment. At the onset of PVR, this mechanism may help RPE cells to attach and migrate on Fn-containing matrices.

Adolescent↗

PubMed2003

Tele-screening for diabetic retinopathy with the retinal thickness analyzer.

OBJECTIVE: To compare the effectiveness of tele-screening using a novel enhanced retinal thickness analyzer (RTA) with onsite routine ophthalmologic examination for diabetic retinopathy. RESEARCH DESIGN AND METHODS: A consecutive series of 31 eyes from diabetic patients were included. All underwent ophthalmologic examination, including stereoscopic dilated funduscopy and scanning with the RTA. The RTA reports consisted of a wide-angle, red-free fundus photograph and a macular-region retinal thickness map. Reports were graded by three independent graders in a masked manner. The diagnoses of proliferative retinopathy, macular edema, and treatment decisions made by the RTA graders and the clinical examiner were compared. RESULTS: On clinical examination 5 of 31 eyes were diagnosed with proliferative diabetic retinopathy (PDR). All five were referred for treatment by two graders and four eyes by one grader. All eyes with PDR and 12 of the 26 eyes with nonproliferative diabetic retinopathy showed severe macular edema. Seven of the 12 eyes with macular edema were clinically eligible for focal laser treatment, and all of them were detected by all RTA graders. Macular thickening was detected in eight eyes by RTA where no treatment was necessary, as judged by clinical examination. Thus, sensitivity was 93% (mean) for detecting PDR and 100% for detecting macular edema, with a specificity of 58-96% depending on the grader. The RTA did not allow valid assessment due to poor image quality in only one case. CONCLUSIONS: Screening for diabetic retinopathy with a combination of wide-angle fundus photography and macular thickness mapping by an objective method, such as optical coherence tomography or the RTA, offers the prerequisites for establishing a successful tele-screening program.

Aged↗