Biomedical subjects

C Hirneiss

Publications and source records attributed to C Hirneiss.

8 recordsLinked to original sources

PubMed2006

Cost utility for penetrating keratoplasty in patients with poor binocular vision.

PURPOSE: Cost-utility and cost-effectiveness analyses are of increasing importance to clinicians and health policy experts. This study determines the costs in Germany and other countries in relation to gain of utility for patients with bilateral poor vision owing to corneal disease undergoing penetrating keratoplasty (PK) in 1 eye. DESIGN: A cost-utility analysis was performed using retrospective clinical data and high-level evidence-based data. PARTICIPANTS: Sixty patients (mean age, 46.3 years) with bilateral poor vision who underwent PK for corneal disease. METHODS: Visual acuity and utility values were obtained before and 1 year after PK and after suture removal. A 10-year graft survival rate of 80% was assumed. Expenses included costs for the corneal transplant and surgery, medication, and optical rehabilitation. A discount rate of 5% was applied for costs and quality-adjusted life years (QALYs). Cost-utility analysis encompassed a 10-year period after surgery. MAIN OUTCOME MEASURES: The number of QALYs was calculated for the study group undergoing PK. This was divided into the cost of the procedure to get the number of euros spent per QALY gained. RESULTS: Median binocular preoperative visual acuity was -log mean angle of resolution (-logMAR) 0.91+/-0.53 (Snellen equivalent 20/160) yielding a utility value of 0.67. After suture removal and optical rehabilitation, binocular visual acuity increased to median -logMAR 0.36+/-0.36 (20/46) with a utility value of 0.79. Over the 10 years after surgery and considering graft survival and discounting, a cost utility of 9551 euros per QALY was gained (equivalent to US11,557 dollars). One-way sensitivity analysis yielded a range from 7706 euros to 12874 euros per QALY, highlighting the robustness of the model. CONCLUSIONS: Although an expensive procedure, PK is cost effective in patients with bilateral poor vision.

Adolescent↗

PubMed2006

[Visual quality of life after vitreoretinal surgery for epiretinal membranes].

PURPOSE: To date, the increase of visual acuity and morphological parameters have been used to assess the benefit of a surgical intervention. The aim of this prospective study was to evaluate changes in patients' visual quality of life due to vitreoretinal surgery for epiretinal membranes. PATIENTS AND METHODS: Twenty patients with unilateral epiretinal membrane and good visual acuity of the fellow eye were included. Best corrected visual acuity and visual quality of life assessed by the visual function index (VF-14) were obtained preoperatively and 3 months after pars plana vitrectomy and peeling. RESULTS: Median visual acuity increased from 0.28 to 0.4 postoperatively. Visual quality of life (VF-14 values) rose from 72.8+/-4.7 (SEM) to 83.3+/-2.9 (p<0.05). Analysis revealed that patients with preoperatively low VF-14 values and preoperatively low visual acuity notably profited from surgery. The increase of visual quality of life can be predicted better than increase of visual acuity. Combined cataract surgery had no significant influence. CONCLUSION: In addition to best corrected visual acuity, quality of life measurements are important predictive and outcome parameters to estimate the value of vitreoretinal surgery.

Aged↗

PubMed2006

[Value-based medicine in ophthalmology].

PURPOSE: Value-based medicine (VBM) unifies costs and patient-perceived value (improvement in quality of life, length of life, or both) of an intervention. Value-based ophthalmology is of increasing importance for decisions in eye care. METHODS: The methods of VBM are explained and definitions for a specific terminology in this field are given. The cost-utility analysis as part of health care economic analyses is explained. RESULTS: VBM exceeds evidence-based medicine by incorporating parameters of cost and benefits from an ophthalmological intervention. The benefit of the intervention is defined as an increase or maintenance of visual quality of life and can be determined by utility analysis. The time trade-off method is valid and reliable for utility analysis. The resources expended for the value gained in VBM are measured with cost-utility analysis in terms of cost per quality-adjusted life years gained (euros/QALY). Numerous cost-utility analyses of different ophthalmological interventions have been published. CONCLUSION: The fundamental instrument of VBM is cost-utility analysis. The results in cost per QALY allow estimation of cost effectiveness of an ophthalmological intervention. Using the time trade-off method for utility analysis allows the comparison of ophthalmological cost-utility analyses with those of other medical interventions. VBM is important for individual medical decision making and for general health care.

Consumer Behavior↗

PubMed2005

[Evaluation of portable TGDc-01 tonometers and comparison with the Goldmann applanation tonometer].

PURPOSE: The aim of this study was to evaluate patients' acceptance and intraocular pressure (IOP) readings of a new digital mobile tonometer (TGDc-01) and compare it to Goldmann applanation tonometry. METHOD: Measurements repeated five times with the TGDc-01 and three times with Goldmann tonometry were performed in 100 eyes of 100 patients by two independent investigators. Patients' acceptance of both techniques was evaluated by a visual analogue scale (VAS). RESULTS: The mean IOP with the TGDc-01 yielded 15.4 mmHg for investigator 1 and 12.7 mmHg for investigator 2 (range: 4-43 mmHg). Results of the measurements with Goldmann tonometry showed 17.6 mmHg for investigator 1 and 17.3 mmHg for investigator 2 (9-42 mmHg). The IOP difference of the two tonometry methods was highly significant (p<0.001). The intraobserver variability was 29% for investigator 1 and 8% for investigator 2. Mean IOP values of the two investigators taken with the TGDc-01 differed significantly (p<0.01) from each other by a mean of 2.6 mmHg. CONCLUSIONS: The new mobile tonometer TGDc-01 is better accepted by patients but IOP values are significantly lower compared to Goldmann tonometry and variability is high. Regarding glaucoma diagnostics it seems to be less suitable than Goldmann tonometry.

Adult↗

PubMed2005

[Ocular changes in tropical malaria with cerebral involvement--results from the Blantyre Malaria Project].

INTRODUCTION: Malaria is a tropical disease causing an estimated 300 million infections and one million deaths per year. In sub-Saharan Africa, most infections are due to Plasmodium falciparum. The hallmark of the clinical syndrome of cerebral malaria is coma, and the associated mortality rate, even in appropriately treated patients, is 15 - 50 %. Funduscopy plays a major role for the ophthalmologist in the differential diagnosis because of the characteristic changes. METHODS: To date more than 1000 children who satisfied the standard clinical case definition of cerebral malaria were admitted to the Blantyre Malaria Project (Malawi, Africa) for inpatient treatment and examined using indirect ophthalmoscopy through fully dilated pupils. The gender distribution was homogeneous and the children were between 2 and 14 years old. The optic nerve head, central and peripheral retina and central and peripheral vessels were described and photographed using a hand-held fundus camera (KOWA). RESULTS: The spectrum and severity of findings of the ocular fundus in children with CM include the following distinct entities: haemorrhages (with and without a white centre), cotton wool spots, papilloedema, retinal whitening and retinal vessel abnormalities that may appear to be orange or white. Most of the retinal haemorrhages (in 40 %) have white centres and resemble Roth spots. Cotton wool spots were seen in only 5 %. Papilloedema was also not commonly seen (8 %) but is a poor prognostic sign. Retinal whitening (in 50 %) is seen more commonly at the posterior pole than in the periphery. 20 % of patients show retinal vessel abnormalities that may be orange or white in colour. CONCLUSION: Ocular fundus changes in CM can be detected by the ophthalmologist using simple means and are decisive for the prognosis and timely therapy for this potentially lethal disease.

Adolescent↗

PubMed2003

[Measuring patient's quality of life in ophthalmology].

BACKGROUND: The assessment of patient's quality of life is not only of vital importance for clinical trials of new therapies but also becomes more and more implemented into daily clinical therapeutical decisions. METHODS: Different methods for evaluating quality of life are available. A well-known questionnaire for measuring global quality of life is the Short Form 36 (SF 36). However, in ophthalmology more specific instruments for measuring visual quality of life are needed. We review the usefulness of specific questionnaires such as the Visual Function 14 (VF-14) or the National Eye Institute Visual Function Questionnaire (NEI-VFQ) in their application to common ophthalmologic diseases such as cataract, age-related macular degeneration and glaucoma. Studies applying these methods were identified by a search in the Medline database. RESULTS: Several instruments to measure visual life quality in ophthalmologic patients are available. Internal consistency and validity are shown. CONCLUSIONS: Evaluating visual quality of life is an important parameter for assessing ophthalmologic diseases and the value of different therapies. It is an important outcome variable in clinical studies. Furthermore, individual visual quality of life should be considered in individual therapeutic decisions and helps to assess the economic effect of current and new therapies.

Aged↗

PubMed2000

Mechanisms of NO/cGMP-dependent vasorelaxation.

Both cGMP-dependent and -independent mechanisms have been implicated in the regulation of vascular tone by NO. We analyzed acetylcholine (ACh)- and NO-induced relaxation in pressurized small arteries and aortic rings from wild-type (wt) and cGMP kinase I-deficient (cGKI(-/-)) mice. Low concentrations of NO and ACh decreased the spontaneous myogenic tone in wt but not in cGKI(-/-) arteries. However, contractions of cGKI(-/-) arteries and aortic rings were reduced by high concentrations (10 micromol/L) of 2-(N:, N-diethylamino)-diazenolate-2-oxide (DEA-NO). Iberiotoxin, a specific blocker of Ca(2+)-activated K(+) (BK(Ca)) channels, only partially prevented the relaxation induced by DEA-NO or ACh in pressurized vessels and aortic rings. DEA-NO increased the activity of BK(Ca) channels only in vascular smooth muscle cells isolated from wt cGKI(+/+) mice. These results suggest that low physiological concentrations of NO decrease vascular tone through activation of cGKI, whereas high concentrations of DEA-NO relax vascular smooth muscle independent of cGKI and BK(Ca). NO-stimulated, cGKI-independent relaxation was antagonized by the inhibition of soluble guanylyl cyclase or cAMP kinase (cAK). DEA-NO increased cGMP to levels that are sufficient to activate cAK. cAMP-dependent relaxation was unperturbed in cGKI(-/-) vessels. In conclusion, low concentrations of NO relax vessels by activation of cGKI, whereas in the absence of cGKI, NO can relax small and large vessels by cGMP-dependent activation of cAK.

Acetylcholine↗

PubMed1998

Defective smooth muscle regulation in cGMP kinase I-deficient mice.

Regulation of smooth muscle contractility is essential for many important biological processes such as tissue perfusion, cardiovascular haemostasis and gastrointestinal motility. While an increase in calcium initiates smooth muscle contraction, relaxation can be induced by cGMP or cAMP. cGMP-dependent protein kinase I (cGKI) has been suggested as a major mediator of the relaxant effects of both nucleotides. To study the biological role of cGKI and its postulated cross-activation by cAMP, we inactivated the gene coding for cGKI in mice. Loss of cGKI abolishes nitric oxide (NO)/cGMP-dependent relaxation of smooth muscle, resulting in severe vascular and intestinal dysfunctions. However, cGKI-deficient smooth muscle responded normally to cAMP, indicating that cAMP and cGMP signal via independent pathways, with cGKI being the specific mediator of the NO/cGMP effects in murine smooth muscle.

Animals↗