Biomedical subjects

G Grütters

Publications and source records attributed to G Grütters.

6 recordsLinked to original sources

PubMed2003

[Impairment of safety in navigation caused by alcohol: impact on visual function].

BACKGROUND: So far in Germany, no legally binding standards for blood alcohol concentration exist that prove an impairment of navigability. The aim of our interdisciplinary project was to obtain data in order to identify critical blood alcohol limits. In this context the visual system seems to be of decisive importance. MATERIALS AND METHODS: 21 professional skippers underwent realistic navigational demands soberly and alcoholized in a sea traffic simulator. The following parameters were considered: visual acuity, stereopsis, color vision, and accommodation. RESULTS: Under the influence of alcohol (average blood alcohol concentration: 1.08 per thousand ) each skipper considered himself to be completely capable of navigating. While simulations were running, all of the skippers made nautical mistakes or underestimated dangerous situations. Severe impairment in visual acuity or binocular function were not observed. Accommodation decreased by an average of 18% ( p=0.0001). In the test of color vision skippers made more mistakes ( p=0.017) and the time needed for this test was prolonged ( p=0.004). CONCLUSIONS: Changes in visual function as well as vegetative and psychological reactions could be the cause of mistakes and alcohol should therefore be regarded as a severe risk factor for security in sea navigation.

Accidents↗

PubMed2003

[Impairment of safety in navigation caused by alcohol: pupillography and measurement of pupil movements].

OBJECTIVE: To evaluate data in an interdisciplinary project (ophthalmology, forensic medicine, internal medicine, psychology,and nautical science) in order to identify critical blood alcohol limits in sea navigation. METHODS: A sea traffic simulator was employed for realistic nautical demands on 21 professional experienced skippers under sober and alcoholized conditions (target blood alcohol concentration: 1.0 per thousand ). After simulated navigation, pupil light reflex, spontaneous pupil movements,nystagmus,and saccades were evaluated by pupillography. Modification of the pupillograph enabled us also to measure optokinetic nystagmus. RESULTS: Evaluation of the pupil light reflex revealed obvious changes in the extent of relative contraction and in redilatation time under the influence of alcohol. Diminished vigilance could be observed in all of the skippers when optokinetic nystagmus was tested. CONCLUSION: The pupillograph represents a suitable device for measuring functions of the visual and vegetative systems. Thus, the impact of these functions on nautical capability can be demonstrated. If further investigations such as ophthalmological, medical, psychological, and nautical evaluations are taken into account, it could be determined that blood alcohol levels of 1.0 per thousand may exclude safe navigation.

Accidents↗

PubMed2002

[Alcohol-induced morphologic and biochemical corneal changes].

In our cornea bank, it was noticed that corneas from donors with alcoholism seemed to be of lower quality than corneas from other donors. High blood ethanol concentrations can induce high alcohol concentrations in aqueous and vitreous humor. This could be demonstrated in the case of a lethal alcohol intoxication. We conducted in vitro experiments to clarify the question of alcohol-induced changes of corneas. The corneas were stored in a standardized culture medium including ethanol, formic acid, methanol, and acetaldehyde in concentrations to be expected in chronic alcoholism. During cultivation over 4 weeks, endothelial morphology and extent of aspartic acid racemization in stromal proteins were evaluated. The extent of aspartic acid racemization served as a biochemical parameter of alcohol-induced protein changes of the corneas. In the in vitro experiments, a drop in the endothelial cell counts could be seen in corneas stored in culture medium with acetaldehyde. The extent of aspartic acid racemization increases in corneas stored in medium containing ethanol, which obviously is the result of alcohol-induced protein degradation. High concentrations of ethanol and its metabolics can be detected in vitreous and aqueous humor in chronic alcoholism. Clearly, these concentrations have a direct toxic effect on the corneal endothelium (acetaldehyde) and on the stromal proteins (ethanol).

Acetaldehyde↗

PubMed2001

[Postmortem evaluation of corneal astigmatism after astigmatism oriented penetrating keratoplasty].

BACKGROUND: Reduction of astigmatism following penetrating keratoplasty can be achieved if the graft is oriented according to astigmatism parameters in donor and host (AOPKP). Postmortem evaluation of these parameters is therefore essential. The aim of our investigation was to compare postmortem measurements using a hand-held keratometer with those of the living donor's astigmatism. METHOD: The 72-year-old female patient had undergone AOPKP on her right eye. After death the astigmatism in the right eye was evaluated 4.5 h postmortem using a hand-held keratometer. After explantation, the eyeball was examined by computer-assisted topography (TMS-1). RESULTS/CONCLUSION: We could show that hand keratometry in situ is reliable for evaluating astigmatism in donor eyes after death. As far as our AOPKP study is concerned, these results are of great interest. Reduction of postoperative astigmatism following penetrating keratoplasty is only possible if data on astigmatism of the donor and host corneas are available.

Aged↗

PubMed2001

[Astigmatism-oriented perforating keratoplasty. A possibility for minimizing postoperative astigmatism?].

BACKGROUND: This pilot study examined whether astigmatism of donor corneas can be evaluated postmortem, and whether there is an effect on the astigmatism following keratoplasty. METHODS: The corneoscleral rims of donors were marked after measurement by a hand keratometer in the 12 o'clock position. We examined 38 patients after penetrating keratoplasty and divided them into three groups. The 12 o'clock position of the donor cornea was fixed in the same position as the recipient (group A, n = 12), or the donor corneas were transplanted with the axis in opposition to the axis of the recipient (group B, n = 12) or in the same orientation (group C, n = 14). Development of postoperative astigmatism was compared with controls (group D, n = 40). RESULTS: In group B we found a new orientation of the astigmatism axis within 2-4 months; in group C the axis maintained the original orientation of the recipient. Mean postoperative astigmatism was 3.5 +/- 1.5 dpt in group A, 2.1 +/- 1.3 dpt in group B, 5.8 +/- 1.6 dpt in group C, and 3.4 +/- 1.5 dpt in group D. After suture removal the axis orientation persisted in all groups. CONCLUSION: This study shows the possibility of evaluating corneal astigmatism in donor eyes. The astigmatism of the donor cornea itself directly influences the postoperative axis of astigmatism in recipient eyes. Astigmatism after corneal grafting can be reduced by orienting the donor astigmatism against the axis of the recipient.

Adult↗

PubMed2000

[Wound or suture insufficiency complicating penetrating keratoplasty].

BACKGROUND: With regard to penetrating keratoplasty methods to culture corneal donor tissues, microsurgical techniques, HLA typing and understanding of basic mechanisms in inflammation and especially graft rejection, and postoperative treatment schedules have been improved in recent years. This now enables successful penetrating keratoplasty in many more patients than previously performed. However, in rare cases relevant problems in wound closure may appear. PATIENTS AND METHODS: A standardized treatment protocol was applied to 1,253 penetrating keratoplasties performed in a single center. Patients were continuously followed up. Simple leakage after corneal grafting was not further analyzed if conservative treatment or additional sutures achieved sufficient wound closure. In 21 cases, however, the causes of large wound dehiscence after corneal grafting were analyzed. RESULTS: During the first week early problems in suturing penetrating keratoplasty in five patients were associated with the instability of the recipients' corneal stroma (stromal thinning in keratoconus or corneal herpes, suture problems in keratomalacia, active herpes keratitis, corneal burns, or rheumatic diseases). Long-term complications in 16 patients were associated with alcoholism, herpes keratitis, rheumatic disorders or traumatic suture defects. Overall, nine patients lost functionally or even anatomically one eye because of wound dehiscence after corneal grafting. CONCLUSIONS: When penetrating keratoplasty is indicated, special attention should be given to (1) the compliance of the patient, (2) sufficient treatment of herpes keratitis or other infections, (3) adequate immunosuppression in autoimmune corneal inflammation, (4) double running continuous sutures as primary suture with sometimes additional single sutures to stabilize the graft, and (5) surgery in time.

Adolescent↗