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Biomedical subjects

H Krastel

Publications and source records attributed to H Krastel.

At least 37 records · Page 2Linked to original sources
PubMed1996

[Sleep modifies anticholinergic mydriasis].

In sleep, the eyelids are closed and the pupils narrow. The pupil width indicates alertness and, if it is narrow, sleepiness. The deeper the sleep, the narrower the pupil: miosis during drowsiness, sleep, sedation and general anesthesia relies on reduced inhibition of the oculomotor nucleus and, even more, on reduced sympathetic tone (it is as sympatholysis that accounts for the miosis exerted by the famous "cocktail lytique" onto an iris whose sphincter is weakened from briskly elevated IOP in angle-closure glaucoma). For whatever reason a lack of sympathetic tone occurs, a poor response to anticholinergic mydriatics will be the consequence. This communication is concerned with children who received tropicamide, cyclopentolate or atropine for diagnostic pupil dilation and cycloplegia but, during subsequent sleep, exhibited an unsatisfactory mydriatic response that could be overcome by additional administration of phenylephrine. Thus, parasympatholytic mydriasis can be proven to be a function of the sympathetic tone. The pupil shrinks during deep sleep even after atropine. If the conditions of deep sleep, sedation or general anesthesia are present and mydriasis needs to be maintained, an additional administration of a sympathomimetic compound is mandatory.

Anesthesia, General↗
PubMed1995

Static fundus perimetry using the scanning laser ophthalmoscope with an automated threshold strategy.

PURPOSE: The purpose of this study was to develop software that allows the performance of routine static threshold perimetry using the scanning laser ophthalmoscope (SLO) and the comparison of the results with conventional computerized cupola perimetry. The original software does not allow performance of static threshold perimetry within a reasonable examination time. METHODS: Static perimetry was performed in random order on 50 healthy eyes using our SLO staircase threshold perimetry technique and the Octopus 500 (program 38). We compared the relative sensitivities for each of 25 corresponding visual field locations. RESULTS: Mean sensitivity in the SLO perimetry amounted to 32.7 dB (range 25-37 dB) while it was 28.7 dB in the Octopus. For all test locations the SLO showed higher dB values on average. The mean difference between both methods was 3.7 +/- 0.8 dB (range 1.4-5.8 dB) when the test locations at the blind spot were excluded (linear regression between the two methods: r = 0.843, P < 0.0001). The mean time interval between two stimulus presentations was 2.5 s with the SLO perimetry. CONCLUSION: With the Heidelberg software, automated static threshold perimetry using the SLO is possible within reasonably short examination times. The mean time interval between two test point presentations is about one tenth of that necessary using the original Rodenstock software. There is a systematic difference between SLO and Octopus fields of about 4 dB which was not very much influenced by the stimulus locations.

Adult↗
PubMed1994

[Coats syndrome in retinitis pigmentosa. Clinical aspects and therapeutic possibilities].

Coats disease itself is a rather rare condition, whereas Coats syndrome has been observed in about 1.2-4.9% of all retinitis pigmentosa (RP) patients. The spectrum of clinical presentations and our therapeutic experience are illustrated with reference to case reports of three patients with clinically and electrophysiologically verified RP and Coats syndrome. As in classic Coats disease, Coats-like changes with RP are defined by aneurysmatic and teleangiectatic vessels and intra- and subretinal lipid deposits leading to exudative retinal detachment. Both entities differ with regard to age of onset, gender, bilaterality and location of the retinal changes. The reports published up to now show that there is no consensus concerning the success of the different treatments of Coats syndrome associated with RP. Laser therapy, cryocoagulation, diathermy and buckling procedures have been suggested for treatment of this complex. As in the therapy of Coats disease, our results confirm that the outcome of laser therapy depends on early detection of Coats-type vascular abnormalities and early initiation of the treatment. Therefore, thorough fundus examination should be regularly performed in all RP patients.

Adolescent↗
PubMed1992

[Early disorders of retinal function in diabetes mellitus].

Thirteen insulin-dependent diabetics, aged 13-30 (mean 19.15) years, entered the study. Patients with retinal ischemia, vascular proliferation, or a Snellen acuity below 0.8 were excluded. Ten normal untrained subjects, aged 20-30 (mean 24) years, provided the normal sample. The battery of special visual function tests consisted of: (1) high luminance Pflüger acuity (acuity/luminance/function, rotatable illiterate "E optotypes, screen luminance 10,000 cd/m2); (2) tests combining color vision with demands on spatial resolution: (a) blue-green chromatic acuity (a Velhagen pseudoisochromatic plate served as optotype, the maximum recognition distance being recorded); (b) standard vs mini-panel D-15 color-arrangement tests; (c) blue preferential computerized perimetry (modified Tübingen automatic perimeter, orange adaptive illumination, Schott cut-off filter OG 550, cupola luminance 5 cd/m2).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[Krypton laser therapy. Use in secondary serous detachment of the retinal pigment epithelium and in multiple idiopathic serous detachments of the retinal pigment epithelium].

Two variants of serious detachments of the retinal pigment epithelium (RPE) are demonstrated with reports of typical cases: (1) secondary serous detachment of the RPE; (2) idiopathic serous detachment of the RPE (pigment epithelium detachment not associated with any other retinal or choroidal disease). Fluorescein angiographic criteria for differential diagnosis and the resulting different techniques of krypton laser coagulation are portrayed: (a) focal krypton laser coagulation of the total area of the pigment epithelium detachment; (b) circular, one-row laser coagulation at the detachment borders. The advantages of circular, one-row laser coagulation of idiopathic serous RPE detachment over coagulation of the total area of the RPE detachment are described: first, these are fewer scotomas following coagulation; second, fewer laser foci are required; and third, the risk of subretinal bleeding is lower. These findings emphasize the efficiency of circular, one-row laser coagulation at the detachment borders in the treatment of idiopathic serous RPE detachments.

Adult↗
PubMed1992

Low-dose methotrexate treatment in noninfectious uveitis resistant to corticosteroids.

A total of 14 patients (10 women and 4 men) ranging in age from 18 to 56 years who presented with active chronic noninfectious uveitis were treated with low-dose methotrexate (MTX). All patients had failed to respond to previous systemic corticosteroid therapy. MTX therapy was initiated in 8 patients at a dose of 40 mg given intravenously once weekly for 4 weeks followed by 15 mg/week given orally; 6 subjects were started on the oral regimen of 15 mg/week. During a follow-up period of 3-24 months, intraocular inflammation improved in all subjects under immunosuppressive therapy with MTX. A concomitant improvement in visual acuity was observed in 11 patients. Side effects included slight elevations in transaminases in 4 patients, transient mucositis in 1 case, partial alopecia in 2 subjects, and nausea in 3 patients. Our initial results suggest that low-dose MTX therapy may be considered as a therapeutic modality in noninfectious, steroid-refractory uveitis.

Administration, Oral↗
PubMed1991

Electrophysiology and colour perimetry in dominant infantile optic atrophy.

A typical finding in dominant infantile optic atrophy (DIOA) is the variation of the phenotypic expression of the DIOA gene even within one family. It is of special interest for genetic consultation to evaluate an examination method for detecting subclinically involved patients. Seven patients of two families were examined. Three of them had the typical symptoms of DIOA: reduced visual acuity, tritan defect, temporal pallor of both optic discs, and a relative central scotoma for white test spots. In visual evoked cortical potentials (VECP) the amplitudes were reduced, and in one patient the latencies were slightly delayed and two patients considerably so. The amplitude of the negative component of the PERG was markedly reduced, while the positive component was normal. In the remaining four family members normal retinal and cortical responses were recorded under standard conditions and visual fields and colour vision (FM 100 hue) were also normal. However, static perimetry with blue test spots showed in two family members enlarged central scotomas, thus proving that they had subclinical DIOA.

Adolescent↗
PubMed1991

Congenital glaucoma in cutis marmorata teleangiectatica congenita.

A case of congenital glaucoma in cutis marmorata teleangiectatica congenita (CMTC, van Lohuizen syndrome) is described. The cutaneous anomaly and heterochromia iridium were noticed at birth. Brown discoloration of one iris was due to iris anterior layer dysplasia, resulting in unilateral glaucoma. Two trabeculotomies were performed until persistent normalization of intraocular pressure could be achieved. The possibility of a genetic basis and hereditary condition of CMTC and its association with congenital glaucoma is discussed. Patients with CMTC should regularly undergo ophthalmological follow-up to rule out development of glaucoma.

Female↗
PubMed1991

[Uveitis: occurrence in rheumatic diseases and immunosuppressive therapy].

In 13/53 patients with uveitis an associated rheumatic condition was found. An infectious etiology could be assumed in 3/53 cases. Methotrexate was used in noninfectious uveitis in 11/53 cases, who were refractory to high doses of systemic steroids: all improved, 5 patients achieved complete remission.

Adult↗
PubMed1990

Ocular digitalis effects in normal subjects.

Several visual functions were examined before and during self-application of therapeutic doses of digitoxin. The ERG recordings showed a reduction of the critical flicker fusion frequency from 70 Hz to 35-40 Hz. Recovery of color vision after macular photostress was examined with Nagel's anomaloscope and Jaeger's tritanomaloscope. After digitoxin intake the matching range at the tritanomaloscope was enlarged. Following macular photostress the recovery time of both the Rayleigh and the Trendelenburg matches was significantly prolonged. The mesoptometer readings did not show any changes during the application of digitalis. This demonstrates that the process of neural adaptation is intact during digitoxin therapy. The error score in the Lanthony desaturated 15 panel test was slightly increased after digitalis application. The Farnsworth-Munsell 100-hue test showed a marked increase in the total error score. There were no changes in the standard panel D-15. The Ishihara pseudoisochromatic plates were read without mistakes after digitalis medication. The chromatic visual acuity for red-green and blue was examined by recording the maximum reading distance for the Velhagen pseudoisochromatic plates "65" (Jaeger's test) and "49". For both plates the reading distance was reduced by 50% during digitoxin therapy. Computerized perimetry by colored stimuli (Tübingen Automatic Perimeter by Aulhorn and Durst) did not reveal any definitive changes in sensitivity thresholds with therapeutic serum levels of digitalis. Spectral increment sensitivity for the isolated blue cone system (Wald-Marré approach) was not influenced by therapeutic doses of digitoxin. Topical digitoxin application (0.02 mg/10 ml) did not interfere with the pupillary light reflex (infrared pupillography) or with the accommodative amplitude or intraocular pressure. It did, however, result in toxic keratopathy with swelling of endothelial cells and edema of the corneal stroma and epithelium. All changes disappeared after withdrawal of digitalis.

Accommodation, Ocular↗
PubMed1989

[Cerebral achromatopsia (symptoms, course, differential diagnosis and examination strategy). II].

To the patient, the sudden onset of cerebral achromatopsia is like switching to black and white on a color TV. As a rule, the defect arises due to bilateral ischemic infarction in the inferior occipitotemporal region. Bilateral upper homonymous quadrantanopsias usually leave the macula more or less unimpaired, so that visual acuity is largely preserved. Prosopagnosia and loss of topographic memory are often associated with central achromatopsia. Investigations of color vision must include color-naming procedures and large-field tests in addition to the conventional methods. Color-naming tasks are indispensable in differentiating cerebral achromatopsia from the aphasic and disconnective types of color anomia. The authors' recommended strategy for investigating color vision relies on records of a case of cerebral achromatopsia obtained six months and two years, respectively, after the onset of symptoms. In addition to the above-mentioned procedures, spectral increment thresholds on white and colored backgrounds were determined. For the first time in cerebral achromatopsia, examinations with large-field spectral matches were performed using the projection anomaloscope. Large-field tests are indispensable for monitoring recovery in cases of central achromatopsia. In the author's patient, recovery of blue-green discrimination was far more complete than that of red-yellow-green discrimination, and for both conditions large-field color vision was far superior to small-field.

Anomia↗
PubMed1989

[Pupillographic perimetry using the "Octopus"].

The Octopus 2000 computerized perimeter (Interzeag, Schlieren, Switzerland) is combined with an infrared videopupillograph (Demel, Haan, FRG) which at the same time records the direct pupil light response and controls fixation. Digital processing of the pupil video image is performed at a rate of 25 cps. A transient oscilloscope display of the pupil surface after each light stimulus covers the subsequent 1000 ms, so that either pupillary light reflexes or the lack of a response can immediately be identified. An additional continuous penwriter printout shows light stimuli, pupil responses and the subject's responses. Thus, potential discrepancies between the pupil response and the subject's response are clearly revealed. The examination conditions slightly deviate from the standard ones used with the Octopus. Stimulus size is analogous to the target Goldmann/V, the stimulus duration 100 ms and the adaptive illumination 1 cd/m2. Pupil fatigue considerably exceeds visual fatigue. Therefore standard Octopus perimetric programs are inconvenient for pupilloperimetric purposes. A Sargon-based pupilloperimetric program determines pupillomotor increment thresholds at 12 stimulus locations throughout the visual field (20 degrees nasal, 0 degrees, 20 degrees and 40 degrees temporal/15 degrees above the 0 degrees meridian, 0 degrees meridian and 15 degrees below the 0 degrees meridian) while applying the normal Octopus strategy of threshold calculation. Instead of the patient's subjective responses, the examiner's assessment of pupil responses provides the basis for threshold determination by the Octopus program. The subjects are unaware of the mode of examination. Their rating of "seen" or "not seen" ist displayed together with the pupil responses, thus providing a hard copy as proof of malingering or of appropriate cooperation.

Computer Systems↗
PubMed1988

[Side effects of external ophthalmologic drugs].

43 patients with suspected adverse reactions to ophthalmic medicaments were tested using three different methods: normal patch test on back skin (ENH), patch test on stripped back skin (HSA) and on scarified skin of the forearm (SKT). The ENH was positive in only 9 patients (20.0%) with one of the used preparations whereas on stripped skin positive reactions were observed in another 14 patients (32.6%). The SKT was solely positive in 10 patients (23.7%). Clinical relevance of these test results has been ascertained in most cases. However, reactions on stripped skin as well as on scarified skin may be false positive. The antibiotics neomycin and gentamicin were the major allergens (13.9% and 9.3%). Some ophthalmic medicaments produced rather severe irritant reactions on scarified skin, confirmed by a positive conjunctival exposure test. In order to detect weak sensitizations or cumulative irritant reactions in patients with long term use of eye medicaments, the application of a method with increased sensitivity such as the patch test on stripped skin or the scarification technique is recommended.

Adult↗
PubMed1988

[Cerebral achromatopsia (symptoms, course, differential diagnosis and strategy of the study). I].

To the patient, the sudden onset of cerebral achromatopsia is like switching to black and white on a color TV. As a rule, the defect arises due to bilateral ischemic infarction in the inferior occipitotemporal region. Bilateral upper homonymous quadrantanopsias usually leave the macula more or less unimpaired, so that visual acuity is largely preserved. Prosopagnosia and loss of topographic memory are often associated with central achromatopsia. Investigations of color vision must include color-naming procedures and largefield tests in addition to the conventional methods. Color-naming tasks are indispensable in differentiating cerebral achromatopsia from the aphasic and disconnective types of color anomia. The authors' recommended strategy for investigating color vision relies on records of a case of cerebral achromatopsia obtained six months and two years, respectively, after the onset of symptoms. In addition to the above-mentioned procedures, spectral increment thresholds on white and colored backgrounds were determined. For the first time in cerebral achromatopsia, examinations with large-field spectral matches were performed using the projection anomaloscope. Large-field tests are indispensable for monitoring recovery in cases of central achromatopsia. In the author's patient, recovery of blue-green discrimination was far more complete than that of red-yellow-green discrimination, and for both conditions large-field color vision was far superior to small-field.

Aged↗