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Biomedical subjects

W Heider

Publications and source records attributed to W Heider.

At least 19 recordsLinked to original sources
PubMed2004

[Long-term influence of pre-, intra-, and postoperative factors on the intraocular pressure in combined cataract and glaucoma surgery].

PURPOSE: The aim of the study was to evaluate the long-term intraocular pressure (IOP)-lowering effect of combined cataract and glaucoma surgery and the influence of peri- and intraoperative factors upon it. METHOD: In a prospective study 300 eyes received simultaneous phacoemulsification and covered goniotrephination at the same site. Intraoperative factors were monitored. Median follow-up was 24 months (8-45). RESULTS: At the last postoperative control the mean IOP was 15.4 mmHg (14.7 mmHg in pseudoexfoliation glaucoma, n=78). Compared to preoperative values 60.3% had a 20% reduction of IOP to a level below 21 mmHg without eye medication. There was no significant rise in IOP during the follow-up time (8th-45th month). Of no or minimal influence (pmax=0.01) were the intraoperative factors, the IOP at the end of surgery, and postoperative complications (fibrin 6%, choroidal detachment 3.3%, hypotony <7 mmHg 5.5%, and blood beneath the whole bleb 5%). Of significant influence were a long lasting glaucoma ( p=0.003) and the usage of IOP-lowering eyedrops ( p<0.0001). CONCLUSION: Combined cataract and glaucoma surgery is a safe alternative to single glaucoma surgery with similar results. Intraoperative factors have minimal influence on the IOP-lowering effect.

Adult↗
PubMed1997

[Corneal topography after cataract surgery with tunnel incision on a steeper meridian in inverse and oblique astigmatism].

Scleral tunnel incision at the 12 o'clock-position for no-stitch cataract surgery can increase preexisting against-the-rule astigmatism by flattening the vertical corneal meridian. An oblique axis can change by operative induction. We investigated, in a prospective study, whether reduction of such a preoperative astigmatism could be induced by locating the tunnel incision on the steeper meridian. Eighteen eyes with senile cataract and against-the-rule or oblique astigmatism of at least 0.7 diopters were operated with a standardized 5 x 6 mm scleral tunnel incision and a 6 mm PMMA posterior chamber lens. We evaluated the astigmatism with a videokeratoscopy TMS-I preoperatively and about 6 months after the surgery. The mean corneal astigmatism was 1.8 diopters pre- and 1.5 diopters postoperatively. A reduction of keratometric astigmatism was reached in 72% of cases; 17% remained unchanged. The surgically induced astigmatism calculated by Jaffer's and Clayman's vector analysis was 0.68 diopters. The technique of scleral tunnel incision with lateral or oblique approach can reduce a preexisting against-the-rule or oblique astigmatism.

Astigmatism↗
PubMed1996

[Intraocular rt-PA injection in fibrin formation after combined glaucoma and cataract operation].

BACKGROUND: The fibrinolytic drug rt-PA, which has been successfully used systemically to treat arterial and venous occlusions, is now available for local, intraocular injection. rt-PA converts plasminogen to plasmin, which in turn is able to lyse fibrin and fibrin clots. Intraocular surgery, trauma and inflammation may lead to intraocular accumulation of fibrin. Treatment of this type of complication with high-dose corticosteroids is protracted and often unsuccessful. PATIENTS: Eight patients (age 59-75 years) with fibrin formation following phacoemulsification and IOL implantation combined with trabeculectomy were treated by intraocular injection of 10 micrograms rt-PA. The intraocular status following the local fibrinolytic therapy was documented by biomicroscopy, photography and laser-flare Tyndallometry on days 1, 2 and 8. RESULTS: In all patients the fibrin clots dissolved completely. Neither relapses nor adverse affects were noted. CONCLUSIONS: The intraocular application of rt-PA results in an efficient fibrinolytic effect, which prohibits potential complications of combined glaucoma and cataract surgery due to fibrin formation.

Aged↗
PubMed1996

[Imaging (resolution and quantification) of corneal findings with ultrasound biomicroscopy].

Important information on the cornea can be obtained by ultrasound biomicroscopy. Intrastromal corneal scars, internal corneal adaptation after penetrating injuries or keratoplasties, corneal dystrophies and other lesions can be demonstrated. The acoustical examination is in competition with optical methods. It has advantages in opaque optical media and in rarely visible regions as well. The cornea is characterized acoustically by three highly reflective layers (epithelial surface, Bowman's membrane, Descemet's membrane) and two zones that are either not very reflective or are only in the middle range (the thin corneal epithelium without internal differentiation and the stroma) in which pathological structures can be seen.

Cornea↗
PubMed1995

[Long-term stability of astigmatism after suture correction in penetrating keratoplasty].

Severe astigmatism after penetrating keratoplasty is frequently a major problem. If one uses a technique to adjust a single running 10-0 nylon suture in the early period after keratoplasty, the suture tension can be redistributed and astigmatism reduced. Eighteen eyes with an average of 8.8 D of postkeratoplasty astigmatism underwent suture adjustment. The mean keratometric astigmatism before suture removal was 3.1 D. After suture removal with an follow-up of 25 months, the mean corneal astigmatism was 3.2 D, only one eye did the suture break during adjustment. No infection, vascularization or rejection occurred.

Adolescent↗
PubMed1993

[Results of preventive Nd:YAG laser iridotomy of the partner eye in glaucoma].

Recent findings suggest that prophylactic ND:YAG laser iridotomy constitutes a valuable therapeutic alternative for the prevention of acute glaucoma in the unaffected eye of a patient with one glaucomatous eye. In our study we tried to evaluate the effectiveness of this non-surgical treatment. We examined 23 patients between 34 and 89 years of age. The clinical course was documented by the assessment of intraocular pressure and visual acuity, slit-lamp examination and gonioscopy. Throughout the entire follow-up period not a single glaucoma attack occurred. In 20 eyes the intraocular pressure remained normal in the absence of any supportive therapy. There was no change in visual acuity and no synechiae or alterations of the anterior chamber were observed. It therefore seems that prophylactic ND:YAG laser iridotomy is a valuable therapeutic procedure for the prevention of acute glaucoma in the fellow eye of one already found to be affected by glaucoma.

Adult↗
PubMed1991

[Detection of retinal visual field defects by sectorial photic stimulation in scotopic luminance ERG].

We developed an electroretinographic procedure to assess visual field defects due to dysfunction of the outer retinal layers. For this objective we determined the amplitude/intensity function of the scotopic b-wave to full field (100 degrees of visual angle), quadrant and hemifield stimulation in 14 healthy volunteers and in patients with visual field disturbances. To prevent stray light effects, we confined the test light illuminance to 10(1.3) of the extrapolated normal ERG threshold (about 10(4.2) the sensory dark threshold). Whereas patients with dysfunction of the proximal retinal layers or the optic nerve did not show any change when the corresponding visual field was stimulated, those suffering from disturbances of the distal retinal layers (e.g., amotio, chorioretinal diseases) showed a reduction in the amplitude/intensity function, which was related to the extension and the degree of the field losses. The method reveals visual field defects caused by disturbances in the outer retinal layers where one-fourth or more of the corresponding retinal quadrant exhibits a sensitivity loss of more than 15 dB.

Adult↗
PubMed1990

Retinal origin of VECP delays as revealed by simultaneously recorded ERG to patterned stimuli.

Electroretinal and electrocortical potentials evoked by reversing checkerboards (PERG, PVECP) were simultaneously recorded in diseases of the central retina (10 patients) and in tumor-related optic nerve disorders (11 patients) exhibiting comparable P-100 delays in the PVECP. Retinal diseases showed a peak-time delay both in the PERG and in the PVECP, while optic nerve disorders revealed no delay in the PERG. Thus, simultaneous recording of PERG and PVECP may differentiate retinal from postretinal disorders of the visual system. The method also may provide information about the site of an underlying disorder in cases of visual disturbance without obvious changes of the ocular fundus.

Cranial Nerve Neoplasms↗
PubMed1990

Pattern electroretinograms in optic neuritis during the acute stage and after remission.

A total of 20 patients with unilateral acute optic neuritis were studied. Each patient had experienced the recent onset of a decrease in visual acuity, a relative afferent pupillary defect, a relative or absolute central scotoma and a colour-vision defect. The pattern-reversal electroretinogram (PERG) of each patient was analysed with regard to the amplitude of the positive and negative components. During the acute stage the amplitude of the positive component was reduced in all patients and that of the negative, in 18 of 20 cases. Parallel to clinical recovery, a steady increase was observed in the amplitude of the positive component to normal values; no statistical differences between affected and fellow eyes was found. In contrast, the amplitude of the negative component remained significantly reduced after clinical recovery.

Acute Disease↗
PubMed1990

[Retinal diseases as a cause of increased latency in the visual evoked cortical potential].

Retinal and cortical potentials to reversing checkerboard stimuli (P-ERG, P-VECP) were recorded simultaneously in ten patients with disease of the central retina and eleven patients with tumor-related optic nerve changes. While both groups exhibited comparable P100 delays in the P-VECP, delays of the q component in the P-ERG were only observed in the group with retinal disease. Thus, measurement of P-ERG and P-VECP latencies enables retinal to be distinguished from post-retinal disease in cases with visual disturbances where there are no obvious fundus changes.

Electroretinography↗
PubMed1990

[Glare test and bright light vision in cataract patients].

Cataract patients and healthy subjects have been examined with the Miller-Nadler Glare-Tester to prove if the results of the glare test show any correlation between the glare disability score and the outdoor visual acuity facing sun. The outdoor vision of cataract patients with a high glare disability score was clearly impaired compared with their indoor vision. Healthy eyes with a normal glare disability score did not show any impairment of visual acuity facing sun. The results of the glare disability examination can therefore be used as a reference for the decision of a cataract operation.

Adult↗
PubMed1989

Electrophysiology and perimetry in acute retrobulbar neuritis.

Eighteen patients with acute retrobulbar neuritis were examined by visual field analysis and electroophthalmological recordings. The visual fields were measured to 30 degrees with the automatic perimeter Octopus 201. The pattern-evoked cortical potential showed an increased P-100 latency followed by a decrease in 12 patients during the first two weeks of the disease. This latency change cannot be explained by remyelinization. Teh positive component of the pattern ERG (P-50) was reduced in all acutely affected eyes in comparison with the fellow eye. During recovery, the amplitude of the positive PERG component increased to normal, but remained slightly reduced in comparison with the response from the fellow eyes. Thirteen patients out of 18 were clinically and electrophysiologically diagnosed as having unilateral retrobulbar neuritis. However, static perimetry showed paracentral scotomas in the fellow eye in 5 cases. Recovery of the severely affected eye was accompanied by complete normalization of the visual field in the fellow eye. Thus static perimetry seems to be a more sensitive test than even the visual evoked potentials for detecting lesions in the visual pathway.

Adult↗
PubMed1989

Pattern electroretinogram peak times as a clinical means of discriminating retinal from optic nerve disease.

Fifty-two patients with unilateral or bilateral retinal or optic nerve disease exhibited abnormal peak times and/or amplitudes in the pattern electroretinogram. While this abnormality in patients with optic nerve diseases was confined to an amplitude reduction, 40% of the eyes with retinal diseases exhibited additionally a peak time delay of the p and/or q component. We conclude that recording of pattern electroretinogram peak times provides an additional means to distinguish retinal from optic nerve diseases.

Adolescent↗
PubMed1989

[Postoperative recovery of visual function in sella tumors: prognostic assessment by electro-ophthalmologic studies].

Preoperative examination of the visual system in patients with tumors of the sellar region is usually limited to checking the visual acuity, assessing the visual field, and ophthalmoscopy of the optic disc. In addition to these tests we investigated pre- and postoperatively 35 patients with meningiomas, pituitary adenomas and other sellar and parasellar tumors by recording the pattern electroretinogram (PERG) and the pattern-evoked cortical potential (PVECP) in order to evaluate functional and possible structural impairment of the visual pathway. Based on electro-ophthalmological tests, the retinal and cortical findings were classified as: regular ERG and VECP (0), regular ERG and irregular VECP (1), irregular ERG and VECP (2). Up to six months postoperatively, eyes with alteration of the VECP alone (category 1) showed recovery of visual function, while those with alteration of ERG as well (category 2) did not recover in visual function. Since loss of the PERG or long-lasting alteration of it is indicative of irreversible impairment of the inner retinal layers including the retinal ganglion cells, repeat examination of the pattern ERG is recommended in disturbances caused by alterations in the central nervous system.

Adenoma↗
PubMed1989

[Pattern electroretinography and pattern visual evoked potentials in maculopathy: a comparison with sensory tests].

The retinal and cortical potentials for pattern reversal were recorded in 58 eyes of 30 patients afflicted with macular disease. The highest incidence of abnormality (79%) was found for the amplitudes P-ERG and P-VECP. Total field EOG and L-ERG were affected less frequently (41% and 25%). The P-ERG amplitude correlated significantly with the sensitivity of the central 10 degrees visual field (static perimetry). The P-VECP threshold check size showed a close correlation with visual acuity. Thus, the recording of pattern-evoked retinal and cortical potentials serves as a supplementary means of assessing types of maculopathy.

Adolescent↗
PubMed1987

Alteration of visual evoked potentials and electroretinograms in Parkinson's disease.

A group of 24 patients with Parkinson's disease (PD) with normal fundi and normal visual acuities was examined electrophysiologically. Checkerboard reversal VEPs and ERGs (P-ERGs) at various contrast levels as well as photopic and scotopic luminance ERGs were recorded and compared with an age-matched group of controls. Earlier reported latency increases of the VEPs of the patients were confirmed for patterns of high contrast only. Scotopic and photopic luminance ERGs of the patients showed normal latencies, but at all light intensities the amplitudes of the scotopic and photopic b wave, as well as the amplitudes of the photopic a waves, were significantly reduced, P-ERG amplitudes were reduced at 50% contrast. Identical results were obtained in patients under dopaminergic treatment (n = 17) and in patients who did not receive any treatment (n = 7). These results suggest that alterations occur already at the retinal level where dopamine receptors have been found. Thus the reported changes of the VEP are not caused by the visual cortex alone.

Adult↗