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Biomedical subjects

W D Ulrich

Publications and source records attributed to W D Ulrich.

At least 19 recordsLinked to original sources
PubMed1996

Detection of disturbed autoregulation of the peripapillary choroid in primary open angle glaucoma.

BACKGROUND AND OBJECTIVE: This study is concerned with perfusion-pressure videoangiographic investigations, performed by combining oculo-oscillo-dynamography and videoangiography. Perfusion-pressure videoangiography permits an evaluation of local vascular resistance in the choroid relative to ciliary perfusion pressure. PATIENTS AND METHODS: Twelve healthy subjects, 21 patients with primary open angle glaucoma (POAG), and 27 patients with ocular hypertension were examined. RESULTS: Perfusion-pressure videoangiograms revealed that the peripapillary choroid (nasal main ciliary artery) filled at distinctly lower perfusion pressures than the paramacular region (temporal main ciliary artery) in all 12 healthy subjects, with a perfusion pressure difference of 12.5 +/- 4.9 mm Hg. In the 21 patients with POAG, the perfusion pressure difference between the beginning of peripapillary and paramacular perfusion was as small as 3.7 +/- 4.5 mm Hg. In the 27 patients with ocular hypertension, the perfusion pressure difference between the two circulatory regions was almost as high as in the healthy subjects. CONCLUSIONS: These examinations showed that (1) there exists efficient autoregulation in the peripapillary choroids of healthy subjects, (2) autoregulation is diminished or even absent in POAG, and (3) autoregulation is normal, increased, or slightly reduced in ocular hypertension.

Adolescent↗
PubMed1994

Influence of suction cup oculopression on corneal astigmatism.

In 11 (right) eyes of 11 ocularly healthy subjects an artificial stepwise intraocular pressure (IOP) elevation was applied by suction cup oculopression. The initial negative pressure in the suction cup was 80 mmHg; it was raised in steps of 40 mmHg. The median of the corneal astigmatism, measured with a Zeiss ophthalmometer, was 0.50 D before oculopression (the values of the 10th and 90th percentiles were 0.30 and 1.10 D, respectively). Corneal astigmatism increased to 2.00 (0.00-5.10) D, 2.25 (1.00-5.55) D, 2.63 (0.63-7.00) D, 3.38 (1.88-6.88) D, 3.38 (2.83-7.25) D, and 4.38 (2.85-5.63) D with 80, 120, 160, 200, 240, and 280 mmHg oculopression, respectively. The astigmatism dropped to 0.75 (0.00-2.30) D immediately after removal of the suction cup. Thus, suction cup oculopression not only influenced IOP but also ocular refraction. This is of particular importance since visual evoked potential (VEP) amplitude is to a high degree dependent on refractive changes. This fact has to be considered if changes in VEP amplitude during suction cup oculopression are used as a tolerance test in glaucoma diagnosis.

Adult↗
PubMed1994

[Effect of change in refraction by increasing intraocular pressure with the suction cup method on pattern reversal VECP].

When IOP is increased by the suction cup method, refraction changes will occur, depending on the shape of the cup and the height of the IOP increase. Similar refraction changes were simulated in six healthy volunteers by employing spherical and cylindrical glasses during pattern-reversal visual evoked cortical potential (VECP) with various check sizes and amount of contrast. While the pattern-reversal VECP latencies were not influenced, the amplitudes were reduced considerably. By using contact lenses and a suitably shaped suction cup, refraction changes could be compensated for. In 22 healthy volunteers pattern-reversal VECPs were derived with and without the application of contact lenses with artificially raised IOP. A comparison showed that the amplitudes differed significantly. Without contact lenses a negative pressure of more than 40 mmHg resulted in a drop in the amplitudes with a plateau formed between 80 and 120 mmHg. With compensation by contact lenses the amplitudes are found to be unaltered or even slightly increased until a negative pressure of 120 mmHg is reached in the suction cup, after which they drop. Plotting the pattern-reversal VECP amplitudes (obtained with refraction changes being compensated for by contact lenses) against ciliary perfusion pressure, one finds the characteristic curve described by Ulrich et al., suggesting an autoregulative capacity between 15 and 20 mmHg in healthy persons. The latencies, which remain uninfluenced by refraction changes, are also not altered within an IOP increase of 15-20 mmHg.

Adult↗
PubMed1993

Refraction changes during elevation of intraocular pressure by suction cup, their reflection in the pattern visual evoked cortical potential and their compensation.

Visual evoked cortical potential studies using pattern stimuli with the intraocular pressure raised artificially by the suction cup method have been reported. Possible changes in the refraction of the eye due to the method employed and their influence on the pattern visual evoked cortical potential have not been considered. Changes in the refraction of the eye during artificial intraocular pressure elevation and the influence of such changes on pattern visual evoked cortical potentials were studied. The refraction changes were found to depend on the shape of the suction cup. They could be compensated for by employing properly shaped suction cups and contact lenses. The behavior of amplitude and latency of the pattern visual evoked cortical potential at artificially elevated intraocular pressure with compensation for refraction changes has been studied and found to depend in a characteristic manner on ocular perfusion pressure.

Adult↗
PubMed1993

[Eye-pressure tonometry in prevention of glaucoma].

Oculo-pression tonometry (OPT) was introduced in 1984 as a clinical method of examining ocular hydrodynamics. The method involves measuring intraocular pressure (IOP) by applanation tonometry performed before, during and after application of a pressure load that disturbs the dynamic balance between aqueous production and aqueous outflow. From the IOP before (P0) and immediately after (Pr0) the 8-min pressure load period, the outflow facility C(u) can be calculated: [formula: see text] The examinations performed so far have shown that (1) reduced outflow facility can be detected by OPT with a high degree of reliability, and (2) reduced outflow facility is always preceded by the development of glaucoma damage to the optic nerve head. A prospective study has shown that in the group of patients with reduced outflow facility but without glaucoma damage, 73% developed glaucoma damage with typical changes of the papilla and visual field within 3-7 years after the first examination.

Equipment Design↗
PubMed1993

[Disordered peripapillary microcirculation in glaucoma patients].

To study the haemodynamics of the peripapillary choroid, perfusion pressure videoangiography (PVA) was performed in six healthy subjects and in seven patients with primary open-angle glaucoma (poag). In healthy subjects the peripapillary part of the choroid starts filling at distinctly lower ocular perfusion pressures than other parts of the choroid. The mean difference in perfusion pressure between peripapillary and perimacular filling was 13.6 mmHg in the six healthy subjects. A different filling pattern of the choroid was found in the seven glaucoma patients. The mean difference in perfusion pressure between the beginning of peripapillary and the beginning of perimacular perfusion of the choroid was found to be as small as 1.9 mmHg. That the filling of the peripapillary choroid observed by PVA in healthy subjects is found to start at lower perfusion pressures than in the other parts is explained by autoregulative dilatation of the peripapillary choroidal arterioles resulting from artificially raised intraocular pressure during the PVA examination. In the poag patients the peripapillary choroidal arterioles were dilated either insufficiently or not at all. The following conclusions are drawn: (1) The peripapillary choroid of healthy persons shows effective autoregulation securing the blood supply to the prelaminar part of the optic nerve. (2) In poag the peripapillary choroid has lost the capability of effective autoregulation.

Adult↗
PubMed1992

Pr VECPs related to ciliary perfusion pressure in primary open angle glaucoma. A study using contact lenses to compensate for refraction changes during artificially raised IOP.

Pr VECP studies in glaucoma patients with the IOP raised artificially by the suction cup method have recently been performed by several authors, who arrived at different results. The reason for those differences may be the changes employed. The refraction changes depend on the shape of the suction cup and the height of the artificial IOP raise. By using contact lenses and a suitably shaped suction cup refraction changes could be compensated for. Studies of the pr VECP with suction cup IOP elevation and simultaneous compensation for refraction changes by applying contact lenses were made on 17 patients with primary open angle glaucoma and 21 healthy volunteers. In healthy subjects pr VECP amplitudes were found unaltered or even slightly increased until 120 mmHg of negative pressure were reached in the cup. Beyond that range they dropped. Latencies remained unaltered over that range of negative pressures. Plotting the pr VECP amplitudes and latencies against ciliary perfusion pressure we obtained unaltered potentials over a range of ca. 20 mmHg, which we interpreted as autoregulative capacity. In the 17 glaucoma patients various degrees of impaired autoregulation were found corresponding to the progression of glaucoma damage.

Adult↗
PubMed1992

[White-noise field campimetry before and after artificial increase of intraocular pressure. Possible applications in diagnosis and evaluation of glaucoma].

A total of 173 eyes (visual field defect stages O-V) of 99 glaucoma patients were investigated by means of conventional threshold-oriented suprathreshold automated test point perimetry using the Tübingen Automatic Perimeter (TAP) and by means of white-noise-field campimetry (flickering random dot pattern) using the Tübingen Electronic Campimeter (TEC). Most eyes were affected by primary open-angle glaucoma (119) or low tension glaucoma (35). The concordance between the two methods was good in 65 eyes (37.6%). Sufficient in 32 (18.5%) eyes, poor in 32 cases (18.5%) and inadequate in 44 eyes (25.4%). Among the last group of 44 eyes, 32 perceived a scotoma in the noise field (NF) but did not show any pathologic defect in conventional automated test point perimetry: the opposite constellation was found in only 12 eyes. In most cases, scotoma in the NF showed a change in both brightness and motion (noise) perception. No clear relationship between the type of glaucoma and a certain constellation of the aforementioned NF specifications could be found. Complete lack of noise perception in the scotoma occurred more frequently in advanced glaucoma (stage > or = IV). In 110 eyes of 63 of the glaucoma patients, white-noise-field campimetry was carried out during artificial IOP elevation achieved by suction-cup oculopression: during steplike increases of the negative pressure in the suction-cup up to maximum of 375 mmHg the following stages could be seen (the percentage of eyes that perceived each phenomena over the negative pressure range is shown in brackets): change in NF perception compared with initial findings (96.4%); impairment of central noise-field perception (78.2%); concentric constriction of NF (61.8%); complete breakdown of noise (field) perception (42.7%). A further, quantitative classification of these eyes was possible by evaluation of the negative pressure in the suction-cup that led to any one of these NF phenomena. The results demonstrate the usefulness of white-noise-field campimetry as a very fast screening method for detecting glaucomatous visual field defects. It can also be performed as a pressure tolerance test and thus be used to classify glaucomatous risk stages.

Adolescent↗
PubMed1991

[Hemodynamic aspects of retinitis pigmentosa].

While retinal vascular attenuation is a typical finding in retinitis pigmentosa (RP), studies on changes in choroidal vasculature have yielded contradictory results. In 44 patients with RP the relative pulse blood volumes were measured, and perfusion pressure videoangiography (PVA) was performed in 7 of them. Follow-up examinations were performed in 14 of the patients between 1.5 and 6 years later. The results show that the choroidal circulation is considerably reduced in RP patients; it was found to be further reduced at the follow-up examinations. PVA shows atrophy of the choroid capillary network. Characteristic changes occur not only in the retinal but also in the choroidal circulation, depending on the form, duration (stage) and prognosis of the disease.

Adolescent↗
PubMed1990

[Birdshot retinochoroidopathy. Case report].

The clinical findings and results of perfusion-pressure videoangiography (PVA) are described in a 50-year old patient suffering from birdshot retinochoroidopathy. PVA according to Ulrich and Ulrich makes it possible to observe the gradual filling of the retinal and choroidal vessels relative to ocular perfusion pressure. The patient's PVA reveals that the fluorescein penetrates the vessel wall in the interstitial tissue in the region of the large choroidal arterioles close to the entry of the short posterior ciliary arteries in the eye. This occurs long before the blood flow has reached the choriocapillaries, i.e., at distinctly lower perfusion pressures than are necessary for filling the leaking choroidal capillaries. The leakage of fluoresceine from the large choroidal arterioles explains the typical birdshot pattern of the fundus.

Blood Pressure↗
PubMed1990

[Functional diagnosis in follow-up of temporal arteritis treatment].

Fourteen patients (28 eyes) suffering from histologically confirmed temporal arteritis were examined with oculo-oscillodynamography (OODG) according to Ulrich and Ulrich as well as with orbital dynamography (ODG) according to Hager. These examinations were performed before and during prednisolone treatment. When ocular and orbital vessels are involved, temporal arteritis will result in a strong reduction of the ocular and orbital pulse blood volumes. Ocular perfusion pressures may also be reduced. In all 28 eyes of the 14 patients, OODG showed the ocular pulse blood volumes to be significantly reduced, while with ODG the ocular pulse blood volumes appeared to be within the normal range in 50% of the cases. Therefore, OODG is more reliable than ODG in the diagnosis of temporal arteritis. When performed during prednisolone treatment, OODG is a very sensitive indicator of successful or unsuccessful therapy. OODG permits an early detection of relapses and helps to avoid their sequelae. Since OODG can be repeated as often as desired and can be performed within a short time, it is very suitable for controlling the management of temporal arteritis.

Aged↗
PubMed1988

[Temporal arteritis--diagnosis and therapeutic control].

33 patients suffering from temporal arteriitis (Morbus Horton) were investigated noninvasively by Oculo-Oscillo-Dynamography (OODG), Orbita-Dynamography (ODG) and Temporalis-Dynamography (TDG). The ocular, orbital and temporal oscillograms and oscillodynamograms revealed characteristic and unmistakable alterations; i.e., striking reduction of the pulse volumes and a decrease of the blood pressures in the respective circulatory regions as a result of a stenosing and occluding vascular process. The 3 methods yielded typical patterns of the occluding process, which led to the conclusion that in untreated persons the stenosing process of the arteritis cranialis tends to start in the vascular branches of the external carotid artery and subsequently includes branches of the internal carotid system, such as the ophthalmic artery. High doses of prednisolone resulted in reopening of the vessels that had been stenosed and occluded by arteritis, and in most cases restored normal circulation in the regions examined within several weeks or months. From the investigations made on 66 eyes of the 33 patients, the authors conclude that combined use of OODG, ODG, and TDG makes it possible to diagnose temporal arteritis with a high degree of certainty. In all 33 cases the disease was diagnosed with OODG, ODG and TDG and confirmed histologically. Since the OODG, ODG, TDG examinations are well tolerated by the patient and can be repeated at any time, it is suggested to employ them for the supervision of therapy as well to detect any possible relapse of the inflammatory occluding vascular process.

Dose-Response Relationship, Drug↗
PubMed1987

[Oculopression tonometry (OPT): a new tonographic procedure in the diagnosis of glaucoma].

OPT is a new tonographic procedure permitting easy and reproducible examination of the regulative IOP behavior and the detection of impaired hydrodynamics as an early sign of glaucoma. OPT avoids errors associated with conventional tonographic procedures, takes measurements in IOP ranges where better separation between healthy and glaucoma eyes may be expected, performs simultaneous examination of both eyes, and permits IOP measurement by applanation tonometry in all phases of the examination process. OPT is easier to perform, is better tolerated by the patient and only takes half as long as conventional tonography. The effectiveness of the new procedure is demonstrated by the results of examinations of 253 eyes.

Glaucoma↗
PubMed1986

Deficient autoregulation and lengthening of the diffusion distance in the anterior optic nerve circulation in glaucoma: an electro-encephalo-dynamographic investigation.

Electro-encephalo-dynamographic investigations taken from 36 glaucoma patients showed that the autoregulative mechanism in the region of the anterior part of the optic nerve (apon) is disturbed and the ciliary perfusion pressure is altered in a characteristic manner. The results lead to the conclusion that glaucomatous ischemia occurring in the apon may mainly be due to the following causes and their combinations: high IOP; low blood pressure in the ciliary arterial circulation; insufficiency of autoregulation, and changes of the local conditions of diffusion of oxygen and nutrients.

Adult↗
PubMed1986

Relationship between ciliary perfusion pressure and pattern-reversal visual evoked cortical potentials: an electro-encephalo-dynamographic investigation.

Pattern-reversal visual evoked cortical potentials (VECP) taken from 25 healthy volunteers before, during and after short-lasting elevation of intraocular pressure proved to be dependent on ciliary perfusion pressure (pp cil) in a characteristic way. Reductions of pp cil to ca. 30 mm Hg did not result in VECP changes. These results point to efficient autoregulation in the retinal circulation and in the circulatory region of the anterior part of the optic nerve. When pp cil was reduced to below 30 mm Hg a marked reduction of VECP amplitudes and prolongation of latencies were observed. An autoregulatory capacity of about 15 mm Hg was found.

Blood Circulation↗