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Biomedical subjects

A Gründler

Publications and source records attributed to A Gründler.

7 recordsLinked to original sources
PubMed1997

The full-field flicker test in early diagnosis of chronic open-angle glaucoma.

PURPOSE: To evaluate whether the full-field flicker test, a psychophysical test employing full-field flickering stimuli to measure temporal contrast sensitivity, can detect glaucomatous optic nerve damage in patients with increased intraocular pressure and glaucomatous optic disk abnormalities but normal visual fields. METHODS: Temporal contrast sensitivity was determined with a sinusoidally flickering light (frequency, 37.1 Hz) of constant mean photopic luminance (10 cd/m2) presented in a full-field bowl of 58-cm diameter. The prospective study included three groups of individuals: the "preperimetric" glaucoma group of 80 patients with increased intraocular pressure, glaucomatous optic disk abnormalities, and normal visual fields; the "perimetric" glaucoma group of 56 glaucomatous patients with increased intraocular pressure and glaucomatous changes of the optic disk and visual field; and the control group of 96 normal subjects. RESULTS: Temporal contrast sensitivity was significantly (P < .001) lower in the two glaucoma groups than in the control group. In the preperimetric glaucoma group, 34% of the patients (27/ 80) were recognized by the full-field flicker test at a specificity of 99%. For all study subjects, temporal contrast sensitivity decreased significantly (P < .001) with decreasing neuroretinal rim area, enlarging peripapillary atrophy, and diminishing retinal nerve fiber layer visibility. CONCLUSIONS: The full-field flicker test can detect glaucomatous optic nerve damage in patients with increased intraocular pressure, glaucomatous optic disk abnormalities, and normal visual fields. Considering its feasibility, simplicity, quick performance, and low costs, the full-field flicker test may be helpful in clinics and in screening examinations as a supplement to glaucoma diagnosis.

Adult↗
PubMed1996

Optic disc morphology in "age-related atrophic glaucoma".

BACKGROUND: This study was performed in order to evaluate whether, in primary open-angle glaucoma (POAG), patients with a different degree of fundus tessellation vary in optic disc morphology and level of intraocular pressure. METHODS: Color stereo optic disc photographs of 562 patients with POAG and a myopic refractive error of less than -8 diopters were morphometrically examined. According to the degree of fundus tessellation, the total group was divided into a tessellated subgroup (n = 256) and a nontessellated subgroup (n = 306), both matched for neuroretinal rim area and refractive error. RESULTS: In the tessellated subgroup, as compared to the nontessellated subgroup, the mean maximal intraocular pressure values were significantly lower, the parapapillary atrophy was significantly larger, the optic cup was significantly more shallow, frequency of disc hemorrhages was lower, the mean visual field defect was significantly more marked, and patient age was significantly higher. Within the whole study group, the degree of fundus tessellation increased significantly (P < 0.005) with decreasing mean maximal intraocular pressure, decreasing optic cup depth, and increasing degree of parapapillary atrophy. In the subgroups with the highest degree of fundus tessellation, parapapillary atrophy was the greatest and the mean maximal intraocular pressure was the lowest compared to other subgroups. CONCLUSION: At the low-pressure end of POAG, marked fundus tessellation is associated with large parapapillary atrophy, shallow disc cupping, mostly concentric emaciation of the neuroretinal rim, and high patient age. The results suggest a distinct subtype of POAG in older patients with relatively low intraocular pressure leading to a mainly diffuse atrophy of the optic nerve.

Female↗
PubMed1996

Optic disc morphology in juvenile primary open-angle glaucoma.

BACKGROUND: The aim of the study was to evaluate whether, in primary open-angle glaucoma (POAG), patients younger than 40 years differ in optic disc morphology from patients older than 40 years. METHODS: Out of a total group of 419 patients with POAG, we formed and compared two subgroups, one consisting of 37 patients with an age of less than 40 years, the other composed of 382 patients with an age equal to or more than 40 years. Both subgroups were matched for neuroretinal rim area. We examined the optic disc morphometrically using stereo disc photographs. RESULTS: The younger subgroup, as compared to the older subgroup, showed deeper and steeper optic disc cupping, concentric emaciation of the neuroretinal rim, a significantly smaller area of parapapillary atrophy, and significantly higher maximal and minimal intraocular pressure measurements (P < 0.001). The size and shape of the optic disc and the diameter of the retinal vessels at the optic disc border did not vary significantly. CONCLUSIONS: In POAG, patients younger than 40 years differ in optic disc morphology from patients older than 40 years. The younger patients with POAG have high minimal and maximal intraocular pressure readings and an optic disc morphology with deep and steep cupping, concentric loss of neuroretinal rim, and an almost unremarkable parapapillary atrophy. POAG in patients under 40 represents chronic high-pressure open-angle glaucoma with mainly diffuse optic nerve damage.

Adult↗
PubMed1995

Advanced primary open-angle glaucoma is associated with decreased ophthalmic artery blood-flow velocity.

Recent findings indicate that low-tension glaucoma is associated with impaired ocular blood flow. In the present study we evaluated the blood-flow in the ophthalmic artery in regulated open-angle glaucoma. Using pulsed Doppler sonography (4 MHz), the blood-flow velocity in the ophthalmic artery of 183 eyes of 95 persons with open-angle glaucoma was examined (mean age, 66.6 +/- 14.5 years). The patients showed advanced glaucomatous optic-nerve atrophy (cup-to-disk ratio, 0.74 +/- 0.27) and regulated intraocular pressure (IOP: range, 8-25 mm Hg; mean, 16.4 +/- 3.9 mm Hg). The blood pressure (BP) was 140 +/- 22 (systolic) and 79 +/- 14 mm Hg (diastolic). The control group (84 eyes of 44 persons: mean age, 69.7 +/- 7.7 years; IOP range, 10-22 mm Hg; mean IOP, 15.2-2.6 mm Hg; BP, 143 +/- 20/81 +/- 9 mmHg was matched for age and circulatory risk factors. The vascular resistance index (RIO) was calculated by the equation RIO = (systolic blood velocity-diastolic blood velocity)/systolic blood velocity. We found that the blood velocity in the ophthalmic artery was significantly decreased in glaucomatous eyes in contrast to normal eyes: systolic peak velocity, 36.9 +/- 16.2 cm/s (normal, 40.2 +/- 10.9 cm/s; P < 0.001); diastolic peak velocity 9.9 +/- 4.4 cm/s (normal, 11.7 +/- 4.0 cm/s, P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Regulation of ocular blood flow during increases of arterial blood pressure.

The blood flow in the uvea in cats and monkeys during acute increases of arterial blood pressure is well controlled by a sympathetic mechanism protecting the eye from overperfusion. Ocular macrocirculation (ophthalmic artery) and ocular microcirculation (iris) were examined in 22 healthy subjects during acute increases of arterial blood pressure induced by physical exercise (125 W). With a data acquisition and storage software in real time mode several parameters of ocular perfusion and systemic functions were measured simultaneously. Blood flow parameters were measured in the ophthalmic artery by pulsed Doppler sonography and in the iris by laser Doppler flowmetry. Systolic, diastolic, and mean velocities of the ophthalmic artery peak velocity pulse curve, the ophthalmic artery mean velocity pulse curve, and the iris velocity pulse curve were estimated off line. The ophthalmic artery mean velocity pulse curve resembles the integrated velocity of all erythrocytes in the vessel including the slowly running cells near the vessel wall. The iris velocity pulse curve was calculated by a special statistic procedure (ALDF). After exercise there was a significant increase in systolic and diastolic blood pressure and heart rate. The pulse curve of the ophthalmic artery showed significantly increased systolic and decreased diastolic velocities. The vascular resistance of the branches of the ophthalmic artery increased significantly. The iridal vasculature showed no significant change in blood cell velocity but an increased vascular resistance. It was observed that the elevated perfusion pressure was associated with an increased vascular resistance and a constant mean blood velocity in the ophthalmic artery and iridal vessels. The parallel elevation of vascular resistance and blood pressure during exercise may be the reason for a constant blood flow in the ophthalmic artery and the iris. This may be accounted for by a sympathetic mechanism for protecting the eye from overperfusion.

Adult↗
PubMed1994

Simultaneous measurement of ocular micro- and macrocirculation, intraocular pressure, and systemic functions.

SIMOMIMA (simultaneous measurement of ocular micro- and macrocirculation) is a 32-channel system for display and analysis of biophysical data on ocular perfusion. Using SIMOMIMA in the real-time mode, several parameters of ocular perfusion and systemic functions were simultaneously measured noninvasively and stored during varying periods of measurement; including ocular macroperfusion (pulsed Doppler sonography: ophthalmic artery), ocular microperfusion (laser Doppler flowmetry; iris, ciliary body, choroid), intraocular pressure, cardiac pulse, respiration, and arterial blood pressure. All data were digitalized and stored by a microcomputer for further data processing. With SIMOMIMA in the off-line mode, several parameters of the ocular and systemic circulation may be examined and correlations between them may be calculated, including absolute values for the ophthalmic-artery blood velocity expressed in centimeters per second; the pulse-wave velocity expressed in centimeters per second; relative values for the microcirculatory blood flow of the iris, ciliary body, or choroid; and absolute values for and the time course of the intraocular pressure, heart rate, and respiration rate. In contrast to the ophthalmic-artery pulse curve, the microcirculatory blood flow in the iris showed no obvious synchronization with the ECG or the respiration rate. The blood-cell velocity and the blood content in the iridal meshwork fluctuated with frequencies ranging between 0.5 and 4 Hz. By a special statistical procedure called averaging laser Doppler flowmetry (ALDF), the influence of the pulsations of the arterial blood pressure (diastolic systolic blood pressure) on the iridial blood flow becomes visible.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗