PubMed Health⌕ Search

Biomedical subjects

O Arend

Publications and source records attributed to O Arend.

At least 19 recordsLinked to original sources
PubMed2003

Colour Doppler imaging and fluorescein filling defects of the optic disc in normal tension glaucoma.

AIM: To investigate the relation between blood flow parameters of the retrobulbar vessels measured by means of colour Doppler imaging (CDI) and fluorescein filling defects of the optic nerve head in patients with normal tension glaucoma (NTG) and control subjects. METHODS: 29 patients with NTG and 29 age and sex matched control subjects were included in this study. Blood flow velocities-peak systolic velocity (PSV), end diastolic velocity (EDV), and resistive indices (RI) of the ophthalmic artery (OA), the central retinal artery (CRA), and of the temporal and nasal short posterior ciliary arteries (TPCA, NPCA)-were measured with CDI. Fluorescein angiograms were performed with a scanning laser ophthalmoscope. The extent of absolute fluorescein filling defects of the optic nerve head in relation to the optic nerve head was assessed. RESULTS: The PSV of the OA, the PSV and EDV of the CRA, and of the TPCA and NPCA were significantly reduced in NTG (p<0.05). The RI of the CRA, the TPCA and NPCA were significantly increased in NTG (p<0.01). The optic nerve head fluorescein filling defects were significantly larger in NTG (p<0.01). The filling defects were significantly negatively correlated (p<0.05) with the PSV and EDV of the CRA (PSV(CRA): r = -0.41; EDV(CRA): r = -0.34), with the PSV and EDV of the NPCA (PSV(NPCA): r = -0.34; EDV(NPCA): r = -0.38), and with the EDV of the TPCA (r = -0.29). A significant positive correlation (p<0.05) was found with the RI of both PCAs (RI(NPCA): r = 0.28; RI(TPCA): r = 0.29). CONCLUSION: Patients with NTG had reduced blood flow velocities and higher resistive indices in most retrobulbar vessels. Optic nerve head fluorescein filling defects were larger compared to controls. The filling defects were correlated with end diastolic velocities and resistive indices of the PCAs and with blood flow velocities of the CRA. Capillary loss of the optic nerve head may be related to higher downstream resistance and reduced blood flow velocities of the retrobulbar vessels.

Blood Flow Velocity↗
PubMed2002

Capillary density and retinal diameter measurements and their impact on altered retinal circulation in glaucoma: a digital fluorescein angiographic study.

AIM: Normal pressure glaucoma (NPG) patients exhibit prolonged retinal arteriovenous passage times in fluorescein angiography and colour Doppler imaging suggests increased resistance downstream from the central retinal and posterior ciliary arteries. The aim of the study was to elucidate the morphological source of decreased perfusion and increased resistance of the ocular circulation in NPG. METHODS: Retinal arteriovenous passage time (AVP) and peripapillary arterial and venous diameters were measured in digital scanning laser fluorescein angiograms. For estimation of retinal capillary density the area of the foveal avascular zone (FAZ) and the perifoveal intercapillary area (PIA) was quantified. 36 patients with NPG (mean age 57 (SD 13) years) and 21 healthy subjects (mean age 51 (13) years) were enrolled in the comparative study. RESULTS: In NPG patients the AVP (2.55 (1.1) seconds) was significantly prolonged (p<0.001) when compared with healthy subject data (AVP: 1.70 (0.39) seconds). No differences for arterial or venous diameter, FAZ, and PIA were observed in NPG patients compared with healthy subjects. FAZ, PIA, arterial and venous diameter were not correlated with visual field indices (except venous diameter with PSD, r=0.35 (p<0.05)) or cup to disc ratios. AVP was significantly correlated (p<0.05) with the size of the optic nerve head (r=-0.28), visual field indices (MD: r=-0.3; PSD: r=0.3; CPSD: r=0.3), and contrast sensitivity (r=-0.34). CONCLUSION: AVP times are significantly prolonged in NPG. The slowing of the retinal transit does not result from capillary dropout, or changes of peripapillary arterial or venous diameters with increased vascular resistance.

Blood Flow Velocity↗
PubMed2001

[Absolute filling defects of the optic disc in fluorescein angiograms in glaucoma--a retrospective clinical study].

BACKGROUND: Analysis of clinical importance of the size of filling defects in fluorescein angiograms in primary open-angle glaucoma (POAG), normal-tension glaucoma (NTG), ocular hypertension and subjects with physiological excavations in comparison to visual field loss, optic nerve head morphology and hemodynamics. PATIENTS AND METHODS: 75 patients (POAG, NTG, ocular hypertension) and 10 healthy subjects with physiological excavations were included in this study. In digitized video fluorescein angiograms (Scanning Laser Ophthalmoscope) the size of absolute filling defects of the optic disc was quantified in the early venous phase and expressed by percentage of the optic disc. Visual fields were obtained by conventional static perimetry (Humphrey 24-2) and graded in stages of glaucoma visual field defects (Aulhorn I-V). Optic disc excavations were evaluated as cup-to-disc-area-ratios. RESULTS: The filling defects correlated with the visual-field loss stages of Aulhorn and the visual field indices MD (mean deviation), PSD (pattern standard deviation) and CPSD (corrected pattern standard deviation). There was no correlation with the index SF (short-term fluctuation) and with systemic hemodynamics (blood pressure, perfusion pressure) or the IOP. Absolute filling defects correlated with the cup-to-disc-area-ratio in NTG. The absolute filling defects were larger in patients with glaucoma (POAG, NTG) in comparison to patients without glaucomatous visual field loss (ocular hypertension, glaucoma-like discs). No difference of filling defects was found in the glaucoma group (POAG, NTG). Patients with NTG had larger excavations and lower systolic blood pressures than patients with POAG. CONCLUSION: The size of fluorescein filling defects may be useful as a parameter for the evaluation of an ischemic lesion of the optic nerve head. Absolute filling defects may differentiate POAG from ocular hypertension and NTG from glaucoma-like discs without field defects. The results support the hypothesis that in POAG and NTG disturbances of the circulation result in similar filling defects of the optic disc and visual field loss.

Adult↗
PubMed2001

Short wavelength automated perimetry in age related maculopathy.

BACKGROUND/AIMS: Previous studies reported the predictive value of the short wavelength sensitive (SWS) cone mediated sensitivity for visual outcome in age related macular degeneration. In this study SWS sensitivity was measured by commercially available blue on yellow perimetry in patients with non-exudative age related maculopathy (ARM) and compared with the presence of morphological risk factors and the status of the fellow eye. METHODS: In a prospective cross sectional study, 126 patients (57 males, 69 females, mean age 71 (SD 6) years) with ARM (visual acuity >20/50) were tested. Central visual fields (blue on yellow) were obtained with a conventional perimeter. Fundus slides were graded by two independent observers for soft drusen and presence of focal hyperpigmentation. RESULTS: Mean sensitivity and standard deviation of all patients exhibited a significant reduction with age. Patients with soft drusen had significantly lower sensitivity than those without, whereas there were no differences in visual acuity (log MAR). Sensitivity was also reduced in those eyes with fellow eyes having a sight threatening complication of age related macular degeneration (AMD). Eyes with focal hyperpigmentation compared with those without had no loss of sensitivity, but did have a significant decrease in the central part of the field compared with the more eccentric. CONCLUSION: SWS sensitivity loss is associated with common risk factors for progression to AMD. Short wavelength automated perimetry is moderately rapid and readily available. It may serve as a tool in future ARM trials.

Aged↗
PubMed2000

[Intra-individual variability of blue-yellow perimetry].

BACKGROUND: Short wavelength automated perimetry (SWAP) is a sensitive method in detection of early glaucomatous damage. In this study, we compared intra-subject variability of global indices of SWAP and conventional white-on-white perimetry (WWP) in normal clinical conditions (without correction for lens yellowing). METHODS: SWAP and WWP (Humphrey field analyzer, 24-2 field, full threshold strategy) was performed in 68 eyes with glaucoma or glaucoma suspect and at the same day. The tests were repeated within 45 days (mean follow-up 16 +/- 13 days). RESULTS: At the follow-up test the mean defect was significantly reduced for both conditions, more pronounced for SWAP. Pattern standard deviation remained statistically equal for both conditions. The coefficient of correlation of baseline to follow-up was for SWAP PSD 0.88 with a slope of 1.05, for WWP PSD 0.7 with a slope of 0.83. The coefficient of variation for PSD was 17% for SWAP and 34% for WWP. CONCLUSIONS: The low intraindividual variability of SWAP enables early detection of glaucomatous field damage in the follow-up.

Adult↗
PubMed2000

[Corneal transplantation and glaucoma].

BACKGROUND: Recent studies have shown that increased intraocular pressure following keratoplasty may cause progressive endothelial cell loss and thereby lead to early transplant failure. This study examined risk groups for development of postoperative glaucoma and thereby transplant failure. MATERIAL AND METHODS: Seventy-five patients with various diagnoses were followed up prospectively for 2, 4, 6, 12, 24, 36, 48, and 60 months. RESULTS: Of the 75 patients 22 showed elevated intraocular pressure after keratoplasty. One-third of these (n = 7) developed a chronic secondary glaucoma. The main risk factor was a preexisting glaucoma (P < 0.05, c2 test), followed by aphakia, especially if aphakia was present before keratoplasty. Three of the six patients with anterior synechia had increased intraocular pressure. Because of the small number of patients neither factors reached statistical significance. CONCLUSION: Intraocular pressure should be closely monitored especially in high-risk patients, although its measurement may not be exact by Schiötz and Goldmann tonometry. Digital impression and controls of the visual field should be carried out additionally.

Corneal Transplantation↗
PubMed2000

A comparative study of betaxolol and dorzolamide effect on ocular circulation in normal-tension glaucoma patients.

OBJECTIVE: To determine whether dosages of a selective beta-blocking agent (betaxolol) and a topical carbonic anhydrase inhibitor (dorzolamide), sufficient to significantly lower intraocular pressure (IOP), have similar or disparate impact on the retinal and retrobulbar circulation. DESIGN: Counterbalanced crossover, with open-label use of medications. PARTICIPANTS: Nine persons with normal-tension glaucoma (NTG). INTERVENTION: After a 3-week drug washout, NTG patients were studied after 1 month of treatment with either dorzolamide or betaxolol, with determinations of IOP and retinal and retrobulbar hemodynamics. MAIN OUTCOME MEASURES: At baseline and after treatment with each drug, retinal arteriovenous passage time was determined by scanning laser ophthalmoscopy after fluorescein dye injection, and flow velocities in the central retinal and ophthalmic arteries were measured with color Doppler ultrasonography imaging. RESULTS: Betaxolol and dorzolamide each lowered IOP significantly, with these changes apparent and maximal after 2 weeks (each P < 0.05). In contrast, dorzolamide (but not betaxolol) accelerated arteriovenous passage of fluorescein dye in the inferior temporal quadrant of the retina (P < 0.05). Neither drug affected arteriovenous passage in the superotemporal retina or any aspect of central retinal or ophthalmic artery flow velocity after either 2 or 4 weeks. CONCLUSIONS: Although both dorzolamide and betaxolol are effective ocular hypotensive agents and their topical instillation leaves retrobulbar hemodynamics unaltered, dorzolamide alone accelerates inferotemporal retinal dye transit.

Adrenergic beta-Antagonists↗
PubMed2000

[Clinical experiences with the "Swedish interactive threshold algorithm" (SITA)].

BACKGROUND: The "Swedish Interactive Threshold Algorithm" (SITA) is a new technique minimizing test time without reduction of data quality. In this retrospective study we compared visual fields assessed with the conventional full-threshold technique with those by SITA and analyzed qualitative and quantitative differences and the test time reduction of SITA. PATIENTS AND METHODS: 113 eyes with different glaucomatous field damage of 66 patients aged from 22 to 89 years were included. The patients underwent perimetry with each strategy within four months. Exclusion criteria were eyes with progressing glaucomatous damage and high rate of false-positive results or artifacts by corrective glasses. RESULTS: The qualitative differences of the analysis were small: full threshold demonstrated more relative scotomas in eyes with normal SITA readings, whereas scotomas assessed with SITA were often pronounced to absolute scotomas. Average time reduction by SITA was 40% and depended on the severity of glaucomatous stage. No reduction was found for advanced glaucoma, whereas normal fields using SITA were performed in half of the time of full threshold strategy. CONCLUSION: Differences of SITA to conventional full threshold testing may be related to fatigue effects of full threshold strategy due to longer test time. The reduction of test time enables more motivation for more frequent visual field examinations and thus a better detection of early glaucoma or progressing visual field damage.

Adult↗
PubMed2000

Macular circulation in patients with diabetes mellitus with and without arterial hypertension.

BACKGROUND: Previous fluorescein angiographic studies have shown alterations in the macular microcirculation in patients with diabetes mellitus and arterial hypertension. In both diseases capillary blood velocity was reduced and capillary density decreased. These changes were more pronounced in diabetic patients. We have examined the influence of arterial hypertension in combination with diabetes mellitus. METHODS: 62 patients with diabetes mellitus and arterial hypertension (group 1) were matched with patients with diabetes mellitus but without arterial hypertension (group 2, match criteria: ETDRS stage of retinopathy). In all subjects fluorescein angiograms were performed with a scanning laser ophthalmoscope. Macular capillary blood velocity (CBV), perifoveal intercapillary area (PIA), the coefficient of variation of both parameters, the area of the foveal avascular zone (FAZ), and the arteriovenous passage time (AVP) were assessed by digital image analysis. RESULTS: Systolic and diastolic blood pressures were significantly increased in the patients with arterial hypertension (systolic p=0.0008; diastolic p=0.03). Neither dynamic measures (AVP: 1.64 (0.49) seconds (group 1), 1.72 (0.58) seconds (group 2); CBV: 1.98 (0.39) mm/s (group 1), 2.09 (0.43) mm/s (group 2)) nor morphological measures (PIA: 7985 (3137) microm(2) (group 1), 8338 (3376) microm(2) (group 2); FAZ: 0.319 (0.206) mm(2) (group 1), 0.363 (0.237) mm(2) (group 2)) were significantly different between the two groups of diabetic patients. CONCLUSION: Arterial hypertension did not result in more severe macular capillary dropout than diabetes without hypertension. This might be explained by the fact that most of the patients were being treated with antihypertensive drugs.

Adult↗
PubMed2000

Altitudinal visual field asymmetry is coupled with altered retinal circulation in patients with normal pressure glaucoma.

AIM: To compare the effect of altitudinal asymmetric glaucomatous damage on retinal microcirculation in patients with normal pressure glaucoma (NPG). METHODS: In a prospective cross sectional study patients with NPG (washed out for antiglaucomatous therapy) and altitudinal asymmetric perimetric findings between the superior and inferior hemisphere (Humphrey 24-2) (n=18) were included and compared with 20 NPG patients with symmetrical field defects and 18 healthy subjects. Fluorescein angiograms were performed using a scanning laser ophthalmoscope. Using digital image analysis, arteriovenous passage time (AVP) and vessel diameters were assessed for comparison of corresponding affected and less affected temporal arcades. RESULTS: Both affected and less affected hemispheres showed significantly prolonged AVP times (p<0.001) when compared with healthy subject data. In hemispheres with more severe glaucomatous field loss the AVP times were significantly (p=0.04) prolonged compared with the less affected hemisphere (AVP affected 3.1 (SD 7) seconds v AVP less affected 2.61 (1.4) seconds). There was no asymmetry effect on arterial and venous diameter measurements. CONCLUSION: Altitudinal visual field defects are linked together with circulatory deficits of the retinal tissue. The attenuated circulation seems to be a considerable factor in the natural course of glaucomatous optic neuropathy.

Cross-Sectional Studies↗
PubMed2000

Single isolated cotton-wool spots.

The presence of isolated cotton-wool spots in normal fundi may indicate serious systemic disease. In this presentation 4 patients were examined for blurred vision or scotomas with sudden onset. Two of them were pregnant. Funduscopic examination revealed soft-appearing white spots in the temporal arcades in 3 patients and in the papillomacular bundle in 1 patient. Due to the lack of other fundus lesions 3 of the patients were initially treated for toxoplasmosis. The patients were seronegative for typical viral (HIV), antinuclear antibodies, bacterial infections, or toxoplasmosis. Blood pressures, glycosylated hemoglobin and blood counts were in the normal range. At the follow-up examinations subjective symptoms had improved and the spots disappeared or were smaller and showed more distinct borders, and no new lesions were detected. These cases suggest that isolated cotton-wool spots may occur without serious systemic disease in otherwise healthy subjects and the spots may be misinterpreted as acute inflammatory retinochoroidal lesions.

Adult↗
PubMed2000

Short-wavelength automated perimetry and capillary density in early diabetic maculopathy.

PURPOSE: To correlate short-wavelength cone-mediated sensitivity (SWS) assessed by blue-on-yellow perimetry with alterations of the perifoveal vascular bed in early diabetic maculopathy. METHODS: Thirty-one patients (21 M, 10 F; mean age, 35 +/- 12 years; no lens opacities) with no clinically significant macular edema were included in this study. All patients underwent short-wavelength automated perimetry (SWAP) and conventional white-on-white perimetry (Humphrey, 10-2). In digitized video fluorescein angiograms (Scanning Laser Ophthalmoscope), the size of the foveal avascular zone (FAZ) and the mean perifoveal intercapillary area (PIA) as a measure of capillary density were quantified interactively. RESULTS: Mean thresholds of SWAP were significantly correlated with increasing size of FAZ (r = -0.51, P = 0.003) and PIA (r = -0.47, P = 0.01), whereas visual acuity expressed by log MAR (FAZ: r = 0.15, P = 0.41; PIA: r = 0.06, P = 0.76) and mean thresholds assessed with white-on-white perimetry (FAZ: r = -0.25, P = 0.20; PIA: r = -0.31, P = 0.14) were unrelated to diabetic changes of the perifoveal capillary network. CONCLUSIONS: The alterations of the perifoveal network are related to selective disturbances of visual function as measured by blue-on-yellow-perimetry. SWAP may act as an early detector of visual function loss in early diabetic maculopathy and serve as a helpful technique to predict early ischemic damage of the macula and to monitor therapy.

Adult↗
PubMed1999

[Retinal hemodynamics in patients with normal pressure glaucoma. Quantification with digital laser scanning fluorescein angiography].

UNLABELLED: Chronic ischemia of the retina and the optic nerve head seems of importance especially in patients with normal-tension glaucoma (NTG). The purpose of this study was to examine the retinal hemodynamics in patients with NTG. PATIENTS: Twenty-five patients with NTG were examined (3 weeks washout period) in this study (age 58 +/- 16 years). The arteriovenous passage (AVP) time and arterial and venous diameters from scanning laser fluorescein angiograms were evaluated by means of digital image analysis. RESULTS: The AVP time in patients with NTG (2.78 +/- 1.1 s) was significantly prolonged (P < 0.0001) compared with healthy subjects (1.58 +/- 0.4 s). No significant correlation was found between arterial and venous diameters, intraocular pressure, blood pressure or calculated perfusion pressure and retinal arteriovenous passage time. CONCLUSION: Patients with NTG showed prolonged retinal passage, which could cause chronic hypoxia. This prolongation of circulation is not correlated with any of the clinical parameters. Thus, a circulatory defect might be a primary factor in the pathogenesis of NTG.

Angiography, Digital Subtraction↗
PubMed1999

Infrared imaging of cystoid macular edema.

BACKGROUND: Cystoid macular edema (CME), a cause of central visual loss, is described in various pathologies. Typically, the fluorescein angiogram confirms the diagnosis and provides qualitative information as to the extent of leakage. This study was performed to investigate the features of cysts and quantify the extent of CME using non-invasive infrared imaging. METHODS: Eighteen eyes of 16 successive patients with CME in association with a broad spectrum of diseases were included in the study. The diagnosis of CME was established clinically and confirmed by fluorescein angiography. Digital infrared imaging was performed with a research scanning laser ophthalmoscope with different apertures, providing direct confocal and indirect imaging modes, to discriminate superficial features from deeper ones and to emphasize sources of multiple laterally scattered light. RESULTS: CME was easily detected with infrared imaging in all eyes. Confocal mode visualized the cysts themselves, while indirect mode emphasized borders. Large central cysts were detected as distinct, non-confluent structures. In addition, folds detected with infrared imaging in the macula in 12 of the 18 eyes were not always observed clinically. CONCLUSION: Infrared imaging provides a quick and safe diagnostic tool for patients with CME. The cystoid structures are readily localized and quantified, useful for monitoring CME. Despite differences in the pathophysiology, cysts did not differ qualitatively in a variety of diseases with infrared imaging.

Adult↗
PubMed1999

Scanning laser ophthalmoscopy-based evaluation of epipapillary velocities: method and physiologic variability.

PURPOSE: Scanning laser ophthalmoscopy is capable of producing high-resolution fluorescein angiograms. Measurements of capillary blood velocities in the fovea are well established. In this study, we used an identical technique to measure particle velocities in the superficial layers of the optic nerve head. We compared these data with simultaneous velocity measurements in the retinal and macular vasculature. METHODS: Fluorescein angiograms were performed in 30 subjects (12 men, 18 women; mean age, 26 years; standard deviation [SD], 3 years). Off-line, the velocities of hypofluorescent particles through the microvasculature of epipapillary and macular vessels were measured by image-processing techniques. We also assessed the arteriovenous passage (AVP) time of the fluorescein dye front. RESULTS: Epipapillary blood velocities ranged from 2.7 to 6.5 mm/sec (mean, 4.0 mm/sec; SD, 0.99 mm/sec) and differed significantly from macular capillary blood velocities (MCBVs), which ranged from 1.67 to 3.31 mm/sec (mean, 2.53 mm/sec; SD, 0.34 mm/sec). The AVP time in all subjects was 1.74 +/- 0.5 sec (mean +/- SD) and correlated with the MCBV (P < 0.05, r = -0.46). Epipapillary blood velocities showed no correlation with either AVP time or MCBV. CONCLUSIONS: The scanning laser methodology, adapted to objectively assess velocities in the epipapillary vasculature, shows that these measurements are neither correlated with velocities in the perifoveal network, nor inversely correlated with overall retinal transit time. Epipapillary blood velocities were found to be substantially higher than those measured in macular capillaries. This result might be explained by the different anatomy of epipapillary vessels compared with macular capillaries.

Adult↗
PubMed1999

Dorzolamide, visual function and ocular hemodynamics in normal-tension glaucoma.

The purpose of this study was to determine how a topical carbonic anhydrase inhibitor, dorzolamide, alters visual function and ocular blood flow in persons with normal-tension glaucoma. Eighteen normal tension glaucoma patients, after washout of other ocular medications, were treated for four weeks with 2% dorzolamide, three times daily. A control group of eleven other normal-tension glaucoma patients received placebo eye drops. Patients were studied before treatment, and after two and four weeks of treatment. Each study included assessment of central visual function (contrast sensitivity), intraocular pressure (IOP), and several aspects of ocular hemodynamics, including measures of retinal arteriovenous passage time, retinal arterial and venous diameters, and flow velocities in the ophthalmic, central retinal, and posterior ciliary arteries. Dorzolamide significantly reduced IOP at two and four weeks (each p<0.01), and at the same time increased contrast sensitivity at both three and six cycles per degree (each p<0.05). Neither of these variables changed significantly in the control group. Dorzolamide also accelerated retinal arteriovenous passage time of fluorescein dye, at constant retinal arterial and venous diameters (p<0.05), but failed to change flow velocities in any retrobulbar vessel. The ability of dorzolamide to improve contrast sensitivity in persons with normal-tension glaucoma may be related to either IOP reduction or altered ocular perfusion.

Blood Pressure↗