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Biomedical subjects

Anke Weber

Publications and source records attributed to Anke Weber.

8 recordsLinked to original sources
PubMed2006

Corneal calcification after chemical eye burns caused by eye drops containing phosphate buffer.

PURPOSE: Chemical burns with calcium containing corrosives as well as irrigation with phosphate buffer solutions after eye burns bear the risk of corneal calcification. The aim of this study was to evaluate the correlation between the occurrence of corneal calcification after chemical injuries and the usage of phosphate buffer containing local therapeutics. METHODS: We reviewed the data of 179 patients who have been treated in the University Eye Clinic Aachen, Germany, between 1941 and 2000. Only when the corrosive did not contain calcium and when the initial irrigating solution did not contain phosphate buffer, respectively, were patients included in the study. The cases were analyse, if the patient was treated with phosphate buffer containing eye drops/ointment during the first 7 days of hospitalization or as an out-patient, and if corneal calcification was visible by slit-lamp examination during the follow-up. Statistical analysis was performed using Fischer's exact test. RESULTS: 152 eyes were included. From 63 eyes treated with phosphate buffer containing eye drops, 31 eyes (49%) developed corneal calcification. From 89 eyes treated without phosphate buffer containing eye drops, only 23 eyes (26%) developed corneal calcification. The two-sided p-value of Fischer's exact test is 0.0036. CONCLUSION: During follow-up after chemical eye burns, eye drops containing phosphate buffer double the risk of corneal calcification. We recommend avoiding these agents in order to prevent the burned cornea from additional opacity. Substances containing phosphate buffer are listed in this article.

Buffers↗
PubMed2005

Imaging polarimetry in central serous chorioretinopathy.

PURPOSE: To evaluate a noninvasive technique to detect the leakage point of central serous chorioretinopathy (CSR), using a polarimetry method. DESIGN: Prospective cohort study. METHODS SETTING: Institutional practice. PATIENTS: We examined 30 eyes of 30 patients with CSR. MAIN OUTCOME MEASURES: Polarimetry images were recorded using the GDx-N (Laser Diagnostic Technologies). We computed four images that differed in their polarization content: a depolarized light image, an average reflectance image, a parallel polarized light image, and a birefringence image. Each polarimetry image was compared with abnormalities seen on fluorescein angiography. RESULTS: In all eyes, leakage area could be clearly visualized as a bright area in the depolarized light images. Michelson contrasts for the leakage areas were 0.58 +/- 0.28 in the depolarized light images, 0.17 +/- 0.11 in the average reflectance images, 0.09 +/- 0.09 in the parallel polarized light images, and 0.11 +/- 0.21 in the birefringence images from the same raw data. Michelson contrasts in depolarized light images were significantly higher than for the other three images (P < .0001, for all tests, paired t test). The fluid accumulated in the retina was well-visualized in the average and parallel polarized light images. CONCLUSIONS: Polarization-sensitive imaging could readily localize the leakage point and area of fluid in CSR. This may assist with the rapid, noninvasive assessment of CSR.

Adult↗
PubMed2005

Topical dorzolamide increases pericentral visual function in age-related maculopathy: pilot study findings with short-wavelength automated perimetry.

PURPOSE: Numerous studies have confirmed the enhancement of ocular circulation by carbonic anhydrase inhibitors (CAIs). Topical CAI treatment with dorzolamide averts the significant pericentral visual function loss accompanying retinal and choroidal vasoconstriction during acute hyperventilation-induced hypocapnia. This study was designed to discern whether dorzolamide might similarly enhance macular function in patients with age-related maculopathy (ARM). METHODS: In a masked, placebo-controlled study, 40 patients with ARM and acuity > 20/50 were randomized to receive either dorzolamide or placebo for 12 weeks, thrice daily. After pre-study perimetric training, pericentral function (mean sensitivity) was quantified using Humphrey 10-2 short-wavelength automated perimetry (SWAP), before and after 12 weeks of topical therapy. RESULTS: Dorzolamide-treated eyes demonstrated a significant increase in mean sensitivity of + 1.55 dB (p = 0.04); placebo-treated eyes showed no significant change (+ 0.58 dB; p = 0.10). Given the non-significant increase of mean sensitivity in the placebo-treated group, fewer than 100 subjects per group would be required to afford > 70% power to yield a significant direct comparative difference between treatment and placebo in a prospective, randomized study of equally short duration. CONCLUSIONS: This study demonstrated a significant increase in short-wavelength sensitivity in ARM with dorzolamide and the lack thereof with placebo. These encouraging pilot study data suggest a potential role for topical CAIs in ARM patients, and establish objective parameters for prospective studies to further evaluate the effects of dorzolamide in ARM.

Administration, Topical↗
PubMed2005

Improved contrast of peripapillary hyperpigmentation using polarization analysis.

PURPOSE: To improve detection and quantification of peripapillary hyperpigmentation, associated with aging, open-angle glaucoma, and age-related macular degeneration. METHODS: A computational approach was implemented with a readily available polarimeter used in glaucoma diagnosis, a nerve fiber analyzer (GDx; Laser Diagnostic Technologies, San Diego, CA). Using near-infrared illumination at each of 20 input polarizations, a series of image pairs was digitized. One image is made from the light returning from the eye that is polarized parallel to the input light, and the other image is made from the light that is rotated by 90 degrees from the input polarization. Using raw data from these 40 images, and a simplified model of ocular polarization properties, images were computed based on their polarization content. Regions of hyperpigmentation, selected using stereo color fundus photographs, were quantified in three types of polarimetry images: (1) a depolarized light image resulting mainly from multiply scattered light; (2) an average image that is typical of confocal images; and (3) a birefringence image. Measurements on versus off hyperpigmentation were made in nine persons with suspected glaucoma or patients with primary open-angle glaucoma, selected to have clinically visible hyperpigmentation. RESULTS: In the depolarized light images, hyperpigmented regions were significantly brighter than comparison areas (P < 0.0425)-that is, had more scattered light and therefore more contrast (P < 0.037) than did color or other polarimetric images. CONCLUSIONS: With this polarimetry imaging method, subretinal tissues such as those with hyperpigmentation can be visualized with increased contrast.

Cross-Sectional Studies↗
PubMed2004

Fluorescein filling defects and quantitative morphologic analysis of the optic nerve head in glaucoma.

OBJECTIVES: To evaluate absolute filling defects of the optic nerve head in normal tension glaucoma (NTG) and primary open-angle glaucoma (POAG) and to compare the filling defects with topographic analysis of the optic disc. METHODS: Twenty-five patients with NTG, 25 patients with POAG, and 25 age-matched controls were included. Fluorescein angiograms were performed by means of a scanning laser ophthalmoscope. The extent of absolute filling defects of the optic nerve head was assessed using digital image analysis of early-phase angiograms. Topographic measurements of the optic disc were acquired using the Heidelberg Retina Tomograph II. RESULTS: Absolute filling defects were significantly larger (P =.001) and were seen more often (P<.001) in patients with NTG (n = 18) and POAG (n = 19) compared with controls (n = 3). Rim area (P =.006), rim volume (P =.007), cup-disc area ratio (P =.008), linear cup-disc ratio (P =.005), maximum cup depth (P =.002), cup shape measure (P =.03), and nerve fiber layer thickness (P =.008) and cross-sectional area (P =.006) were significantly different between patients with glaucoma and controls. Absolute filling defects were significantly correlated with cup area (r = 0.31; P =.007), rim area (r = -0.38; P<.001), rim volume (r = -0.35; P =.002), cup-disc area ratio (r = 0.49; P<.001), linear cup-disc ratio (r = 0.48; P<.001), cup shape measure (r = 0.27; P =.02), and nerve fiber layer thickness (r = -0.33; P =.004) and cross-sectional area (r = -0.30; P =.009). CONCLUSIONS: Fluorescein filling defects of the optic disc are present in NTG and POAG. The extent of these filling defects is correlated with the morphologic disc damage.

Blood Pressure↗
PubMed2003

Short-wavelength automated perimetry in patients with diabetes mellitus without macular edema.

BACKGROUND: The short-wavelength-sensitive (SWS) cone-mediated sensitivity is a sensitive indicator of functional changes of the macula in diabetic maculopathy. This study was performed to investigate whether functional losses of the macula are detectable in patients without a significant macular edema. METHODS: In 45 patients with diabetes mellitus with clear optical media and no macular edema, conventional white-on-white perimetry (WWP) and short-wavelength automated perimetry (SWAP) were performed in the central 10-deg field. Fifty-eight healthy subjects ranging in age from 16 to 62 years served as controls. The two groups did not differ in age. RESULTS: Variance analysis (ANOVA) revealed significantly lower sensitivity in patients with diabetes than in controls. SWAP thresholds were significantly more greatly reduced by diabetes than those of WWP (ANOVA interaction: P=0.003). Post-hoc testing revealed a sensitivity reduction of 2.8 dB ( P=0.0003) in patients with diabetes for SWAP versus 0.46 for WWP ( P=0.15). Subgroup analysis revealed that mean thresholds of SWAP and WWP predominantly were reduced in patients with advanced disease. In patients with no retinopathy, sensitivity was not affected at all. CONCLUSION: SWS sensitivity may be affected in patients with diabetic retinopathy without clinically significant macular edema. Sensitivity loss was pronounced with increasing severity of retinopathy, reflecting the global status of the eye.

Adolescent↗
PubMed2002

Latanoprost and brimonidine: therapeutic and physiologic assessment before and after oral nonsteroidal anti-inflammatory therapy.

PURPOSE: To assess, before and during oral nonsteroidal anti-inflammatory drug coadministration, latanoprost's and brimonidine's hypotensive action in eyes at risk of glaucomatous progression, assessing the effect of each drug on ocular perfusion and visual function. METHODS: Twenty consenting adults with open-angle glaucoma or ocular hypertension underwent a double-masked, bilateral, randomized prospective study. Treatment started with either latanoprost 0.005% in the morning and placebo in the evening, or brimonidine 0.2% twice daily in one eye; after 1 week starting the other in the fellow eye. After another week, oral indomethacin 25 mg four times a day, commenced for 2 more weeks. Intraocular pressure, ocular circulation, and visual function were monitored pretreatment, after unilateral monotherapy (day 7), bilateral ocular therapy (day 14), and coadministered oral indomethacin (day 28). Intrasubject differences (interocular and intraocular relative to baseline) were determined by two-tailed paired t test. RESULTS: A loss of the significance of intraocular pressure reduction with brimonidine was noted after oral indomethacin coadministration (-14%; P =.004 for brimonidine alone versus -11%; P =.3 with indomethacin). Significant intraocular pressure reduction with latanoprost persisted despite indomethacin (-25%; P <.0001 for latanoprost alone versus -30%; P <.0001 with indomethacin). Pulsatile ocular blood flow increased 40% with latanoprost, but was unchanged with brimonidine (interdrug difference, P =.004). Midperipheral retinal microcirculation increased 23% (P =.03) with latanoprost. Humphrey perimetry and contrast sensitivity remained consistently at or above baseline with both latanoprost and brimonidine. Indomethacin had no significant effect on ocular perfusion or visual function measures. CONCLUSIONS: Circulatory and hydrodynamic findings differed substantially for the two drugs. The loss of significance of intraocular pressure reduction with brimonidine during indomethacin treatment may be clinically important.

Administration, Oral↗