Biomedical subjects

M Schaumberger

Publications and source records attributed to M Schaumberger.

12 recordsLinked to original sources

PubMed2006

[Long-term functional results after macular hole surgery. Results of a prospective study].

PURPOSE: This study reports on the long-term results of macular hole surgery with peeling of the ILM. METHODS: A total of 88 consecutive patients (71 female, 17 male, mean age 67 years) were prospectively evaluated. All patients underwent a standard pars plana vitrectomy with removal of the ILM and an intraocular gas tamponade. Preoperatively, as well as on each follow-up visit, a clinical examination including measurement of best corrected visual acuity, Goldman perimetry, and OCT was performed. RESULTS: The mean postoperative follow-up was 49 months; 83 (94%) patients were pseudophakic at the last examination. Anatomic closure was achieved in 84 (95%) patients. No late reopening of the macular hole was observed. Best corrected visual acuity improved in 82 patients (93%), remained unchanged in 2, and deteriorated in 4 patients. Best corrected visual acuity improved from a median of 0.2 preoperatively to a median of 0.6 postoperatively (p<0.001). Duration of symptoms as well as low preoperative visual acuity had no significant impact on anatomic and functional success. CONCLUSIONS: Macular hole surgery leads to good functional and anatomical results, even in the long term. A long history of visual impairment and low visual acuity before surgery are not contraindications to surgical intervention.

Aged↗

PubMed2002

[Relationship between lens power in refraction].

BACKGROUND: To achieve emmetropia, several components such as the cornea and lens power, and axial length have to be coordinated. Until now, not much is known about the influence of these factors on each other. METHODS: A total of 66 healthy subjects were enrolled in this study. Ocular dimensions including anterior chamber depth, lens thickness, vitreous chamber depth, and axial length were measured by A-scan ultrasonography. Corneal radius and corneal refractive power were determined by ophthalmometry. The equivalent lens power was calculated by a method based on the Gullstrand schematic eye. RESULTS: As expected, a good correlation was found to exist between refraction and axial length. Lens power was independent of refraction, but in emmetropic eyes a good correlation between lens power and axial length could be found. Higher axial length was related to lower values of lens power and vice versa. CONCLUSION: In emmetropic eyes, deviation of axial length seems to be compensated by lens power and if this mechanism does not function, ametropia results.

Adult↗

PubMed2002

[Correlation between ICG angiography verified networks in uveal melanomas and rate of tumor regression after brachytherapy].

INTRODUCTION: The post-irradiation regression rate of uveal melanomas is a prognostically significant factor for the development of metastases. Other predictive factors for metastases are histological networks which are imagable with confocal ICG angiography. The purpose of this study was to evaluate a possible connection of networks in the ICGA and tumor regression rates. METHODS: We compared the post-irradiation regression rates (as %) in 20 patients 1 year after brachytherapy with networks identified in pre-treatment indocyanine green angiography (ICGA). The ICG angiography was performed before irradiation, 10 patients were irradiated with Ru-106 and 10 were irradiated with Id-125. RESULTS: The mean preoperative maximum apical height was 5.2 mm [SD: 1.5 mm; Ru106 group: 5.7 mm (SD: 1.0 mm); Id-125 group: 5.0 mm (SD: 1.9 mm)]. In 11 patients (55%) (Ru-106: 5; Id-125: 6) we found networks in the preoperative ICG. The mean regression rate in tumors with networks was 51.3% (SD: 14.7%) and 28.0% (SD: 16.4%) in the group without networks. The difference between both groups was statistically significant (p = 0.003, Mann-Whitney test). No statistically significant difference in the regression rates was found between the two groups of brachytherapy Ru-106 and Id-125 (p = 0.165, Mann-Whitney test). DISCUSSION: Highly proliferative tumors are known to be more sensitive to irradiation. This may be one reason why tumors with a rapid post-irradiation regression are the more aggressive ones with regard to later development of metastases. Histopathological networks are also known to be a strong indication of more aggressive, metastasizing tumors. These networks are also imagable in ICG angiography. Our observation emphasizes a connection between networks in ICG angiography and regression rates of uveal melanomas after brachytherapy.

Adult↗

PubMed2002

Macular hole size as a prognostic factor in macular hole surgery.

BACKGROUND/AIM: In 1991 there was a series of successful closures of a macular hole after vitrectomy and membrane peeling. Today this technique has become a standard procedure. The aim of this study was to evaluate the role of optical coherence tomography in diagnosing and staging, as well as in predicting, the functional and anatomical outcome after macular hole surgery. METHOD: In a prospective study 94 consecutive patients (20 male, 74 female) with a mean age of 67.6 (SD 6.0) years and a macular hole stage II (n = 8), III (n = 72), and IV (n = 14) according to the classification by Gass were examined with optical coherence tomography (OCT) before pars plana vitrectomy. Macular hole diameters were determined at the level of the retinal pigment epithelium (base diameter) and at the minimal extent of the hole (minimum diameter). Calculated hole form factor (HFF) was correlated with the postoperative anatomical success rate and best corrected visual acuity. The duration of symptoms was correlated with base and minimum diameter of the macular hole. RESULTS: In eyes without anatomical closure of the macular hole after one surgical approach (13/94) the base diameter (p1) and the minimum diameter (p2) were significantly larger than in cases with immediate postsurgical closure (p1 = 0.003; p2 = 0.028). There was a significant negative correlation between both the base and the minimum diameter of the hole and the postoperative visual function (p1 = 0.016; p2 = 0.002). In all patients with HFF >0.9 the macular hole was closed following one surgical procedure, whereas in eyes with HFF <0.5 anatomical success rate was 67%. Better postoperative visual outcome correlated with higher HFF (p = 0.050). There was no significant correlation between the duration of symptoms and base or minimum diameters (p1 = 0.053; p2 = 0.164), respectively. CONCLUSION: Preoperative measurement of macular hole size with OCT can provide a prognostic factor for postoperative visual outcome and anatomical success rate of macular hole surgery. The duration of symptoms did not correlate with the diameters measured. Base and minimum diameters especially seem to be of predictive value in macular hole surgery.

Aged↗

PubMed2001

Macular changes after peeling of the internal limiting membrane in macular hole surgery.

PURPOSE: To report the incidence of macular changes following pars plana vitrectomy with peeling of the internal limiting membrane (ILM) for idiopathic macular hole. DESIGN: Prospective consecutive series. METHODS: In a prospective study 105 eyes of 105 patients underwent vitrectomy for idiopathic macular holes. Surgery consisted of a standard three-port vitrectomy, induction of a posterior hyaloid detachment, removal of epiretinal membranes including the ILM, fluid-air exchange and intraocular gas tamponade (15% hexafluoroethane (C2F6) gas mixture) followed by head-down positioning for at least five days. No adjuvants were used during surgery. In addition to the clinical examination, static microperimetry using a Rodenstock scanning laser ophthalmoscope (SLO-105) was performed pre- and 6 or 12 weeks postoperatively. The stimulus size was 0.2 degrees (Goldmann II), intensities employed were 0 and 12 dB. For all tests, 20-degree fields were used. RESULTS: Anatomic closure of macular holes was achieved in 92 (87.6%) of 105 patients by one operation. Eight patients underwent a successful second procedure. The closure rate after two operations was 95.2%. Best corrected visual acuity increased from a median of 0.2 (range 0.05 to 0.5) preoperatively to a median of 0.5 (range 0.05 to 1.0) postoperatively. Anatomical macular changes were found in 8 (7.6%) patients: There were two cases of macular edema following secondary cataract extraction and six cases of retinal pigment epithelium changes. Formation of postoperative epiretinal membranes or late reopenings were not noted. Small, mostly asymptomatic paracentral scotomata were seen in 59 (56.2%) of 105 patients. CONCLUSION: Anatomical changes of the macula following vitrectomy with removal of the ILM are infrequent. However, paracentral scotomata observed in our series might be caused by a trauma to the nerve fibers during ILM peeling. To achieve reliable results a standardized procedure for microperimetry should be developed.

Aged↗

PubMed2001

Peripheral visual field defects after macular hole surgery: a complication with decreasing incidence.

AIM: To prospectively evaluate peripheral visual fields after vitrectomy for idiopathic macular holes. METHODS: Goldmann perimetry was performed in 105 patients before, as well as 6 weeks and 12 months after macular hole surgery. RESULTS: Only one patient (< 1%) with a stage III macular hole developed an asymptomatic postoperative visual field defect. The scotoma was wedge-shaped, peripherally located in the temporal quadrant, and remained unchanged during the following 12 months. CONCLUSION: Peripheral visual field defects after macular hole surgery can be a complication of very low incidence. A rather low pressure set during air-fluid exchange as well as special aspects of the surgical technique may be responsible for this low incidence of peripheral visual field defects.

Aged↗

PubMed2000

Spatial summation of blue-on-yellow light increments and decrements in human vision.

In the primate retina, blue-OFF cells are less numerous than blue-ON cells but no psychophysical equivalent of this asymmetry has been found so far. The hypothesis put forward in the present study is that the ON-OFF asymmetry should manifest itself in the size and effectiveness of spatial summation of S-cone signals of opposite polarity. To test this hypothesis upon selective stimulation of the S-cones in man, a 3 cd/m(2) blue light was superimposed on a 300 cd/m(2) yellow background and the test stimulus consisted in a luminance increment or decrement of the blue light from its steady level over a circular area of variable size. The test stimuli were presented at 12.5 degrees retinal eccentricity. Within the test-stimulus spectral band, sensitivity was that of Stiles' pi(1) mechanism. Increasing stimulus area reduced more the decrement threshold than the increment threshold, and Ricco's area was larger for luminance decrements (0.8-2 degrees ) than for increments (0.6-0.9 degrees ). Experiments with red-on-red stimuli confirmed that the large summation area and stimulus-polarity-dependent spatial summation are specific for the isolated S-cone signals. The sign-dependency of spatial summation is probably a psychophysical correlate of the asymmetry of the ON- and OFF- visual pathways receiving S-cone input.

Adult↗

PubMed1997

Investigations on subjective and objective cyclorotatory changes after inferior oblique muscle recession.

PURPOSE: To determine subjective and objective cyclorotatory changes after surgery for oblique muscle disorders and to analyze the mechanisms of the well-known, long-term, postoperative, subjective cyclotorsional changes. METHODS: Twenty-six patients underwent unilateral inferior oblique muscle recession for strabismus sursoadductorius (inferior oblique overfunction). Subjective and objective cyclodeviation were examined before surgery with and without diagnostic occlusion, as well as 1 day, 3 days, and 4 months after surgery. Subjective cyclodeviation was assessed by Harms' tangent scale. Objective cycloposition was measured by means of fundus cyclometry, a novel method using an infrared scanning laser ophthalmoscope. RESULTS: Diagnostic occlusion did not lead to significant changes in either objective or subjective cyclodeviation. Preoperative objective excycloposition was nearly equally distributed between affected eyes and fellow eyes. Early surgically induced incyclorotatory effects were more pronounced objectively than subjectively. On long-term follow-up, a reduction in the incyclorotatory effect was found to be smaller subjectively than objectively. A significant difference between subjective and objective cycloposition was seen early after surgery, and a significant difference between subjective and objective cyclorotatory change was found immediately after surgery and on long-term follow-up. CONCLUSIONS: Long-term regression of the incyclorotatory effect after inferior oblique muscle recession was confirmed objectively and subjectively and can be explained as a cessation of preoperatively required binocular compensatory innervation. The authors conclude that the difference between objective and subjective regression is caused by sensory cyclofusion.

Adolescent↗

PubMed1995

Simulations for FASTPAC and the standard 4-2 dB full-threshold strategy of the Humphrey Field Analyzer.

PURPOSE: This study evaluates the accuracy, reproducibility, and efficiency of FASTPAC, a new fast strategy for automated perimetry using 3-dB steps with single threshold crossing, compared to the standard 4-2 dB full threshold strategy by means of computer simulations. METHOD: An "artificial patient" module was developed to create responses to stimuli by a Monte-Carlo technique from a given probability distribution. The authors performed 10,200 simulations with threshold values ranging from 0 to 50 dB. RESULTS: Results demonstrate an 18% decrease in the number of presentations per threshold determination, which is equal to a similar reduction in testing time. For both strategies, there is a considerable influence of the starting deviation (difference between starting value and actual threshold) on threshold error (difference between estimated threshold and actual threshold): negative starting deviations lead to negative threshold errors and vice versa. This relationship is more pronounced for FASTPAC (slope 0.18 dB/dB, P < 0.0001) than for the full-threshold strategy (slope 0.13 dB/dB, P < 0.0001). In addition, fluctuations of the determined thresholds, described as the distance between the 16th and 84th percentiles of the threshold errors, increase with increasing absolute starting deviations. This is particularly true of FASTPAC: CONCLUSIONS: The influence of the starting value on the threshold determination may lead to a considerable underestimation of visual field defects, accompanied by a higher fluctuation. This is an intrinsic property of both staircase procedures. FASTPAC, however, is more affected than the standard 4-2 dB full-threshold strategy. FASTPAC, therefore, provides time reduction at the expense of accuracy and reliability.

Algorithms↗

PubMed1995

Glaucomatous visual fields. FASTPAC versus full threshold strategy of the Humphrey Field Analyzer.

PURPOSE: This study examined how FASTPAC, a fast strategy for the Humphrey Field Analyzer (HFA), compares to the standard 4/2-dB full threshold strategy in patients with glaucoma. METHOD: The author tested one eye each of 50 patients with glaucoma (23 with only relative defects, 27 with at least one absolute defect; age range, 25 to 79 years; median age, 61.5 years) with both strategies using program 30-2 of the HFA (stimulus size III). Global visual field indices as calculated by Statpac, unweighted mean sensitivity, and examination time were compared. In addition, a point by point analysis of the sensitivity values was performed. RESULTS: Between the two strategies, no significant differences were found for indices directly related to the sensitivity values (mean sensitivity [MS], mean deviation [MD]) or for the actual thresholds. For the entire population, FASTPAC showed higher mean short-term fluctuation (SF; P = 0.018), lower mean pattern standard deviation (PSD; P = 0.006), and mean corrected PSD (CPSD; P < 0.001) values and a time reduction of more than 30% (P < 0.001) compared to the standard strategy. These differences between the strategies were found to be independent of the amount of field loss, except for PSD (P = 0.001). No age influence was present. Statistically significant linear regression (r > 0.70, P < 0.001) was found between the FASTPAC values of MS, MD, PSD, CPSD, and the corresponding values determined with the standard strategy. No correlation exists for SF (r < 0.46, P > 0.030). CONCLUSIONS: FASTPAC provides a considerable time reduction at the cost of higher threshold fluctuation. This may lead to problems in detecting relative defects or changes in differential light threshold in follow-up examinations.

Adult↗

PubMed1994

The different effects of aging on normal sensitivity in flicker and light-sense perimetry.

PURPOSE: To verify whether or not an accelerated loss at an older age for normal sensitivity in the central visual field is present when using the stimulus configuration of conventional white/white automated light-sense perimetry and the stimulus configuration of the automated flicker perimeter developed by one of the authors (BJL). METHODS: One hundred thirty eyes of 130 normal subjects aged 9 to 86 years were tested with the Humphrey-Field-Analyzer 640, program 30-2, and our automated flicker perimeter. In addition, short introductory learning programs were used for both techniques. All tests were performed in random order. RESULTS: Mean critical flicker fusion frequency shows a linear loss over the entire age range (r = -0.5546, P < 0.0001, slope a = -0.3820 dB/decade), whereas mean light difference sensitivity decreases only slightly up to 46 years of age (r = -0.0118, P = 0.9226, slope a = -0.0153 dB/decade), with a marked acceleration above 46 years of age (r = -0.7304, P < 0.0001, slope a = -2.0640 dB/decade). CONCLUSIONS: The absence of an accelerated loss at an older age for critical flicker fusion frequency (CFF) and the presence of such a loss for light-difference sensitivity (LDS) might be attributed to the independence of a flickering stimulus from distributing effects induced by the ocular media at an older age as proposed by one of the authors. The different age effects for CFF and LDS could also be explained by different age-related losses at different sites and for different neuronal populations throughout the visual pathways.

Adolescent↗

PubMed1988

Ophthalmic artery blood flow velocity in healthy term and preterm neonates.

Ophthalmic artery blood flow velocity (OA-BFV, cm/s), cerebral blood flow velocity (C-BFV, cm/s), and cardiac output (ml/min) were measured by pulsed Doppler sonography in 15 healthy term and 10 well preterm (26-35 wk) infants in the first week of life. OA-BFV did not increase with increasing gestational age (preterm: peak systolic BFV 29 +/- 5 cm/s, mean BFV 7.2 +/- 1.5 cm/s; term: peak systolic BFV 27 +/- 5 cm/s, mean BFV 6.6 +/- 1.3 cm/s), unlike C-BFV (preterm: peak systolic BFV 34 +/- 8 cm/s, mean BFV 9.4 +/- 2.3 cm/s; term: peak systolic BFV 43 +/- 9 cm/s, p less than 0.05; mean BFV 11 +/- 3.0 cm/s, p less than 0.05) and cardiac output (preterm 329 +/- 128 ml/min, term 732 +/- 112 ml/min; p less than 0.001). The ratio of OA-BFV/C-BFV was significantly higher in preterm than in term infants (p less than 0.01). In preterm infants, but not in term infants, there was a positive linear correlation of OA-BFV to C-BFV (r = 0.88). We conclude that it is possible to measure opthalmic artery blood flow velocity in neonates by pulsed Doppler sonography. Gestational age has different effects on OA-BFV and on C-BFV. Although it is a point of discussion if blood flow velocities are reflecting absolute blood flow, Doppler assessment of OA-BFV could be a tool for monitoring risk factors for retinopathy of prematurity.

Blood Flow Velocity↗