Randolf A. Widder

Influence of membrane differential filtration on the natural course of age-related macular degeneration: a randomized trial.

Purpose: Membrane differential filtration is able to optimize rheologic parameters by eliminating high molecular weight proteins and lipoproteins from the blood. Following the hypothesis that these changes result in an improvement of the microcirculation, the authors tested the efficacy of membrane differential filtration in improving visual function in patients with age‐related macular degeneration (ARMD). Methods: Forty patients (40 eyes) were randomized into two groups. The treatment group was treated five times over a period of 21 weeks. In both groups, 9/20 of the eyes showed subfoveolar subretinal neovascularization. The main parameter of the study was visual acuity (VA). Electroretinogram (ERG), electrooculogram, and macular visual evoked potentials were also recorded. Plasma and whole blood viscosity and erythrocyte aggregation were measured. Results: The 20 patients treated repeatedly over a period of 21 weeks showed a mean improvement of 0.63 lines (SD 1.8) of VA on Early Treatment Diabetic Retinopathy Study charts. The control group showed a deterioration of 0.94 lines (SD 1.7) compared to VA at baseline examination. The amplitude of the ERG photopic a‐wave and the flicker ERG was significantly increased. The rheologic parameters were lowered in all treated patients. Conclusion: Repetitive treatment with membrane differential filtration is able to improve visual acuity of patients with ARMD and the natural course of this disease. Several questions arise from the results of this study. Further research will show if it is possible to optimize the selection of patients for subgroups with predictive responses through morphologic and functional tests and how to create an optimized and individual treatment strategy determined by the quality, intensity, and frequency of treatment sessions.

Electrophysiological abnormalities in age-related macular degeneration

Abstract · Background. Results from psychophysical tests indicate that in age-related macular degeneration (ARMD) retinal function is globally impaired. Observations in single ARMD cases showing abnormalities of the electrooculogram (EOG) and electroretinogram (ERG) encouraged us to systematically examine ARMD patients by means of electrophysiological tests to confirm a global retinal dysfunction in ARMD. · Methods. Sixty-six patients with ARMD were examined clinically and by means of EOG, ERG, triple scotopic ERG, and fluorescein angiography (FA). · Results. EOG data were considerably reduced in ARMD. Scotopic a- and b-waves of the ERG were mildly affected. The bright flash response showed reduced b-waves with normal implicit times. The amplitude of the oscillatory potential OP2 was significantly reduced and photopic responses were also pathologic compared with an age-matched control group. Geographic atrophy and pigment epithelium detachment showed specific abnormalities in the ERG, whereas in soft drusen EOG changes were more conspicuous. · Conclusions. In addition to data from psychophysical tests the results from electrophysiological examinations indicated a global reduction of retinal function in ARMD which seemed to be present not only in the macula but also elsewhere in the retina.

Clinical efficacy of haemorheological treatment using plasma exchange, selective adsorption and membrane differential filtration in maculopathy, retinal vein occlusion and uveal effusion syndrome

The aim of the study was to test the clinical efficacy of haemorheological treatment with extracorporeal techniques in ocular diseases. We treated patients suffering from maculopathies of different origin: age-related (AMD, n = 17), uveitis-associated (n = 14) and myopia-associated maculopathy (n = 5). We also treated patients with uveal effusion syndrome (n = 3) and central retinal vein occlusion (n = 4) resistant to haemodilution or steroid therapy. The treatment consisted of plasma exchange, selective adsorption with a tryptophan-polyvinylalcohol adsorber and membrane differential filtration. Maculopathy patients underwent two treatments while the other patients received between 1 and 7 treatments. Pulsatile ocular blood flow was measured in 10 patients before and after therapy. The main parameter for evaluating clinical outcome was the change in visual acuity. Severe side-effects did not occur. The rheological parameters including plasma viscosity, whole blood viscosity and erythrocyte aggregation were statistically significantly lowered. Of 36 patients suffering from maculopathy, 25 showed an improvement of at least 1 line of visual acuity after therapy, 7/17 patients in AMD, 6/14 in uveitis and 0/5 in myopia improved 3 lines or more. All patients suffering from retinal vein occlusion improved at least 1 line and two showed an improvement of 3 lines or more. In uveal effusion syndrome, an improvement of 3 lines or more was reached in all patients. Plasma exchange, selective adsorption and membrane differential filtration are effective rheological treatment approaches to improving visual acuity in patients suffering from maculopathy except myopia-associated maculopathy. Efficacy in patients suffering from central retinal vein occlusion and uveal effusion syndrome was proven, even when the patients were resistant to previous haemodilution or steroid therapy. We conclude that a rheological approach should be considered before invasive methods such as laser coagulation, radiation therapy or surgery are applied.

Corneal injury after carbon dioxide laser skin resurfacing

PURPOSE To describe a corneal injury in both eyes of a patient who had undergone carbon dioxide laser skin resurfacing. METHOD Case report. RESULTS A 67-year-old woman had severe pain and decreased vision in both eyes after undergoing laser skin resurfacing treatment with a pulsed carbon dioxide laser. Clinical examination disclosed a corneal ulcer, a bullous keratopathy, and intrastromal bleeding. After perforating keratoplasty, the histologic examination of the cornea showed signs of thermal injury. CONCLUSIONS The results of the histologic examination and the onset of symptoms within 24 hours after therapy suggest that the laser application caused the corneal damage. Safety guidelines for this procedure should be reviewed.

Improvement of visual acuity in patients suffering from diabetic retinopathy after membrane differential filtration: a pilot study

BACKGROUND Membrane differential filtration is an extracorporeal treatment procedure which eliminates high molecular weight proteins and lipids from the blood. This pilot study was initiated to investigate the short-term effects on blood rheology and visual function in patients suffering from diabetic retinopathy. METHODS Six patients with non-proliferative diabetic retinopathy, clinically significant macular edema (five patients, nine eyes) and inactive proliferative diabetic retinopathy (one patient, one eye) underwent a single treatment with a hollow fiber secondary plasma filter. The main parameter measured was visual acuity prior to and after treatment. Biochemical and rheological parameters (whole blood and plasma viscosity, and erythrocyte aggregation) were also measured. The mean follow-up was 25 (range 4-90) days after treatment. RESULTS The mean improvement of visual acuity was 1.4 lines (SD 0.8 lines, p = 0.002) 24 h after therapy. This remained stable during the follow-up period. The rheological measures were significantly lowered. A significant reduction of total protein, fibrinogen, IgG, IgM, IgA, alpha-2-macroglobulin, total cholesterol, LDL and HDL was found. CONCLUSION This study demonstrates the rheological impact of membrane differential filtration. It was shown that rheological changes correlated with clinical improvement in patients suffering from diabetic retinopathy with clinically significant macular edema.

Limits of two-dimensional planimetry in the follow-up of glaucomatous optic discs

Abstract•Background: To test the intra-observer, intra-photographic variability of two-dimensional measurements of the optic nerve head we used computer-assisted planimetry. Depending on the variability, we calculated the confidence intervals of the optic disc parameters which could be indicative of glaucomatous damage on follow-up.•Methods: Slides of the optic disc were taken from 10 eyes of 10 patients (n = 6 open angle glaucoma, n = 4 ocular hypertension) using a Zeiss fundus camera. All eyes were evaluated 10 times within a random sequence on 10 different days. We obtained the absolute values of the disc radii and the cup radii in steps of 1, 10, and 45 deg in predefined quadrants and the mean radii.•Results: The confidence interval of the cup radius on follow-up, depending on sector size, ranged between 62 and 38 % for small cups (radius 0.2 mm) and between 12 and 7% for large cups (radius 0.8 mm). The confidence intervals of the cup/disc ratio distinguishable from the disc boundary, depending on sector size, ranged between 0.81 and 0.89 for small discs (radius 0.5 mm) and from 0.90 to 0.94 for large discs (radius 1.0 mm). The confidence intervals of the cup/disc ratio indicating an increase on the cup radius in follow-up, distinguishable from the boundary of the disc, ranged, depending on sector size, between 0.57 and 0.75 for small discs (radius 0.5 mm) and from 0.81 to 0.89 for large discs (radius 1.0 mm). 9 Conclusion: The smaller the disc, the more difficult is the detection of glaucomatous damage, and the larger the cup, the more difficult is the detection of progression of glaucomatous damage.

Changes of Hemorheological and Biochemical Parameters after Plasma Perfusion Using a Tryptophan-Polyvinyl Alcohol Adsorber Leading to Clinical Improvement in Patients Suffering from Maculopathy

Background: Selective adsorption is an extracorporeal treatment able to reduce high-molecular-weight proteins and lipids. We evaluated its efficacy in lowering hemorheological parameters to achieve a better microcirculation of the retina. Patients and Methods: Ten patients suffering from maculopathies of various origin underwent a selective plasma adsorption procedure using the TR-350. Plasma and whole blood viscosity, erythrocyte aggregation and proteins and lipids were determined before and 24 h after therapy. Results: Selective adsorption therapy reduced the high-molecular-weight proteins and lipids. Plasma viscosity, standardized whole blood viscosity and erythrocyte aggregation were significantly lowered to 87, 88 and 65%, respectively, of their values prior to treatment. An improvement of visual acuity was achieved in 6/10 patients. Minor side effects were noted in 2/10 patients. Conclusions: Selective adsorption using the TR-350 adsorber is a safe technique, showing a high impact on blood rheology. The changes of hemorheological parameters led to clinical improvement in 6/10 patients suffering from retinal disorders.

Kombinierte Phakoemulsifikation mit Trabekelaspiration bei Pseudoexfoliations-Glaukom mit unterschiedlichem Ausgangsdruck – eine retrospektive Studie

INTRODUCTION The aim of this study was to differentiate the pressure-reducing results following trabecular aspiration combined with small incision cataract surgery in eyes with pseudoexfoliation depending on preoperative pressure and medication score. PATIENTS AND METHODS A retrospective analysis was made of 104 exfoliative eyes of 104 patients who underwent combined phaco/trabecular aspiration. Success was defined as a relative reduction of IOP of at least 20 %, absolute IOP of ≤ 20 mmHg, stable or reduced medication score and a lack of any further pressure-reducing surgery. RESULTS The success rate was 0.68 and 0.64 after 1 and 2 years. In eyes with medically uncontrolled preoperative IOP (> 20 mmHg) the IOP dropped significantly from 25.4 ± 4.3 mmHg to 17.0 ± 3.4 mmHg after two years. In eyes with preoperative controlled IOP the pressure lowering effect was low (17.1 ± 2.3 to 15.9 ± 2.3 mmHg) with a significant reduction of medication. CONCLUSIONS Combined cataract surgery and trabecular aspiration is a reasonable option in exfoliative eyes with IOP values in the low twenties in order to achieve a reduction of topical medications and to reach a stable IOP level.

The effect of membrane differential filtration on the colloid osmotic pressure in patients with age-related macular degeneration: significance to visual function?

Abstract:  To investigate the effect of membrane differential filtration (MDF) on plasma colloid osmotic pressure (COP) and visual functions in age‐related geographic macular degeneration (AMD). Ten consecutive patients with non‐exudative AMD underwent one MDF cycle. Primary endpoint was COP. Secondary endpoints were visual acuity and the mean defect of visual field. The COP was markedly reduced after one MDF cycle by 23.9% (P = 0.001). Compared with the baseline examination, visual acuity and the mean defect of visual field improved significantly after MDF. A significant positive correlation was found between the improvement in visual field and the decrease in COP (Pearsons coefficient = 0.65; P= 0.04). Membrane differential filtration lowers plasma colloid osmotic pressure in patients with non‐exudative AMD. Based on the observation that visual field and COP are correlated, one may hope for a means to improve decreased central retinal function in eyes with geographic AMD by modulation of COP plasma level.

Changes of haemorheological parameters when using plasma exchange, selective adsorption and membrane differential separation

At present, conventional haemorheotherapy consists of changes in life-style, drug therapy and haemodilution. Extracorporeal therapy has been considered only for the treatment of hyperviscosity syndromes. However, a wide range of viscosity-related syndromes may be amenable to rheological therapy if appropriate techniques were available. According to our data, plasma exchange, selective adsorption and membrane differential filtration may lead to an improvement of haemorheology and clinical conditions. For reasons of economy and feasability, membrane differential filtration is favoured over other techniques of differential separation therapy.