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M Reim

Publications and source records attributed to M Reim.

At least 37 records · Page 2Linked to original sources
PubMed1997

A histochemical study of the distribution of dextran 500 in human corneas during organ culture.

PURPOSE: The aim of this histochemical study was to demonstrate the absorption of dextran 500 and its distribution in the cornea after storage under standard eye bank conditions. Furthermore, an attempt was made to distinguish between the soluble and insoluble parts of dextran 500 absorbed by the cornea, in order to see how much dextran remains in the cornea after transplantation. METHODS: Forty-nine fresh and 65 organ-cultured human corneas were investigated. The corneas were cultured for 28 days in a dextran-free medium, followed by a period of 1-14 days in a medium containing 5% dextran 500. Cryosections were stained by aqueous PAS and a modified alcoholic PAS to determine the amount of dextran. RESULTS: Dextran was not found in the epithelium, stroma or endothelium of fresh human corneas. By contrast, extra- and intracellular positive staining reactions were detected in corneas following storage in a medium containing dextran. Dextran 500 absorption was relatively diffuse in the epithelium after storage in a dextran medium. Initial accumulations were found in the stroma near Bowman's and Descemet's membranes and also in the central part of the cornea, as the period of culture in the medium containing dextran lengthened. We also observed interaction between the stroma and endothelium: decreasing amounts in the endothelium were followed by an increase of same in the stroma. Intracellular deposits of dextran were detected after only one day. A much greater part of the extracellular dextran than previously described was found to be insoluble. CONCLUSIONS: As the amount of dextran in the cornea increases over a longer storage time, we conclude that the period of storage in a medium containing dextran should be limited to four days. The fact that the cornea is saturated with dextran after seven days has been shown in further studies to interfere with mitochondrial function and may also cause severe post-operative swelling of the transplant, hence leading to a longer recovery period for the patient.

Cornea↗
PubMed1997

Video fluorescein angiography of the anterior eye segment in severe eye burns.

PURPOSE: Severe eye burns often result in extensive necrosis of the conjunctiva and episcleral tissue. Video fluorescein angiography was performed to reveal the perfusion of the anterior eye segment after severe eye burns. METHODS: A scanning laser ophthalmoscope was used for anterior segment fluorescein angiography in 12 patients (14 eyes) with severe burns grade III-IV and in 7 healthy volunteers. RESULTS: Necrotic tissues occurred as non perfused areas and remained dark throughout the whole angiogram. In general, the borders from healthy to necrotic conjunctival tissue were sharply demarcated. Thus, the extent of scleral and limbal ischemia could be determined exactly. Injured vessels showed hyperfluorescence with late leakage. Damage of the subconjunctival tissue appeared as a deep weak fluorescence in the early angiography and exhibited patchy leakage in the late angiogram. CONCLUSIONS: Anterior segment angiography provides a basis for deciding the extent of surgical debridement of necrotic tissue in the acute phase of the burn. The determination of the extent of limbal and scleral ischemia may give useful information for early plastic-reconstructive procedures.

Adult↗
PubMed1997

Morphologic changes of the macula in a patient with Purtscher's retinopathy.

Purtscher's retinopathy is a rare complication after trauma to the chest or bone fractures. We report about a patient, which we examined 6 months after a serious car accident. Visual acuity was 20/20 in both eyes. Examination with the Amsler grid revealed a paracentral scotoma in the left eye. In the fluorescein angiography of the left eye performed with a scanning laser ophthalmoscope we found capillary dropout, which corresponded well to the scotoma. Measured by digital image analysis, the area of the foveal avascular zone was eccentrically enlarged by a factor of 4. The mean perifoveal intercapillary area was also enlarged in the corresponding quadrant. This reflects that focal capillary dropout may result in scotoma rather than in a decrease in visual acuity as reported in other diseases.

Adult↗
PubMed1997

Tenonplasty: a new surgical approach for the treatment of severe eye burns.

BACKGROUND AND OBJECTIVE: In the acute stage of most severe eye burns, the primary goal is survival of the globe. Initial tissue destruction may lead to extensive necrosis of the conjunctiva and underlying tissue down to the fornices, with resulting ischemia. These circumstances may cause a polymorphonuclear cell response, with resulting corneo-scleral ulceration and early melting of the globe. To reestablish the ocular surface, Tenonplasty was performed as a plastic procedure to reconstruct the conjunctival matrix of the globe up to the limbus. PATIENTS AND METHODS: Vital Tenon's sheets from the orbital region were prepared and advanced up to the limbus to cover the ischemic or ulcerating sclera with healthy, vascularized tissue. Fifty-nine patients with 75 severely burned eyes were treated with this procedure between 1987 and 1994. A total of 243 Tenon's flaps were prepared. RESULTS: In all cases, scleral ulcerations were prevented or healed. Epithelialization of the advanced Tenon's sheets was complete within 21 days in 80% of the cases and in all eyes within 54 days. Primary epithelialization of the burned cornea was achieved in approximately 31% of the cases. Fornices were sufficiently deep in about 74%, but severe symblepharon formation occurred in 26% of the cases. CONCLUSION: Tenonplasty may be an alternative surgical procedure to transplantation of autologous conjunctival or mucous grafts in restoring the conjunctival surface of the globe in severely burned eyes.

Adolescent↗
PubMed1997

Tarsoconjunctival advancement: a modified surgical technique to correct cicatricial entropion and metaplasia of the marginal tarsus.

Severe eye burns and mucocutaneous cicatricial disorders frequently cause upper and lower lid entropion with metaplasia of the tarsal conjunctiva, dislocation of the meibomian gland orifices, trichiasis, and tarsal scars near the lid margin. Between 1985 and 1993, 26 patients (29 eyes, 36 lids) were treated by excision of pathologic tissue and advancement of the tarsoconjunctival layer. The presented procedure is used mainly in cicatricial entropion with keratinization of the marginal tarsus.

Cicatrix, Hypertrophic↗
PubMed1996

Electrolytes in the cornea: a therapeutic challenge.

BACKGROUND: Reported here are the results of electrolyte measurements in different layers of 70 apparently normal human corneas. METHODS: Samples were examined by energy-dispersive X-ray analysis under calibrated conditions in a scanning electron microscope. The method allows the simultaneous quantitative analysis of, among others, sodium (Na), chloride (Cl), phosphorus (P) and potassium (K). The results are related to the dry weight of the analyzed samples. Four distinct layers, subepithelium, middle stroma, posterior stroma and Descemet's membrane, were analysed in each cornea. RESULTS: In the middle stroma we found concentrations of: sodium 0.609 +/- 0.13, chloride 0.557 +/- 0.115, potassium 0.058 +/- 0.02 and phosphorus 0.038 +/- 0.01 (mol/kg dry weight) [corrected]. CONCLUSION: The collation of normal electrolyte concentrations provides reference values for future studies on changes of the corneal electrolyte composition in diseased or injured eyes. The electrolyte composition of rinsing fluids or eye drops should be adjusted to that of the corneal stroma. Phosphate buffer, for example, is not a good vehicle for topical eye treatments and should be replaced by organic buffering systems.

Adult↗
PubMed1996

Haemorheology in patients with branch retinal vein occlusion with and without risk factors.

PURPOSE: The study was carried out to ascertain the role of blood viscosity in patients with branch retinal vein occlusion (BRVO) with and without risk factors. METHODS: In 292 patients with acute BRVO (mean age 65 +/- 10 years) and 292 controls matched for gender, age, and cardiovascular risk factors, haematocrit, plasma viscosity, erythrocyte aggregation and erythrocyte rigidity were measured. A subgroup analysis in patients with and without risk factors was performed. RESULTS: Haematocrit and plasma viscosity values were significantly higher in BRVO patients than in controls, but erythrocyte rigidity and erythrocyte aggregation did not differ. Subgroup analysis revealed no differences in haematocrit and plasma viscosity values between patients with and those without cardiovascular risk factors. CONCLUSIONS: This study shows increased plasma viscosity and haematocrit values in patients with BRVO which are not associated with the presence of other cardiovascular risk factors. Thus, changes in blood fluidity appear to be important factors in the pathogenesis of BRVO.

Adult↗
PubMed1996

Does the human cornea contain silicon?

BACKGROUND: Our study investigated the presence, type and quantity of silicon in the human cornea. We report the results of silicon measurements in the corneas of silicotic individuals, bricklayers and apparently normal human individuals and offer a hypothesis for the mechanism of silicon deposition in the human cornea. METHODS: We examined corneas from 13 decreased subjects who suffered from silicosis, 2 bricklayers and 6 apparently healthy subjects. Cornea samples were examined by energy-dispersive x-ray analysis (EDXA) under calibrated conditions in a scanning electron microscope (SEM). The EDXA detector was a silicon-free germanium crystal. Five distinct layers (epithelium, Bowman's membrane, central stroma. Descemet's membrane and endothelium) were analyzed in each cornea. The method allows simultaneous semiquantitative analysis of, among other elements, silicon, calcium and oxygen. We measured amorphous silicon and visible particles of silicon. RESULTS: We found amorphous silicon in low concentrations in 38% of the silicotic corneas and in very low concentrations in 29% of the healthy corneas. Bricklayers showed high concentrations of amorphous silicon. These accumulations of silicon were predominantly located in Descemet's membrane. Silicotic corneas showed significantly more silicon-containing particles than corneas of healthy controls (chi 2-test, P < 0.01). CONCLUSION: Normal corneas contain very low amounts of silicon. Longterm exposure to inhalative silicon dusts results in only very slightly increased levels of amorphous silicon in the cornea. However, silicon-containing particles accumulate in the cornea of silicotic individuals. Bricklayers incorporate more amorphous silicon into the cornea.

Aged↗
PubMed1996

[Effect of different single agent antihypertensive therapies on peri-foveal microcirculation in patients with arterial hypertension].

PURPOSE: Arterial hypertension is known to be an important risk factor for cerebral and cardiovascular disease. Previous studies have demonstrated alterations in the perifoveal microcirculation in patients with essential hypertension. During follow-up a progression of these alterations has been reported. In the present study we quantified the retinal microcirculation of patients with hypertension under different systemic antihypertensive medication. METHODS: The patients were divided into three groups according to their medication. Group 1 was treated with beta-blocker (n = 17), group 2 with ACE inhibitors (n = 10), and group 3 with calcium channel blockers (n = 11). All patients underwent fluorescein angiographic studies with a scanning laser ophthalmoscope. Perifoveal intercapillary areas (PIA) and the mean perifoveal capillary velocity were quantified from the angiograms. RESULTS: Compared with reference values, all three groups of patients with essential hypertension showed significantly increased PIA and significantly decreased capillary velocity. No difference could be detected between the three groups of patients treated with beta-blocker, ACE inhibitor or calcium channel blocker. CONCLUSION: Alterations of the perifoveal network are found in patients with arterial hypertension. These alterations are similar under antihypertensive monotherapy using beta-blocker, ACE inhibitor or calcium channel blocker.

Adult↗
PubMed1996

Role of rheologic factors in patients with acute central retinal vein occlusion.

PURPOSE: To assess the rheologic findings in acute central retinal vein occlusion (CRVO) with respect to associated risk factors, the clinical appearance of ischemic or nonischemic CRVO, and to elucidate the etiology of possible changes. METHODS: The authors enrolled 173 patients with acute CRVO (ischemic, 33%; nonischemic, 67%) in this prospective study. One hundred seventy-three patients who were matched for age, sex, and cardiovascular risk factors served as control subjects. All patients underwent testing to determine hematocrit values, plasma viscosity (PV), erythrocyte aggregation (SEA), and erythrocyte rigidity (SER). RESULTS: Hemocrit values and PV were increased significantly (P<0.01) in patients with ischemic and nonischemic CRVO compared with control subjects but did not differ significantly between the two groups. No significant differences were found in SEA and SER values between the clinical subsets of patients with CRVO and when the patients were compared with matched control subjects. Analysis revealed that hemocrit and PV values were (P<0.001) increased significantly independent of associated cardiovascular risk factors. CONCLUSION: These results suggest that increased hemocrit and PV values may be contributing factors in the pathogenesis of CRVO.

Acute Disease↗
PubMed1996

[Quantification of cystoid changes in diabetic macular edema].

BACKGROUND: Cystoid changes in diabetic macular oedema can result in severe visual consequences and were previously difficult to quantify. This study was performed to introduce reliable measurements of the area covered by cysts, of their quantification and relation to visual acuity. PATIENTS AND METHODS: 58 diabetic patients suffering from cystoid macular oedema were examined by means of a scanning laser ophthalmoscope. Fluorescein angiography provides a detailed recognition of well demarcated cystoid formations in the early transit. In three different sampling areas from the center of the fovea (1.2 deg, 2.5 deg and 5 deg) and in the foveal avascular zone (FAZ) itself the area covered by cystoid changes was quantified as well as the number of cysts and their shortest distance from the center of the FAZ. RESULTS: The mean area covered by cystoid formations in the 2.5 degrees area was 0.128 +/- 0.08 micron2, the number of cysts ranged from 1 to 7. In all sampling areas there was a significant correlation between area of cysts and visual acuity. Their number and distance from the center of the FAZ did not show a significant correlation to vision. Measurements within the 2.5 degrees area seem to have the highest predictability concerning visual function. CONCLUSION: Fluorescein angiography allows the quantification of number and area covered by cystoid formations in patients with diabetic macular oedema. There is a significant correlation of visual acuity to the area covered by these cystoid changes. The distance of cysts from the center of the FAZ does not correlate significantly to visual acuity. These measurements can prove useful in following cystoid changes and in monitoring the effect of currently used therapy regimen.

Adult↗
PubMed1996

Autologous transplantation of nasal mucosa after severe chemical and thermal eye burns.

Between February 1992 and March 1994, reconstruction of the fornices in 17 patients with extensive symblephara or lid fusion after most severe eye burns was performed with nasal mucosa from the inferior conchae as graft material. The time between accident and transplantation ranged from 2-64 months. All patients were followed for 6 to 31 months. Reconstruction of the fornices was achieved in 13 patients. Postoperative Schirmer-tests revealed markedly improved results. Impression cytology showed a persistence of goblet-cells and an excess of mucus. We have subsequently performed keratoplasties in 5 of these patients and are planning penetrating keratoplasties in a further 8 cases. In 4 patients, partial symblepharon formation recurred within 2-3 months after transplantation of nasal mucosa. The main advantage of nasal mucosa over buccal or labial mucosa may be the transplantation of intraepithelial goblet cells, leading to an improvement and stabilisation of the tear film.

Adolescent↗
PubMed1996

Retinal hemodynamics during increased intraocular pressure.

The pathogenesis of primary chronic open-angle glaucoma (POAG) remains uncertain. It has been proposed that some of these patients may present with a deficiency in retinal hemodynamic autoregulation. It is also thought that visual field loss in POAG could be related to poor retinal perfusion. The present study was undertaken to evaluate the capacity of retinal autoregulation to maintain constant retinal circulation despite an acute rise in intraocular pressure (IOP). A total of 22 healthy subjects were recruited to this study. Retinal hemodynamics were assessed by digital video fluorescein angiograms using a scanning laser ophthalmoscope at normal (13.8 +/- 1.5 mmHg) and increased IOP (33.8 +/- 3.4 mmHg). Suction cups were used for raising the IOPs. The angiograms were performed at baseline and after 1 min of increased IOP. To quantify retinal hemodynamics the arm-retina time (ART) and arteriovenous passage time (AVP) were evaluated. The ART increased significantly from 9.4 +/- 1.8 to 11.8 +/- 2.2 s (P < 0.05) during elevated IOP, and the AVP was significantly prolonged from 1.6 +/- 0.4 to 3.0 +/- 0.8 s (P < 0.01) with IOP elevation as well. The increase in ART and AVP indicates an insufficiency of retinal autoregulation after an acute rise in IOP, even in healthy subjects. It appears that IOP values of > or = 30 mmHg may be detrimental to retinal perfusion in normals as well as in patients with POAG, who may have compromised retinal perfusion to begin with.

Adult↗
PubMed1996

Indocyanine-green angiography in patients with occult choroidal neovascularization.

Several studies have stressed the role of indocyanine-green (ICG) angiography in patients with occult choroidal neovascularization (O-CNV) secondary to age-related maculopathy (ARM). The present study was undertaken to evaluate the percentage of eyes that could be converted from O-CNV without suffering pigment epithelial detachment (PED) in well-defined CNV using ICG angiography with a scanning laser system. A total of 112 patients with ARM and O-CNV without PED were included in this prospective study. All patients underwent ICG angiography with a scanning laser system. The early phase (first 3 min) of the ICG angiogram was analyzed for the presence of a neovascular network, whereas focal or irregular hyperfluorescence was noted in the late phase. The early phase of the ICG angiograms revealed in 62 (55%) eyes a well-defined CNV. In 55 of these eyes, late irregular hyperfluorescent and hypofluorescent zones were observed. Another 27 eyes presented with focal hyperfluorescent areas in the latephase studies without having shown a well-demarcated area of neovascularization in the early phase of the ICG angiogram. This study confirms that ICG angiography is an important adjunctive method to fluorescein angiography. In more than 50% of eyes with O-CNV the ICG angiograms obtained with a scanning laser ophthalmoscope enable the visualization of a neovascular network in the early phase.

Aged↗
PubMed1995

The relationship of macular microcirculation to visual acuity in diabetic patients.

OBJECTIVE: To assess the perifoveal microcirculation in diabetic maculopathy without clinically significant macular edema and its relationship to visual acuity. DESIGN: Prospective analysis. SETTING: A teaching hospital. PATIENTS: Fifteen patients with impaired visual acuity of 20/50 or worse, a diabetic control population with unaffected visual acuity (matched age, gender, retinopathy stage), and 52 healthy controls were enrolled. INTERVENTIONS: Study consisted of video-fluorescein angiography with image analyses and hemoglobin A1c measurements. MAIN OUTCOME MEASURES: Macular capillary blood velocity, capillary density (perifoveal intercapillary area), and foveal avascular zone. RESULTS: The capillary blood velocity was significantly reduced in both diabetic groups (P < .001) when compared with healthy controls, but did not differ significantly among the two diabetic groups. The perifoveal intercapillary area and foveal avascular zone were significantly enlarged in both diabetic groups compared with healthy controls (P < .001). The foveal avascular zone (P < .01) and perifoveal intercapillary area (P = .01) were further enlarged in the diabetics with reduced visual acuity. The visual acuity correlated significantly with foveal avascular zone (R2 = .51) and perifoveal intercapillary area (R2 = .24), indicating an association between enlargement and declined visual acuity. CONCLUSIONS: Capillary blood velocity remained unchanged regardless of presence of visual impairment, whereas foveal avascular zone and perifoveal intercapillary area indicated ischemia. This may help in defining a critical hypoxic threshold for visual loss and identifying the presence of an ischemic diabetic maculopathy.

Adult↗