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Biomedical subjects

H Freyler

Publications and source records attributed to H Freyler.

At least 19 recordsLinked to original sources
PubMed1996

In vivo study of cell reactions on poly(methyl methacrylate) intraocular lenses with different surface properties.

PURPOSE: To evaluate the biocompatibility of three poly(methyl methacrylate) (PMMA) intraocular lenses (IOLs) with different surface properties. SETTING: University Eye Clinic, Vienna, Austria. METHODS: Cell reactions on the surfaces of unmodified, heparin-surface-modified (HSM), and surface-passivated (SP) PMMA IOLs were documented in vivo using a Zeiss specular microscope. Risk factors for such reactions were also determined. RESULTS: During the first postoperative days, small round and spindle-shaped cells were found on all IOLs. Cell density was higher in eyes with increased postoperative inflammation. After several days, epithelioid and foreign-body giant cells were seen on some IOLs. Cells appeared significantly less often on the IOLs with hydrophilic surfaces (HSM) than on those with hydrophobic surfaces (unmodified, SP). CONCLUSION: The significantly lower incidence of foreign-body reactions on hydrophilic than on hydrophobic IOL surfaces is consistent with the results of previous studies on hydrogel and silicone IOLs.

Aged↗
PubMed1994

[Pseudoexfoliation syndrome--a risk factor in modern cataract surgery?].

BACKGROUND: The pseudoexfoliation (PEX) syndrome has been described in the ophthalmic literature as a major risk factor of cataract surgery. Most of the authors have reported extracapsular cataract extraction (ECCE) complication rates of more than 10% for zonular dialysis, capsular rupture, and vitreous loss. However, Osher et al. (1993) found that these complications from in situ phacoemulsification (PE) cataract surgery were less than 1%. We compared ECCE with PE by using the same surgeons for both procedures and evaluated retrospectively the complications for each in our patients. PATIENTS AND METHODS: Of 10,450 patients who underwent cataract surgery from 1986 to 1993, 102 PEX cases (0.98%) occurred. ECCE was performed on 34 of these patients, PE on 68 of the 102 patients. The average age of the PEX patients was 78 years. Miosis of 4 mm or less occurred in 19 eyes. To dilate the pupils, sphincterectomies were performed and iris retraction hooks were applied to the iris in the last two years. Eight surgeons (four with long-term experience and the remainder in training) performed the operations. RESULTS: The complication rates were 16.6% altogether for zonular dialysis, capsular rupture and vitreous loss, 26.47% for ECCE, and 11.76% for PE (p = 0.0664), in contrast to 1.3% for uncomplicated age-related cataract operations. However, these complications occurred in 14.28% of the ECCE patients and 9.09% of the PE patients with more or less normal dilation of the pupil. Still PE with miosis had fewer complications (23.07%) and was, thus, significantly safer (p = 0.0022) than ECCE (83.33%). Slight phakodonesis, observed during capsulorhexis, and an additional diagnosis of chronic open-angle glaucoma did not provide significant differences between the two surgical methods resulting in PEX. CONCLUSION: Miosis is beside phacodonesis the primary risk factor of PEX associated with cataract surgery. Compared with ECCE, PE had significantly fewer complications from PEX with miosis, not from PEX with phacodonesis. Applying the small iris retraction hooks appeared to decrease the complication risks stemming from miosis.

Adult↗
PubMed1993

[Pneumatic retinopexy--a study of 7 years experience].

BACKGROUND: The goal of this study is the evaluation of effectivity and the complications of pneumatic retinopexy in the treatment of rhegmatogenous retinal detachment as a long-term follow-up. MATERIAL AND METHODS: This retrospective long-term study covers 89 eyes with rhegmatogenous retinal detachment treated by pneumatic retinopexy between January 1985 and December 1991. With a postoperative follow-up averaging 4.8 years, it constitutes the longest such period published to-date in literature. RESULTS: The first intervention induced anatomical healing in 73% of all cases. However, 5.5% relapsed with retinal detachment after one month. Following a second intervention (excepting 2 cases) performed with conventional retinal detachment surgery consisting of exoplants + kryopexy + subretinal drainage, successrate was stepped up 97%. A total of 5 eyes required maximum surgery, i.e. vitrectomy + silicone oil tamponade. In 3% this procedure presented the third intervention. Finally anatomical healing was attained in 100% of the eyes. However, after one month 18% developed new retinal tears and after a follow-up period of 5.5 years this figure had risen to 27.7%. CONCLUSION: Judged on the basis of the above results, pneumatic retinopexy should only be recommended for the very simplest cases of rhegmatogenous retinal detachment (a single tear in the upper fundus half between 10 and 2 o'clock and no pathological changes in the lower fundus half). Also, check-ups at short intervals are required following pneumatic retinopexy. In our opinion standard buckling surgery with additional gas tamponade is preferable.

Adolescent↗
PubMed1991

[Differences in the pathogen spectrum of the conjunctival sac before and after irrigation of the lacrimal apparatus].

The microbial flora in the conjunctival sac of 30 patients was investigated. Qualitative and quantitative differences before and after irrigation of the lacrimal system were found. In some cases a quantitative increase was registered. In 12 cases conjunctival samples before and after irrigation changed. Negative results before and bacterial growth of coagulase-negative staphylococci after irrigation were found in 4 cases. In 3 cases unfavourable changes were seen. Pseudomonas, Klebsiella and beta-hemolytic streptococci were isolated after irrigation in these cases. In the other cases differences were insignificant. The sense of preoperative irrigation of the lacrimal system is discussed and questioned.

Aged↗
PubMed1990

[Laser therapy of diabetic maculopathy. A comparative study of the argon green laser and dye red laser].

One hundred eyes with (pre)-proliferative diabetic retinopathy underwent central laser treatment for macular involvement. Fifty eyes were treated with the dye red 630 nm, the other 50 with the argon green 514 nm laser. Eighty of the eyes had previously undergone panretinal photocoagulation; in the other 20 this was performed 1.5-3 months after treating the macula because the central retinal changes were predominant. In accordance with the clinical angiographic classification of diabetic maculopathy, into an exudative, an edematous, and an ischemic type, three photocoagulation techniques were employed as appropriate, i.e., focal coagulation, (modified) grid coagulation, and extensive centripetal panretinal coagulation. Neither postoperative visual acuity, nor the fluorescein angiogram, nor fundus color photography revealed any significant difference in the results obtained with the two laser wavelengths.

Diabetic Retinopathy↗
PubMed1988

[Comparison of the effectiveness and safety of levobunolol and timolol in ocular hypertension and chronic open-angle glaucoma].

Twenty-six patients with open-angle glaucoma or ocular hypertension were studied in a concomitant double-masked clinical trial lasting three months, in which the ocular hypotensive efficacy and safety of levobunolol (0.5%) and timolol (0.5%), topically administered twice daily, were compared. At all follow-up examinations there was a significant decrease in mean intraocular pressure from baseline in both treatment groups, with no significant difference between them in this regard. Few changes were seen in either treatment group in cup/disk ratio, visual fields, visual acuity, biomicroscopy, or ophthalmoscopy. In both groups slight decreases in mean blood pressure were observed. Levobunolol and timolol were similarly effective and safe in reducing intraocular pressure in patients with chronic open-angle glaucoma and those with ocular hypertension.

Adult↗
PubMed1988

Coagulation factors of contact phase of haemostasis are normal in well-controlled type-I diabetic patients despite presence of diabetic retinopathy.

Alterations of plasma coagulation factors have been reported in diabetic patients with severe microangiopathy and metabolic derangement. No information is available, however, for well-controlled type-I diabetic patients. Thus, we studied coagulation factors of the contact phase and inhibitors in 80 fairly well-controlled diabetics (42 female, 38 male, age 28 +/- 11 SD years). Mean HbA1c in these patients was 6.6 +/- 1.0 SD, duration of diabetes ranged from 6 months to 30 years, and 36% had retinopathy shown by fluorescein angiography. The well-controlled diabetic patients did not differ from controls in terms of the activity of prekallikrein, factor XII, high molecular weight kininogen, kallikrein inhibitor, C-1-esterase inhibitor and antithrombin III. Only alpha-2-macroglobulin, an inhibitor of the contact phase of blood coagulation, was elevated significantly in these patients (p less than 0.05). Diabetics with retinopathy had similar activities of prekallikrein, factor XII, high molecular weight kininogen, kallikrein inhibitor, c-1-esterase inhibitor and antithrombin III when compared with patients without retinopathy and controls respectively. alpha-2-macroglobulin did not differ in patients with and without diabetic retinopathy but were significantly elevated in both groups compared with controls. Correlation analysis showed significant positive correlation between HbA1c and the activity of high molecular weight kininogen, kallikrein inhibitor and alpha-2-macroglobulin. In patients with poor metabolic control (n = 11; 6 female, 5 male; age 25 +/- 5 SD years; HbA1C 10.7 +/- 0.9) prekallikrein (p less than 0.05), kallikrein inhibitor (p less than 0.005) and alpha-2-macroglobulin (p less than 0.005) were significantly elevated compared to the controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

No evidence for increased growth hormone responses to growth hormone-releasing hormone in patients with diabetic retinopathy.

Several studies report increased growth hormone (GH) responses to provocative stimuli in patients with diabetic retinopathy. We studied GH responses to 1 microgram/kg body wt human pancreatic GH-releasing hormone 1-44 (hpGHRH 1-44) in 33 patients with type I diabetes mellitus, 31 patients with type II diabetes mellitus, and 2 control groups (N = 11 and 8). Based on the results of fundoscopy and fluorescein angiography, the diabetic patients were subdivided into patients without diabetic retinopathy, patients with nonproliferative diabetic retinopathy, and patients with proliferative diabetic retinopathy. Growth hormone responses to hpGHRH 1-44 in diabetic patients with proliferative or nonproliferative retinopathy or without retinopathy were not significantly different regardless of the type of diabetes. Remarkably, GH responses to hpGHRH 1-44 in type I diabetic patients without retinopathy were significantly higher than the matched controls. Our data suggest that diabetic retinopathy in type I and in type II diabetes is not associated with increased GH responsiveness to hpGHRH 1-44, whereas in type I diabetes mellitus without diabetic retinopathy, a GH hyperresponsiveness to hpGHRH seems to occur.

Adult↗
PubMed1986

Combined vitrectomy and scleral resection in the therapy of massive epiretinal fibrous membranes due to diabetic retinopathy.

Between December 1981 and June 1984 scleral resection was performed in 35 patients suffering from end-stage proliferative diabetic retinopathy with traction retinal detachment involving the macula. In all cases, vitrectomy, membranectomy, segmentation, and delamination proved to be insufficient to mobilize the "shrunken" retina. In 22 cases (63%), retinal detachment was at least partially flattened in the area of the posterior pole of the eye. Visual acuity thus achieved ranged between 6/24 and 1/60, corresponding to an improvement of visual acuity compared with the preoperative situation in about one-third of the cases successfully treated (8 eyes).

Diabetic Retinopathy↗
PubMed1986

[Pseudophakic keratoplasty].

The author reports on 12 unselected consecutive penetrating keratoplasties performed for pseudophakic bullous keratopathy, in which the intraocular lens was retained. The visual results achieved were significantly better than those in aphakic eyes.

Corneal Diseases↗
PubMed1986

[Diabetic choroidopathy--a retrospective fluorescein angiography study. Preliminary report].

Both histologic studies and findings with Indocyanin green angiography furnish clear indications of the existence of diabetic choroidopathy. Out of 19,387 fluorescein angiograms made over the last 15 years at the First Ophthalmological Clinic of Vienna University, 902 were selected in which the choroidal vascular system is at least partially visible due to melanin hypopigmentation. The pathologic changes in the choroid observed in these angiograms can be allocated in two basic types of pathologic fluorescence: on the one hand hyperfluorescent lesions such as drusen in Bruch's membrane in suprisingly young diabetics, extremely hyperfluorescent lobules of the choriocapillaris, choroidal aneurysms, and neovascularizations; on the other hand, hypofluorescent lesions or structures were observed, such as delayed filling of the choriocapillaris and, in the late phase of angiography, varicose and tortuous choroidal vessels, drained and appearing dark in contrast to the diffuse background fluorescence.

Aneurysm↗
PubMed1986

[20 years' experience at a special department for diabetic retinopathy at the 1st University Eye Clinic in Vienna. A status determination].

This survey summarizes the results of almost 20 years of scientific research into diabetic retinopathy. On the basis of examinations and experience in the treatment of 5734 diabetics suffering from retinopathy, present knowledge with regard to the epidemiology, pathogenesis, prophylaxis, and treatment of diabetic retinopathy is communicated and discussed.

Austria↗
PubMed1986

[Retinal pseudothrombosis].

As opposed to florid diabetic retinopathy, pseudothrombosis in type I diabetics has a favorable prognosis and responds well to panretinal photocoagulation therapy. In the past decade eight cases of retinal pseudothrombosis were evaluated, treated and kept under observation at the department for diabetic eye complications of the 1st University Eye Clinic, Vienna. Photocoagulation therapy repeated at brief intervals halted progression in all cases and improved visual acuity. In the follow-up period (2-10 years) no further episodes of progression were seen.

Adolescent↗
PubMed1985

[Use of neodym-YAG-lasers in ophthalmology].

Structures within the eye bulb diminishing visual acuity can be cut by means of neodymium-YAG-laser without surgical opening of the globe. The First Eye Department has had the first instrument of this kind in Vienna at its disposal since the summer of 1984. Up to now it has been used for posterior capsulotomy, iridotomy, opening pupillary membranes and for cutting vitreous membranes in 84 operations altogether. The advantages of neodymium-YAG-laser are minimal psychological and physical stress for the patient and the possibility of out-patient surgery. A possible transient increase in the eye pressure and endothelial cell loss are disadvantages. Our experiences with the Lasertek Neodymium-YAG-laser model 135 are reported.

Cataract Extraction↗
PubMed1985

[Ultrastructural findings in secondary lipoidosis of the cornea].

A patient suffering from a progressive keratopathy which could not be identified clinically underwent penetrating keratoplasty. Light microscopy showed cholesterol deposits in deep stromal regions. Further ultrastructural investigations confirmed these findings and, in addition, fibrous long spacing collagen was found in that region; this represents a new factor in the possible pathogenesis of corneal lipid degenerations.

Cholesterol↗
PubMed1985

[Peripheral fluorescence angiography in diabetic retinopathy].

Using the CANON CG 6 60 Z wide-angle fundus camera, fluorescein angiographic examinations of the fundus periphery were performed on 90 diabetic patients presenting with exudative diabetic maculopathy. The peripheral angiogram demonstrates that perimacular hyperpermeability - the main cause of diabetic maculopathy - is preceded by extensive disturbances of capillary perfusion in the midperiphery.

Adult↗
PubMed1985

[Use of the neodymium YAG laser following posterior chamber lens implantation].

The authors report on the neodymium-YAG laser used after extracapsular cataract extraction with the implantation of a posterior chamber lens in 1726 patients. The most common indication was capsular fibrosis necessitating posterior capsulotomy. The alternative to the YAG laser would be a bulbus-opening procedure via pars plana using a Sato knife. The advantage of the YAG laser in comparison with capsulotomy with a Sato knife is that there is no danger of intraocular infection or bleeding (which may result from tension on the fibers with the first method). A disadvantage of the YAG laser method is a possible transitory increase in intraocular pressure and an endothelial cell loss. In 1726 cases with posterior chamber lenses 45 capsulotomies using the YAG laser were necessary. A further indication for the YAG laser are posterior chamber lenses decentered by capsular fibrosis (3 cases). A third indication is chorepraxia after posterior chamber lens implantation. In three cases with posterior chamber lenses a flattening of the pupil occurred because remnants of the anterior capsule had shifted into the anterior chamber. In two cases a pupil became decentered for no apparent reason. In these cases YAG laser therapy is indicated. In at least three cases pupillary membranes were cut with the YAG laser. The authors treated their patients with the Lasertec model 135 YAG laser (Q-switched mode).

Humans↗