Search PubMed⌕ Search

Biomedical subjects

F Grehn

Publications and source records attributed to F Grehn.

At least 37 records · Page 2Linked to original sources
PubMed2000

Success criteria and success rates in trabeculectomy with and without intraoperative antimetabolites using intensified postoperative care (IPC).

PURPOSE: To define the success rate of trabeculectomy for surgical treatment of glaucoma under intensified postoperative care (IPC) conditions in cases of severe visual field damage or progression of visual field loss. METHODS: In a retrospective study, we evaluated the outcome of trabeculectomy in 99 eyes of 99 patients from October 1995 to June 1997. In 23 eyes, antimetabolites were used intraoperatively. Regarding intraocular pressure (IOP), success was defined as lowering the preoperative, maximally treated IOP by more than 20% in addition to a postoperative IOP level lower than 21 mmHg without using further glaucoma medication. Success rate was defined by stabilisation of visual acuity and visual field in addition to IOP reduction. RESULTS: The postoperative IOP was 14.7 mmHg (+/- 3.4 mmHg) following standard trabeculectomy (preoperative IOP 24.3 +/- 6.7 mmHg) and 15.8 mmHg (+/- 4.9 mmHg) following trabeculectomy with intraoperative antimetabolites (preoperative IOP 27.0 +/- 9.5 mmHg). The success rate concerning the IOP was 83% in standard trabeculectomy and 74% following trabeculectomy with intraoperative antimetabolites. The visual acuity showed stabilisation in 93% of cases following standard trabeculectomy and in 100% following trabeculectomy with intraoperative antimetabolites. The visual field showed stabilisation according to the Aulhorn criteria in 95% and 94% of cases following standard trabeculectomy and trabeculectomy with intraoperative antimetabolites, respectively. The total success rate using all criteria together was 76% following standard trabeculectomy and 74% following trabeculectomy with intraoperative antimetabolites. CONCLUSION: The overall outcome after trabeculectomy is good with appropriate follow-up and timely decisions for after-treatment to ensure good development of the filtering bleb.

Adult↗
PubMed2000

Erbium-YAG laser-assisted preparation of deep sclerectomy.

BACKGROUND: Deep sclerectomy and viscocanalostomy are becoming more and more popular as non-penetrating filtering procedures. The purpose of the present study was to simplify the technique of this procedure and to reduce the rate of unintended perforations during the preparation of the deep lamella. METHODS: 20 enucleated porcine eyes were used. A superficial lamellar scleral flap with an area of 5x5 mm as for trabeculectomy was surgically prepared. Using a pulsed erbium:YAG laser the deep lamella (220 +/- 40 microm) with an area of 4x3 mm was removed. Ablation was performed with an energy of 40-100 mJ, a frequency of 1-10 Hz and a spot size of 500 microm and 1 mm (divergent beam). During the procedure the intraocular pressure was kept constant by continuous infusion. Finally the eyes were analyzed histologically. RESULTS: After initial trials it was possible to ablate the remaining deep corneoscleral lamella with the erbium:YAG laser without perforating into the anterior chamber. Starting with an energy of 70-85 mJ and a reduction to 40-60 mJ when reaching deeper layers, a spot size of 500 microm and a 10 Hz repetition rate gave the highest safety and efficiency in preparation. After a learning curve it was possible to preserve Descemet's membrane and intact trabecular meshwork in 10 consecutive operations as demonstrated by histology. CONCLUSION: Erbium:YAG laser-assisted deep sclerectomy offers an alternative to microsurgical preparation of the deep scleral lamella. The thermal damage is minimal (10-40 microm) and scarring may therefore not be stimulated.

Animals↗
PubMed2000

Trabeculotomy in congenital glaucoma.

BACKGROUND: Congenital glaucoma is a potentially blinding disease that requires surgical therapy. This paper describes the outcome of trabeculotomy in primary congenital glaucoma. METHODS: Thirty-nine eyes of 22 children with congenital glaucoma who underwent trabeculotomy with or without a simultaneous trabeculectomy between 1992 and 1997 were retrospectively analyzed. RESULTS: Mean follow-up was 24.7+/-17.9 months. A mean of 1.3 operations per eye were performed. The mean IOP at the end of follow-up (n=39) was 17.7+/-6.0 mmHg; in 8 eyes (20.5%) the IOP was >21 mmHg, in 31 eyes (79.5%) it was < or =21 mmHg. The mean difference between pretreatment IOP and IOP at the end of follow-up (n=39) was -10.5+/-9.4 mmHg (-37.2%). Success rates were calculated: IOP was < or =21 mmHg in 36/39 eyes (92.3%) after 1/2 year of follow-up, in 25/27 eyes (92.6%) after 1 year, in 15/18 eyes (83.3%) after 2 years, in 8/12 (66.7%) eyes after 3 years, in 4/8 eyes (50%) after 4 years and in 4/4 (100%) eyes after 5 years of follow-up. Complications included hypotony (three eyes), subchoroidal bleeding (one eye ), detachment of Descemet's membrane (one eye) and macular pucker (one eye in which later mitomycin C was used). Visual acuity (VA) was tested with various methods in 35 eyes. VA was within the normal nomogram range in 12 eyes and below the normal range in 23 eyes at the end of follow-up. Axial length measurements showed normalization according to the age nomogram in 22 of 35 eyes. CONCLUSION: This study shows that trabeculotomy is an effective surgical procedure in congenital glaucoma with satisfactory success rates up to 5 years of follow-up.

Child↗
PubMed1999

A prospective randomized comparison of two techniques of combined cataract-glaucoma surgery.

BACKGROUND: Small-incision cataract surgery combined with trabeculectomy offers new options for surgical treatment of patients with glaucoma and cataract. The purpose of this prospective randomized study was to compare the efficacy and safety of two different techniques of combined surgery: a one-site and a two-site approach. METHODS: Fifty eyes of 50 patients were included in this study. Twenty-five patients were randomly assigned to the one-site procedure and 25 patients to the two-site procedure. The one-site approach consisted of a superior tunnel phacoemulsification under a scleral flap with subsequent trabeculectomy. The two-site approach included a temporal corneal phacoemulsification combined with a separate-incision superior trabeculectomy. RESULTS: The preoperative mean intraocular pressure (IOP) of 29.8+/-4.9 mmHg dropped significantly to 15.9+/-3.2 mmHg. The mean follow-up time was 19+/-4. 3 months (range 4-25 months). The reduction of IOP was more pronounced in the two-site group (50.1%) than in the one-site group (43%), but the difference was not statistically significant. Patients needed 2.2+/-1.7 antiglaucomatous medications preoperatively vs 0.52+/-1.39 postoperatively. Three patients (6%) required needling of encapsulated bleb, and two patients underwent a reoperation to control IOP. Mean visual acuity improved from 0. 14+/-0.36 to 0.38+/-0.30 postoperatively. The most common complications after combined surgery were fibrinous exudation (24%) and hyphema (12%). CONCLUSION: Both techniques of combined cataract and glaucoma surgery proved to be efficient and safe procedures to control IOP and to improve visual acuity. The reduction of IOP did not differ between the one-site approach and the two-site approach.

Aged↗
PubMed1999

Ocular ochronosis in alkaptonuria patients carrying mutations in the homogentisate 1,2-dioxygenase gene.

AIMS: To assess the involvement of the recently identified human homogentisate 1,2-dioxygenase gene (HGO) in alkaptonuria (AKU) in two unrelated patients with ochronosis of the conjunctiva, sclera, and cornea. METHODS: A mutation screen of the entire coding region of the HGO gene was performed using single stranded conformational analysis after polymerase chain reaction with oligonucleotide primers flanking all 14 exons of the HGO gene. Fragments showing aberrant mobility were directly sequenced. RESULTS: Two homozygous missense mutations, L25P and M368V, were identified, each of which leads to the replacement of a highly conserved amino acid in the HGO protein. CONCLUSIONS: The authors describe a novel mutation, L25P, in the German population and bring to 18 the total number of known HGO mutations.

Aged↗
PubMed1998

Classification of filtering blebs in trabeculectomy: biomicroscopy and functionality.

The long-term success of filtering surgery is not dependent on surgical technique alone. The development of the filtering bleb in the postoperative period, in particular with regard to wound healing and subconjunctival scarring, is equally important. Morphologic changes of the developing filtering bleb after trabeculectomy can predict early failure even if the intraocular pressure is still normal. A basic understanding of wound healing processes and histologic changes of the developing filtering bleb are mandatory to interpret correctly the morphologic appearance of the developing filtering bleb. In clinical practice, follow-up of the filtering bleb according to a standardized morphologic classification may help to predict outcome and provide clues for the necessity and timing of further treatment.

Aqueous Humor↗
PubMed1997

[Reduction of endothelial cell number by cataract operation with intraocular thymoxamine administration. A randomized, double-blind study].

BACKGROUND: Thymoxamine, an alpha-1-receptor blocker, considerably enhances miosis when given intraocularly in combination with acetylcholine. We investigated whether intraocular use of thymoxamine 0.02% reduced the number of endothelial cells. PATIENTS AND METHODS: After phacoemulsification of 59 eyes, either thymoxamine 0.02%, acetylcholine 1.0% or buffered saline solution was given intraocularly. With a contact specular microscope, corneal endothelial cell photographs were taken on the day before treatment and 3 days and 6 weeks after surgery. RESULTS: There were no statistically significant differences between endothelial cell counts of eyes treated with thymoxamine (-7.2%), acetylcholine (-10.2%) or BSS (-9.4%). CONCLUSION: This study shows for the first time that thymoxamine, when given in the anterior chamber after phacoemulsification, does not cause a greater loss of endothelial cells than acetylcholine or buffered saline solution.

Acetylcholine↗
PubMed1997

[Trochlear paralysis within the scope of acute herpes hominis virus (HHV) 6 subtype B infection].

PATIENT: A 33-year-old woman developed progressive trochlear palsy without further neurological disorders. HHV-6 subtype B viremia was found in serological examination. TREATMENT: To prevent necrotizing encephalitis, a dangerous complication of untreated symptomatic acute HHV 6 subtype B infection, intravenous antiviral treatment consisting of initially ganciclovir, then ganciclovir and foscarnet in alternating combination and finally solitary foscarnet was performed. The result was complete eradication of viremia and restitution of the palsy. CONCLUSION: Bearing the risk of necrotizing encephalitis, acute HHV-6 subtype B infection should be taken into consideration as a possible cause for progressive neuroophthalmological disturbances of unknown etiology.

Antiviral Agents↗
PubMed1995

The value of trabeculotomy in glaucoma surgery.

Trabeculotomy has received increasing interest as a glaucoma procedure not only in congenital glaucoma but also in adult-onset open-angle glaucoma. In this review, the development, surgical technique, mechanism of action, and results after trabeculotomy in different types of glaucoma are described. Combined trabeculotomy and trabeculectomy and combined cataract and trabeculotomy techniques are discussed. Some remarks are given on laser trabeculotomy ab interno and other developments of trabecular surgery.

Cataract Extraction↗
PubMed1995

[Ultrasound biomicroscopy findings in various forms of glaucoma].

Ultrasound biomicroscopy is a new imaging technology that uses high-frequency ultrasound and thus allows depiction of the anterior portion of the globe in microscopic resolution. It is independent on the clarity of the optical media and allows, for the first time, a non-invasive demonstration of the structures of the posterior chamber and their relationship to each other. Therefore, it is especially suitable for diagnosis and research on the various forms of glaucoma. Our examinations were performed with an ultrasound biomicroscope (UBM Humphrey Model 840) with a 50 MHz transducer. This allows resolution of structures up to 50 microns. Thirty-nine patients with different forms of glaucoma were examined: POAG, pigmentary glaucoma, pseudoexfoliation glaucoma, pupillary block, plateau iris syndrome, ciliolenticular block, congenital glaucoma, traumatic glaucoma and situations after glaucoma surgery. The following findings could be demonstrated: configuration of the anterior chamber angle region, iris curvature, ciliary body and lens position, differentiation between solid and cystic tumors, traumatic changes and trabeculectomy openings. With this information ultrasound biomicroscopy offers additional details for the differential diagnosis and treatment of various forms of glaucoma.

Anterior Chamber↗
PubMed1995

[The Müller-ectomy in endocrine orbitopathy].

Thyroid ophthalmopathy frequently causes significant upper- and lower-eyelid retraction. This is not only cosmetically disfiguring, but also causes the cornea to be exposed so that a lid-correcting procedure becomes necessary. We used the Mueller ectomy technique with mechanical disinsertion of the levator muscle of the upper eyelid, as described by Putterman et al. in 1972, and operated on ten patients with thyroid ophthalmopathy. By means of the Mueller ectomy and mechanical disinsertion of the levator muscle of the upper eyelid, the eyelid was lowered by 5.0 mm compared with the preoperative findings (measured as the distance between the edge of the upper eyelid and the center of the pupil). In 3 cases the postoperative result was a temporal upper eyelid flare that required operative correction in one case; in one case a ptosis resulted postoperatively. Transconjunctival Mueller ectomy with mechanical disinsertion of the levator muscle of the upper eyelid gives good cosmetic and functional results in patients with significant upper-eyelid retraction. The transconjunctival approach avoids external scar formation and leaves the external lid structures intact so that a revision can be performed by an external lid incision.

Adult↗
PubMed1995

Color Doppler imaging: a new technique to assess orbital blood flow in patients with diabetic retinopathy.

PURPOSE: Color Doppler imaging is a new noninvasive technique that enables measuring blood flow velocity in small orbital vessels, arteries as well as veins. Because hemodynamic changes are seen in patients with diabetic retinopathy by other techniques, the authors compared 61 eyes with proliferative, 59 eyes with nonproliferative, and 26 eyes with preproliferative diabetic fundus changes with a matched control group of 70 patients without diabetes (128 eyes). METHODS: The central retinal artery (CRA), short posterior ciliary artery (PCA), and ophthalmic artery (OA) of all patients were examined, and the systolic, diastolic, and mean velocities were measured for each vessel. RESULTS: Differences between the groups were most prominent in the CRA. The perfusion velocity was significantly lower (P < 0.001) in proliferative eyes (Vsystolic 5.7 +/- 1.8 cm/sec) than in the control group (Vsystolic 9.4 +/- 1.2 cm/sec) or in nonproliferative eyes (Vsystolic 8.4 +/- 1.8 cm/sec). In the preproliferative group, there was greater variability in velocity distribution. Consequently, no statistically significant difference could be deduced, either in the group with background retinopathy or in the group with proliferative diabetes. In the OA and PCA, neither group showed significant differences from normal. CONCLUSIONS: Measurements indicate a correlation between severity of diabetic retinopathy and decreased flow velocity in the CRA.

Adult↗
PubMed1995

Cataract extraction combined with trabeculotomy.

Eyes with glaucomatous damage as well as eyes showing a clear elevation of intraocular pressure (IOP) to levels above normal frequently develop a permanent elevation of IOP after phacoemulsification or extracapsular cataract extraction, whereas the pressure in normal eyes usually decreases. In eyes with glaucomatous damage, we therefore combined cataract extraction with an antiglaucomatous operation, especially if a moderate pressure elevation was present: trabeculotomy and cataract extraction were performed in the same procedure. A corneal incision was used for phacoemulsification or extracapsular cataract extraction. The effects of the operation on the IOP and the visual acuity as well as the incidence of postoperative complications were investigated. In 44 operated eyes, the combination of cataract extraction and trabeculotomy proved to result in few complications and had a sufficient pressure-decreasing effect that continued throughout the 18 months of postoperative follow-up.

Aged↗
PubMed1995

Prophylactic Nd:YAG-laser iridotomy versus surgical iridectomy: a randomized, prospective study.

Both surgical iridectomy and YAG-laser iridotomy have been shown to prevent angle-closure glaucoma. However, it remains unknown as to which procedure is superior. We therefore conducted a prospective randomized study, which compared the effect of the two methods on visual acuity, intraocular pressure, endothelial cell density, depth of the anterior chamber, and iris configuration as well as acceptance by the patients. A total of 30 patients, who were treated for acute angle-closure glaucoma in one eye, were subjected to either surgical iridectomy or Nd:YAG-laser iridotomy in the other eye according to a randomized protocol. All patients were followed for 12 months by examination at the 1st, 6th, and 12th month post treatment. No significant difference between the two treatments was found regarding visual acuity or intraocular pressure. The peripheral anterior chamber increased in depth following both methods, whereas the central depth of the anterior chamber was unaffected. A better gonioscopic visibility of the trabecular meshwork resulted from the increased width of the chamber angle. Whereas the number of endothelial cells remained constant in the patients treated with laser iridotomy, a small decrease was observed in the group of patients who underwent iridectomy (-7.2% after 12 months; difference not significant). The subjective acceptance by the patients was better in the group treated with laser iridotomy. We conclude that the two methods are equivalent with regard to intraocular pressure and visual acuity. The constant number of endothelial cells and the better acceptance by the patients suggest Nd:YAG-laser iridotomy to be the preferable method for prophylaxis of acute angle-closure glaucoma.

Acute Disease↗