Biomedical subjects

Walter Konen

Publications and source records attributed to Walter Konen.

7 recordsLinked to original sources

PubMed2007

Cyclodialysis ab interno as a surgical approach to intractable glaucoma.

PURPOSE: In glaucoma filtration surgery, the problem of subconjunctival scarring has still not been satisfactorily solved. Suprachoroidal drainage of aqueous humour offers a promising, alternative option for intractable glaucoma. We here present a clinical study on the surgical approach of gonioscopic cyclodialysis ab interno. PATIENTS AND METHODS: Twenty-eight eyes of 20 patients with intractable glaucoma were included in this prospective, consecutive, case-control study. The eyes had had a mean of 4.4 +/- 2.4 previous antiglaucomatous interventions. Baseline intraocular pressure (IOP) was 34.3 +/- 10.5 mmHg despite maximum therapy. Under gonioscopic control, cyclodialysis ab interno was performed over two clock times to gain access to the suprachoroidal space. No additional trabecular meshwork surgery was performed. Success was defined as a lowering of IOP to below 21 mmHg without the need for further medication or intervention. RESULTS: Mean postoperative IOP was 14.6 +/- 12.4 mmHg. Mean follow-up (FU) for all eyes was 121.8 days. After a mean of 60 days, 21 eyes (75%) needed further surgical intervention. Qualified success was seen in four eyes (14.3%), with a mean FU of 383.6 days. Three eyes (10.7%) showed absolute success after a mean FU period of 202.7 days. In our series, we obtained the best results for phakic eyes, followed by pseudophakic and aphakic eyes. CONCLUSION: The results of this study do not provide convincing evidence of the functional efficacy of cyclodialysis ab interno. Nevertheless, the technique is easy to perform and offers safe and atraumatic access to the resorptive capability of the choroid. Conjunctival manipulation is avoided. Contrary to reports in the current literature, in our series, the best results were obtained for phakic eyes, though the small number of eyes included does not allow reliable statistics. Further studies will need to focus on the use of different space-retaining substances or a widening of the cyclodialysis cleft to improve surgical outcome.

Adult↗

PubMed2006

A novel approach to suprachoroidal drainage for the surgical treatment of intractable glaucoma.

PURPOSE: In glaucoma surgery, scarring of the artificial fistula is the limiting factor for long-term control of intraocular pressure (IOP). Several devices and surgical techniques have been developed for artificial aqueous humor drainage in intractable glaucoma. The authors describe a novel surgical technique that uses a silicone tube as a shunt for aqueous flow from the anterior chamber to the suprachoroidal space. PATIENTS AND METHODS: Thirty-one eyes of 31 patients with uncontrollable refractory glaucoma were included in this prospective consecutive case-control study. Each eye had undergone an average of 3.5+/-1.9 previous interventions for glaucoma. The baseline IOP was 44.25+/-8.7 mm Hg despite maximum therapy. As in trabeculectomy, a limbus-based scleral flap was prepared. The suprachoroidal space was accessed via a deep posterior scleral flap. The silicone tube was inserted as an intrascleral connection from the anterior chamber to the suprachoroidal space. Cyclodialysis was avoided by this surgical approach. Success was defined as a lowering of IOP to below 21 mm Hg without the need for further medication or intervention. RESULTS: The mean functional shunt survival was 55.9+/-45.6 weeks. IOP was reduced to 12.9+/-5.2 mm Hg in 70% of all eyes after 30 weeks postoperatively. After 52 weeks, 60% of the eyes could be classified as representing success, and 76 weeks after surgery, 40% of the eyes still showed controlled IOP. In none of the eyes were severe postoperative hypotony or suprachoroidal bleeding observed. No localized or general inflammation or infection was seen in connection with the silicon tube. Two patients needed anterior chamber lavage because of bleeding. In 2 patients the tube had to be removed because of corneal endothelial contact. Shunt failure of the tube was caused in some cases by connective tissue formation at the posterior lumen of the tube. CONCLUSION: This novel surgical approach and the placement of the silicone tube described here have several advantages. Its intrascleral course minimizes the risk of conjunctival erosion and associated infections. No cyclodialysis is performed. Connection to the suprachoroidal space exploits the resorptive capability of the choroid. It guarantees drainage but also provides a natural counterpressure, avoiding severe postoperative hypotony. The suprachoroidal shunt presented here achieves good follow-up results in terms of IOP control. No serious complications have been observed. This new method promises to be an effective surgical technique and presents a new therapeutic option in intractable glaucoma. Fibroblast reaction obstructing the posterior lumen, seemed to be the only factor limiting drainage. Further studies and experiments will be needed to elucidate the exact physiologic mechanisms underlying the draining, the capacity and duration of the draining effect, and the histologic background of suprachoroidal scarring.

Adult↗

PubMed2004

Contact lens, hyperopia and endothelial changes. A case report.

INTRODUCTION: We report on a 62-year-old healthy woman who suffered from bilateral predescemetic opacities, where the underlying disorder could not be identified. She had bilateral keratopathy with corneal edema, a diffuse predescemetic avascular haze and deszemetic folds. Because of high hyperopia (right +7.50/left +7.75) she weared soft contact lenses for years. METHODS: Removal of contact lenses. Treatment with local steroids and tear substitutes. RESULTS: One year after cessation of contact lenses VA recovered from RE 0.3/LE 0.1 to 0.8/0.63, the deep stromal opacity cleared up, the corneal edema recessed slightly. DISCUSSION: The differential diagnosis concludes either a pure contact lens change that is not completely reversible or a possible posterior polymorphous dystrophy that worsens with long-term contact lens wear and improves on cessation.

Contact Lenses, Hydrophilic↗

PubMed2004

Late hypotony as a complication of viscocanalostomy: a case report.

BACKGROUND: We report a long-term hypotony syndrome after deep sclerectomy, associated with intermittent rise in intraocular pressure (IOP) due to steroid response. PATIENT PRESENTATION: A 55-year-old woman with high myopia (RE -9.25, LE -10.50) suffering from uncontrolled pigment open-angle glaucoma, despite laser trabeculoplasty and a cyclodestructive procedure, underwent an uneventful viscocanalostomy. FOLLOW-UP: Intraocular pressure was between 9 and 17 mm Hg with local steroid medication 5 times a day, but became unstable with steroid reduction to 3 times a day and the patient developed hypotonous IOP (3-5 mm Hg) in the fourth postoperative month. With intensification of local steroid therapy, IOP rose to 49 mm Hg, and a reduction in medication was followed by hypotony. The instability of IOP with steroid medication could not be controlled and the IOP response due to steroids diminished with time; a long-term hypotony syndrome with maculopathy developed. Surgical inspection 10 months later with repeated preparation of the scleral flap showed (like ultrasound biomicroscope examination) a normal status after viscocanalostomy, without signs of leakage. CONCLUSIONS: Late hypotony syndrome should be considered as a potential complication of viscocanalostomy, perhaps especially in cases of myopia and former cyclodestructive procedures. In our case, despite nonpenetrating glaucoma surgery, the steroid response at first observed indicated additional outflow via the trabecular meshwork. After some months it could not be provoked any longer, leaving us to consider whether a gradual change in the trabecular meshwork hinders steroid medication changing aqueous outflow facility.

Antihypertensive Agents↗

PubMed2002

Risk profile of deep sclerectomy for treatment of refractory congenital glaucomas.

OBJECTIVES: To evaluate the effectiveness and risk profile of deep sclerectomy in surgery for refractory congenital glaucoma. DESIGN: Retrospective non-comparative interventional case series. PARTICIPANTS AND INTERVENTIONS: Ten eyes of eight consecutive patients underwent deep sclerectomy for refractory congenital glaucoma. The procedure was converted to a trabeculectomy in four eyes and supplemented by a trabeculotomy in two eyes. Six eyes had primary congenital glaucoma, and four eyes had secondary congenital glaucoma. The patients' ages at the time of surgery in our department ranged from 8 months to 14 years. All eyes had a history of previous glaucoma surgery. MAIN OUTCOME MEASURES: The surgical outcome was assessed in terms of complication rate, intraocular pressure (IOP) change, need for surgical revision, or additional glaucoma medication. RESULTS: Preoperatively, the mean IOP was 31.9 mmHg (standard deviation [SD], 5.6 mmHg). At first follow-up 1 week after surgery, the mean IOP for all eyes was 12.7 mmHg (SD, 6.8 mmHg). The average reduction of IOP was statistically significant (P < 0.001). In accordance with the success criteria, all eyes were ultimately classified as failures. Average time to failure was 2.1 months (SD, 3.6 months). Specific complications were seen in terms of non-identification of Schlemm's canal (40%), choroidal deroofing (10%), and visible perforation of the trabeculodescemetic membrane (20%). Further complications were hyphema (40%), ocular hypotony (10%), vitreous hemorrhage (10%), and vitreous loss with subsequent retinal detachment (10%). CONCLUSIONS: Although deep sclerectomy may reduce the IOP in patients with refractory congenital glaucoma, this study indicates a specific risk profile associated with deep sclerectomy in surgery for refractory congenital glaucoma.

Adolescent↗

PubMed2002

A prospective randomized trial of viscocanalostomy versus trabeculectomy in open-angle glaucoma: a 1-year follow-up study.

PURPOSE: To assess the intraocular pressure-lowering efficacy and the postoperative complication profile of viscocanalostomy versus trabeculectomy. PATIENTS AND METHODS: Sixty eyes of 60 patients with medically uncontrolled open-angle glaucoma were randomized either to the viscocanalostomy or to the trabeculectomy group of the trial. Viscocanalostomy was performed according to Stegmann's technique using high-molecular-weight sodium hyaluronate to fill the ostia of the Schlemm canal. For trabeculectomy, a modified Cairns-trabeculectomy was performed. Examinations were performed before surgery and postoperatively daily for 1 week. Follow-up visits were scheduled 1, 6, and 12 months after surgery. RESULTS: The mean (SD) preoperative intraocular pressure was 27.1 (7.1) mm Hg for all patients enrolled. One day after surgery, mean (SD) intraocular pressure was 15.9 (5.2) for the trabeculectomy group (P <0.001) and 15.7 (3.6) for the viscocanalostomy group (P <0.001), respectively. The success rate, defined as an intraocular pressure lower than 22 mm Hg without medication, was 56.7% in the trabeculectomy group and 30% in the viscocanalostomy group at 12 months postoperatively (P = 0.041). The number of postoperative complications was lower in the viscocanalostomy group than in the trabeculectomy group. CONCLUSIONS: In eyes with open-angle glaucoma, viscocanalostomy is less effective in reducing intraocular pressure than standard filtering surgery. However, postoperative complications are more frequent after filtering surgery.

Conjunctiva↗

PubMedDate not supplied

Treatment of granular dystrophy with soft contact lenses.

PURPOSE: To prevent recurrence of granular dystrophy by treatment with soft contact lenses. METHODS: After penetrating keratoplasty, a soft contact lens was fitted in a 61-year-old woman patient with granular corneal dystrophy. The lens was worn continuously for 53 months. RESULTS: No recurrence was observed. However, the other eye, which was operated on first and not treated with a contact lens, showed severe recurrence of the underlying disease, with granular deposits in the stroma. CONCLUSIONS: Fitting of a soft contact lens should be considered in this disease after penetrating keratoplasty.

Contact Lenses, Hydrophilic↗