PubMed Health⌕ Search

Biomedical subjects

Thomas Theelen

Publications and source records attributed to Thomas Theelen.

7 recordsLinked to original sources
PubMed2006

A pilot study on slit lamp-adapted optical coherence tomography imaging of trabeculectomy filtering blebs.

BACKGROUND: Our study aims to identify anatomical characteristics of glaucoma filtering blebs by means of slit lamp-adapted optical coherence tomography (SL-OCT) and to identify new parameters for the functional prognosis of the filter in the early post-operative period. METHODS: Patients with primary open-angle glaucoma, aged 18 years and older, scheduled for primary trabeculectomy at the Department of Ophthalmology, Radboud University Nijmegen Medical Centre, were considered for our study. All patients underwent standardized trabeculectomy with intra-operative application of mitomycin C. The filtering blebs were evaluated clinically and with SL-OCT on day 1 and 1, 2, 4 and 12 weeks following surgery. The resulting data were analysed and weighed against surgical success. To better understand the SL-OCT data a small comparative histologic study was performed. RESULTS: The study included 20 eyes of 20 patients. After completion of our study, 15 eyes of 15 patients (mean age+/-SD 67 +/- 16 years) were eligible for data analysis and 5 eyes missed at least one follow-up visit. Filtering surgery was considered successful (intraocular pressure < or = 21 mmHg without antiglaucomatous medication) in 11 of 15 eyes. SL-OCT frequently demonstrated multiple hypo-reflective layers within Tenon's capsule ("striping" phenomenon) in the first post-operative week. Presumably, these layers corresponded with drainage channels in the histological specimen. These channels were present in functional filters but not in the failures. In addition, the visualisation of the sclera below the filtering zone was better defined in failures compared with successful filtering blebs ("shading" phenomenon). We observed no differences in the volume and clinical aspect of the blebs in the successful group compared with the unsuccessful group. CONCLUSIONS: Successful filtering blebs show characteristic optical properties on SL-OCT. These phenomena suggest a diffusely enhanced fluid content and the presence of intra-bleb drainage channels in functional filtering blebs.

Aged↗
PubMed2004

Autosomal dominant rhegmatogenous retinal detachment--clinical appearance and surgical outcome.

PURPOSE: To study the clinical appearance and surgical results of autosomal dominantly inherited rhegmatogenous retinal detachments (RRDs). METHODS: After prospective examination of all but two family members, the medical records of 16 affected patients (21 eyes) of two families from the Netherlands with autosomal dominantly inherited RRD were retrospectively evaluated. Special attention was paid to the age at onset, the ocular morphology and the clinical appearance of the RRD. The type and number of the various surgical procedures were analyzed with respect to preoperative appearance of the RRD, postoperative results and final visual acuity. RESULTS: The mean age at onset of RRD of affected individuals in families A and B was 37 +/- 18 years and 19 +/- 10 years, respectively. The mean ocular axial length in the two families was 24.7 mm and 26.7 mm. The mean number of retinal defects preoperatively found was 2.2 in family A and 7.1 in family B. Round, atrophic retinal holes predominated. Two of 21 affected eyes showed significant preoperative proliferative vitreoretinopathy. Pars plana vitrectomy was the primary procedure in 4 cases; extra ocular buckling was the initial procedure in 15 cases. One eye received scleral folding with diathermy as primary surgery. Redetachment following surgery occurred in 5 of 10 cases in family A and 4 of 10 eyes in family B. Anatomical success could be achieved in 9 of 10 and 8 of 10 eyes in families A and B, respectively. CONCLUSIONS: In these families the prevalence of RRD is high. Most patients were affected at a relatively young age compared with non-genetically linked forms of RRD. Because of the low success rate of surgical intervention and, subsequently, the high number of operations necessary to achieve reattachment of the retina, the use of diagnostic genetic techniques to identify individuals at risk would be advisable. In these subjects measures to prevent RRD are an option, even when anatomical substrates of precursors of RRD are absent.

Adolescent↗
PubMed2004

Intraocular inflammation following endotamponade with high-density silicone oil.

BACKGROUND: The use of a mixture of silicone oil and partially fluorinated alkanes (high-density silicone oil) has recently been suggested as intraocular tamponade in complicated retinal detachment of the inferior quadrants. We describe a series of patients who developed a clinical picture resembling anterior granulomatous uveitis following endotamponade with high-density silicone oil. METHODS: We evaluated 19 eyes of 18 patients who underwent pars plana vitrectomy and intraocular tamponade with high-density silicone oil (Oxane HD). The indication for this type of intraocular tamponade was limited to cases with complicated retinal detachment of the inferior quadrants. Oxane HD was removed after a mean period of 3 months. RESULTS: One to eight weeks following vitrectomy with high-density silicone oil, an intraocular inflammation was observed in 7 of 19 eyes (37%). These eyes presented with keratic precipitates (KP), pigmented clumps in the inferior part of the anterior chamber and increased anterior chamber cellular reaction. This inflammatory response did not react to topical steroids. In addition to KP a considerable amount of cellular precipitation was noted on the surface of the oil bubble. Strikingly, the intraocular inflammatory signs completely resolved following removal of the high-density silicone oil. CONCLUSIONS: An inflammatory response, resembling granulomatous uveitis, occurs in a significant number of patients after high-density silicone oil endotamponade. It is likely that this vitreous substitute is an immunogenic agent, given the complete resolution of the inflammation after removal of the high-density silicone oil. The routine use of this newly developed silicone oil should therefore await the outcome of additional controlled clinical trials.

Aged↗
PubMed2003

A novel technique for self-sealing, wedge-shaped pars plana sclerotomies and its features in ultrasound biomicroscopy and clinical outcome.

PURPOSE: To investigate a new type of self-sealing pars plana sclerotomy clinically and by means of ultrasound biomicroscopy and to compare the outcome with conventionally sutured sclerotomies. DESIGN: Prospective, nonrandomized clinical trial. METHODS: Twenty-one patients underwent pars plana vitrectomy either with (control group) or without suturing (study group) at the Institute of Ophthalmology, University Medical Centre Nijmegen, The Netherlands, between January 1 and March 31, 2002. One day and 6 to 8 weeks postoperatively, the sclerotomy sites were studied by clinical examination and ultrasound biomicroscopy. Results were graded according to verbal descriptor scales. RESULTS: The study included 21 patients scheduled for pars plana vitrectomy of one eye. Mean follow-up time was 6.5 weeks (range, 6-8). Three patients were lost to follow-up. Of the remaining patients, 12 had self-sealing wedge-sclerotomies and six were conventionally operated. No intraoperative complications occurred in any participant and no visual loss or postoperative hypotony was observed. On the first day after surgery there was significantly more scleral dehiscence in the control group (P =.012). This divergence disappeared during the follow-up period. All other differences noticed were not statistically significant. CONCLUSIONS: Our novel technique of sutureless wedge-shaped sclerotomy allows the creation of simple, reliable, and self-sealing pars plana openings. Clinical examination and assessment by ultrasound biomicroscopy showed results to be at least as safe as conventionally sutured sclerotomies. This new method allows stable intraoperative ocular pressure conditions and seems promising.

Adult↗