Biomedical subjects

A M Verbeek

Publications and source records attributed to A M Verbeek.

At least 19 recordsLinked to original sources

PubMed2000

[Facial dysmorphism due to complicated congenital nasolacrimal duct obstruction].

Congenital nasolacrimal duct obstruction (in the literature also called congenital nasolacrimal mucocele or dacryocystocele) presents either as a simple nasolacrimal obstruction with epiphora or as a complicated obstruction on both sides of the lacrimal sac with midfacial deformation and respiratory insufficiency. Five neonates were treated for such complicated congenital nasolacrimal duct obstruction. Symptoms varied from an inner canthal purple-red swelling in the medial corner of the eye, with epiphora, to a serious midfacial deformation with respiratory insufficiency. The presence of a bilateral nasolacrimal mucocele leads to a broadened nasal bridge, which may be falsely interpreted as a dysmorphic feature of a congenital syndrome. Recognition of the condition allows a quick and efficient diagnosis and prevents unnecessary diagnostic procedures and anxiety. Differential diagnosis mainly includes frontobasal encephalocele and haemangioma. Treatment consists of massage, and catheterization if necessary.

Congenital Abnormalities↗

PubMed2000

Relationship between anticoagulant medication and massive intraocular hemorrhage in age-related macular degeneration.

BACKGROUND: A massive intraocular hemorrhage in the course of age-related macular degeneration (AMD) is a devastating event. We set out to determine the role of anticoagulant therapy prescribed for vascular or cardiac indications in the development of a massive hemorrhage. METHODS: A retrospective case-controlled study was conducted of 50 cases of age-related macular degeneration complicated by massive subretinal and vitreous hemorrhage. The control group consisted of 50 cases of AMD with small subretinal hemorrhage. RESULTS: There was a significant difference in the use of anticoagulant medication (warfarin sodium) between the groups. The difference in the use of antiplatelet medication (aspirin) between the groups was not significant. A patient with a massive intraocular hemorrhage and AMD is 11.6 times more likely to use anticoagulant medication. It appeared that more than 50% of the patients in the massive hemorrhage group were allowed to stop the anticoagulant medication. CONCLUSION: Anticoagulant medication poses a significant risk in the development of a massive intraocular hemorrhage in patients with exudative AMD. Antiplatelet medication poses a less significant risk. Physicians prescribing anticoagulant medication should be informed about the macular status of the patient. the In case of neovascular AMD, anticoagulant medication should be prescribed only for absolute systemic indications.

Aged↗

PubMed1996

Recurrent intrascleral cyst after strabismus surgery.

BACKGROUND: Intrascleral epithelial inclusion cysts have been described after ocular trauma, scleral buckling and strabismus surgery. They are usually small, asymptomatic and located anteriorly. CASE REPORT: The clinical history of a 9-year-old girl who developed a huge epi- and retrobulbar intrascleral cyst in both the upper and the lower nasal quadrants after multiple strabismus operations is described. RESULTS: Surgical resection of the cyst wall was twice unsuccessful. Drainage of the cyst, followed by the injection of tetracycline (30 mg/ml) in the cyst site, led to complete recovery. CONCLUSION: Recurrent posteriorly located intrascleral cyst can occur after strabismus surgery. Therapy consisting of drainage combined with intrascleral administration of tetracycline solution (30 mg/ml) to induce sclerodesis appeared to be effective during a 2-year follow-up period.

Anti-Bacterial Agents↗

PubMed1995

Conventional diagnostic ultrasound of iris lesions.

Eighty patients, referred for further evaluation of prominent iris lesions, were examined with conventional B-mode ultrasound equipment combined with a simplified immersion technique. The axial resolution of this system is about 350 microns. In 20.3% of the cases, the lesion was too small for ultrasound detection. A cystic lesion was diagnosed in 26% and a solid lesion in 53.7% of the patients studied. In 33.4% of the cases, the lesions were not confined to the iris but also appeared in the ciliary body. This last result shows the diagnostic value of the conventional ultrasound examination in the evaluation apparent iris lesions.

Adolescent↗

PubMed1995

A spider hits the eye.

To determine the necessary medical care and permanent ocular damage of a particular type of preventable ocular trauma, an observational study of 22 patients referred to the University Hospital Nijmegen (1983-1993) with eye injuries caused by the accidental release of tightened elastic straps of the so-called "spider' design was performed. Although the traumatized eyes of the 22 patients could be saved from blindness by extensive medical and surgical treatment in the majority of cases, 13 patients (59%) had residual permanent visual impairment (visual acuity < or =6/10, or aphakia) at the end of the follow-up period. Three of them had lost the perception of light in the involved eye; one painful blind eye had to be removed. It is concluded that elastic straps with free-end metal hooks should not be used to secure luggage because of the potential risk of irreversible damage to the eye.

Adolescent↗

PubMed1994

Echographic classification of intraocular tumours. A 15-year retrospective analysis.

The data on echographic routine diagnosis of intraocular tumours (prominence equal to, or larger than 2 mm) during the years 1976-1990 in the authors' department, were analyzed by multivariate statistical methods, using the final diagnosis either from pathology after enucleation or from the confirmed clinical diagnosis. The material consisted of melanomas (n = 325), metastases (n = 44), haemangiomas (n = 19) and other intraocular tumours (n = 16). The best set of echographic parameters in descending order of significance was: reflectivity (A-mode), choroidal excavation (B-mode), shape (B-mode), and regularity (A/B mode). Echographic differentiation by computer analysis of data on the three main kinds of tumours (melanoma/metastasis/haemangioma) separate from all the remaining tumours was expressed by the correct fraction: melanoma 89%, metastasis 80% and haemangioma 97%. The clinical echographic classification for these cases was 89%, 93% and 99.5%, respectively. The simultaneous differentiation between the three classes was found to yield a correct fraction of 85% by computer statistics and 95% by routine echography. The results of the present study might be used for prospective classification through the use of the parameter 'knowledge base' contained in the statistical classification procedure.

Choroid Neoplasms↗

PubMed1994

A comparison of rocuronium and vecuronium: the pharmacodynamic, cardiovascular and intra-ocular effects.

The aim of this study was to compare, in 30 patients, the pharmacodynamics of equipotent intubating doses of rocuronium and vecuronium and to compare their effects on heart rate, arterial pressure and intra-ocular pressure under steady state propofol anaesthesia. Baseline readings of heart rate and arterial pressure, using a Dinamap, and intra-ocular pressure, using a Tonopen, were made after induction of anaesthesia. The effects of the administration of the relaxants on these parameters were measured, recorded and compared. Rocuronium had a faster onset time than vecuronium, but had a similar duration of action. Vecuronium had no significant cardiovascular effects. Rocuronium caused a rise in mean arterial pressure (10-15%) and a slight rise in heart rate (5-10%). Both vecuronium and rocuronium caused similar falls in intra-ocular pressure. With its rapid onset time and lack of intra-ocular pressure effects, rocuronium is perhaps the relaxant of choice in patients with penetrating eye injuries requiring emergency endotracheal anaesthesia where a longer-acting relaxant is not contraindicated.

Adolescent↗

PubMed1993

A new ultrasonographic method to detect disease activity and predict response to immunosuppressive treatment in Graves ophthalmopathy.

PURPOSE: To determine whether the internal reflectivity of the eye muscles on A-mode ultrasonography serves as indicator for disease activity in Graves ophthalmopathy, thereby predicting response to immunosuppressive treatment. METHODS: Eye muscle reflectivity, expressed as percentage of the initial scleral spike, was measured in the superior, medial, and lateral recti, and normal values were determined in 23 healthy controls. These were compared with values in 16 consecutive patients with untreated, moderately severe Graves ophthalmopathy. The accuracy of the measurement was assessed by calculating the intra- and interobserver coefficient of repeatability. Baseline eye muscle reflectivity in the 16 patients was correlated to the therapeutic outcome 24 weeks after start of immunosuppressive therapy. The response to treatment served as indicator for pretreatment disease activity. RESULTS: Eye muscle reflectivity could be measured reliably, with an intraobserver coefficient of repeatability of 8.2% in controls and 10.2% in patients. Patients had lower reflectivity than controls (54.6 +/- 17.4% versus 70.7 +/- 6.6%; P < 0.001). Reflectivity in eye muscles with the lowest echogenicity was lower in responders than in nonresponders (25.8 +/- 8.4% versus 40.6 +/- 13.6%; P = 0.02). From the individual data, a cut-off value of 40% was derived, which appeared as an accurate predictor of outcome (positive predictive value 73%; 95% confidence interval 39%-94%). CONCLUSIONS: Measuring eye muscle reflectivity in Graves ophthalmopathy appears to be a reliable new method to determine disease activity, with a promising accuracy in predicting therapeutic outcome of immunosuppressive treatment.

Adult↗

PubMed1992

Echographic differentiation of intraocular melanomas by computer analysis.

The aim of this study was to assess the differentiation of histologically different types of choroidal melanomas by means of clinical and quantitative acoustic/texture parameters of echograms. Clinical parameters were graded by morphological, kinetic and quantitative statements about the A- and B-mode echograms by a skilled diagnostician. Acoustic/texture parameters were obtained by processing and analysing radio frequency, AM-demodulated and FM-demodulated echograms. The latter data were preprocessed to remove influence induced by beam diffraction and focusing. The best set of four clinical echographic parameters enabled a retrospective classification of spindle type melanomas vs. mixed+epithelioid type melanomas with an accuracy of 77% (area under the ROC-curve of 86%). The discriminant analysis performed with the best four acoustic/texture parameters (n = 30) yielded a sensitivity of 89%, a specificity of 92%, and an area under the ROC-curve which corresponds to a probability of correct classification of 96.6%. When using these data prospectively to classify tumours of unknown cell type (n = 21), this classification could be performed in 86% of cases.

Algorithms↗

PubMed1991

B-mode echography of choroidal melanoma; echographic and histological aspects of choroidal excavation.

The B-mode images of 32 patients affected with a malignant melanoma of the choroid were studied, in particular with respect to choroidal excavation. The degree of visibility of choroidal excavation at the B-scan was compared with the thickness of the choroid, scleral invasion, vascularisation, retinal detachment and the reflectivity of the tumour. None of these histological and echographical features appeared to be significantly related to the degree of the visibility of choroidal excavation. Also the condition of the choroid was studied. At examination of all the histological sections no choroid was found between tumour and sclera. This implies that choroidal excavation should be visible at echograms in every case instead of only in 75% of the cases as was found for our series.

Choroid↗

PubMed1991

Diagnostic ultrasound: an aid in the differentiation of anterior segment lesions of the eye.

Because the part of the globe in direct contact with the transducer cannot be visualised and focussed transducers have poor imaging qualities at a distance less than 5-8 mm from their surface, diagnostic ultrasound of the anterior eye segment has been treated in a stepmotherly way. With a simplified immersion technique we can visualize quite accurately a variety of pathologic conditions of the cornea, anterior chamber, iris, lens and ciliary body. The B-mode information is superior to the A-mode in this part of the eye.

Anterior Chamber↗

PubMed1991

Uveal melanomas diagnosed in the 6 months after lens-implant surgery.

During a five-year period uveal melanoma was diagnosed in 11 patients in the 6 months after lens-implant surgery. Pre-operatively all but one of the patients had bilateral senile cataract. The tumours were remarkably large and localised in the periphery rather than in the posterior pole (mean maximum tumour diameter 12.5 mm); they were therefore present at the time of surgery. An adequate pre-operative diagnostic ultrasound examination had not been performed in any of the patients. A plea is therefore made for the performance of an echographic examination in all eyes with opaque media in order to exclude solid lesions or other pathology in the vitreous cavity.

Aged↗

PubMed1991

Echographic differentiation of histological types of intraocular melanoma.

The aim of this study was to assess the differentiation of histologically different types of choroidal melanomas by means of clinical and quantitative acoustic/texture parameters of echograms. Clinical parameters were graded by morphological, kinetic and quantitative statements about the A- and B-mode echograms by a skilled diagnostician. Acoustic/texture parameters were obtained by processing and analysing radio frequency, AM-demodulated and FM-demodulated echograms. The data were preprocessed to remove influences induced by beam diffraction and focusing. The correlations between the clinical parameters were lower than 0.5 but significant in a few cases. The best set of four clinical echographic parameters enabled a retrospective classification of spindle type melanomas vs. mixed + epithelioid type melanomas with an accuracy of 77% (area under the ROC-curve of 86%). These figures do not enable, however, a prospective diagnosis. The correlations of the clinical parameters with the acoustic/texture parameters were investigated. The mutual correlations between the latter parameters were also assessed, the most significant (0.70) being between the speckle size and the slope of the linearized backscattering spectrum. The discriminant analysis performed with the best four acoustic/texture parameters (n = 30) yielded a sensitivity of 89%, a specificity of 92% and an area under the ROC-curve corresponding to a probability of correct classification of 96.6%. When using these data prospectively to classify tumours of unknown cell type (n = 21), this classification could be performed in 86% of cases.

Algorithms↗

PubMed1991

Ultrasonic differentiation of intraocular melanomas: parameters and estimation methods.

In this study, the estimation of ultrasound parameters is evaluated for in vivo differentiation of intraocular melanomas. For this purpose, both tissue and image parameters of the ultrasound signal are considered. These parameters comprised, respectively, the frequency dependent attenuation and backscattering coefficient of the melanoma tissue, and the first and second-order statistics of the amplitude-modulated and phase-derivative images of the melanomas. A diffraction correction procedure has been applied prior to the estimation of the parameters to correct the ultrasound signals for the echographic equipment used and for the various distances of the region-of-interest to the transducer. In addition, a pre-processing to select a homogeneous region from the tumours was implemented to obtain consistent estimates of the ultrasound parameters, because the accuracy and the precision of the parameters would be greatly reduced by the inhomogeneity of the melanoma tissue. The estimation methods are evaluated by means of the accuracy and precision of the parameters estimated from simulated ultrasound data and data obtained from a tissue-mimicking phantom. The mutual correlations of the parameters are discussed for the ultrasound data obtained from the melanomas. This study enabled a preselection of the independent ultrasound parameters that could be used in a discriminant analysis to perform a differentiation of intraocular melanomas. The sensitivity and specificity of differentiating spindle cell type from mixed-epitheloid meleanomas were 92 and 89 percent, respectively.

Choroid Neoplasms↗

PubMed1990

Choroidal metastasis of oesophageal squamous cell carcinoma.

A case report of a choroidal metastasis from an oesophageal squamous cell carcinoma is described. The computerised tomographic, ultrasonographic, histologic and immunohistochemic findings are presented with a review of the literature.

Carcinoma, Squamous Cell↗

PubMed1990

The electro-oculogram in uveal melanoma. A prospective study.

The electro-oculogram in 52 patients with a suspected malignant melanoma of the choroid or ciliary body was plotted in a diagram constructed for the differential diagnosis of malignant melanoma, metastasis, naevus and retinal detachment. Thirty-one patients were diagnosed as suffering from malignant melanoma on clinical grounds (19 histologically confirmed). Twenty-six were classified correctly as a melanoma using our EOG probability score. Rupture of Bruch's membrane and tumor localization were of no influence on the EOG classification. Accompanying retinal detachment lowered the Lp/Dt-ratio significantly without affecting the Dt, as was also the case in tumors with a prominence equal to or greater than 6 mm when compared with smaller tumors. However melanomas were still classified correctly in the majority of the patients by means of EOG. We conclude that an acceptable differentiation can be made between melanomas, retinal detachments and naevi. Melanomas cannot be differentiated from choroidal metastases.

Choroid Neoplasms↗

PubMed1990

Dominant inherited tilted disc syndrome and lacquer cracks.

Three patients with the tilted disc syndrome from one family were examined. The presence of the trait in three consecutive generations suggests an autosomal dominant mode of inheritance, although in these patients with variable expression. The propositus showed bilateral inferonasal retinal ectasia, with atrophic subretinal scars. Linear-like lacquer cracks, radiating from the central scars, were also present running parallel to the margin of the optic nerve head. The linear streaks were very similar to those usually seen in traumatic tears of Bruch's membrane. The mechanical stretching of the ectatic area, and its abnormal location inferonasal to the optic disc might have been responsible for the unusual pattern of the lacquer cracks in our patient.

Adult↗

PubMed1989

Radiotherapy of choroidal metastases.

With binocular indirect ophthalmoscopy, fluorescin angiography and ultrasonography 68 choroidal metastases in 52 eyes of 39 patients were diagnosed. The primary tumors were mainly breast cancer (81%) and lung cancer (10%). After radiation treatment the visual acuity improved in 17 eyes (38%), stabilized in 15 eyes (33%), whereas in 13 eyes (29%) deterioration could not be prevented (seven eyes unknown). Regression of the lesions or its accompanying secondary retinal detachment was seen in 78% of the eyes treated. Acute transient side effects of radiation therapy were kerato-conjunctivitis (nine patients) and acute glaucoma in one patient. No cataractous changes of the lens were observed in the post radiation period (one to 42 months). Irradiation of choroidal metastases can contribute to improvement of the quality of life with a treatment scheme of 30 Gy in ten daily fractions.

Adolescent↗