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Biomedical subjects

J S Stilma

Publications and source records attributed to J S Stilma.

At least 19 recordsLinked to original sources
PubMed2006

6,220 institutionalised people with intellectual disability referred for visual assessment between 1993 and 2003: overview and trends.

AIMS: To summarise the results of visual performance tests and other data of institutionalised people with intellectual disability referred to a visual advisory centre (VAC) between 1993 and 2003, and to determine trends in these data. METHODS: A retrospective medical record review was undertaken of 6,220 consecutive people examined ophthalmologically according to a standard protocol by one VAC that specialised in visual assessment and treatment of people with intellectual disability, between 1993 and 2003. chi2 test for linear trend was used and linear regression coefficients were calculated. RESULTS: The proportion of people aged > or =50 years increased from 19.3% to 34.2% between 1995 and 2003 (p<0.001); the combined figure of severe or profound intellectual disability decreased from 80.0% to 52.6% (p<0.001); the proportion of mobile people increased from 52.1% to 98.0% (p<0.001); the combined proportion of people with visual impairment or blindness decreased from 70.9% to 22.9% (p<0.001), and that of people with visual disorders decreased from 89.6% to 75.3% (p<0.001). Causes of intellectual disability were identified in 58.4% people; 20.8% had Down's syndrome. CONCLUSION: Many ocular diagnoses were found, indicating the need for ophthalmological monitoring. Specialised centres are helpful, because assessment and treatment of people with intellectual disability is complicated and time consuming. Protocols for efficient referral will have to be developed. A major task lies ahead to improve the treatment rates of refractive errors, cataract and strabismus, and to find specific causes of intellectual disability.

Adolescent↗
PubMed2006

Chiasmal misrouting and foveal hypoplasia without albinism.

BACKGROUND/AIMS: To present the ophthalmological and electrophysiological characteristics of three darkly pigmented, female patients with misrouting and foveal hypoplasia. One of the patients had primary ciliary dyskinesia and situs inversus totalis (Kartagener syndrome). METHODS: Fundus photographs were taken and the angles at which the main temporal arterial branches leave the optic nerve head (ONH) were analysed. Optical coherence tomography (OCT) was performed through the presumed foveal region. Pattern onset visually evoked potentials (VEPs) (check sizes 60', 40/400 ms) were recorded and the chiasmal coefficient was calculated to detect misrouting. RESULTS: Fundus photography showed normally pigmented fundi with absence of the usual foveal hyperpigmentation, foveal avascular zone, and macular and foveal reflexes. On OCT no foveal pit was found. The VEP recordings showed the largest positive CI component over the right hemisphere for the left eye, and over the left hemisphere for the right eye, with the CI almost absent over the ipsilateral hemispheres. The differential derivations showed opposite polarity for the recordings of the two eyes. The chiasmal coefficients of all three patients were significantly indicative of misrouting (-0.99, -0.91, and -0.99, respectively). CONCLUSION: Based on the investigations in these patients the authors propose the hypothesis that foveal hypoplasia and misrouting exist as a distinct entity, and do not comprise the exclusive hallmark of albinism. The findings suggest that misrouting may exert a retrograde influence on foveal development.

Adolescent↗
PubMed2005

Prevalence of visual impairment in adults with intellectual disabilities in the Netherlands: cross-sectional study.

PURPOSE: To obtain the first representative and valid population-based prevalence figures on visual impairment and blindness in adults with intellectual disabilities (ID) and to identify risk groups. METHODS STUDY DESIGN: Cross-sectional survey. An age-Down's syndrome-stratified random sample of 1,598 persons from a base population of 9,012 adult users of ID services with mild to profound intellectual disabilities was screened. Participants underwent protocollised on-site screening of visual functions. Results were related to degree of ID, occurrence of Down's syndrome (DS) and age. MAIN OUTCOME MEASURE: Prevalences of visual impairment and blindness in the study population and in subgroups and weighted prevalences in the total Dutch population using ID services. RESULTS: Prevalences of visual impairment ranged from 2.2% (95% confidence interval (CI), 0.5-6.4) in young adults with mild ID and no Down's syndrome to 66.7% (95% CI, 41.0-86.7) in older adults with profound ID and Down's syndrome; prevalences of blindness ranged from 0.7% (95% CI, 0.1-4.1) to 38.9% (95% CI, 28.1-50.3). Weighted prevalences of visual impairment and blindness in the total Dutch population of adult users of intellectual disability services are 13.8% (95% CI, 9.3-18.4) and 5.0% (95% CI, 3.8-6.2), respectively. Prior to this study, visual impairment or blindness had remained undiagnosed in 106/261 (40.6%) persons. CONCLUSIONS: As compared to published figures for the general Dutch population aged 55 years and over (visual impairment 1.4%, blindness 0.5%), prevalences of visual impairment and blindness are higher in all subgroups with intellectual disabilities, including the young and mildly handicapped group. The diagnosis is too often missed. All persons with severe or profound intellectual disabilities, and all older adults with Down's syndrome, should be considered visually impaired until proved otherwise.

Adult↗
PubMed2005

[Optical coherence tomography, an important new tool in the investigation of the retina].

Optical coherence tomography, an important new tool in the investigation ofthe retina Recently optical coherence tomography (OCT) has been introduced into the field of ophthalmology to enhance visualization ofthe various retinal layers. OCT uses interference of near infra-red, low-coherent light reflected from the retina and from a reference mirror, to create transverse sections of the retina. The strength of the signal is a measure of the reflection of the retinal layer which is situated at the same distance from the light source as the mirror. Accurate placement ofthe mirror gives a transverse view of the retina with an axial resolution of 10 microm, with which the resolution of a histological section can be approximated. OCT is used in ophthalmic diseases such as macular oedema, macular holes and other abnormalities on the retinal-vitreous border, following photodynamic therapy and in treating glaucoma. OCT has been used to detect early glaucoma by measuring the thickness of the retinal nerve fibre layer. OCT and fluorescence angiography complement one another as diagnostic methods but OCT is superior in the diagnosis of macular oedema and macular holes. OCT provides images of retinal pathology which can easily be interpreted by both ophthalmologists and patients.

Diagnostic Techniques, Ophthalmological↗
PubMed2003

Visual performance in specific syndromes associated with intellectual disability.

PURPOSE: To report visual performance in adults with specific causes of intellectual disability (ID) and to compare the test results to published reports. METHODS: In a large-scale multicenter epidemiologic study of sensory impairments in 1598 adults with ID, the authors performed ocular assessments in 1539 persons. They compared the test results of those with five specific genetic disorders (Angelman syndrome, Prader-Willi syndrome, fragile X syndrome, Williams-Beuren syndrome, and tuberous sclerosis). RESULTS: An overrepresentation of strabismus, low vision, and refractive errors was found. Apart from fragile X syndrome and Prader-Willi syndrome (with in general mild to moderate ID), the other syndrome groups contained one or more subjects with visual impairment or blindness. A number of them had never been seen by an ophthalmologist. CONCLUSIONS: The authors confirm a number of ocular features previously reported by other studies and suggest some additional ocular features. They found increased frequencies of treatable ophthalmologic conditions in the subgroups. Because reliable ocular assessment is feasible for 85% of persons with ID, the results are an incentive to address visual functioning in people with ID in order to correct ocular problems and maximize their possibilities.

Abnormalities, Multiple↗
PubMed2001

The value of electrophysiology results in patients with epilepsy and vigabatrin associated visual field loss.

PURPOSE: To determine the value of electrophysiological findings in patients with temporal lobe epilepsy and to relate these findings to the amount of concentric contraction of the visual field and the use of vigabatrin. METHODS: Electro-retinograms and electro-oculograms were done on 30 patients, operated for temporal lobe epilepsy. The patients were divided into three groups: (A) concentric contraction of the visual field associated with a history of vigabatrin medication (15 patients), (B) normal visual field with vigabatrin use (11 patients) and (C) normal visual field without vigabatrin medication (4 patients). RESULTS: Electrophysiological abnormalities were found in 50% of the patients in group A. The Arden ratio of the EOG was lowered in 57%. Abnormalities in the ERG were found: b-wave implicit time photopic F was prolonged (50%), b-wave amplitudes scotopic B (53%), C (73%) and G (50%) and photopic H (50%) were diminished. The amount of visual field loss and the total dose of vigabatrin used, showed only slight correlation with the ERG and EOG. The use of vigabatrin during the ERG and EOG recording in group A, gave a higher b-wave amplitude scotopic G in 64% of cases. The a-wave implicit times scotopic G (73%) and photopic G (59%) and H (73%) were shortened in group B. CONCLUSION: EOG was abnormal in 57% in group A. ERG abnormalities could only be found in 50% of group A, mainly in the inner retina. Since also the total dose of vigabatrin and the amount of visual field loss did not really show a correlation with the electrophysiological findings and results of literature are not unanimous, electrophysiology does not appear at present to be a good method to detect patients with, or at risk of, vigabatrin associated visual field loss. Regularly performed visual field examination remains the cornerstone in screening.

Adult↗
PubMed2001

Visual field loss associated with vigabatrin: quantification and relation to dosage.

PURPOSE: To describe the correlation between visual field loss and the duration, dosage, and total amount of vigabatrin (VGB) medication in a group of patients with epilepsy. Co-medication of antiepileptic drugs (AEDs) and compliance were also studied. METHODS: Ninety-two patients (53 male and 39 female) taking VGB medication in the past or the present, attending the Outpatient Epilepsy Clinic in Utrecht, were examined with the Goldmann perimeter. The amount of visual field loss was calculated by the Esterman grid method and by a new method, with which the percentage surface loss of the visual field is measured. A complete drug history was compiled, specifying the amount and duration of VGB medication. Concomitant AED medication was noted. Serum levels of AEDs were determined. RESULTS: Linear regression showed the total amount of VGB as the most significant parameter to predict visual field loss (p < 0.001). Further, men were more affected than women (p = 0.026). Compliance was good, and other AEDs did not influence the results. CONCLUSIONS: Because prolonged use of VGB medication is correlated with the amount of visual field loss, VGB should be prescribed only when there are no alternatives. In such cases, we recommend an examination of the peripheral visual field before starting therapy and a repeated examination every 6 months.

Adult↗
PubMed2000

[Vigabatrin: balancing effectiveness vs. (irreversible) visual field loss as a side effect].

The antiepileptic drug vigabatrin causes an asymptotic concentric contraction of the visual field in 30 to 40% of the patients. The visual field loss seems to be correlated with the cumulative dose of vigabatrin and is not reversible. The cause of this field loss is located in the inner retina (the horizontal and/or amacrine cells). The exact mechanism is still unknown. Though abnormalities in electrophysiology and colour vision are found, regular visual field examination remains the cornerstone in detecting visual field loss. A careful judgement has to be made in individual patients before starting or continuing vigabatrin medication.

4-Aminobutyrate Transaminase↗
PubMed2000

Retinal detachment in ocular toxoplasmosis.

PURPOSE: To report on the clinical course and prognosis of retinal breaks and detachment occurring in patients with ocular toxoplasmosis. DESIGN: Retrospective cross-sectional observational study. PARTICIPANTS: One hundred fifty consecutive patients with ocular toxoplasmosis. INTERVENTION: A review of all records of patients with ocular toxoplasmosis who had consulted our department from 1990 through 1997 was performed. MAIN OUTCOME MEASURES: The presence of retinal detachment or breaks and possible risk factors, such as age, myopia, the interval between the last recurrence of inflammation and the onset of retinal detachment, severity of vitritis, previous treatment methods, and the location of the retinal abnormalities, were analyzed. RESULTS: We found a frequency of 6% (9/150) for retinal detachment and an additional 5% (7/150) for retinal breaks among our patients with ocular toxoplasmosis. Attacks of active ocular toxoplasmosis preceding the retinal detachment or retinal breaks were characterized by severe intraocular inflammation. The frequency of myopia in our patients with retinal detachment or retinal breaks was significantly higher than in patients with ocular toxoplasmosis without retinal detachment or retinal breaks. The functional prognosis for the patients with retinal detachment was poor; legal blindness (visual acuity < or = 20/200) resulting from retinal detachment occurred in five of the nine patients. CONCLUSIONS: Careful retinal examination in ocular toxoplasmosis is warranted, especially in patients with myopia and severe intraocular inflammation.

Adolescent↗
PubMed2000

Concentric contraction of the visual field in patients with temporal lobe epilepsy and its association with the use of vigabatrin medication.

PURPOSE: To describe concentric visual field loss found in the presurgical evaluation of patients with drug-resistant temporal lobe epilepsy and relate the findings to potential causative factors. METHODS: A series of 157 consecutive patients with drug-resistant temporal lobe epilepsy, who had been selected for neurosurgical treatment, was examined in a study set up as a prospective investigation of their visual fields, to document the loss of visual field resulting from surgery. Pre-as well as postoperative visual field examinations were performed following a standard protocol using static and kinetic perimetry. As a number of patients appeared to have an unexplained concentric visual field contraction in the presurgical examination, a relation with potentially causative factors was analyzed in a cross-sectional study of all these patients. Correlations were sought with duration and severity of the seizure disorder, underlying pathology as indicated by magnetic resonance imaging (MRI) and demonstrated by pathology, any type of antiepileptic drug (AED) ever prescribed, and gender. RESULTS: In this cross-sectional analysis of 157 consecutive patients who were candidates for surgery for temporal lobe epilepsy, absolute concentric contraction of the visual field of 10 to 30 degrees was found in the presurgical examination in 20 (17%) of 118 patients who had ever used vigabatrin (VGB) and in none of 39 who had not had this medication. This difference was significant (p = 0.004). In addition, men [15 (21%) of 72] were significantly more often affected (p = 0.007) than women [five (6%) of 85]. The degree of visual field loss, as indicated by the Esterman grid, showed a positive correlation with the duration of VGB medication. There was no correlation of visual field contraction with a history of meningitis as potential cause of the epilepsy, duration of the epilepsy, status epilepticus in the medical history, or histologic abnormality of the brain tissue removed. Ophthalmologic examination of the patients with concentric contraction revealed no abnormalities. None of the patients with concentric contraction complained spontaneously of their visual field loss. CONCLUSIONS: VGB medication is a causative factor in concentric visual field loss. Visual field examination of patients using VGB should be seriously considered.

Anticonvulsants↗
PubMed2000

Long term changes in the visual fields of patients with temporal lobe epilepsy using vigabatrin.

AIM: To study the long term changes in the concentric contraction of the visual field in patients with temporal lobe epilepsy on vigabatrin medication. METHODS: Repeated Goldmann visual field examinations were compared in 27 patients with drug resistant temporal lobe epilepsy and concentric contraction of the visual field. Two groups were studied: 16 patients who had already stopped vigabatrin medication before surgery and 11 patients who continued vigabatrin medication. RESULTS: Concentric contraction of the visual field did not change in 16 patients who stopped vigabatrin before the first examination; there was slight but significant progress in visual field loss in 11 patients who continued the use of vigabatrin. CONCLUSION: Long term follow up of concentric contraction in this selected group of patients indicates that vigabatrin associated visual field loss is not reversible and that progression is possible when vigabatrin is continued.

Anticonvulsants↗
PubMed1997

Occurrence of retained lens fragments after phacoemulsification in The Netherlands.

PURPOSE: To determine the incidence of retained lens fragments after phacoemulsification in The Netherlands and to evaluate the effect of vitrectomy on this complication. SETTING: Eleven vitreoretinal centers in The Netherlands. METHODS: We performed a retrospective analysis of all patients with retained lens fragments (N = 70) who were referred for vitreoretinal surgery to 11 specialized centers. Seven patients (10%) were treated with medication alone, and 63 (90%) had pars plana vitrectomy. Minimum follow-up after vitrectomy was 3 months. RESULTS: The incidence of retained lens fragments in The Netherlands was calculated at 0.9/1000 cataract operations. Retained lens fragments occurred during the learning curve and with experienced surgeons. After medical or surgical treatment, visual acuity was 20/40 or better in 43 of 70 patients (61%). Uveitis disappeared in all cases. Retinal detachment occurred in 10 patients (14%). Attached retinal breaks were treated in an additional 5 patients. Corneal grafting was performed in 2 patients. Patients who had immediate vitrectomy did not have better functional results than patients in whom vitrectomy was delayed. The iris-fixated claw lens was implanted successfully when capsular support was insufficient. CONCLUSIONS: The introduction of phacoemulsification in The Netherlands is associated with an increase of patients with retained lens fragments. Retained lens fragments are complicated by an increased risk for retinal detachment and corneal decompensation. Vitrectomy resulted in a marked improvement of visual acuity and clearing of uveitis.

Aged↗
PubMed1996

Elevated serum angiotensin-converting enzyme activity in onchocerciasis.

Our objective was to measure serum angiotensin-converting enzyme (ACE) activity in patients with onchocerciasis. Serum ACE activity is commonly used in the diagnosis and follow-up of patients with sarcoidosis. However, serum ACE activity can also be elevated in a number of other granulomatous disorders. In onchocerciasis, a parasitic disease affecting millions of people in Africa and Central and South America, granulomatous tissue around adult worms has been identified, yet raised serum ACE activity has not been reported so far. We measured serum ACE activity in serum samples from 42 onchocerciasis patients and 39 endemic controls previously enrolled in two studies concerning the side effects after invermectin treatment in Sierra Leone, West Africa. The mean ACE activity in the patient group was 53.8 units/liter (S.D. 19.8) compared with 35.2 units/liter (S.D. 14.0) in the control group (p < 0.0001). Nine of 42 patients had elevated ACE activity (mean of the endemic controls +/- 2 S.D.) compared with 1 of 39 controls (p = 0.01). Sensitivity and specificity of elevated ACE in serum from onchocerciasis patients from Sierra Leone was 21 and 97%, respectively. ACE activity was not related to the microfilarial skin load or development of side effects after ivermectin treatment. Serum ACE activity can be elevated in onchocerciasis. Clinicians should be aware of this phenomenon when determining serum ACE activity in persons from endemic areas.

Adult↗
PubMed1996

Aetiology of uveitis in Sierra Leone, west Africa.

BACKGROUND: In 1992, non-onchocercal uveitis caused 9% of blindness, 8% of visual impairment, and 11% of uniocular blindness among patients visiting an eye hospital in Sierra Leone, west Africa. The aim of this study was to determine the aetiology of uveitis in this population. METHODS: General and ophthalmic examination complemented by serum and aqueous humour analyses for various infectious agents was performed for 93 uveitis patients and compared with serum (n = 100) and aqueous humour (n = 9) analysis of endemic controls. RESULTS: At the initial examination, 45 patients (48%) proved to be severely visually handicapped. After clinical and laboratory analyses, an aetiological diagnosis was established for 49 patients (52%). Toxoplasma gondii was the most important cause of uveitis (40/93; 43%). Anti-toxoplasma IgM antibodies were detected in serum samples of seven of 93 patients (8%) compared with one of 100 controls (1%, p < 0.05). At least six patients (15%) with ocular toxoplasmosis had acquired the disease postnatally. Antibodies against Treponema pallidum were detected in 18 of 92 patients (20%) and in 21 controls (21%). Other causes of uveitis were varicella zoster virus (one patient), herpes simplex virus (two patients), and HLA-B27 positive acute anterior uveitis with ankylosing spondylitis (one patient), while one patient had presumed HTLV-I uveitis. CONCLUSIONS: In a hospital population in Sierra Leone, west Africa, uveitis was associated with severe visual handicap and infectious diseases. Toxoplasmosis proved to be the most important cause of the uveitis. Although the distribution of congenital versus acquired toxoplasmosis in this population could not be determined, the results indicate an important role of postnatally acquired disease. The results further suggested minor roles for HIV, tuberculosis, toxocariasis, and sarcoidosis as causes of uveitis in this population.

Adolescent↗
PubMed1995

Ivermectin detection in serum of onchocerciasis patients: relationship to adverse reactions.

Ivermectin treatment of onchocerciasis patients can be accompanied by adverse reactions. Not much is known concerning the pathogenesis of these reactions. Previous studies have demonstrated that the occurrence and extent of adverse reactions are related to infection intensity. However, some severely infected patients experience relatively few adverse effects. The aim of the present study was to investigate whether this seeming discrepancy could be due to diminished ivermectin absorption. Ivermectin concentrations one and two days after treatment were measured by high-performance liquid chromatography in sera of 71 skin snip-positive onchocerciasis patients (21 without reactions, 25 with mild reactions, 14 with moderate reactions, and 11 with severe reactions). The overall mean +/- SD ivermectin concentrations one and two days after a single oral dose (150 micrograms/kg) were 16.4 +/- 6.4 and 6.6 +/- 3.1 ng/ml, respectively. The overall mean +/- SD half-life was estimated to be 19.9 +/- 8.6 hr. The data presented did not show a relationship between ivermectin concentrations and the grade of adverse reactions.

Chromatography, High Pressure Liquid↗
PubMed1994

C-reactive protein and interleukin-6 are elevated in onchocerciasis patients after ivermectin treatment.

Ivermectin treatment of onchocerciasis can induce adverse reactions. Mechanisms underlying these reactions are poorly understood but may include activation of neutrophils. This study investigated the acute-phase response in onchocerciasis patients during 2 days after ivermectin treatment. The acute-phase protein C-reactive protein (CRP) and cytokines that mediate the acute-phase response (tumor necrosis factor-alpha [TNF alpha] and interleukin-6 [IL-6]) were measured in 144 skin snip-positive onchocerciasis patients and 12 skin snip-negative controls who received one dose of ivermectin (150 micrograms/kg). No elevated TNF alpha levels were found, but IL-6 and CRP were elevated in 25.7% and 50.7% of the patients, respectively, after ivermectin treatment. Most patients (89.2%) with raised IL-6 also had raised CRP. Such increases were not observed in controls and in patients were correlated with adverse reactions and microfilarial densities. These findings suggest a possible role of the acute-phase response in microfilarial destruction following ivermectin treatment.

Biomarkers↗
PubMed1994

Blindness from uveitis in a hospital population in Sierra Leone.

A retrospective study was conducted to assess the causes of blindness and visual impairment in patients who visited an eye hospital in Sierra Leone, West Africa, in 1989 and 1992. These data were compared with figures from 1981. Throughout the years, senile cataract was the major cause of blindness, followed by uveitis (including onchocerciasis). Uveitis remained the second most important cause of blindness in this population, despite the significant decrease in blindness from onchocerciasis (from 30% in 1981 to 15% in 1992). An increasing number of patients with uveitis from non-onchocercal origin was observed: almost 10% of the blindness found in 1992 was due to uveitis of non-onchocercal origin. A reduction in visual handicap in patients with non-onchocercal uveitis could be achieved if local hospitals could obtain more accurate diagnoses in these patients.

Age Distribution↗