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Biomedical subjects

J C van Meurs

Publications and source records attributed to J C van Meurs.

At least 19 recordsLinked to original sources
PubMed2006

An outbreak of endophthalmitis after extracapsular cataract surgery probably caused by endotoxin contaminated distilled water used to dissolve acetylcholine.

AIM: To study possible causes of an outbreak of severe endophthalmitis after planned extracapsular cataract surgery in Medan, Indonesia. METHODS: In a 3 week period in November 2001, 17 of 43 patients developed signs of endophthalmitis after planned extracapsular cataract surgery. A search for possible causes was undertaken 4 months later. RESULTS: In autoclaved stored distilled water used to dissolve acetylcholine (used in 16 of 17 patients with endophthalmitis) a high amount of endotoxin was detected in a human blood essay, as well as a small number of non-typeable Pseudomonas spp. CONCLUSIONS: These findings suggest that distilled water used as solvent for acetylcholine was responsible for this outbreak of endophthalmitis. As a consequence, we now rely on solvents that are regularly checked for impurities such as an intravenous infusion fluid, rather than on vials with distilled water that is presumed to be sterile and kept for some time.

Acetylcholine↗
PubMed2004

Autologous peripheral retinal pigment epithelium translocation in patients with subfoveal neovascular membranes.

AIM: To evaluate the possibility of translocating autologous peripheral retinal pigment epithelial (RPE) cells and enhance their adhesion to improve functional outcome after choroidal neovascular membrane extraction in patients with subfoveal neovascular membranes. METHODS: A prospective, non-controlled surgical study in eight consecutive patients operated between February and July 2001 with final data monitoring in July 2002. All patients had mixed subfoveal membranes of 2-4 disc diameters. Functional tests included Snellen vision and central fixation testing. During vitrectomy, after the extraction of the neovascular complex, 8 x 10(4)-16 x 10(4) RPE cells were removed from the periphery and translocated under the macula following the submacular injection of 2 microg of poly-L-lysine to promote adhesion of the cells. RESULTS: With a follow up ranging from 3 months to 16 months, a pigmented area was seen in the extraction bed of the neovascular membrane in only one patient. Fixation was at the edge of the extraction bed in three patients. Vision remained the same in five patients and deteriorated in three (all with retinal detachment). Retinal detachment due to proliferative vitreoretinopathy occurred in three patients. CONCLUSIONS: The translocation of autologous peripheral RPE cells after membrane extraction was technically possible in a sterile manner, but was associated with a high proliferative vitreoretinopathy rate and in the present series had no measurable positive effect on functional outcome.

Adult↗
PubMed2001

Symptoms predictive for the later development of retinal breaks.

OBJECTIVE: To identify symptoms in patients with isolated posterior vitreous detachment predictive for the later development of retinal breaks. METHODS: Two hundred eighty consecutive patients seen with symptoms of posterior vitreous detachment were prospectively asked to complete a questionnaire detailing their symptoms. At the time of presentation and follow-up, all patients had a full ophthalmologic examination including slitlamp biomicroscopy with Goldmann 3-mirror contact lens after maximal pupil dilatation. Two hundred fifty patients with an isolated posterior vitreous detachment were included and reexamined 6 weeks after the onset of symptoms. If small retinal or vitreous hemorrhages were detected, patients were reexamined after 2 weeks. RESULTS: In 13 patients (5.2%) a retinal break was detected at reexamination. Logistic regression analysis with backward elimination revealed that symptoms of flashes in combination with clouds or multiple (>10) small dots at the time of the initial examination or an increase of floaters after the initial examination were statistically significantly (P<.001) related to the development of new breaks. These symptoms had a predictive value for the presence or absence of a new retinal break of 75.0% and 99.6%, respectively. CONCLUSIONS: Specific symptoms can identify patients at risk for the development of new retinal breaks after an initial examination in which no abnormalities were found and may obviate the need for follow-up appointments of patients not at risk.

Diagnostic Techniques, Ophthalmological↗
PubMed2001

Intravitreal vancomycin and gentamicin concentrations in patients with postoperative endophthalmitis.

BACKGROUND/AIMS: To study the intravitreal antibiotic concentrations and the efficacy of an intravitreal dosing regimen to treat patients with postoperative bacterial endophthalmitis. This regimen, based on pharmacokinetic/pharmacodynamic considerations, relies on a repeat antibiotic injection of a lower dose than is generally used. METHODS: In consecutive patients with suspected postoperative endophthalmitis a vitreous biopsy for bacterial culture was taken before 0.2 mg vancomycin and 0.05 mg gentamicin were injected intravitreally. After 3 or 4 days a second biopsy was taken for bacteriological culture and to measure intravitreal vancomycin and gentamicin concentrations, followed by a repeat injection of 0.2 mg vancomycin. RESULTS: 17 patients entered the study. In 11 patients the initial bacterial culture was positive, predominantly coagulase negative staphylococci. All second vitreous biopsies were sterile. Intravitreal vancomycin levels varied between 2.6 and 18.0 microg/ml (mean 10.3 (SD 4.1) microg/ml) after 3 days and between 3.1 and 16.6 microg/ml (mean 7.5 (6.2) microg/ml) after 4 days which is well above the minimal inhibitory concentration for most micro-organisms. Concentrations of intravitreal gentamicin varied between 0.90 and 3.3 microg/ml (mean 1.6 (0.72) microg/ml) after 3 days and between 1.2 and 2.6 microg/ml (mean 1.9 (0.99) microg/ml) after 4 days. CONCLUSION: This dosing regimen resulted both in adequate intravitreal vancomycin and gentamicin levels for over a week as well as in negative second cultures. This study also provides new information on intravitreal vancomycin and gentamicin concentration over time in patients with postoperative endophthalmitis.

Aged↗
PubMed2000

Retinal vasculitis occurring with common variable immunodeficiency syndrome.

PURPOSE: To report severe retinal vasculitis causing decreased vision in three patients with the common variable immunodeficiency syndrome. METHOD: Case report. Three patients with common variable immunodeficiency syndrome developed decreased vision secondary to retinal vasculitis. Fluorescein angiography was performed in all three patients. Peribulbar injections were given in one patient, and two patients were treated with oral steroids and cyclosporin. RESULTS: All three patients were young and had classic common variable immunodeficiency syndrome. Bilateral retinal vasculitis and diffuse retinal edema were present in all three patients, and two patients had retinal neovascularization in the absence of ischemia. No evidence of intraocular infection was present, and none was detected systematically. Visual acuity decreased in five of the six eyes and was responsive to treatment in only one patient (both eyes). CONCLUSION: Retinal vasculitis may be another autoimmune manifestation of common variable immunodeficiency syndrome.

Capillary Permeability↗
PubMed2000

Dexamethasone concentration in the subretinal fluid after a subconjunctival injection, a peribulbar injection, or an oral dose.

PURPOSE: To determine dexamethasone concentrations in the subretinal fluid of patients after a peribulbar injection, a subconjunctival injection, or an oral dose of dexamethasone and to compare the results with those of previous similar studies of dexamethasone concentrations in the vitreous. DESIGN: Prospective, nonrandomized, comparative trial. PARTICIPANTS: One hundred forty-eight patients with a rhegmatogenous retinal detachment. METHODS: Fifty patients received a peribulbar injection of 5 mg dexamethasone disodium phosphate, 49 received a subconjunctival injection of 2.5 mg dexamethasone disodium phosphate, and 49 received an oral dose of 7. 5 mg dexamethasone at various time intervals before surgery. At the time of surgery, a subretinal fluid sample was taken from each patient. MAIN OUTCOME MEASURES: The dexamethasone concentration in the subretinal fluid measured by radioimmunoassay. RESULTS: The estimated maximum dexamethasone concentrations in the subretinal fluid after the peribulbar injection, the subconjunctival injection, and the oral dose were, respectively, 82.2 ng/ml (standard error, 17. 6), 359 ng/ml (standard error, 80.2), and 12.3 ng/ml (standard error, 1.61). Corrected for dose, the maximum dexamethasone concentrations after subconjunctival injection and peribulbar injection were, respectively, 120 (95% confidence interval, 54/180) and 13 (95% confidence interval, 6.8/20) times greater than after oral administration. CONCLUSIONS: A subconjunctival injection of dexamethasone disodium phosphate is more effective in delivering dexamethasone into the subretinal fluid of patients with a rhegmatogenous retinal detachment compared with peribulbar injection or oral administration. The subretinal dexamethasone concentrations were higher than concentrations measured in the vitreous in previous studies with a similar setup after all three delivery methods.

Administration, Oral↗
PubMed1999

Follow-up of functionally lost eyes after vitrectomy and silicone oil tamponade for tractional retinal detachment.

BACKGROUND: Is there any association between, on the one hand, retention or removal of silicone oil or any specific ocular finding in patients with functionally lost eyes after vitrectomy and silicone oil tamponade for tractional retinal detachment and, on the other, a greater chance of preservation of the eye? This information is important in deciding whether to remove silicone oil, as well as in counseling patients about their individual chances of preserving their eye. METHODS: Seventy-three consecutive patients with a functionally lost eye with a minimum follow-up of 3 years were retrospectively studied. The relation between the variables at study entry or the removal of silicone oil during the follow-up period and a subsequent intervention (enucleation, evisceration or conjunctival cover with a scleral shell) were tested for statistical significance with Cox proportional hazards analysis. RESULTS: The absence or removal of silicone oil was not associated with a greater chance of finally preserving the eye. Nor could we identify other factors which predicted better chances of preservation. CONCLUSION: The notion that functionally lost eyes after treatment with vitrectomy and silicone oil tamponade for complicated tractional retinal detachment have better chances of preservation of the eye without silicone oil is not supported by our study.

Blindness↗
PubMed1999

High concentration of dexamethasone in aqueous and vitreous after subconjunctival injection.

PURPOSE: To determine the dexamethasone concentration in aqueous, vitreous, and serum of patients after a subconjunctival injection with dexamethasone disodium phosphate and to compare the effectiveness of a subconjunctival injection as a method of delivering dexamethasone into the vitreous with that of two previously tested routes: peribulbar injection and oral administration. METHODS: In a prospective study, 50 phakic patients who underwent a pars plana vitrectomy received a single subconjunctival injection with 2.5 mg of dexamethasone disodium phosphate, aqueous solution (after topical anesthesia and a subconjunctival injection with lidocaine) at varied intervals before surgery. An aqueous and a vitreous sample were taken from each patient, and serum samples were collected at multiple time points from nine of 50 patients. Dexamethasone concentrations were measured by radioimmunoassay. RESULTS: The estimated maximum dexamethasone concentration in the aqueous was 858 ng per ml at 2.5 hours after injection, and in the vitreous, 72.5 ng per ml at 3 hours. In serum, a mean maximum concentration of 32.4 ng per ml was measured at approximately 30 minutes after injection. CONCLUSIONS: Subconjunctival injection of 2.5 mg of dexamethasone disodium phosphate resulted in an estimated vitreous dexamethasone peak concentration three and 12 times higher, respectively, than after a peribulbar injection of 5 mg of dexamethasone disodium phosphate and an oral dose of 7.5 mg of dexamethasone. Thus, a subconjunctival injection is the most effective method of delivering dexamethasone into both the anterior and posterior segments of the eye. Systemic drug absorption is considerable and is of the same order of magnitude as after peribulbar injection.

Adult↗
PubMed1998

Dexamethasone concentration in vitreous and serum after oral administration.

PURPOSE: To determine the dexamethasone concentration in vitreous and serum of patients after oral administration of dexamethasone and to compare the results with the concentrations in vitreous and serum found in a previous study with peribulbar injection of 5 mg dexamethasone disodiumphosphate. METHODS: In a prospective study, 54 patients who were scheduled for vitrectomy received 7.5 mg dexamethasone orally at varied time intervals before surgery. A vitreous sample was taken from each patient and serum samples were collected at multiple time points from 32 out of 54 patients. Dexamethasone concentrations were measured by radioimmunoassay. RESULTS: Dexamethasone concentrations in serum ranged from 2.5 to 98.1 ng/ml (median, 61.6 ng/ml) between 1 and 3 hours after oral administration of 7.5 mg dexamethasone. Serum concentrations after peribulbar injection of 5 mg dexamethasone disodiumphosphate (containing 3.75 mg dexamethasone) were lower by a factor of 1.5. Concentrations in vitreous ranged from 1.7 to 23.4 ng/ml (median, 5.2 ng/ml) between 4 and 10 hours after oral administration. After peribulbar injection of 5 mg dexamethasone disodiumphosphate, the intravitreal concentrations were 3.9 times higher. CONCLUSIONS: An oral dose of 7.5 mg dexamethasone resulted in an intravitreal corticosteroid concentration with an anti-inflammatory potency that is clearly above physiological level. This concentration, however, is several times lower than is the intravitreal concentration after a peribulbar injection of 5 mg dexamethasone disodiumphosphate, although the two routes of administration resulted in nearly equal dexamethasone concentrations in serum. The higher intravitreal concentration after peribulbar injection is probably caused by diffusion from the serum and additional transscleral diffusion.

Administration, Oral↗
PubMed1997

Peribulbar corticosteroid injection: vitreal and serum concentrations after dexamethasone disodium phosphate injection.

PURPOSE: To study the dexamethasone level reached in human vitreous after a peribulbar injection of 5 mg of dexamethasone disodium phosphate and to assess its systemic uptake. METHODS: In a prospective study, 61 eyes of 61 patients scheduled for vitrectomy received a single peribulbar injection of 5 mg of dexamethasone disodium phosphate at varied intervals before surgery. At the start of vitrectomy, an undiluted vitreous sample was taken. In 22 patients, multiple serum samples were collected. Dexamethasone concentrations were measured by radioimmunoassay. The physiologic cortisol concentration was determined in the vitreous of 12 eyes of 12 patients who did not receive dexamethasone. RESULTS: An average dexamethasone peak concentration of approximately 13 ng/ml was reached in vitreous 6 to 7 hours after peribulbar injection. In serum the average peak concentration was approximately 60 ng/ml 20 to 30 minutes after peribulbar injection. The average physiologic cortisol concentration in vitreous was 5.1 ng/ml. CONCLUSIONS: After a peribulbar injection of 5 mg of dexamethasone disodium phosphate, an average intravitreal dexamethasone concentration is reached with a 75 times greater anti-inflammatory potency than physiologically present cortisol. Dexamethasone concentration in serum, however, is several times higher. Peribulbar injection is not just a local treatment but results in serum levels comparable to those achieved by a high oral dose.

Adult↗
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

Rubeosis of the iris in proliferative vitreoretinopathy.

PURPOSE: The authors report the findings and clinical course of rubeosis in patients with essentially reattached retinas after vitrectomy and silicone oil for proliferative vitreoretinopathy (PVR). METHODS: From 1989 on, the authors prospectively noted all patients with rubeosis and with attached retina posterior to the buckle after vitrectomy and silicone oil for PVR as a complication of rhegmatogenous retinal detachment. RESULTS: Thirty-eight patients (38 eyes) were studied. Mean follow-up after the appearance of rubeosis was 27 months (range, 6-66 months) in all patients, peripheral residual retinal detachment coexisted with rubeosis. Hypotony occurred in six patients. Cyclocryocoagulation for neovascular glaucoma had been performed in four patients. The peripheral detached retina was removed in 16 patients, resulting in total disappearance of rubeosis in 7 patients and regression in 4 more patients. In patients with visible, nonradially oriented iris vessels, the authors found vessels in the anterior chamber angle crossing the trabecular meshwork. The frequently present anterior synechiae in association with vessels never totalled more than three clock hours (except in the four patients who underwent cyclocryocoagulation). CONCLUSIONS: Detached retina peripheral to dense photocoagulation scars was present in all of these patients. Removal of this peripheral detached retina was statistically significantly associated with disappearance of rubeosis, which suggests that the peripheral detachment was a causative factor. Extensive anterior synechiae are not formed frequently in this condition. This may explain the infrequent (11%) occurrence of neovascular glaucoma. However, hypotony is more frequent.

Fluorescein Angiography↗
PubMed1994

Cytokines in vitreous humor: interleukin-6 is elevated in proliferative vitreoretinopathy.

PURPOSE: To measure the levels of interleukins (IL) 1 beta, 6, and 8, and tumor necrosis factor-alpha (TNF alpha) in the vitreous of patients with proliferative vitreoretinopathy (PVR), proliferative diabetic retinopathy (PDR), vitreous hemorrhage, and macular pucker. METHODS: Vitreous samples were collected, undiluted, from patients with PVR, PDR of varying severity, and miscellaneous lesions (vitreous hemorrhage from trauma, macular degeneration, vein occlusion, and non-PVR patients with giant tear, retinal detachment, and macular pucker). Immunoreactive levels of the cytokines, IL-1 beta, IL-6, IL-8, and TNF alpha were determined by enzyme-linked immunoadsorbent assays, and samples were analyzed for protein and hyaluronic acid content using standard assays. RESULTS: The levels of TNF alpha were below detection limits of the assay (< 3 pg/ml). In 45 of the 47 samples tested, IL-1 beta levels also were below detection limits of the assay (< 3 pg/ml). IL-6 levels ranged from < 30 to 5487 pg/ml, with the highest values observed in the PVR patients. IL-8 levels ranged from < 20 to 1900 pg/ml, and were consistently high in the miscellaneous group. Some of the PVR patients with C2 and C3 level severity also exhibited IL-8 levels exceeding 100 pg/ml. In a second study, IL-6 content of vitreous from miscellaneous and PVR patients was compared. In this study, significantly elevated levels of IL-6 were observed in the PVR patients (91.5 +/- 18 pg/ml) compared to the miscellaneous group (10.3 +/- 3.7 pg/ml) CONCLUSIONS: Elevated levels of IL-6 in the vitreous occur in PVR, implicating a role for this cytokine in the pathogenesis of this ocular disorder.

Adult↗
PubMed1993

Five-year results of vitrectomy and silicone oil in patients with proliferative vitreoretinopathy.

The purpose for this study was to evaluate the results of silicone oil use in patients who have undergone vitrectomy for proliferative vitreoretinopathy (PVR). The authors reviewed the 5-year results of 50 consecutive patients (52 eyes) with grade C1/D3 PVR operated on in 1987. Silicone oil has been removed in 42 eyes. The retina remained attached in 38 eyes. Visual acuities were finger counting in 12 eyes and 0.1 or greater in 19 eyes. Glaucoma was thought to be the major cause of loss of visual acuity after an initial improvement (9 eyes), as well as the most frequent complication of surgery (13 eyes). Silicone oil was deemed nonremovable in 10 operated eyes. A questionnaire was developed to determine the patients' perceptions of the use of silicone oil, and 46 patients responded to the questionnaire. Four patients indicated that they would not have elected to have surgery again. Six patients thought that surgery was not worthwhile, but would permit treatment again. Most patients thought that a modest amount of improvement had taken place and that vision was stable. Subjectively, most patients believed that surgery was worthwhile.

Evaluation Studies as Topic↗
PubMed1992

Endophthalmitis: incidence, therapy and visual outcome in the period 1983-1992 in the Rotterdam Eye Hospital.

From 1983 to 1992, 134 patients were treated for clinically suspected endophthalmitis. 61% of this endophthalmitis population consisted of cases that were referred to our clinic. In this nine year period antibiotic treatment was carried out according to three consecutively used guidelines. These three treatment schemes differed in antibiotic spectrum and mode of antibiotic delivery. In 68 patients we performed vitrectomy on account of clinical deterioration under antibiotic treatment. We did not find significant differences in visual outcome between the three treatment groups. The incidence of endophthalmitis following cataract or vitreous surgery did not change throughout the study period. There was however a dramatic decrease in incidence of post-traumatic endophthalmitis following the introduction of a prophylactic antibiotic treatment scheme consisting of fortified gentamicin and cefazolin eyedrops, and intravenously and subconjunctivally administered gentamicin, cefazolin, and clindamycin. In 55 of 68 cases in which vitrectomy was performed in conjunction with intravitreal antibiotics, a vitreous or anterior chamber specimen was cultured. 36 patients had a positive culture result. In the group with positive culture result 42% had better visual acuity in the post-treatment period than before treatment. In the group with a sterile culture result 79% had better vision after treatment.

Anti-Bacterial Agents↗
PubMed1992

Retinal vessel autoregulation in sickle cell patients.

We tested retinal vessel autoregulation in 16 sickle cell patients and 6 controls by computer-assisted measurements of constriction of the superior and inferior temporal veins and arteries after pure oxygen breathing. Compared to the controls and corrected for age, we found a decrease of vasoconstriction in three of the four vessels measured in the sickle cell group, which was statistically significant only for the superior temporal artery (P 0.009). The number of patients was too small to allow a separate analysis of possible contributory factors within the sickle cell group, such as sickle cell hemoglobin subtype and extent of retinal ischemia. Our findings indicate a factor not yet well known in the pathophysiology of sickle cell disease: an abnormality of local microvascular control.

Adult↗