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Results for “Fluorophotometry”

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At least 19 recordsLinked to original sources

PubMed1992

Quantification of blood-aqueous barrier function using laser flare measurement and fluorophotometry--a comparative study.

Fluorophotometry allows calculation of the permeability coefficient k(a) of the blood-aqueous barrier to fluoresceine after i.v. dye application; aqueous flare can be graded objectively by laser flare measurement and permits in vivo estimation of over-all protein concentration in the aqueous humor. To evaluate a formal relationship between both procedures we performed laser flare measurements on 40 eyes (clinically ranged from healthy to mild uveitis) before and during fluorophotometry. Laser flare count [mec-1] raises exponentially (r = 0.8; p = 0.05) with an increasing permeability coefficient to fluoresceine k(a) [10(-4)min-1]. Laser flare count during the fluorophotometry procedure is not increased (p = 0.05) compared to the prescan. Reproducability was 14% +/- 7.5% for laser flare measurements and 13% +/- 5% for fluorophotometry. Malfunction of the blood aqueous barrier possibly increases the permeability to molecules of high molecular weight not proportional to that of hydrophilic particles of low molecular weight. The exponential regression between the data achieved with both procedures suggests that fluorophotometry is more sensitive in detecting early changes in blood aqueous barrier function whereas laser flare detection could be appropriate in more severe cases of barrier dysfunction.

Adult↗

PubMed1993

A comparison of the laser flare cell meter and fluorophotometry in assessment of the blood-aqueous barrier.

PURPOSE: To evaluate and compare the use of the Kowa laser flare cell meter and intravenous anterior chamber fluorophotometry in assessment of the blood-aqueous barrier after cataract surgery. METHOD: Laser flare and cell measurements and fluorophotometry were performed at 1 and 3 months after surgery in 48 eyes of 44 patients admitted for routine cataract surgery. The fellow pseudophakic eyes of these patients were used as controls. RESULTS: The two techniques measure different parameters, but both methods are able to document the integrity or breakdown of the blood-aqueous barrier. However, the laser flare cell meter is more sensitive in quantifying subtle changes in barrier function to large molecules (proteins). Various methods of assessing anterior chamber fluorophotometry data were also compared. Measurement of a diffusion coefficient (requiring the measurement of plasma fluorescence) was not found to be more sensitive than other methods and did not alter the clinical significance of data obtained from the measurement of anterior chamber fluorescence alone. CONCLUSIONS: Both the laser flare cell meter and fluorophotometry provide a method for the assessment of the postoperative blood-aqueous barrier. However, the laser flare cell meter is rapid, noninvasive, and relatively easier to use. Therefore, for clinical use, it has great practical advantages over fluorophotometry.

Adult↗

PubMed1987

Vitreous fluorophotometry in patients with cataract surgery.

Cystoid macular edema frequently complicates recovery from cataract surgery. Our understanding of this disease would be enhanced by more sensitive and quantitative methods to evaluate it. We performed vitreous fluorophotometry in 66 nondiabetic patients who had recently undergone cataract surgery. Eyes with definite macular edema on fluorescein angiography were ranked according to the severity of the leakage. The rank of the leakage correlated significantly with the vitreous fluorophotometry values (P less than 0.01). The mean fluorophotometry result in the eyes with cystoid macular edema was greater than that in the phakic, control group (P less than 0.01). However, eyes with minimal or no leakage visible on fluorescein angiography had fluorophotometry values indistinguishable from normal. The quantitative vitreous fluorophotometry results provided an indicator of cystoid macular edema that may prove useful in following this problem and evaluating therapy for it.

Aged↗

PubMed1995

The blood-ocular barrier in type I diabetes without diabetic retinopathy: permeability measurements using fluorophotometry.

For the evaluation of a possible malfunction of the blood-retinal (BRB) and the blood-aqueous barrier (BAB) in type I diabetes without manifest angiopathy, after i.v. injection of sodium fluorescein, the permeability of BRB (P) and the diffusion coefficient of BAB [P(a)] were studied simultaneously by fluorophotometry in 34 eyes of 34 type I diabetics (HbA1c = 6.6 +/- 0.9%) without retinopathy whose ages ranged from 19 to 38 years (30.5 +/- 5); diabetes' duration was between 5 and 18 years. Fluorescein angiography was performed to exclude nonperfused areas. In all, 34 eyes of 34 healthy volunteers whose ages ranged between 23 and 34 years (28.5 +/- 3.3) served as controls; in this group, fluorophotometry was performed twice to evaluate reproducibility. The mean BAB diffusion coefficient in diabetics [P(a) = 5.3 +/- 1.8/min] was significantly increased (p = 0.00003) as compared to controls [P(a) = 3.7 +/- 0.7/min]; BRB permeability in diabetes (P = 3.2 +/- 1.4 x 10(-7) cm/s) was raised with this elevation being of lower significance (p = 0.019; controls: P = 2.6 +/- 0.7 x 10(-7) cm/s). We found a decrease in BRB permeability depending on diabetes' duration (r = -0.15; p = 0.007) that was not significant in BAB (r = -0.1; p = 0.24). No correlation was found to exist between permeability and HbA1c values either in BAB or in BRB. The reproducibility in controls was 9% in BRB determinations and 12% in BAB measurements. These results may suggest that early structural alterations without the manifestation of retinopathy possibly cause elevation in BRB permeability and are even more obvious in BAB permeability. Whereas the reliability of vitreous fluorophotometry in detecting early BRB malfunction has to be judged critically, anterior segment fluorophotometry is a reliable procedure for the monitoring of BAB affection in type I diabetes without retinopathy.

Adult↗

PubMedDate not supplied

[Rupture of the hemato-ocular barrier, studied by fluorophotometry, in uveal melanoma patients. Preliminary results].

PURPOSE: To evaluate the use of intravenous vitreous fluorophotometry in assessment of the blood-aqueous barrier in eyes with uveal melanoma. METHOD: Vitreous fluorophotometry was performed before treatment in 14 patients with uveal melanoma. Both eyes of patients were examined, and fifteen control healthy patients were examined between November 1996 and December 1996 at the department of ophthalmology of Bicêtre hospital. RESULTS: Tumors with height > 6 mm and serous retinal detachments were accompanied by marked alterations of the blood-aqueous barrier, vitreous fluorophotometry showed diffusion of dye in posterior, mid and anterior vitreous: 2.99 ng/ml in the posterior vitreous and 5.20 ng/ml in the anterior vitreous. The posterior vitreous fluorescence at 60 minutes in the control eyes was 1.43 ng/ml and 1.30 ng/ml in the anterior vitreous. Diffusion of dye was present in the posterior vitreous in patients with tumor height less than 6 mm: 2.38 ng/ml (1.43 ng/ml in control eyes) at 60 minutes. CONCLUSIONS: Fluorophotometry provides a method for the assessment of the blood-aqueous ocular barrier in eyes with choroidal melanoma.

Aged↗

PubMed1982

Reversal of abnormalities in ocular fluorophotometry in insulin-dependent diabetes after five to nine months of improved metabolic control.

Abnormalities in ocular fluorophotometry occur in human and experimental diabetes mellitus. To determine the reversibility of these abnormalities, we studied prospectively 11 intensively treated and 25 conventionally treated insulin-dependent diabetics (IDD) preselected because of abnormal vitreous fluorophotometry. Among the 25 IDD treated conventionally with one or two insulin injections daily, hemoglobin A1C concentrations remained elevated and fluorescein concentration, 1 h after the intravenous injection of fluorescein (7 mg/kg), did not change significantly in either the anterior chamber or the posterior vitreous. Among 11 IDD treated intensively with home blood glucose monitoring and pumped subcutaneous insulin or three or more injections daily, hemoglobin A1C fell dramatically (10.4 +/- 0.7% to 7.5 +/- 0.2%) and anterior chamber fluorescein concentration decreased (73.9 +/- 7.7 to 49.5 +/- 5.3 ng/ml). Two patients with proliferative retinopathy showed no improvement in their massive vitreous fluorescein accumulation and subsequently required photocoagulation. In the nine subjects without proliferative retinopathy, vitreous fluorescein accumulation decreased in eight (10.6 +/- 0.7 to 6.5 +/- 0.5 ng/ml) and was normal in six after 1 yr. The only subject with increasing vitreous fluorescein accumulation also had concurrent worsening of background retinopathy. These studies support the hypothesis that moderate abnormalities in ocular fluorophotometry are due to reversible changes in ocular tissues, such as retinal pigment epithelium. Fluorescein leakage emanating from the advanced vascular or retinal abnormalities of proliferative retinopathy were not reversed with the degree and duration of metabolic control achieved in the present study. The long-term significance of the reversal of moderate abnormalities in fluorophotometry is not clear at the present time.

Adolescent↗

PubMed1979

Detection of early retinal changes in diabetes by vitreous fluorophotometry.

A series of 77 patients with overt diabetes and with apparently normal fundi on ophthalmoscopy and fluorescein angiography was examined by vitreous fluorophotometry. Breakdown of the blood-retinal barrier, which appears to be the earliest clinically detectable change in the retina in diabetes, was a constant finding. Quantitative measurement by vitreous fluorophotometry of the breakdown of the blood-retinal barrier could be correlated with degree of metabolic control and previous duration of diabetic disease. Significantly higher vitreous fluorophotometry values, indicating a more marked breakdown of the blood-retinal barrier, were recorded in patients under poor metabolic control than in patients whose diabetes was under relatively better control. Similarly, patients who has had diabetes for longer periods of time showed higher vitreous fluorophotometry values than those recorded in patients with diabetes of shorter duration.

Diabetic Retinopathy↗

PubMedDate not supplied

Noninvasive monitoring of intraocular pharmacokinetics of daunorubicin using fluorophotometry.

PURPOSE: Daunorubicin is a cytotoxic drug, which, in nontoxic doses, is effective in preventing cellular proliferation in experimental vitreoretinopathy. We studied dose and clearance of daunorubicin in various ocular tissues using fluorophotometry techniques. METHODS: In vitro tests: The emission of fluorescence from the daunorubicin solution having a concentration range of 0.1 to 10 micrograms/mL in phosphate buffer was measured using an excitation wavelength range of 489 +/- 10 nm. The emission of fluorescence was measured at 514 nm; the linearity of the response was determined using linear regression analysis. There is a fluorescence peak of daunorubicin at 485 nm. The validity and reproducibility of the method were examined. In vivo tests: The rabbits were randomized into three groups and daunorubicin concentrations of 4, 6, or 8 micrograms/mL were injected into the vitreous. Fluorophotometry scanning from the retina to the anterior chamber was performed with a commercially available fluorophotometer at various times up to 48 hours after injection to quantify fluorescence emission of daunorubicin. RESULTS: The standard curve of fluorescence versus concentration of daunorubicin was linear in the range of 0.1 to 8 micrograms/mL. It was sensitive up to 0.1 microgram. The daunorubicin time concentration profile showed a dose response relationship over the 48-hour period studied. The half-life of daunorubicin in the vitreous was about 5 hours. CONCLUSION: We performed fluorophotometry using a fluorophotometer whose exciter emits light at 489 nm, which is very close to an absorption peak of daunorubicin. These two values are close enough to obviate the need for modifying the commercial fluorophotometer. Therefore the concentration of daunorubicin in the vitreous cavity can be measured noninvasively.

Absorption↗

PubMed2002

Lens fluorophotometry after trabeculectomy in primary open-angle glaucoma.

OBJECTIVE: To evaluate the loss of lens transparency incurred by patients undergoing trabeculectomy. DESIGN: A prospective cohort study. PARTICIPANTS AND CONTROLS: Data corresponding to 33 eyes of 33 consecutive patients with primary open-angle glaucoma (POAG) subjected to trabeculectomy (group 1) were compared with those corresponding to 12 eyes of 12 patients with POAG receiving topical antiglaucomatous treatment (group 2). INTERVENTION: Lens fluorophotometry was performed on the group 1 patients before and 12 months after surgery. In group 2, fluorophotometry was conducted at the onset of the study and at 12 months of follow-up. MAIN OUTCOME MEASURES: Starting and final lens autofluorescence and transmittance values corresponding to each subject group were compared. RESULTS: In group 1, starting and final autofluorescence was 556.3 +/- 184.3 and 691.1 +/- 179.3 Eq ng/ml, and starting and final transmittance was 0.78 +/- 0.11 and 0.67 +/- 0.14, respectively. Respective values for group 2 were 574.3 +/- 94.8 and 595.2 +/- 107.0 Eq ng/ml and 0.72 +/- 0.17 and 0.71 +/- 0.16. The mean change between final and initial autofluorescence was statistically different between groups (134.7 +/- 123.7, group 1, 20.9 +/- 25.1 Eq ng/ml, group 2; P < 0.001). Similarly, a significant difference (P < 0.001) in transmittance change was observed between the surgery and control groups (-0.11 +/- 0.072, group 1; 0.02 +/- 0.008, group 2) CONCLUSIONS: It was demonstrated by lens fluorophotometry that trabeculectomy in POAG leads to a loss in lens transparency.

Aged↗

PubMed1993

Assessment of the blood-aqueous barrier by fluorophotometry following poly(methyl methacrylate), silicone, and hydrogel lens implantation in rabbit eyes.

Intraocular lenses of silicone, hydrogel, or acrylic materials that can be implanted through small incisions are being proposed as an alternative to conventional poly(methyl methacrylate) lenses. The potential of each of these materials to stimulate intraocular inflammation is important in their selection as an implantable material. To investigate the potential of each material, we assessed by clinical slitlamp examination, fluorophotometry, and histopathology the inflammatory response induced in the rabbit eye following phacoemulsification and implantation of hydrogel, silicone, or poly(methyl methacrylate) intraocular lenses. All lenses seemed to be equally well tolerated. In general, the degree of inflammation seen clinically decreased over the four-month study; however, anterior segment fluorophotometry showed continued mild interruption of the blood-aqueous barrier in all lens groups. Fluorophotometry is a sensitive method to assess persistent subclinical anterior segment inflammation.

Animals↗

PubMed2006

Fluorophotometry as a diagnostic tool for the evaluation of dry eye disease.

BACKGROUND: Dry eye disease is a common debilitating ocular disease. Current diagnostic tests used in dry eye disease are often neither sensitive nor reproducible, making it difficult to accurately diagnose and determine end points for clinical trials, or evaluate the usefulness of different medications in the treatment of dry eye disease. The recently developed fluorophotometer can objectively detect changes in the corneal epithelium by quantitatively measuring its barrier function or permeability. The purpose of the study is to investigate the use of corneal fluorescein penetration measured by the fluorophotometer as a diagnostic tool in the evaluation of dry eye patients. METHODS: Dry eye patients (16 eyes), who presented with a chief complaint of ocular irritation corresponding with dry eye, low Schirmer's one test (<10 mm after 5 minutes) and corneal fluorescein staining score of more than two, were included in the study. Normal subjects (16 eyes), who came for refraction error evaluation, served as controls. Institutional Review Board (IRB) approved consent was obtained before enrolling the subjects in the study and all questions were answered while explaining the risks, benefits and alternatives. All Fluorophotometry of the central corneal epithelium was done utilizing the Fluorotron Master. Each eye had a baseline fluorescein scan performed, after which 50 l of 1% sodium fluorescein dye was instilled. Three minutes later, the fluorescein was washed with 50 ml of normal saline. Fluorescein scans were then started immediately after washing and were recorded at 10, 20, 40, and 60 minutes thereafter. The corneal peak values of fluorescein concentration were recorded within the central cornea in both dry eyes and in controls. RESULTS: Ten minutes after fluorescein installation, patients with dry eye disease averaged a five-fold increase in corneal tissue fluorescein concentration (mean = 375.26 +/- 202.67 ng/ml) compared with that of normal subjects (mean = 128.19 +/- 85.84 ng/ml). Sixty minutes after dye installation, patients with dry eye disease still revealed higher corneal tissue fluorescein concentration (mean = 112.87 +/- 52.83 ng/ml) compared with that of controls (mean = 40.64 +/- 7.96 ng/ml), averaging a three-fold increase. CONCLUSION: Patients with dry eye disease demonstrated an increased corneal permeability and a slower rate of elimination to topically administered fluorescein when measured by the fluorophotometer. This suggests that fluorophotometry may serve as a valuable quantitative and objective tool for the diagnosis of dry eye disease, and in following patients' response to new treatment modalities. Fluorophotometry may serve as an objective non-invasive tool for end-point analysis in clinical trials of new treatments for dry eye disease.

Adult↗

PubMed1989

[Follow-up of early diabetic maculopathy by angiography and fluorophotometry].

We evaluated prospectively for 12 months 22 patients with late-onset diabetes mellitus and minimal retinopathy by fluorescein angiography and fluorophotometry. The study showed that early retinopathy changes were not permanent or invariably progressive, but may regress. Microaneurysm gradings worsened in 24%, improved in 14% and remained stabilized in 62%. Capillary closure worsened in 33%, improved in 10% and remained stabilized in 57%. The evolution of early diabetic maculopathy is slow and irregular, and this study has shown that vitreous fluorophotometry must be included when short follow-up periods of up to 12 months are considered. Finally, eyes with higher fluorophotometry values at entry showed significantly more deterioration during the 12-months follow-up period (p less than 0.05).

Diabetes Mellitus, Type 2↗

PubMed1995

[Fluorophotometry of changes of hemato-ocular barriers in intermediate uveitis].

PURPOSE: Intermediate uveitis presents a characteristic clinical picture with inflammation in the vitreous and peripheral retina. From a physiological point of view, the disease is characterised by a rupture of blood-ocular barriers. To determine the sites involved, a vitreous fluorophotometry was performed in patients with intermediate uveitis and in a group of healthy patients. METHODS: Seventy-one patients with an intermediate uveitis were studied by vitreous fluorophotometry. Anterior chamber and posterior segment fluorophotometric findings were measured 5 and 60 minutes after injection of fluorescein. Results were compared to a group of healthy patients. RESULTS: Vitreous fluorophotometry demonstrated abnormal leakage of fluorescein in all vitreous sectors of the patients suffering from uveitis compared with the control group (p < 0.001). In the anterior chamber, leakage of fluorescein was not significantly different between the two groups (p > 0.05). CONCLUSION: Results obtained suggest that intermediate uveitis involves a generalized permeability disturbance of the posterior segment secondary to a diffuse vasculitis. However, in the anterior segment this disturbance is not found.

Adolescent↗

PubMed1996

In vivo quantitation of peroxides in the vitreous humor by fluorophotometry.

PURPOSE: To detect intravitreal peroxides in vivo by a new fluorophotometric method with a hydrogen peroxide (H2O2)-sensitive fluorescent dye. METHODS: The authors used a 2',7'-dichlorofluorescin (DCFH) assay to measure oxidative status in the rabbit vitreous. In the presence of H2O2 and lipid hydroperoxides, nonfluorescent DCFH in the vitreous is oxidized to highly fluorescent 2',7'-dichlorofluorescein (DCF; excitation, 495 nm; emission, 520 nm) that is detectable by fluorophotometry. Reactions of DCFH with various concentrations of H2O2 were investigated in vitro and in vivo. An inhibitory effect of catalase also was monitored. Vitreous fluorophotometry with DCFH was performed immediately and at 3, 7, and 28 days after constant light exposure to the retina (1800 lux, 24 hours) as an oxidative stress. RESULTS: In vitro study revealed that H2O2 oxidized DCFH to DCF in a dose-dependent manner, ranging from 0.1 to 100 mmol/1 in concentration. Catalase inhibited DCF production. Vitreous fluorophotometry demonstrated that H2O2 oxidized DCFH to DCF in vivo in a dose-dependent manner, ranging from 0.06 to 60 mmol/1 in concentration. DCF production in the vitreous significantly increased immediately (P = 0.03) and at 3 days (P = 0.01) and 7 days (P = 0.01) after light exposure, and it returned to the pretreatment level by day 28. CONCLUSIONS: The results suggest that this fluorophotometric method quantitatively can detect intravitreal peroxides in vivo. This method will be helpful to study the oxidative status in some experimental pathologic conditions.

Animals↗

PubMed1996

[Axial and para-axial fluorophotometry in optic neuropathies].

PURPOSE: To investigate optic neuropathies, with normal results in fluorescein fundus angiography, by axial and paraaxial fluorophotometry (a type of topographic vitreous fluorophotometry) in order to determine differences examined in the amount of fluorescein leakage in macular and optic disc. MATERIAL AND METHODS: We studied 12 eyes with unilateral idiopathic retrobulbar inflammatory optic neuropathy and 4 eyes with unilateral posterior ischaemic optic neuropathy during the acute phase: control group consisted of 5 healthy eyes. After 3-4 months, in final stage of optic neuropathies, in which primary atrophy of optic disc developed (6 eyes), fluorophotometric examinations were repeated. All cases of control group underwent axial and paraaxial fluorophotometry. Complete ophthalmic, physical and neurological examinations were performed. RESULTS: The mean fluorophotometric values of PVPR (posterior vitreous penetratio-ratio) for f-scans (foveal) were lower than for t-scans (PVPRf < PVPRt) in all neuropathies during the acute phase but all values of PVPR were higher than in control eyes. In late phase of the neuropathies in which primary atrophy of optic disc developed we found a trend: PVPRt < PVPRf, but all values of PVPR were lower than in control eyes. We noticed increased permeability of the blood-ocular barrier and difference between fluorophotometric readings for optic disc directions (t-paraaxial scans) and for foveal directions (f-axial scans) in optic neuropathies during the acute phase, when the findings on ophthalmoscopic and fluorescein fundus angiography were normal.

Adult↗

PubMed1986

Vitreous fluorescein accumulation determined by in vivo fluorophotometry and by vitreous extraction in normal and diabetic rats.

Vitreous fluorophotometry was performed on pigmented male rats (Piebald strain) 2 weeks after induction of diabetes by streptozotocin. In vivo fluorophotometry data were compared with measurements obtained by direct extraction of the vitreous 60 min after an intravenous injection of sodium fluorescein. In addition, the rate of fluorescein disappearance from blood plasma, plasma protein binding of fluorescein and the effect of insulin treatment of diabetic animals were investigated. Age-matched nondiabetic animals served as controls. In vivo fluorophotometric measurements showed a good correlation with fluorescein determinations after direct extraction of the vitreous. Vitreous fluorescein concentrations were similar in diabetic and normal rats and were strongly related to the dye plasma levels within each group of animals. In the diabetic rats, however, the elimination of plasma fluorescein was accelerated and the percentage of free fluorescein, as determined by ultrafiltration and equilibrium dialysis, was consistently higher (130-150% of controls). The ratios of vitreous to total or free plasma fluorescein levels were elevated in diabetic rats. Experimental data indicate that plasma concentration of free fluorescein is crucial for vitreous dye accumulation. Insulin treatment of diabetic rats markedly improved their metabolic state and normalized the plasma fluorescein elimination and the vitreous to plasma fluorescein concentration ratios. It is concluded that vitreous fluorophotometry can be adequately applied to pigmented rats, provided that plasma fluorescein elimination rate and protein binding are considered in the interpretation of the results, since both influence the vitreous fluorescein accumulation and both may be altered by disease and drug treatment.

Animals↗

PubMed1979

Early detection of retinal involvement in diabetes by vitreous fluorophotometry.

Vitreous fluorophotometry is a new quantitative method for evaluation of the blood-retinal barrier (BRB). The application of this method to a series of diabetic patients with apparently normal fundi revealed the presence of a significant breakdown of the BRB in the early stages of retinal involvement in diabetes. This alteration of the BRB appears to be the earliest clinically detectable change to occur in the retina in diabetes. Higher vitreous fluorophotometry values, indicating a more marked breakdown of the BRB, occurred in patients who were under worse metabolic control. Higher vitreous fluorophotometry values were also associated with the development of visible retinal lesions.

Diabetes Mellitus↗

PubMed1982

Vitreous fluorophotometry in optic nerve disease.

Posterior vitreous fluorophotometry measurements have been shown to be increased in patients with acute retrobulbar neuritis. We studied 12 patients who had optic neuropathy by posterior vitreous fluorophotometry, with and without correction for blood fluorescein concentration. Both uncorrected and corrected posterior vitreous measurements were increased in patients with inflammatory, obstructive, and infiltrative optic neuropathies. Concurrent values from anterior chamber fluorophotometry were not increased in any of the 8 patients studied.

Adult↗