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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↗

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↗

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↗

PubMed1991

[Fluorophotometry and corneal endothelium].

The corneal endothelium plays a major part in corneal deturgence and hydratation by functioning as a barrier and a pump. Fluorophotometry enables assessment of this barrier function because of endothelial permeability to fluorescein. After a description of the technique of fluorophotometry, the authors show its interest in the understanding of endothelial physiopathology: during aging, in compensated or decompensated endothelial dystrophy, during lens and corneal surgery, in irido-corneal endothelial syndrome and in pharmacology.

Biological Transport↗

PubMed1990

Fluid movement across the blood-retinal barrier: a review of studies by vitreous fluorophotometry.

Vitreous fluorophotometry was used to study the fluid movement across the blood-retinal barrier. The effect of plasma osmolality and intraocular pressure on the movement of the fluorescent tracer confirmed the interaction between the tracers and the fluid flow across the blood-retinal barrier. The measurement of outward and inward permeabilities to carboxyfluorescein revealed the existence of a posteriorly directed fluid flow in the vitreous cavity of cynomolgus monkey eyes with retinal detachment. Fluid movement across the blood-retinal barrier was shown to be inhibited by furosemide and enhanced by acetazolamide. Furthermore, vitreous fluorophotometry proved to be useful in estimating the in vivo fluid dynamics in the vitreous and across the human retina.

Animals↗

PubMedDate not supplied

[Functional evaluation of the corneal endothelium using anterior segment fluorophotometry].

The AA have studied the permeability of the corneal endothelium by anterior segment fluorophotometry using instillation of fluorescein. The Fluorotron Master TM has been modified with the introduction of a new slit (58.4 microns) and of the voltage output (6.5 v) has also been increased. The resolution has been improved from 2.39 mm to 0.59 mm. Of this study, we have examined 20 patients submitted to extracapsular cataract extraction with intraocular lens implantation (ECCE + IOL). The patients have been divided in two groups, according to the surgical technic used: "can-open" and intracapsular. Each patient have been submitted before surgery and 1 week after to an ophthalmologic examination, paquimetry and anterior segment fluorophotometry. The permeability coefficient (PAC) increases with the duration of surgery and when using "can-opener" instead of endocapsular.

Aged↗

PubMed1990

[Fluorophotometry of the vitreous body in diabetics without retinopathy or with minimal retinopathy].

Vitreous fluorophotometry using the Fluorotron Master, was performed on the two eyes of 56 diabetics patients 45,65 year-old +/- 14,91 (mean +/- S.D.), duration of diabetes was 15,14 years +/- 9,17; and on one eye of 17 normal subjects 39,18 years old +/- 11,19. According to biomicroscopic and angiographic examinations, only diabetic subjects with either no or microaneurysmal retinopathy were included. Three groups of right and three groups of left eyes were made: Groups 1: no retinopathy (28 right eyes, 27 left eyes); Groups 2: 1 to 5 microaneurysms (11 right eyes, 20 left eyes); Groups 3: greater than 5 microaneurysms (11 right eyes, 9 left eyes) For the two eyes, posterior vitreous penetration ratio increased with the degree of retinopathy. In the eyes without retinopathy (Groups 1), the penetration ration is not statistically different from the normal subjects; it was the opposite for the eyes with microaneurysmal retinopathy (Groups 2 et 3). The results indicated a breakdown of the blood-retinal barrier only when clinical diabetic retinopathy was present. The relation between fluorophotometric evaluation and the degree of retinopathy showed that vitreous fluorophotometry can be useful in the follow-up of diabetic subjects.

Adolescent↗

PubMed1978

Vitreous fluorophotometry in juvenile-onset diabetes mellitus.

Vitreous fluorophotometry was carried out in 99 juvenile-onset, insulin-dependent diabetics and 31 control subjects. The mean vitreous fluorescein concentration one hour after intravenous administration of fluorescein, 7 mg/kg, was 5.4 +/- 0.3 ng/ml (mean +/- SEM) for controls and 9.5 +/- 0.4 ng/ml for diabetics (P less than .005). Diabetic patients with or without background retinopathy, when randomly matched for age or duration of their disease, had similar vitreous fluorophotometry measurements. The break-down of the blood-retinal barrier to fluorescein appears to be the earliest detectable ocular abnormality of diabetes.

Adolescent↗

PubMed1979

Kinetic vitreous fluorophotometry in experimental diabetes.

Kinetic vitreous fluorophotometry was used to measure dynamic alterations in blood-retinal barrier function. Normal hooded rats were compared with diabetic animals before and after insulin treatment. Rats with streptozocin-induced diabetes demonstrated significantly longer (P less than .001) half-periods of fluorescein loss from the vitreous when compared with controls, and insulin treatment significantly reduced (P less than .001) the mean half-period toward control values without normalization of serum glucose. These results suggest that kinetic vitreous fluorophotometry is a good indicator of blood-retinal barrier function and that sufficient amounts of insulin may be more important than normal blood glucose levels in recovery of altered barrier function in diabetes.

Animals↗

PubMed1979

Vitreous fluorophotometry in adult-onset diabetes mellitus.

We studied the breakdown of the blood-retinal barrier in 83 patients with adult-onset diabetes mellitus, by using vitreous fluorophotometry. The patients were in good stable metabolic control and were receiving injectible insulin or oral hypoglycemic agents. Vitreous fluorophotometry readings were abnormally high but similar in both groups of patients, and no significant differences were found between those with and those without early background diabetic retinopathy. Significantly more patients taking oral agents were hypertensive, and significantly fewer of these patients had background retinopathy.

Adult↗

PubMed1979

Ocular fluorophotometry in streptozotocin diabetes mellitus in the rat: effect of pancreatic islet isografts.

Fluorophotometry was used to evaluate the integrity of the blood-ocular barriers to fluorescein in experimental diabetes mellitus in rats. This technique allowed quantitation of ocular fluorescein concentrations following intravenous injection. Streptozotacin-induced diabetes resulted in an increased fluorescein accumulation in the anterior chamber (1.52 +/- 0.17 microgram/ml, mean +/- S.E.M.) and vitreous (0.82 +/- 0.11) over baseline nondiabetic levels (0.68 +/- 0.80 and 0.40 +/- 0.03, respectively). Fluorophotometry was repeated at 5, 13, and 20 days following portal vein pancreatic islet transplantation. At 5 days anterior chamber (1.40 +/- 0.17) and vitreous (0.61 +/- 0.08) fluorescein concentrations remained elevated. However, at 13 and 20 days following islet transplantation, ocular fluorescein concentrations were identical to levels observed prior to the induction of diabetes. Intravenous glucose (0.5 gm/kg) tolerance testing was performed 5 and 13 days following transplantation. The glucose responses to the tolerance test were normal and similar at both times. However, at 5 days the insulin response was abnormal with a decreased initial peak and an absent second peak. At 13 days there was a normal biphasic insulin response. In experimental diabetes mellitus ocular vascular permeability was more closely correlated with insulin than blood glucose abnormalities.

Animals↗

PubMed1979

Effects of therapy on vitreous fluorophotometry in diabetes mellitus.

Quantitative vitreous fluorophotometry was used to study the alteration of the blood-retinal barrier in 116 patients with diabetes mellitus of adult onset. The patients were in good stable metabolic control on injectable insulin, oral hypoglycaemics, or diet therapy. Vitreous fluorophotometry readings were abnormally high but similar in all three groups and in those with or without early background retinopathy. A higher incidence of systemic hypertension was noted in those patients requiring oral agents compared to those on insulin or diet therapy.

Biological Transport↗

PubMed1990

Vitreous fluorophotometry in insulin-dependent diabetes mellitus. Correlation with microalbuminuria and diastolic blood pressure.

Vitreous fluorophotometry was performed on 240 eyes of 120 young subjects who had insulin-dependent diabetes mellitus (type I) and various grades of retinopathy. The concentration of fluorescein was measured in the anterior chamber and posterior vitreous 1 hour after intravenous injection of fluorescein. There was a significant association (P less than .001) between the grade of retinopathy and the level of posterior vitreous leakage. The amount of posterior vitreous leakage in each eye also had a significant association with borderline elevation of diastolic blood pressure. Subjects with excessive posterior vitreous leakage had significantly higher levels of urinary microalbumin excretion. In a multiple linear regression analysis for posterior vitreous leakage, retinal grade consistently entered the model at a significant level (P less than or equal to .00001 to .003). Blood pressure also entered the model for posterior vitreous leakage at a significant level for retinal grades of the right and left eyes and of the worst eye. These results demonstrate an association between leakage of retinal and renal vessels, possibly linked at least in part to elevation in diastolic blood pressure.

Adolescent↗

PubMed1991

Determination of basal tear turnover in insulin-dependent diabetes mellitus patients by fluorophotometry.

The tear turnover was determined by fluorophotometry in 25 insulin-dependent diabetes mellitus (IDDM) patients without retinopathy and 29 IDDM patients with (pre-)proliferative retinopathy. The results were compared with those in 34 healthy controls, to investigate the lacrimal gland function in diabetic patients. The tear turnover was calculated from the decay of the relative tear fluorescein concentration values measured after instillation of one microliters of fluorescein. The tear turnover values in both patient groups did not correlate significantly with age or diabetes duration (linear correlation coefficients: r less than 0.3). The tear turnover values in patients both without retinoplathy and with (pre-)proliferative retinopathy did not differ significantly from those in healthy controls (mean +/- SD in %/min: 13.7 +/- 4.5, 14.7 +/- 5.8 and 15.5 +/- 5.1, respectively; P greater than 0.16). The tear turnover was significantly decreased in eyes having a BUT shorter than 10 seconds compared with eyes having a BUT longer than 10 seconds (P less than 0.05). The tear turnover values correlated significantly with the HbA1c and Schirmer-test values in patients with (pre-)proliferative retinopathy (r = 0.7 and r = 0.4, respectively; P less than 0.02) and with the blood glucose values in patients without retinopathy (r = 0.41, P = 0.04). Since the tear turnover was not significantly decreased in IDDM patients in comparison with healthy controls the corneal disorders which are more frequently seen in these patients than in a healthy population may not be attributed to a decrease in tear production.

Adult↗

PubMed1991

Epithelial permeability in corneal grafts by fluorophotometry.

The epithelial permeability to fluorescein of 27 clear corneal grafts in 23 patients was determined by fluorophotometry at greater than 1 year after penetrating keratoplasty (PKP) so as to study the recovery of corneal epithelial function. The mean epithelial permeability of the corneal grafts did not differ significantly from that of normal corneas (0.042 +/- 0.016 and 0.038 +/- 0.017 nm/s, respectively; P greater than 0.3). Multiple linear regression analysis showed that permeability correlated with recipient age but not with donor age (permeability increase, 0.00054 nm/s per year; r = 0.6, P less than 0.005 and r = 0.1, P greater than 0.5, respectively). These results indicate that corneal grafts can regain a normal epithelial barrier function and that recovery of epithelial function is better in young than in old recipients.

Adult↗

PubMed1991

Effect of eledoisin on tear volume and tear flow in humans as assessed by fluorophotometry.

Topical application of the endekapeptide eledoisin has been reported to increase tear secretion in patients with dry eye. However, to date the efficacy of eledoisin has been proved only by methods that are not easily reproduced and have an enormous intraindividual scatter range (Schirmer test, basic secretion test). In the present study the effect of topically applied eledoisin on tear volume and tear flow was determined quantitatively by means of objective fluorophotometry in 40 subjects, 20 of whom suffered from severe dry eyes. Both tear volume and tear flow were found to be significantly increased up to 2 h after instillation, reaching a maximum 1 h after application (tear volume: +87% and +35% for dry eyes and healthy controls, respectively; tear flow: +250% and +27% for dry eyes and healthy controls, respectively).

Administration, Topical↗

PubMed1992

Axial and para-axial fluorophotometry in glaucoma simplex.

In this fluorophotometric study, in 25 eyes with middle advanced stages of glaucoma simplex (visual field defects ranged from 500 dB to 800 dB) and treated with topical antiglaucomatous agents, the posterior vitreous penetration ratio (PVPR) was compared with that from normal subjects. Vitreous fluorophotometry (Fluorotron Master, Coherent) was used to measure posterior vitreous fluorescein concentration. Due to additional fixation light in horizontal plane, three scans were taken along the following directions: temporal (t), foveal (f), nasal (n). The angle of deviation from the foveal scan was 15 degrees in each direction. The average values of posterior vitreous penetration ratio in group of patients with glaucoma were higher in comparison with those in healthy subjects. In both groups the PVPR was significantly lower in nasal (n) scan (optic disc area) in comparison with temporal (t) or foveal (f) scans (p < 0.05).

Adult↗

PubMed1992

Study on the aqueous humor flow measured by fluorophotometry after argon laser trabeculoplasty.

We have investigated the variations in the aqueous humor flow (F) after argon laser photocoagulation (ALT) in the trabecular meshwork. The research has been done on 60 eyes with primary open angle glaucoma within initial stages. The argon laser trabeculoplasty was made around 360 degrees in anterior trabecular meshwork with 100 burns. The flow (F) has been studied by fluorophotometry using Yablonsky's protocol. Aqueous humor flow has been measured after 24 hours and after 7 days, to determine the immediate effects of laser trabeculoplasty; and also after 6 months for the long term effects. The initial aqueous humor flow was 1.35 microliters/min. By means of ANOVA we found statistically significant differences on aqueous humor flow after the 7th day (F = 1.67 microliters/min, p < 0.01), which remain six months later (F = 1.71 microliters/min, p < 0.01). This findings suggest that the effects of argon laser trabeculoplasty, either by mechanical or biological changes in the trabecular meshwork do not appear until the 7th day and remain throughout the follow up study.

Aged↗