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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↗
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↗
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↗
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↗
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↗
PubMed1987

Vitreous fluorophotometry in patients with senile macular degeneration.

Twenty-two phakic eyes of 16 patients with varying stages of senile macular degeneration (SMD) underwent vitreous fluorophotometry. The upper tolerance limit of the penetration ratio in 17 eyes of 17 age-matched controls was 6.33 X 10(-6) min-1. Ten of the 22 eyes with SMD had values exceeding this, indicating abnormal blood-retinal barrier function. When the fluorescence recorded in the vitreous but not related to the local intravitreal dye was evaluated, it was greater in those eyes with more severe forms of the disease. All ten eyes with drusen alone and no SMD had normal fluorophotometry values. Vitreous fluorophotometry may be helpful in the diagnosis and classification of SMD.

Aged↗
PubMed1990

Vitreous fluorophotometry in patients with Best's macular dystrophy.

Ten patients with Best's macular dystrophy were examined with vitreous fluorophotometry and results were compared with a normal population. Seventeen of the 20 affected eyes demonstrated an intact blood-retinal barrier with normal inward permeability of fluorescein dye. Despite diffuse functional impairment of the retinal pigment epithelium (RPE), determined by electro-oculography, as well as accumulation of a lipofuscin or lipofuscin-like substance within virtually all RPE cells, the blood-retinal barrier function of these cells remained intact as determined by clinical fluorophotometry. Similar findings have previously been noted in another hereditary retinal disorder (fundus flavimaculatus) in which a lipofuscin-like substance also accumulates diffusely within RPE cells.

Adolescent↗
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↗
PubMed1987

Evaluation of vitreous body integrity in retinitis pigmentosa by vitreous fluorophotometry.

We performed vitreous fluorophotometry on 23 eyes of 15 normal individuals and on 29 eyes of 15 patients with retinitis pigmentosa one hour after the systemic administration of sodium fluorescein. The concentration gradient of fluorescein in the posterior vitreous was evaluated from the results of the testing. Patients with retinitis pigmentosa showed a significantly flat gradient compared with normal subjects, implying that fluorescein is distributed more rapidly in the vitreous body of the patients. It is suggested that patients with retinitis pigmentosa have an abnormal vitreous gel structure that causes more rapid distribution of fluorescein. If verified, this would indicate that vitreous fluorophotometry could be useful to evaluate changes in the integrity of the vitreous body in vivo.

Adolescent↗
PubMed1987

Anterior segment fluorophotometry in acute anterior uveitis.

Anterior segment fluorophotometry was used to assess the severity of blood-aqueous barrier disruption in 25 patients with acute anterior uveitis. The results indicated that HLA-B27-positive patients had a more severe inflammation than did HLA-B27-negative patients, which was not discernible when judged by clinical signs and symptoms. Follow-up studies showed that the blood-aqueous barrier was disturbed for longer than the clinical signs indicated, and sometimes a temporary subclinical relapse was demonstrated on early withdrawal of topical therapy. The blood-aqueous barrier appeared to be restored after each attack of acute anterior uveitis in the majority of patients, with no evidence of progressive damage from repeated attacks. Our results indicated that fluorophotometry provides an objective and sensitive method of assessing anterior uveitis.

Acute Disease↗
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↗
PubMed1986

Ocular fluorophotometry in the normal- and diabetic monkey.

Normal- and diabetic rhesus monkeys without retinopathy demonstrable by ophthalmoscopy or fluorescein angiography were examined with ocular fluorophotometry to detect alterations in their blood-ocular barriers. All vitreous fluorophotometry values were corrected for fluorescence attributable to background levels and then normalized to a blood fluorescein level of 10 micrograms ml-1. Reproducibility studies demonstrated an average coefficient of variation of 0.17 for all animals combined. Insulin-dependent monkeys, both pancreatectomized and streptozotocin-treated, demonstrated significantly higher posterior vitreous fluorescence levels than either control animals or monkeys treated with streptozotocin that were not insulin-dependent. These results cannot be attributed to differences in fluorescein binding or to vitreous abnormalities. However, 14 out of 24 (58%) of the insulin-dependent animals exhibited posterior vitreous fluorescence values within two standard deviations of the control mean. No correlation was apparent between the vitreous values and age or duration of treatment. No difference in anterior chamber concentrations was found between groups after correction. Our results indicate that alterations in blood-retinal barrier can occur in insulin-dependent diabetic monkeys before development of retinopathy.

Aging↗