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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↗

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↗

The influence of vitreous change on vitreous fluorophotometry.

Thirteen patients with retinitis pigmentosa were graded in terms of vitreous change and compared by vitreous fluorophotometry to an equal number of normal patients. A highly significant difference was found between groups. A high correlation was also noted between severity of vitreous change and midvitreous fluorophotometry values. Certain types of vitreous detachments appear to produce a characteristic "cancer hump" in the resultant data. A possible explanation for the increased values is discussed.

Adult↗

Vitreous fluorophotometry in congenital stationary nightblindness.

Vitreous fluorophotometry was performed on eyes with three kinds of congenital stationary nightblindness: Oguchi's disease (two cases), X-linked congenital stationary nightblindness (two cases), and fundus albipunctatus (one case). The results were compared with the electroretinogram (ERG) and the electro-oculogram (EOG). In spite of the variable degree of abnormality of the ERG and EOG, all eyes showed normal values on vitreous fluorophotometry. These results strongly suggest that the blood-retinal barrier in congenital stationary nightblindness is intact and that the electrophysiological results and the functioning of the blood-retinal barrier do not correlate in these diseases.

Adolescent↗

Vitreous fluorophotometry in patients with hypertension.

Vitreous fluorophotometry performed on 22 patients with moderate to severe hypertension showed that patients with active retinopathy, as manifested by retinal hemorrhages, cotton-wool spots, retinal exudates and edema, or disc edema, generally had elevated values (20/28 eyes). Control of the BP resulted in a decrease in the values toward the normal range. Patients with only arteriolar sclerosis, even some with particularly high BP, generally had normal fluorophotometric values (14/16 eyes). The two exceptions showed minimal elevations. Vitreous fluorophotometry is a useful tool to quantitate the blood-retinal barrier in patients with moderate to severe hypertension and may be a sensitive indicator of treatment efficacy.

Adult↗

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↗

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↗

Technical variables in vitreous fluorophotometry.

The technical variables that affect vitreous fluorophotometry are presented. Serum fluorescein pharmacokinetics are discussed with respect to early and late fluorescein appearance in the vitreous. The problem of axial resolution was analyzed systematically and parameters to minimize or eliminate choroidal fluorescence were defined. The timing of fluorophotometry and the effects of eye movement on fluorescein spread appear to be important factors. A vitreous diffusion model is presented that may minimize artifact introduced by these factors.

Eye Movements↗

Vitreous fluorophotometry studies in retinitis pigmentosa.

Six patients with various genetic types of retinitis pigmentosa and ten carriers of the X-linked recessive type were studied by vitreous fluorophotometry. Kinetic vitreous fluorophotometry showed an alteration of the blood-retinal barrier (BRB) in patients with retinitis pigmentosa, even in those who had minimal fundoscopic abnormalities and only minor changes on the electroretinogram. Furthermore, an alteration of the BRB could be detected in the carriers of the X-linked recessive form of retinitis pigmentosa. In general, higher concentration of fluorescein in the vitreous correlated topographically with the extent of photoreceptor and retinal pigment epithelial disease, as well as with the presence of leakage from retinal capillaries.

Adolescent↗

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↗

Diagnosing acute retrobulbar neuritis by vitreous fluorophotometry.

We studied six patients with acute retrobulbar neuritis (including two with definite multiple sclerosis) during acute episodes and in convalescence, clinically and with fluorescein angiography and vitreous fluorophotometry. We compared vitreous fluorophotometric readings with visual-evoked responses. In seven of ten eyes with abnormal visual-evoked responses, there was an acute increase in posterior vitreous fluorophotometric readings. Vitreous fluorophotometry may be useful as objective evidence of (1) acute retrobulbar neuritis, (2) involvement of the asymptomatic eye in acute retrobulbar neuritis, (3) the duration of neuritic inflammation in acute retrobulbar neuritis, (4) a recurrence of acute retrobulbar neuritis, (5) alterations in the blood-ocular barrier in patients with acute retrobulbar neuritis in multiple sclerosis, and (6) the effects of corticosteroids and other therapeutic agents in the treatment of acute retrobulbar neuritis.

Acute Disease↗

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↗

Role of fluorescein glucuronide and its metabolism in vitreous fluorophotometry.

Rabbits were given fluorescein or fluorescein glucuronide intravenously. Fluorescein and fluorescein glucuronide concentrations in plasma and vitreous samples were measured by high-performance liquid chromatography. Vitreous fluorophotometry was performed using the Fluorotron Master to compare scans after administration of fluorescein and fluorescein glucuronide, and for comparison of in vivo fluorescence with in vitro high-performance liquid chromatography analysis. Fluorescein glucuronide was shown to enter the vitreous as early as 1 hr after injection. Fluorescein glucuronide was the dominant molecule in both vitreous and plasma of all rabbits at 6 hr. Because fluorescein glucuronide has a lower fluorescence than fluorescein, the fluorophotometer overestimates the vitreous concentration of fluorescein after its administration. Since fluorescein is metabolized rapidly to fluorescein glucuronide in man, entry of fluorescein glucuronide into the eye should be considered in measurements of blood-ocular barrier permeability by vitreous fluorophotometry.

Animals↗

Kinetic vitreous fluorophotometry in normals and noninsulin-dependent diabetics.

Kinetic vitreous fluorophotometry was performed up to five hours after intravenous injection of fluorescein in seven normal subjects and seven noninsulin-dependent diabetic patients without retinopathy. The leakage of fluorescein into the vitreous was measured, and fluorescein dynamics were assessed after correction for the most important artifacts. A detailed description of the movements of fluorescein between the blood and the chambers of the eye across the blood-ocular barriers was obtained in normal and diabetic eyes. The diabetic population could be differentiated best from the normal one with vitreous fluorophotometry measurements performed close to the retina-choroid one hour after injection.

Adult↗

The correlation of the results of vitreous fluorophotometry and fluorescein angiography in nonproliferative diabetic retinopathy.

The authors examined 103 eyes of 53 patients with insulin-dependent diabetes mellitus simultaneously by fluorescein angiography and vitreous fluorophotometry and correlated the stage of diabetic retinopathy with the posterior vitreous leakage (PVL) level, calculated from the preinjection-, bolus-, and measurement scans. There was a significant correlation between stage of retinopathy and PVL level, but there was a large variation of PVL readings within each group of retinopathy stages. All eyes were reexamined after a mean period of 11.84 months. In 15 of 16 eyes with progressive retinopathy the first PVL readings were within the distribution range of the respective retinopathy level. A progression of retinopathy was not accompanied by a significant change of the PVL. It was concluded that vitreous fluorophotometry alone is not sufficient for the grading of diabetic retinopathy and has only little prognostic value for the course of the disease.

Diabetic Retinopathy↗

Photometric oculometry. I. An analysis of the optical principles in slit-lamp fluorophotometry.

The optical principles of slit-lamp fluorophotometry are analysed by aid of a mathematical model of the optical system. The analysis forms the theoretical basis for a slit-lamp technique called photometric oculometry, which makes possible an estimation of intraocular axial distances and axial length. The technique is based on a calculation--by aid of a mathematical model of the eye--of the ratio between intraocular movement of the slit-lamp focal plane and corresponding movement of the slit-lamp. Intraocular axial distances can be calculated by aid of this ratio and a direct measurement of the slit-lamp movement when the focal plane is moved in the optical axis from retina to cornea. These items are prerequisites for a quantitative determination of the blood-retinal barrier permeability to fluorescein during vitreous fluorophotometry.

Eye↗

Fluorescein angiography and fluorophotometry of the iris in pseudoexfoliation of the lens capsule.

Fluorescein iris angiography and fluorophotometry were performed on a series of 9 patients with bilateral and 11 with unilateral pseudoexfoliation, 12 bilateral aphakes with pseudoexfoliation, and 7 unilateral aphakes with bilateral pseudoexfoliation. Angiography showed a loss of radial iris vessels, a heavy leak of fluorescein from the pupil margin, progressive neovascularisation of the outer 2/3 of the iris, and less constantly a network of fine new vessels in the inner 1/3 of the iris stroma. These changes were absent in unaffected eyes. After cataract extraction there seemed to be a definite lessening of fluorescein leak from the pupil margin. Fluorophotometry showed a much higher fluorescein concentration at the anterior focus in eyes with pseudoexfoliation than in normal controls or in fellow unaffected eyes. There was a much smaller rise in fluorescein concentration at the posterior focus in a minority of affected eyes. The ranges of fluorescein concentrations at the anterior focus in both phakic and aphakic patients with bilateral pseudoexfoliation did not differ significantly. The concentration at the anterior focus of unilateral aphakes with bilateral pseudoexfoliation was lower than in the fellow phakic eye. These findings suggest that the neovascular reaction seen in pseudoexfoliation is associated with patchy occlusion of the normal iris vasculature, occurs in the anterior segment of the eye, and does not continue to progress after removal of the lens.

Aged↗