INTERNATIONAL SOCIETY OF OCULAR FLUOROPHOTOMETRY
Updated June 5, 2005
International Society of Ocular
Fluorometry Symposium
May 2005
S.E.
Moroi1,
Pauline A Radenbaugh1,
Ning C. McLaren1,
David C. Musch,1,2
1Department
of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI; 2Department
of Epidemiology, University of Michigan, Ann Arbor, MI
GRANT SUPPORT: This work was supported by NIH EY00353 (SEM), NIH core grant EY07003, Midwest Eye-Banks and Transplantation Center (SEM), and M01-RR00042 (fluorophotometry studies were conducted in the General Clinical Research Center, University of Michigan Medical Center).
Methods:
Results: One eye from 20 subjects (12 males, 8 females;
average age of 27.9 years + 8.5 sd, range 18-44) showed an average flow between
Conclusions: There is evidence that IOP has genetic
determinants. Aqueous flow is a major variable for determining the diurnal IOP
fluctuations. The findings of strong diurnal concordance in individual flow phenotype are
consistent with the hypothesis of genetic determinants for the physiological trait of
aqueous flow.
Diurnal and Nocturnal Aqueous Humor Dynamics in Patients with Ocular Hypertension
Toris
CB, Fan S, Zhan G, Camras CB
Department
of Ophthalmology, University of
PURPOSE:
The objective of this study was to evaluate the circadian rhythms of aqueous humor
dynamics in 24 patients with ocular hypertension.
METHODS:
Patients were scheduled for one daytime and one nighttime visit. Intraocular pressure was
measured by pneumatonometry, aqueous flow and outflow facility by fluorophotometry, and
uveoscleral outflow by mathematical calculation. Two days later measurements were repeated
between the hours of
RESULTS:
Variable
Daytime
Nighttime
IOP (mmHg)
23.5±5.2
23.2±5.9
Aqueous flow (µl/min)
2.37±0.11 1.78±0.10*
Uveoscleral outflow (µl/min) 0.54±0.19 0.13±0.36
Outflow facility(µl/min/mmHg) 0.22±0.02
0.17±0.04
* p<0.05, compared to Daytime
CONCLUSION:
Aqueous flow is significantly reduced at night and the reason that there is no circadian
rhythm in IOP is that it appears that uveoscleral outflow and outflow facility also may be
reduced at night.
Fluorophotometric Assessment of Blood-Aqueous Barrier Integrity in Rhesus Monkeys
M.J.
Ogidigben. Ophthalmic Research, Merck & Co,
Purpose:
To quantify the diffusion coefficient (Kd) of the blood aqueous barrier (BAB) in rhesus
monkeys and determine the amount of toxin required to compromise barrier integrity.
Methods: Adult female rhesus monkey (macaca mulatta) were first subjected to slit lamp
examination for flare, then scanned fluorophotometrically 2 hr. following topical
bilateral application of saline or intravenous injection of lipopolysaccharide (LPS). Six
monkeys received saline in the first week and two weeks later, monkeys from the same group
were treated intravenously with various doses of LPS (0.5, 10 and 20 ug / kg). Sodium
fluorescein (8 mg/Kg) was used as the tracer dye and applied intravenously. The Fluorotron
Master (OcuMetrics) anterior chamber adaptor was mounted for fluorophotometric
measurements. Baseline fluorescence of each eye was recorded, followed by dye application
and subsequent fluorophotometry at 30, 45 and 60 min. Blood was collected from each animal
at 5, 35 and 55 min post fluorescein application. After ultrafiltration with microcon
tubes, unbound plasma fluorescin concentration was determined fluorophotometrically. BAB
diffusion coefficient was calculated using the EuroEye-Software, BRB of Dr. van Best.
Results: In saline-treated rhesus monkeys, the calculated Kd = 101.8 ±5.1 X 10-6. LPS
produced dose-dependent increases in barrier permeability to sodium fluorescein. LPS (0.5,
10 and 20 ug/kg) calculated Kds = 105 ±2.4 X 10-6, 168.8 ±12.8 X 10-6 and 262.8 ±12.8 X
10-6 , respectively. Conclusions: This study showed that the BAB diffusion coefficient in
normal rhesus monkeys is approximately 101.8 ±5.1 X 10-6. In addition, an intravenous LPS
dose of 10 ug/kg is sufficient to induce flare in this species as potential animal model
of uveitis.
Basal tears in healthy males and females.
LUMC,
Purpose: Basal tear turnover can be defined as the tear
turnover after stimulation of
reflex
lacrimation. The differences in basal tear turnover and reflex lacrimation between
healthy
males and females were determined.
Methods: 20 healthy males and 20 females were selected. After instillation the decay of fluorescein
concentration in tears was measured by fluorophotometry over 10 minutes for determination
of the steady state tear turnover. Then reflex lacrimation was induced by stimulating the
trigeminal nerve with ethanol vapor via the nostrils. Thereafter a second measurement of
tear turnover was performed. The index of reflex lacrimation was calculated by forward and
backward extrapolation of both tear turnover
fluorescein decay curves. The differences in both tear turnover values and in the index of
reflex lacrimation were evaluated using the Student t test.
Results:
The age of males and females did not differ significantly (p=0.25). The average first tear
turnover was 13.48 +/- 5.98 %/min and 13.05 +/- 8.83 %/min
for males and females, respectively. The index of reflex lacrimation was
55.04 +/- 28.20 % and 68.68 +/- 17.01 %. The second or basal tear turnover was 11.08 +/-
3.68 %/min and 6.61 +/- 6.20 %/min., respectively. The first tear turnover and the index
of reflex lacrimation did not differ significantly between males and females (p=0.86 and
0.074, respectively)), the second (basal) tear turnover did differ (p=0.0095).
Conclusions: Females have a lower basal tear turnover than
males, probably as a result of a higher index of reflex lacrimation.
Changes in lens and cornea autofluorescence wavelength with age.
B.M.
Ishimoto and R.J. Ishimoto. OcuMetrics, Inc.,
Fluorescence
of the crystalline lens has a strong age dependency. Previous
studies have included a wide range of ages, but, heretofore, none have included a large
number of pre-adolescent subjects. The present
study seeks to characterize the age dependency of crystalline lens autofluorescence in
pre-adolescent, adult and elderly subjects. Multiple
excitation and emission wavelengths were used in order to study changes in Stokes Shift
with age.
Methods:
The
lens and cornea autofluorescence of 5 school age children with no history of diabetes or
ocular disease were measured with a Fluorotron™ Master ocular fluorophotometer
(OcuMetrics, Inc.,
Results:
The age dependencies in the subjects under study
were:
Lens
Fluorescence 1 (ex=477, em=530) -> Age (year) X 14.08
Lens
Fluorescence 2 (ex=477, em=565) -> Age (year) X 11.19
Lens
Fluorescence 3 (ex=520, em=565) -> Age (year) X 8.58
LF
2 / LF 1 -> Age (year) X –0.24 (Stokes Shift)
LF
3 / LF 2 -> Age (year) X 5.82 (Absorption Ratio)
Cornea
Fluorescence 1 (ex=477, em=530) -> Age (year) X 2.04
Cornea
Fluorescence 2 (ex=477, em=565) -> Age (year) X 0.06
CF
2 / CF 1 -> Age (year) X –1.84 (Stokes Shift)
The
cornea fluorescence at ex=520 em=565 is not reported here as it appeared to be
contaminated by light leakage from specular reflections.
Conclusions:
There is a very strong age related increase in lens
autofluorescence. There is also a slight shift
in the absorption ratio to higher wavelengths, but the present study found no increase in
Stokes Shift at the wavelengths measured. The
cornea autofluorescence did not change significantly with age nor did the Stokes Shift
change significantly with age.
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