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Nancy E. M. L. Tang, Paul L. Zuure, Raiza D. Pardo, Rob J. W. de Keizer, Jaap A. Van Best; Reflex Lacrimation in Patients with Glaucoma and Healthy Control Subjects by Fluorophotometry. Invest. Ophthalmol. Vis. Sci. 2000;41(3):709-714.
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© ARVO (1962-2015); The Authors (2016-present)
purpose. Steady state tear turnover (TTO), defined as TTO under normal
physiological conditions, is significantly lower in patients with
untreated glaucoma than in healthy control subjects. To obtain more
information on the effect of glaucoma on lacrimation, a method for
quantification of reflex lacrimation was developed and applied to
patients with glaucoma or ocular hypertension and healthy control
methods. After instillation of 2 μl of fluorescein (2%), the decay of
fluorescein concentration in tears was measured by fluorophotometry
over 10 minutes to determine steady state TTO. Then, reflex lacrimation
was induced by stimulating the trigeminal nerve with ethanol vapor via
the nostrils. Thereafter, the decay of fluorescein and corresponding
steady state TTO were determined again. An index of reflex lacrimation,
defined as the percentage decrease in fluorescein concentration as a
result of stimulation, was calculated by forward and backward
extrapolation of the steady state decay of the fluorescein
concentration in tears, relative to the time of stimulation.
results. The index of reflex lacrimation was determined in 16 patients with
newly discovered but not yet treated glaucoma, 16 patients with
untreated ocular hypertension, and 16 healthy control subjects. The
values did not differ between groups (mean ± SD, 67.0% ±
17.7%, 63.5% ± 21.3%, and 70.4% ± 19.6%, respectively; ANOVA, P > 0.25). Surprisingly, the steady state TTO
after stimulation was lower than that before stimulation in each group
(ratio, 0.62 ± 0.46; paired t-test, P < 0.04).
conclusions. The method developed is appropriate for the quantification of reflex
lacrimation. Reflex lacrimation is not influenced significantly by
glaucoma or ocular hypertension. The decreased steady state TTO after
reflex stimulation may be caused by exhaustion of the lacrimal glands
after excessive reflex lacrimation, indicating that normal lacrimation
probably also contains reflex tears.
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