Temporal characteristics of sodium fluorescein in the tear meniscus

Markoulli, Maria and Md Isa, Nur Amalina and Papas, Eric B. (2017) Temporal characteristics of sodium fluorescein in the tear meniscus. Optometry and Vision Science, 94 (2). pp. 166-173. ISSN 1538-9235

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Abstract

Purpose To observe the emission intensity profile of sodium fluorescein in the human tear film as a function of time and concentration. Methods Twenty-two participants with no dry eye signs or symptoms were randomly allocated to receive 1 μL of either a 2 or 10% concentration of fluorescein to one eye. Images of the inferior tear meniscus were captured at regular intervals over 30 minutes and the process repeated for the other eye with the alternate concentration. Fluorescence intensity was quantified on the basis of the grayscale pixel values in the tear meniscus images. The fluorescein-decay profile over time and between concentrations was determined. Results Peak fluorescence intensity was reached in 3.9 ± 3.0 and 8.7 ± 4.4 minutes after instillation for the 2 and 10% concentrations, respectively. The 10% concentration of fluorescein maintained its peak fluorescence intensity longer than the 2% concentration (about 9 and 2 minutes, respectively). The peak fluorescence intensity was not significantly different between the higher and lower concentrations (44 ± 37 vs. 38 ± 32 units, P = .22). For both concentrations, the observed intensity did not return to baseline levels by the end of the 30-minute observation time. Conclusions The fluorescence intensity of fluorescein in a clinical setting varies with time such that both the onset and duration of maximum brightness are concentration dependent. At low concentration (2%), maximum brightness occurs almost immediately after instillation and lasts about 2 minutes. With a higher concentration (10%), the effective working window is delayed for about 7 to 8 minutes. Irrespective of initial concentration, observable fluorescence remains in the tear film beyond 30 minutes post-instillation.

Item Type:	Article (Journal)
Additional Information:	9452/86369
Uncontrolled Keywords:	fluorescein, tear meniscus, fluorescence, decay profile, quenching
Subjects:	Q Science > Q Science (General)
Kulliyyahs/Centres/Divisions/Institutes (Can select more than one option. Press CONTROL button):	Kulliyyah of Allied Health Sciences > Department of Optometry and Visual Science Kulliyyah of Allied Health Sciences
Depositing User:	Nur Amalina Md Isa
Date Deposited:	22 Dec 2020 17:09
Last Modified:	22 Dec 2020 17:09
URI:	http://irep.iium.edu.my/id/eprint/86369

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