Corneal epithelial permeability to fluorescein in humans by a multi-drop method.
PURPOSE:The permeability of the corneal epithelium to fluorescein Pdc is an indicator of the health of the ocular surface. It can be measured in a clinical setting by determining the accumulation of fluorescein in the stroma following administration of the dye on the ocular surface. Here we demonstr...
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doaj-4b99753e5d7f47e4a5cdca2b719efa342020-11-25T01:45:53ZengPublic Library of Science (PLoS)PLoS ONE1932-62032018-01-01136e019883110.1371/journal.pone.0198831Corneal epithelial permeability to fluorescein in humans by a multi-drop method.Sangly P SrinivasArushi GoyalDeepti P TaleleSanjay MahadikRachapalle Reddi SudhirP Pavani MurthySudhir RanganathUday B KompellaPrema PadmanabhanPURPOSE:The permeability of the corneal epithelium to fluorescein Pdc is an indicator of the health of the ocular surface. It can be measured in a clinical setting by determining the accumulation of fluorescein in the stroma following administration of the dye on the ocular surface. Here we demonstrate a new multi-drop method for the measurement of Pdc by a spot fluorometer. METHODS:Twenty-nine healthy participants were recruited for this study. First, a probe-drop of fluorescein (0.35%, 2 μL) was instilled on the conjunctiva. The clearance of the dye from the tears was immediately measured using the fluorometer. Following this, two loading drops (2%; 6 μL each) were administered 10 min apart. Fifteen minutes later, the ocular surface was washed and fluorescence from the stroma Fs was measured. Permeability was calculated using Pdc = (Q x Fs)/ (2 x AUC), where Q is the stromal thickness and AUC is the area under the fluorescence vs. time curve for the loading drops. RESULTS:After the probe drop, the tear fluorescence followed an exponential decay (elimination rate constant; kd = 0.41 ± 0.28 per min; 49 eyes of 29 subjects), but the increase in Fs was negligible. However, after the loading drops, the measured Fs was ~ 20-fold higher than the autofluorescence and could be recorded at a high signal to noise ratio (SNR > 40). The intra-subject variability of kd was insignificant. Since fluorescein undergoes concentration quenching at > 0.5%, the value of AUC for the loading drops was estimated by scaling the AUC of the probe drop. The calculated Pdc was 0.54 ± 0.54 nm/sec (n = 49). A Monte Carlo simulation of the model for the multi-drop protocol confirmed the robustness of the estimated Pdc. CONCLUSIONS:The new multi-drop method can be used in place of the single-drop approach. It can overcome a lack of sensitivity in fluorometers of high axial resolution. The Pdc estimated by the multi-drop method is ~ 11-fold higher than previously reported but closer to the value reported for other drugs with equivalent octanol/water partition coefficient.http://europepmc.org/articles/PMC6007839?pdf=render |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Sangly P Srinivas Arushi Goyal Deepti P Talele Sanjay Mahadik Rachapalle Reddi Sudhir P Pavani Murthy Sudhir Ranganath Uday B Kompella Prema Padmanabhan |
spellingShingle |
Sangly P Srinivas Arushi Goyal Deepti P Talele Sanjay Mahadik Rachapalle Reddi Sudhir P Pavani Murthy Sudhir Ranganath Uday B Kompella Prema Padmanabhan Corneal epithelial permeability to fluorescein in humans by a multi-drop method. PLoS ONE |
author_facet |
Sangly P Srinivas Arushi Goyal Deepti P Talele Sanjay Mahadik Rachapalle Reddi Sudhir P Pavani Murthy Sudhir Ranganath Uday B Kompella Prema Padmanabhan |
author_sort |
Sangly P Srinivas |
title |
Corneal epithelial permeability to fluorescein in humans by a multi-drop method. |
title_short |
Corneal epithelial permeability to fluorescein in humans by a multi-drop method. |
title_full |
Corneal epithelial permeability to fluorescein in humans by a multi-drop method. |
title_fullStr |
Corneal epithelial permeability to fluorescein in humans by a multi-drop method. |
title_full_unstemmed |
Corneal epithelial permeability to fluorescein in humans by a multi-drop method. |
title_sort |
corneal epithelial permeability to fluorescein in humans by a multi-drop method. |
publisher |
Public Library of Science (PLoS) |
series |
PLoS ONE |
issn |
1932-6203 |
publishDate |
2018-01-01 |
description |
PURPOSE:The permeability of the corneal epithelium to fluorescein Pdc is an indicator of the health of the ocular surface. It can be measured in a clinical setting by determining the accumulation of fluorescein in the stroma following administration of the dye on the ocular surface. Here we demonstrate a new multi-drop method for the measurement of Pdc by a spot fluorometer. METHODS:Twenty-nine healthy participants were recruited for this study. First, a probe-drop of fluorescein (0.35%, 2 μL) was instilled on the conjunctiva. The clearance of the dye from the tears was immediately measured using the fluorometer. Following this, two loading drops (2%; 6 μL each) were administered 10 min apart. Fifteen minutes later, the ocular surface was washed and fluorescence from the stroma Fs was measured. Permeability was calculated using Pdc = (Q x Fs)/ (2 x AUC), where Q is the stromal thickness and AUC is the area under the fluorescence vs. time curve for the loading drops. RESULTS:After the probe drop, the tear fluorescence followed an exponential decay (elimination rate constant; kd = 0.41 ± 0.28 per min; 49 eyes of 29 subjects), but the increase in Fs was negligible. However, after the loading drops, the measured Fs was ~ 20-fold higher than the autofluorescence and could be recorded at a high signal to noise ratio (SNR > 40). The intra-subject variability of kd was insignificant. Since fluorescein undergoes concentration quenching at > 0.5%, the value of AUC for the loading drops was estimated by scaling the AUC of the probe drop. The calculated Pdc was 0.54 ± 0.54 nm/sec (n = 49). A Monte Carlo simulation of the model for the multi-drop protocol confirmed the robustness of the estimated Pdc. CONCLUSIONS:The new multi-drop method can be used in place of the single-drop approach. It can overcome a lack of sensitivity in fluorometers of high axial resolution. The Pdc estimated by the multi-drop method is ~ 11-fold higher than previously reported but closer to the value reported for other drugs with equivalent octanol/water partition coefficient. |
url |
http://europepmc.org/articles/PMC6007839?pdf=render |
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