Corneal epithelial permeability to fluorescein in humans by a multi-drop method.
<h4>Purpose</h4>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 surfa...
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Public Library of Science (PLoS)
2018-01-01
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| Series: | PLoS ONE |
| Online Access: | https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0198831&type=printable |
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| author | Sangly P Srinivas Arushi Goyal Deepti P Talele Sanjay Mahadik Rachapalle Reddi Sudhir P Pavani Murthy Sudhir Ranganath Uday B Kompella Prema Padmanabhan |
| 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 |
| collection | DOAJ |
| description | <h4>Purpose</h4>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.<h4>Methods</h4>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.<h4>Results</h4>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.<h4>Conclusions</h4>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. |
| format | Article |
| id | doaj-art-4b99753e5d7f47e4a5cdca2b719efa34 |
| institution | DOAJ |
| issn | 1932-6203 |
| language | English |
| publishDate | 2018-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj-art-4b99753e5d7f47e4a5cdca2b719efa342025-08-20T02:46:01ZengPublic 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 Padmanabhan<h4>Purpose</h4>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.<h4>Methods</h4>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.<h4>Results</h4>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.<h4>Conclusions</h4>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.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0198831&type=printable |
| 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 |
| title | 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_short | 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 |
| url | https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0198831&type=printable |
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