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Evidence of Tear Thickness Changes Following Instillation of Tear Lubricants
TEAR FILM & OCULAR SURFACE TEMPORAL CHANGES IN TEAR PROTEINS DURING ONSET OF DRY EYE DISEASE IN A MOUSE MODEL OF SJÖGREN’S SYNDROME. Lori L. Boggs, Joy Nanni-Prewitt, Ammon B. Peck. Department of Oral Biology, University of Florida, Gainesville, FL USA. Purpose. The NOD mouse, as well as the newly constructed C57BL/6.NOD-Aec1Aec2 mouse, have been shown to exhibit numerous disease parameters that parallel Sjögren’s syndrome (SjS) in humans, including loss of stimulated fluid secretion concomitant with the appearance of leukocytic infiltrates in the lacrimal and salivary glands. In the present study, we have catalogued the temporal changes in tear proteins with the onset of dry eye disease in these two mouse strains. Methods. Tears, collected from CD-1, NOD.B10-H2b and C57BL/6.NOD-Aec1Aec2 mice at 3, 8, 14, and 20 weeks of age, were labeled with either Cy-3 (green) or Cy-5 (red) dye. Labeled tear proteins were separated individually on pH3-10 NL18 cm IPG strips, then electrophoresed through 8-16% Tris-HCl SDS-polyacrylamide gels. Each gel was scanned for visualization using ImageQuant software. Each gel was compared by ImageMaster 2-D Elite software to identify unique protein difference. Each protein spot was sequenced using MOLDI-TOF. Results. NOD.B10-H2b and C57BL/6.NODAec1Aec2 mice exhibited marked losses in their tear protein concentrations compared to CD-1 mice. To date, nearly 50 protein spots have been compared between the autoimmune and nonautoimmune mice. Some 10 tear proteins remained unchanged through 20 weeks of age (e.g., lacrimal androgen binding protein); however, the majority of tear proteins showed some increased levels in the autoimmune mice (e.g., DNAseI orglobulin IV precursor), while >12 spots were lost in conjunction with the onset of dry eye disease. Conclusions. Onset of dry eye disease in mice exhibiting SjS-like disease is associated with loss of tear volume, decreased tear protein concentrations, loss in expression of several tear proteins, plus appearance of altered proteins. Commercial Relationship(s): ABP is a scientific consultant for and stockholder in Ixion Biotechnology, Inc.; Support: NIH grants DE13769, DE014344 & DE015152
EVIDENCE OF TEAR THICKNESS CHANGES FOLLOWING INSTILLATION OF TEAR LUBRICANTS. Noel A. Brennan,1 M-L Chantal Coles,1 Peter A. Simmons,2 Joseph Vehige.2 Brennan Consultants, Melbourne, Australia;1 Allergan LLC, Irvine, CA, USA.2 Purpose. To determine whether a high-resolution pachometer can enable isolation of tear film thickness changes following instillation of lubricant eye drops. Methods. The Haag-Streit Pachμmeter measures total corneal thickness to an accuracy of 1μm. Our initial investigations suggested that this instrument measures the thickness between the anterior tear film and the posterior endothelial surface. To evaluate the potential of the instrument to measure tear film thickness changes, we measured the total corneal thickness of six subjects before and after instillation of a drop of tear lubricant containing either 1% carboxymethylcellulose (CMC; Refresh Liquigel™, Allergan, Irvine, CA) or 0.4% polyethylene glycol, 0.3% propylene glycol and hydroxypropyl guar (PG; Systane™, Alcon Laboratories, Fort Worth, TX) versus a control solution consisting of unpreserved saline. Measurements were made at frequent intervals (up to once every five seconds) to follow the time course of thickness changes. Differences to baseline were binned into discrete time intervals and averaged across subjects. Results. The total measured corneal/tear thickness increased by an average of 10.3 (± 7.9) μm during the first minute after instillation of the drop containing CMC compared to 1.8 (± 1.2) μm for the PG drop and 1.1 (± 0.8) μm for the saline drop. The thickness increase for the CMC drop averaged 8.5 (± 7.2), 7.2 (± 5.1), 5.7 (± 4.5), 3.6 (± 2.9) and 2.3 (± 1.5) μm at the 1-3, 3-5, 5-7.5, 7.5-10 and 10-15 minute time intervals respectively. The thickness increase was statistically significant for the drop containing CMC both compared to baseline and the other solutions at all timepoints up to and including the 10-15 minute interval (p < 0.05). Conclusion. A protracted increase in tear film thickness following drop instillation is one strategy for treating dry eye disease. A change in total cornea/tear thickness can be demonstrated following instillation of a lubricant eyedrop with high viscosity. It is unlikely given the time frame that the immediate thickness increase is due to anything other than thickening of the tear film. The technique described here offers potential for optimizing eyedrop formulation to maximize influence on tear film thickness. Further development of the instrument may enable direct measurement of tear film thickness. Support: Allergan LLC
NON-NEWTONIAN TEAR FILM DRAINAGE WITH EVAPORATION AFTER A BLINK. Richard J. Braun, L. Pamela Cook. Department of Mathematical Sciences, University of Delaware, Newark DE, USA. Purpose. The drainage of the tear film after a blink has been approached theoretically by a number of authors. Very few have used known, measured non-Newtonian fluid dynamic properties in their models. We aim to theoretically describe the tear film drainage to better understand tear film behavior for healthy and dry eyes. Methods. Equations of fluid dynamics using appropriate fluid properties are derived. The equations include the FENE-P model which includes appropriate shear-thinning and elastic behavior for the tear film; the properties are fit to measured data. Evaporation from the free surface of the film is included as well. An asymptotic simplification known as lubrication theory simplifies those equations to a single partial differential equation for the shape of the tear film. This equation is solved numerically on a computer, and in limited cases analytically. The numerical method is an application of the method of lines: finite difference methods are used in the spatial coordinate and then the resulting ordinary differential equations at the grid points are solved with the public domain software DASPK. Results. The tear film thins near the menisci at the lid margins much as in the previously considered Newtonian models, but the thinning there is more localized than before and the interior of the tear film away from the lids moves less than in the Newtonian case. Evaporation can cooperate with this thinning near the lids to produce tear film break up far faster than evaporation alone. Conclusions. The tear film drainage is substantially slowed away from the lid margins when the theory uses appropriate shear-thinning behavior for the viscosity. Evaporation can still contribute to the tear film break up in reasonable times for dry eye patients as was seen in the Newtonian case.
THE OCULAR SURFACE / JANUARY, 2005, VOL. 3, NO. 1 / SUPPLEMENT
S49
EVIDENCE OF TEAR THICKNESS CHANGES FOLLOWING INSTILLATION OF TEAR LUBRICANTS. Noel A. Brennan,1 M-L Chantal Coles,1 Peter A. Simmons,2 Joseph Vehige.2 Brennan Consultants, Melbourne, Australia;1 Allergan LLC, Irvine, CA, USA.2 Purpose. To determine whether a high-resolution pachometer can enable isolation of tear film thickness changes following instillation of lubricant eye drops. Methods. The Haag-Streit Pachμmeter measures total corneal thickness to an accuracy of 1μm. Our initial investigations suggested that this instrument measures the thickness between the anterior tear film and the posterior endothelial surface. To evaluate the potential of the instrument to measure tear film thickness changes, we measured the total corneal thickness of six subjects before and after instillation of a drop of tear lubricant containing either 1% carboxymethylcellulose (CMC; Refresh Liquigel™, Allergan, Irvine, CA) or 0.4% polyethylene glycol, 0.3% propylene glycol and hydroxypropyl guar (PG; Systane™, Alcon Laboratories, Fort Worth, TX) versus a control solution consisting of unpreserved saline. Measurements were made at frequent intervals (up to once every five seconds) to follow the time course of thickness changes. Differences to baseline were binned into discrete time intervals and averaged across subjects. Results. The total measured corneal/tear thickness increased by an average of 10.3 (± 7.9) μm during the first minute after instillation of the drop containing CMC compared to 1.8 (± 1.2) μm for the PG drop and 1.1 (± 0.8) μm for the saline drop. The thickness increase for the CMC drop averaged 8.5 (± 7.2), 7.2 (± 5.1), 5.7 (± 4.5), 3.6 (± 2.9) and 2.3 (± 1.5) μm at the 1-3, 3-5, 5-7.5, 7.5-10 and 10-15 minute time intervals respectively. The thickness increase was statistically significant for the drop containing CMC both compared to baseline and the other solutions at all timepoints up to and including the 10-15 minute interval (p < 0.05). Conclusion. A protracted increase in tear film thickness following drop instillation is one strategy for treating dry eye disease. A change in total cornea/tear thickness can be demonstrated following instillation of a lubricant eyedrop with high viscosity. It is unlikely given the time frame that the immediate thickness increase is due to anything other than thickening of the tear film. The technique described here offers potential for optimizing eyedrop formulation to maximize influence on tear film thickness. Further development of the instrument may enable direct measurement of tear film thickness. Support: Allergan LLC
NON-NEWTONIAN TEAR FILM DRAINAGE WITH EVAPORATION AFTER A BLINK. Richard J. Braun, L. Pamela Cook. Department of Mathematical Sciences, University of Delaware, Newark DE, USA. Purpose. The drainage of the tear film after a blink has been approached theoretically by a number of authors. Very few have used known, measured non-Newtonian fluid dynamic properties in their models. We aim to theoretically describe the tear film drainage to better understand tear film behavior for healthy and dry eyes. Methods. Equations of fluid dynamics using appropriate fluid properties are derived. The equations include the FENE-P model which includes appropriate shear-thinning and elastic behavior for the tear film; the properties are fit to measured data. Evaporation from the free surface of the film is included as well. An asymptotic simplification known as lubrication theory simplifies those equations to a single partial differential equation for the shape of the tear film. This equation is solved numerically on a computer, and in limited cases analytically. The numerical method is an application of the method of lines: finite difference methods are used in the spatial coordinate and then the resulting ordinary differential equations at the grid points are solved with the public domain software DASPK. Results. The tear film thins near the menisci at the lid margins much as in the previously considered Newtonian models, but the thinning there is more localized than before and the interior of the tear film away from the lids moves less than in the Newtonian case. Evaporation can cooperate with this thinning near the lids to produce tear film break up far faster than evaporation alone. Conclusions. The tear film drainage is substantially slowed away from the lid margins when the theory uses appropriate shear-thinning behavior for the viscosity. Evaporation can still contribute to the tear film break up in reasonable times for dry eye patients as was seen in the Newtonian case.
THE OCULAR SURFACE / JANUARY, 2005, VOL. 3, NO. 1 / SUPPLEMENT
S49