A model of tear-film breakup with continuous mucin concentration and viscosity profiles

2018 ◽  
Vol 858 ◽  
pp. 352-376 ◽  
Author(s):  
Mohar Dey ◽  
Atul S. Vivek ◽  
Harish N. Dixit ◽  
Ashutosh Richhariya ◽  
James J. Feng
Keyword(s):  
Ocular Surface ◽  
Tear Film ◽  
Viscosity Model ◽  
Mucus Layer ◽  
Advection Diffusion ◽  
Van Der Waals Attraction ◽  
Aqueous Layer ◽  
Distinct Boundary ◽  
Breakup Time ◽  
Layered Models

We propose an alternative to the prevailing framework for modelling tear-film breakup, which posits a layered structure with a mucus layer next to the cornea and an aqueous layer on top. Experimental evidence shows continuous variation of mucin concentration throughout the tear film, with no distinct boundary between the two layers. Thus, we consider a continuous-viscosity model that replaces the mucus and aqueous layers by a single liquid layer with continuous profiles of mucin concentration and viscosity, which are governed by advection–diffusion of mucin. The lipids coating the tear film are treated as insoluble surfactants as previously, and slip is allowed on the ocular surface. Using the thin-film approximation, we carry out linear stability analysis and nonlinear numerical simulations of tear-film breakup driven by van der Waals attraction. Results show that for the same average viscosity, having more viscous material near the ocular surface stabilizes the film and prolongs the breakup time. Compared with the layered models, the continuous-viscosity model predicts film breakup times that are in better agreement with experimental data. Finally, we also suggest a hydrodynamic explanation for how pathological loss of membrane-associated mucins may lead to faster breakup.

Correlation between Non-Invasive Tear Breakup Time and Invasive Tear Breakup Time for Dry Eye Syndrome Diagnosis

The Eye ◽  
2021 ◽  
Vol 23 (1) ◽  
pp. 15-22
Author(s):  
K. A. Mubarakova ◽  
S. A. Mukhanov ◽  
I. F. Saliyev ◽  
N. H. Habibullayeva
Keyword(s):  
Dry Eye ◽  
Ocular Surface ◽  
Tear Film ◽  
Optical Power ◽  
Dry Eye Syndrome ◽  
Non Invasive ◽  
Syndrome Diagnosis ◽  
Breakup Time ◽  
Test Result ◽  
Schirmer I Test

Introduction: in today’s digital environment, dry eye complaints step forward in all age groups. Along with dry eye syndrome, the diagnosis of which is not complicated, there are other causes of dryness such as dysfunction of the tear film and Meibomian glands, etc. For the early detection of the above conditions, invasive diagnostic methods are mainly used.Aim: to compare Non-Invasive Tear Breakup Time (NITBUT) assessed with LacryDiag ocular surface analyzer to results of invasive tests for dry eye syndrome diagnosis to determine the possibility of a wider use of LacryDiag in practical ophthalmology. Materials and Methods: 50 patients with dry eye, burning and feeling of a foreign body complaints participated in this study. Mean age amounted to 28.85 ± 5.86 years. NITBUT was assessed with LacryDiag ocular surface analyzer. The data obtained was compared to the results of Invasive Tear Breakup Time (TBUT) – Norne test, and Schirmer I test.Results: both quantitative and qualitative values of tear film stability were analyzed in all participants. Based on results of the Schirmer I test, patients were divided into subgroups: where it was greater than 21 mm, between 11 and 20 mm, between 6 and 10 mm, and less than 5 mm/ The mean value of the Schirmer I test result amounted to 15.32 ± 6.05 mm/5 min, NITBUT amounted to 9.59 ± 4.37 s, while invasive TBUT amounted to 8.98 ± 3.79 s. It was found that invasive TBUT is in a strong direct correlation with NITBUT values (p <0.001, r = 0.554). No correlation was discovered between Schirmer I test results and TBUT (p = 0.15, r = 0.207) as well as between Schirmer I test result and NITBUT (p = 0.17, r =0.228). No correlation was found between the optical power of the cornea and the tear film structure abnormalities.Conclusion: a strong correlation was found between results of invasive and non-invasive methods of tear film breakup time assessment. No correlation was found between the optical power of the cornea and the tear film disruption. The non-invasive test was found to be an effective and objective method for diagnosing dry eye.

scholarly journals The Effects of Topical Antiglaucoma Drugs as Monotherapy on the Ocular Surface: A Prospective Study

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Sevda Aydin Kurna ◽  
Semih Acikgoz ◽  
Ahmet Altun ◽  
Nurver Ozbay ◽  
Tomris Sengor ◽  
...  
Keyword(s):  
Prospective Study ◽  
Ocular Surface ◽  
Beta Blockers ◽  
Squamous Metaplasia ◽  
Tear Film ◽  
Eye Drops ◽  
Group 2 ◽  
A Prospective Study ◽  
Breakup Time ◽  
Corneal Staining

Purpose. The aim was to compare the effects of antiglaucoma eye drops on the tear functions and ocular surface.Method. Eighty-five eyes of 43 patients with glaucoma were included into this randomized prospective study. Timolol without preservative (1), timolol with benzododecinium bromide (2), latanoprost (3), bimatoprost (4), travoprost with benzalkonium chloride (5), and brimonidine with purite (6) were given to 6 groups. Schirmer I, tear film breakup time (TBUT), staining scores, and impression cytology samples were evaluated before and during 12-month-follow-up period.Results. At the end of 12 months, there was no detected change in Schirmer I and TBUT tests indicating dry eye. Corneal staining scores were higher in groups 1 and 2, while conjunctival staining scores were higher in group 6. Goblet cell count decreased in groups 1 and 5 in superior and inferior, group 2 in superior, and groups 3 and 6 in inferior conjunctiva. Squamous metaplasia grades showed a significant increase in groups 1 and 2 at 3rd, 6th, and 12th month controls (P<0.05).Conclusion. We observed nonserious impact on tear functions and ocular surface with antiglaucoma monotherapy. Beta blockers induced more damage on the ocular surface suggesting the role of the dosing and active substances beside preservatives.

scholarly journals Factors associated with ocular surface epithelial damage in patients with primary Sjögren’s syndrome

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ji Eun Kim ◽  
Na Rae Kim ◽  
Hee Seung Chin ◽  
Kyoung Yul Seo ◽  
Tae-im Kim ◽  
...  
Keyword(s):  
Ocular Surface ◽  
Tear Film ◽  
Meibomian Gland ◽  
Primary Sjögren’S Syndrome ◽  
Primary Sjogren’S Syndrome ◽  
Laboratory Findings ◽  
Surface Parameters ◽  
Primary Sjögren's Syndrome ◽  
Epithelial Damage ◽  
Breakup Time

Abstract Background The aim of this study was to evaluate the effects of systemic parameters, laboratory findings, oral parameters, and other ocular surface parameters on ocular surface epithelial damage in patients with primary Sjögren’s syndrome (pSS). Methods A total of 82 dry eye disease (DED) patients with pSS were enrolled in this study. Ocular surface epithelial damage was measured by ocular staining score (OSS). Systemic parameters, laboratory findings including serologic markers, oral parameters, and other ocular surface parameters were collected. Other ocular surface parameter assessments such as the Schirmer’s test, fluorescein tear breakup time, meibomian gland examinations, noninvasive keratographic tear film break-up time measurements using the Keratograph® 5 M were performed, and the Ocular Surface Disease Index was determined. Results In a multivariate analysis, decreased age and increased duration of pSS were significantly related to increased logarithm-transformed OSS (β = -0.011, P = 0.043 and β = 0.003, P = 0.008). Among the ocular surface parameters, decreased fluorescein tear breakup time and increased MGD grade were significantly associated with increased logarithm-transformed OSS (β = -0.183, P < 0.001 and β = 0.192, P = 0.049). Conclusions Ocular surface epithelial damage in patients with pSS was associated with young age, long duration of disease, unstable tear film, and decreased meibomian gland function.

scholarly journals Ocular Surface Cooling Rate Associated With Tear Film Characteristics and the Maximum Interblink Period

2021 ◽  
Author(s):  
Jennifer Ding ◽  
Young Hyun Kim ◽  
Sarah M Yi ◽  
Andrew D Graham ◽  
Wing Li ◽  
...  
Keyword(s):  
Ocular Surface ◽  
Tear Film ◽  
Test Strip ◽  
Surface Cooling ◽  
Non Invasive ◽  
Film Evaporation ◽  
Ocular Discomfort ◽  
Tear Meniscus Height ◽  
Film Characteristics ◽  
Breakup Time

Abstract The surface of the human eye is covered with a protective tear film that refreshes with each blink. Natural blinking occurs involuntarily, but one can also voluntarily blink or refrain from blinking. The maximum time one can refrain from blinking until the onset of discomfort is the maximum inter-blink period (MIBP). In between blinks the tear film thins and evaporates from the ocular surface. Tear film evaporation can be measured with various instruments. Infrared thermography provides a non-invasive measure of the ocular surface temperature (OST). Due to evaporation, ocular surface cooling (OSC) generally occurs when the eyes are open and exposed to the environment. The purpose of our study was to investigate the effect of OSC on the MIBP, and to investigate the association of the MIBP with tear film characteristics in subjects who do and do not exhibit OSC. The MIBP was measured simultaneously with OST over time. Non-invasive tear breakup time, tear meniscus height, tear lipid layer thickness, and Schirmer I test strip wetted lengths were measured on a day prior to the thermography visit. Subjects were divided into cooling and non-cooling groups based on OSC rate, and demographic and tear film characteristics were tested for inter-group differences. A faster rate of OSC was associated with an exponentially shorter duration of the MIBP overall and within the cooling group alone. Faster non-invasive tear breakup time was significantly associated with a shorter MIBP in both groups. These results suggest that tear film evaporation initiates a pathway that results in the onset of ocular discomfort and the stimulus to blinking. The presence of a subset of subjects with no or minimal OSC who nevertheless have a short MIBP indicates that evaporative cooling is not the only mechanism responsible for the onset of ocular discomfort.

Assessment of Tear Film Anomalies in Childhood Obesity

2021 ◽  
Author(s):  
Alper Halil Bayat ◽  
Emre Aydemir ◽  
Gozde Aksoy Aydemir ◽  
Hasim Gencer
Keyword(s):  
Insulin Resistance ◽  
Childhood Obesity ◽  
Ocular Surface ◽  
Tear Film ◽  
Disease Index ◽  
The Body ◽  
Test Results ◽  
Schirmer Test ◽  
Ocular Surface Disease Index ◽  
Breakup Time

Abstract Purpose To determine if childhood obesity has an effect on the ocular surface and tear film of children who are afflicted. Methods Patients who had childhood obesity, 85 eyes, and patients who were healthy, 75 eyes, were enrolled in this prospective and comparative study. The tear film breakup time (TF-BUT), tear meniscus area and height (TMA and TMH) values, Schirmer test scores, and ocular surface disease index (OSDI) scores were obtained for all participants. Results The TMH, TMA, TF-BUT, and Schirmer test results were statistically significantly lower in the obesity group (p < 0.001 for all). The children with obesity and insulin resistance had lower TMH, TMA, TF-BUT, and Schirmer test results when compared to the children without insulin resistance (p < 0.05 for all). The body mass index was found to be correlated with the TMH, TMA, TF-BUT, and Schirmer test results (p < 0.001 for all). Conclusion Children with obesity had lower TMA, TMH, TF-BUT, and Schirmer test results than healthy subjects. When insulin resistance was added to obesity, these values were even lower.

scholarly journals Efficacy of cyclosporine 0.05% in patients with dry eye syndrome

2019 ◽  
Vol 6 (8) ◽  
pp. 3339
Author(s):  
Jitender Phogat ◽  
Ritesh Verma ◽  
Manisha Rathi ◽  
Sumit Sachdeva ◽  
Latika Pandey
Keyword(s):  
Dry Eye ◽  
Ocular Surface ◽  
Tear Film ◽  
Dry Eye Syndrome ◽  
Paper Test ◽  
Inflammatory Reactions ◽  
Ocular Symptoms ◽  
Body Sensation ◽  
Ocular Discomfort ◽  
Breakup Time

Background: An even and smooth ocular surface is vital for the functioning and comfort of the eyes. Dry eye is a group of disorders of the tear film which is due to either decreased production or increased evaporation and is associated with symptoms of ocular discomfort. Smoking and drugs have been suggested as risk factors in various studies. Cyclosporine has been shown to reduce the cell-mediated inflammatory reactions associated with the inflammatory ocular surface disease.Methods: 50 eyes of 25 patients suffering from dry-eye syndrome were included in this study. Three major ocular symptoms of dry eye i.e., ocular pain, burning, and foreign body sensation were studied in this study. Each symptom was given a score from 0 to 1 so that the ocular symptoms were given a score from 0 to 3.Results: There was a significant reduction in ocular symptoms score (OSS) 2.25 before treatment to 0.6 after 3 months of treatment (p=0.01). In addition, the Schirmer's paper test scores improved from 1.23 mm to 5.91 mm, which is significantly different (p=0.001). The tear film breakup time also improved from 5.49s to 9.86s.Conclusions: Cyclosporine 0.05% has been established to be effective and safe in our study.

Structural and Molecular Tear Film Changes in Glaucoma

2019 ◽  
Vol 26 (22) ◽  
pp. 4225-4240 ◽  
Author(s):  
Rodolfo Mastropasqua ◽  
Luca Agnifili ◽  
Leonardo Mastropasqua
Keyword(s):  
Ocular Surface ◽  
Tear Film ◽  
Meibomian Gland ◽  
Eye Drops ◽  
Potential Candidate ◽  
Lipid Layer ◽  
Inflammatory Status ◽  
Quality Of Vision ◽  
Aqueous Layer

: The Tear Film (TF) is a trilaminar and dynamic fluid covering the entire Ocular Surface (OS), consisting of a mucus, aqueous, and lipid layer deeply interacting between them. Because of its structure and functions, TF plays a pivotal role in the preservation of the OS integrity and the quality of vision. Medical therapy for glaucoma is recognized to profoundly disturb the OS homeostasis by altering all components of the ocular surface unit, including TF. The presence of preservatives, the number of daily eye drops instillations, and the duration of therapy are the main contributors to TF changes. From the physio-pathological side, TF alterations are induced by toxic and allergic mechanisms and result from goblet cell and Meibomian gland loss, dysfunction of accessory lacrimal glands, and epithelial disruption. : In detail, TF changes are represented by mucus layer thinning, reduced mucin concentration, aqueous layer volume reduction, and lipid layer thinning with increased tear evaporation. Hyper- osmolarity and instability represent the main hallmarks of these changes and are an expression of a iatrogenic form of dry eye. TF undergoes also molecular modifications that primarily reflect a therapy- or disease-induced inflammatory status of the OS. Over the last years, this field of research aimed a progressively growing interest since molecular variations may be considered as potential candidate biomarkers of glaucoma. The aim of this review is to report the main TF changes occurring during glaucoma, exploring the relationship they may have with the glaucoma-related ocular surface disease and the patient quality of life, and their utility as potential biomarkers of disease.

Plasma rich in growth factors for the treatment of dry eye from patients with graft versus host diseases

2018 ◽  
Vol 30 (1) ◽  
pp. 94-103 ◽  
Author(s):  
Ronald M Sanchez-Avila ◽  
Jesus Merayo-Lloves ◽  
Francisco Muruzabal ◽  
Gorka Orive ◽  
Eduardo Anitua
Keyword(s):  
Growth Factors ◽  
Graft Versus Host Disease ◽  
Ocular Surface ◽  
Tear Film ◽  
Visual Analog Score ◽  
Eye Drops ◽  
Ocular Surface Disease Index ◽  
Host Disease ◽  
Graft Versus Host ◽  
Breakup Time

Purpose: To evaluate the efficacy and safety of plasma rich in growth factors eye drops for the treatment of corneal and ocular surface disorders in patients with graft versus host disease. Methods: This retrospective and longitudinal study included graft versus host disease patients with ocular disorders. The resolution of corneal ulcers (area and density staining) was evaluated as primary outcome. Best corrected visual acuity, intraocular pressure, tear film breakup time, Schirmer test, ocular surface disease index, and visual analog score were evaluated as secondary outcomes. All variables were analyzed before and after plasma rich in growth factors treatment. The safety of plasma rich in growth factors treatment was also assessed. Results: Twelve patients (23 eyes) with ocular graft versus host disease were evaluated. Statistically significant improvement in the area (75.7%) and density (73.3%) of the corneal staining, in best corrected visual acuity (74.7%), in ocular surface disease index scale (75.4%), visual analog score frequency (81.4%) and visual analog score severity (81.9%), and an increase of 3.8 s in tear film breakup time and 6 mm in Schirmer test was observed after plasma rich in growth factors treatment (p < 0.001). Some potential modifiers of the therapeutic effect were identified. All patients achieved corneal stability without perforation risk. No adverse events associated with the plasma rich in growth factors were observed. Conclusion: Immunosafe plasma rich in growth factors eye drops for the treatment of patients with ocular graft versus host disease could be safe and effective, showing a high rate of corneal ulcer resolution and dry eye disease control. Plasma rich in growth factors eye drops may help to maintain corneal stability and prevent it against higher ocular complications.

The Fluid Mechanics of the Eye and the Role of the Mucus Layer

2010 ◽  
Author(s):  
Douglas Platt ◽  
Ashwin Vaidya
Keyword(s):  
Fluid Mechanics ◽  
Tear Film ◽  
Protective Layer ◽  
Second Grade ◽  
Mucus Layer ◽  
Stress Effects ◽  
Grade Fluid ◽  
Generalized Second Grade Fluid ◽  
Aqueous Layer

We discuss the role of the mucus layer in the eye. The tear film in the eye is composed of a mucus layer, an aqueous layer and a lipid layer. While the aqueous and lipid layers are Newtonian, the mucus layer is non-Newtonian. It is commonly believed that the mucus layer serves as a lubricant for the cornea. However, we hypothesize that it serves a greater purpose as a protective layer from foreign particles; the normal stress effects of a viscoelastic fluid under the blinking motion of the eyelid would act towards pushing out any particle embedded in this layer. To prove this hypothesis, we mathematically study the fluid mechanics of a viscoelastic, shear thinning fluid modeled by a generalized second grade fluid. As a first step, we investigate the flow and stresses induced by a shearing motion (part of a blink cycle) and its effect upon an embedded particle, which is modeled by the Wiberg-Smith equation.

scholarly journals Factors Associated with Ocular Surface Epithelial Damage in Patients with Primary Sjögren's syndrome

2020 ◽  
Author(s):  
Ji Eun Kim ◽  
Na Rae Kim ◽  
Hee Seung Chin ◽  
Kyoung Yul Seo ◽  
Tae Im Kim ◽  
...  
Keyword(s):  
Ocular Surface ◽  
Tear Film ◽  
Meibomian Gland ◽  
Primary Sjögren’S Syndrome ◽  
Primary Sjogren’S Syndrome ◽  
Laboratory Findings ◽  
Surface Parameters ◽  
Primary Sjögren's Syndrome ◽  
Epithelial Damage ◽  
Breakup Time

Abstract Background: The aim of this study was to evaluate the effects of systemic parameters, laboratory findings, oral parameters, and other ocular surface parameters on ocular surface epithelial damage in patients with primary Sjögren's syndrome (pSS).Methods: A total of 82 dry eye disease (DED) patients with pSS were enrolled in this study. Ocular surface epithelial damage was measured by ocular staining score (OSS). Systemic parameters, laboratory findings including serologic markers, oral parameters, and other ocular surface parameters were collected. Other ocular surface parameter assessments such as the Schirmer’s test, fluorescein tear breakup time, meibomian gland examinations, noninvasive keratographic tear film break-up time measurements using the Keratograph® 5M were performed, and the Ocular Surface Disease Index was determined. Results: In a multivariate analysis, decreased age and increased duration of pSS were significantly related to increased logarithm-transformed OSS (β = -0.011, P = 0.043 for and β = 0.040, P = 0.008). Among the ocular surface parameters, decreased fluorescein tear breakup time and increased MGD grade were significantly associated with increased logarithm-transformed OSS (β = -0.183, P < 0.001 and β = 0.192, P = 0.049).Conclusions: Ocular surface epithelial damage in patients with pSS was associated with young age, long duration of disease, unstable tear film, and decreased meibomian gland function.

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