Clinical application of the tear film prism.
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ABSTRACT:
SUBMITTER: Malik M
PROVIDER: S-EPMC8169868 | biostudies-literature | 2021 Jun
REPOSITORIES: biostudies-literature
Publications
Clinical application of the tear film prism.
Eye (London, England) 20200728 6
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Project description:This study aims at determining the thickness of the tear lipid layer (LL) observed from a placido-disc-based tear film analyzer. We prospectively collected reflections of placido-disk LL images using a tear film analyzer (Keratograph® 5M, Oculus) from subjects with dry eye symptoms. The LL thickness (LLT) over the inferior half of the cornea was estimated with the use of interference color analysis and the preprocessing of images with and without ring segmentation were obtained and analyzed. Moreover, LLTs before and after 1 h of applying topical ointment (Duratears, Alcon) were compared to validate the estimation of LLT. Our results suggested that the tear LLT can be assessed using a placido-disk-based tear film analyzer and interference color analysis. We verified a high correlation between non-segmented and segmented LL images and estimated LLT increase after applying ointment. In addition, we concluded that LLT can be evaluated by direct interference analysis without segmentation preprocessing.
| S-EPMC7345488 | biostudies-literature
Project description:Purposeω-3 and ω-6 polyunsaturated fatty acids modulate inflammatory processes throughout the body through distinct classes of lipid mediators that possess both proinflammatory and proresolving properties. The purpose of this cross-sectional study was to explore the relationship between lipid profiles in human tears and dry eye (DE) symptoms and signs.MethodsForty-one patients with normal eyelid and corneal anatomy were prospectively recruited from a Veterans Administration Hospital over 18 months. Symptoms and signs of DE were assessed, and tear samples was analyzed by mass spectrometry-based lipidomics. Statistical analyses comparing the relationship between tear film lipids and DE included Pearson/Spearman correlations and t-tests.ResultsArachidonic acid (AA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA) were present in more than 90% of tear film samples. The ratio of ω-6 (AA) to ω-3 (DHA+EPA) fatty acids was correlated with multiple measures of tear film dysfunction (tear breakup time, Schirmer 2 scores, and corneal staining; all P < 0.05). Arachidonic acid-derived prostaglandin E2 was detected in the majority of samples and correlated with low tear osmolarity, meibomian gland plugging, and corneal staining.ConclusionsBoth ω-3 and ω-6 lipid circuits are activated in the human tear film. The ratio of ω-6:ω-3 tear lipids is elevated in DE patients in proportion to the degree of tear film dysfunction and corneal staining. Metabolic deficiency of ω-3 tear film lipids may be a driver of chronic ocular surface inflammation in DE.
| S-EPMC4857833 | biostudies-literature
Project description:PurposeThe thinning of the precorneal tear film between blinks and tear film breakup can be logically analyzed into contributions from three components: evaporation, flow into the cornea, and tangential flow along the corneal surface. Whereas divergent tangential flow contributes to certain types of breakup, it has been argued that evaporation is the main cause of tear thinning and breakup. Because evaporation is controlled by the tear film lipid layer (TFLL) it should therefore be expected that patterns of breakup should match patterns in the TFLL, and this hypothesis is tested in this study.MethodsAn optical system is described for simultaneous video imaging of fluorescein tear film breakup and the TFLL. Recordings were made from 85 subjects, including both with healthy and dry eyes. After instillation of 5 μL2% fluorescein, subjects were asked to blink 1 second after the start of the recording and try to maintain their eyes open for the recording length of 30 or 60 seconds.ResultsAreas of tear film thinning and breakup usually matched corresponding features in the TFLL. Whereas thinning and breakup were often matched to thin lipid, surprisingly, the corresponding lipid region was not always thinner than the surrounding lipid. Occasionally, a thin lipid region caused a corresponding region of greater fluorescence (thicker aqueous layer), due to convergent tangential flow.ConclusionsAreas of tear thinning and breakup can generally be matched to corresponding regions of the TFLL as would be expected if breakup is largely due to evaporation. Surprisingly, in some examples, the corresponding lipid area was not thinner and possibly thicker than the surrounding lipid. This indicates that the lipid was a poor barrier to evaporation, perhaps because of deficiency in composition and/or structure. For example, bacterial lipases may have broken down esters into component acids and alcohols, causing a defective TFLL structure with increased evaporation.
| S-EPMC3720150 | biostudies-literature
Project description:In this study, mass spectrometry was used to explore the canine tear proteome. Tear samples were obtained from six healthy dogs, and one-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis (1D SDS-PAGE) was used as a first step to separate intact proteins into 17 bands. Each fraction was then trypsin digested and analysed by matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI-TOF-MS/MS) to characterize the protein components in each fraction. In total, 125 tear proteins were identified, with MCA (Major Canine Allergen), Serum albumin, UPF0557 protein C10orf119 homolog, Collagen alpha-2(I) chain, Tyrosine -protein kinase Fer, Keratine type II cytoskeletal, Beta-crystallin B2, Interleukin-6 and Desmin occurring as the most confident ones with the highest scores. The results showed that the proteomic strategy used in this study was successful in the analysis of the dog tear proteome. To the best of our knowledge, this study is the first to report the comprehensive proteome profile of tears from healthy dogs by 1D SDS PAGE and MALDI-TOF. Data are available via ProteomeXchange with identifier PXD003124.
| S-EPMC4689550 | biostudies-literature
Project description:The aim of this study was to investigate the proteins found in tear film of healthy domestic cats. Schirmer tear test strips were used to collect tear samples of twelve healthy cats, which were mixed, centrifuged, and placed in a single 1.5 mL microtube that was frozen at -20°C, until analysis by two-dimensional polyacrylamide gel and mass spectrometry associated with high-performance liquid chromatography. The resulting spectra were analyzed and compared with the Swiss-Prot search tool. Forty peptides were detected in the analyzed protein fragments of 90 spots, with 16 proteins identified. Of these, the authors confirmed what has been already found in other studies: lactotransferrin, serum albumin, allergenic lipocalins, and neutrophil gelatinase-associated lipocalin. Others were considered novel in tear film samples of all species: cyclin-dependent protein kinase, serine/arginine repetitive matrix protein, apelin receptor, secretory protein related to C1q/TNF, Wee1, α-1,4 glucan phosphorylase, and WD repeat domain 1. The network was divided into 11 clusters, and a biological function was assigned. Most of the proteins have functions in the defense and maintenance of feline ocular surface homeostasis. Serum albumin is a bottleneck protein, with a high betweenness value. This paper is a pioneer in reporting, in-depth, the tear film proteome of domestic cats.
| S-EPMC8302406 | biostudies-literature
Project description:Importance:Tear film breakup time assessment is an integral component of dry eye evaluation. To our knowledge, the comparative discriminative ability of the noninvasive Keratograph (Oculus) vs conventional fluorescein method in detecting dry eye is unknown. Objective:To compare tear film stability measurements obtained with an automated noninvasive corneal topographer vs conventional fluorescein methods and evaluate their respective discriminative ability in detecting dry eye. Design, Setting, and Participants:This investigator-masked randomized crossover trial was conducted at a single-center university clinic between May 26, 2016, and October 3, 2016, and included 74 participants 18 years or older. Participants were recruited into 2 equally sized age, sex, and race/ethnicity-matched groups, with and without symptomatic dry eye (Ocular Surface Disease Index ≥13). Interventions:Participants were assigned to receive a noninvasive keratograph evaluation and topical fluorescein instillation in a randomized order. Main Outcomes and Measures:Noninvasive keratograph breakup time (NIKBUT) and fluorescein breakup time (TBUT). Area under the receiver operating characteristic curve, Youden-optimal diagnostic cutoff sensitivity, and specificity of NIKBUT and TBUT in detecting dry eye. Results:Seventy-four participants (74 eyes; 43 women [58.1%]) with a mean (SD) age of 24 (4) years were randomized. Noninvasive keratograph breakup time was significantly longer than TBUT in participants with dry eye (median, 6.3 seconds vs 4.3 seconds [difference, 2.0 seconds]; 95% CI, 1.1-3.4 seconds; P = .003), and healthy participants (median, 11.9 seconds vs 5.0 seconds [difference, 6.9 seconds]; 95% CI, 4.7-7.6 seconds; P < .001). Fluorescein breakup time measurements were more narrowly distributed in both the dry eye (variance, 188 seconds2 vs 27.9 seconds2; P < .001) and control groups (variance, 113 seconds2 vs 13.4 seconds2; P < .001). The discriminative ability of NIKBUT in detecting dry eye (area under the receiver operating characteristic curve, 0.68; 95% CI, 0.56-0.81; P = .007) was greater than that of TBUT (area under the receiver operating characteristic curve, 0.57; 95% CI, 0.44-0.70; P = .31). The optimal diagnostic cutoff for NIKBUT was 9 seconds or less with a sensitivity of 68% (95% CI, 50%-82%), specificity of 70% (95% CI, 53%-84%), positive likelihood ratio of 2.27 (95% CI, 1.32-3.91), and negative likelihood ratio of 0.46 (95% CI, 0.28-0.77). The optimal threshold for TBUT was 5 seconds or less with a sensitivity of 54% (95% CI, 37%-71%), specificity of 68% (95% CI, 50%-82%), positive likelihood ratio of 1.67 (95% CI, 0.96-2.89), and negative likelihood ratio of 0.68 (95% CI, 0.45-1.03). Conclusions and Relevance:Conventional fluorescein tear film breakup time measurements were significantly shorter with narrower distributions, while automated noninvasive keratograph readings displayed superior discriminative ability in detecting dry eye. Trial Registration:anzctr.org.au Identifier: ACTRN12617001428358.
| S-EPMC5885903 | biostudies-literature
Project description:In this study, mass spectrometry was used to explore the canine tear proteome. Tear samples were obtained from six healthy dogs, and one-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis (1D SDS-PAGE) was used as a first step to separate intact proteins into 17 bands. Each fraction was then trypsin digested and analysed by matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI-TOF-MS/MS) to characterize the protein components in each fraction. In total, 125 tear proteins were identified, with MCA (Major Canine Allergen), Serum albumin, UPF0557 protein C10orf119 homolog, Collagen alpha-2(I) chain, Tyrosine -protein kinase Fer, Keratine type II cytoskeletal, Beta-crystallin B2, Interleukin-6 and Desmin occuring as the most confident ones with the highest scores. The results showed that the proteomic strategy used in this study was successful in the analysis of the dog tear proteome. To the best of our knowledge, this study is the first to report the comprehensive proteome profile of tears from healthy dogs by 1D SDS PAGE and MALDI-TOF.
2015-11-23 | PXD003124 | Pride
Project description:PurposeAge-related macular degeneration (AMD) is the main reason for blindness in elderly people in the developed countries. Current screening protocols have limitations in detecting the early signs of retinal degeneration. Therefore, it would be desirable to find novel biomarkers for early detection of AMD. Development of novel biomarkers would help in the prevention, diagnostics, and treatment of AMD. Proteomic analysis of tear film has shown promise in this research area. If an optimal set of biomarkers could be obtained from accessible body fluids, it would represent a reliable way to monitor disease progression and response to novel therapies.MethodsTear films were collected on Schirmer strips from a total of 22 patients (8 with wet AMD, 6 with dry AMD, and 8 control individuals). 2D electrophoresis was used to separate tear film proteins prior to their identification with matrix-assisted laser desorption/ionization time of flight spectrometer (MALDI-TOF/TOF) and matching with functional databases.ResultsA total of 342 proteins were identified. Most of them were previously described in various proteomic studies concerning AMD. Shootin-1, histatin-3, fidgetin-like protein 1, SRC kinase signaling inhibitor, Graves disease carrier protein, actin cytoplasmic 1, prolactin-inducible protein 1, and protein S100-A7A were upregulated in the tear film samples isolated from AMD patients and were not previously linked with this disease in any proteomic analysis.ConclusionThe upregulated proteins supplement our current knowledge of AMD pathogenesis, providing evidence that certain specific proteins are expressed into the tear film in AMD. As far we are aware, this is the first study to have undertaken a comprehensive in-depth analysis of the human tear film proteome in AMD patients.
| S-EPMC5956098 | biostudies-literature
Project description:Dry eye disease is one of the most common ophthalmological complaints and is defined by a loss of tear film homeostasis. Establishing a diagnosis can be time-consuming, resource demanding and unpleasant for the patient. In this pilot study, we retrospectively included clinical data from 431 patients with dry eye disease examined in the Norwegian Dry Eye Clinic to evaluate how artificial intelligence algorithms perform on clinical data related to dry eye disease. The data was processed and subjected to numerous machine learning classification algorithms with the aim to predict decreased tear film break-up time. Moreover, feature selection techniques (information gain and information gain ratio) were applied to determine which clinical factors contribute most to an unstable tear film. The applied machine learning algorithms outperformed baseline classifications performed with ZeroR according to included evaluation metrics. Clinical features such as ocular surface staining, meibomian gland expressibility and dropout, blink frequency, osmolarity, meibum quality and symptom score were recognized as important predictors for tear film instability. We identify and discuss potential limitations and pitfalls.
| S-EPMC9741582 | biostudies-literature
Project description:Long-acting diquafosol ophthalmic solution (DQS-LX) has significant advantages regarding patient adherence owing to the reduced frequency of required eye drops; however, some patients prefer conventional diquafosol ophthalmic solution (DQS) over DQS-LX. Herein, to clarify the characteristics of patients according to their preference for ophthalmic solutions, dry eye (DE) and meibomian gland (MG) findings were retrospectively investigated. This study enrolled 341 patients with DE (mean age, 62.1 ± 11.7 years) treated at the Itoh Clinic between November 8, 2022, and July 31, 2023, who switched from DQS to DQS-LX. Patients were divided into two groups: those who continued DQS-LX administration (DQS-LX group) and those who wished to revert to conventional DQS (DQS group). Data regarding subjective symptoms assessed using the Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire, tear film breakup time (BUT), tear meniscus height (TMH), corneal and conjunctival fluorescein staining (CFS), conjunctival hyperemia/papilla, meiboscore, plugging, vascularity, meibum grade, and Schirmer's score at the time of DQS-LX switch were evaluated. Of the 341 patients, 31 (9.1%) wished to revert to conventional DQS. In total, 16 eyes of 16 patients in the DQS group and 32 eyes of 32 patients in the DQS-LX group-for whom complete data were available-were included in the analysis. The DQS-LX group had higher SPEED scores, lower TMHs (P < 0.001, respectively), shorter FBUTs, greater CFS findings, larger meibum grades, lower Schirmer scores, and more pluggings compared with the DQS group (P = 0.005, 0.001, 0.001, 0.046, 0.003, respectively). Meiboscores and vascularity did not differ significantly between the two groups (P = 0.73 and 0.39, respectively). In conclusion, patients with low tear film volume and DE complicated by moderate or severe meibomian gland dysfunction (MGD) preferred DQS-LX, while those with allergic findings preferred conventional DQS.
| S-EPMC11426461 | biostudies-literature