More eyes with 20/10 distance visual acuity at 12 months versus 3 months in a topography-guided excimer laser trial: Possible contributing factors.

PURPOSE: To study eyes with 20/10 uncorrected distance visual acuity (UDVA) 3 months and 12 months after topography-guided LASIK for myopia and myopic astigmatism, and to identify factors predictive of this excellent level of visual acuity. SETTING: Nine practices in the USA. DESIGN: Prospective unmasked study of safety and effectiveness. METHODS: The percentage of eyes with UDVA of 20/10 or better at 3 months and 12 months after topography-guided laser in situ keratomileusis (LASIK) with the Contoura Vision excimer laser in a U.S. Food and Drug Administration clinical trial was compared, and possible contributing factors were investigated. RESULTS: Preoperatively, only 1% of eyes had 20/10 corrected distance visual acuity (CDVA). Postoperatively, 7.0% of eyes had 20/10 or better UDVA at 3 months, and this number increased to 16% at 12 months (odds ratio, 2.48; 95% confidence interval, 1.33-4.61). The lower preoperative corneal astigmatism and postoperative refractive cylinder correlated with better postoperative UDVA and CDVA, respectively (P < .01 in all cases). The postoperative UDVA correlated with the postoperative CDVA (P < .01). CONCLUSION: The number of eyes with UDVA of 20/10 increases significantly between 3 months and 12 months after topography-guided LASIK and correlates with better postoperative CDVA. Eyes with lower preoperative corneal astigmatism are more likely to achieve 20/10 or better UDVA postoperatively. A significant improvement in the number of eyes with 20/10 or better from 3 months to 12 months after LASIK might be unique to topography-guided treatment.

A Randomized, Controlled Treatment Trial of Eyelid-Warming Therapies in Meibomian Gland Dysfunction.

AIM: The main treatment for meibomian gland dysfunction (MGD), a major cause of dry eye, is eyelid warming. Lack of compliance is the main reason for treatment failure. This has led to the development of eyelid-warming devices that are safe, effective and convenient. To obtain robust evidence demonstrating their efficacy, the authors conducted a 3-arm randomized clinical study. METHODS: The authors conducted a 3-month assessor-blinded, randomized, controlled trial of patients from the Singapore National Eye Centre experiencing at least one of eight dry eye symptoms 'often' or 'all the time'. Patients who wore contact lenses, had an active infection or known diagnosis of thyroid dysfunction and rheumatoid arthritis were excluded from the study. MGD participants were randomly assigned to warm towel (n = 25), EyeGiene(®) (Eyedetec Medical Inc., Danville, CA, USA) (n = 25) and Blephasteam(®) (Spectrum Thea Pharmaceuticals LTD, Macclesfield, UK) (n = 25) treatments. The primary efficacy and safety outcomes included the proportions of participants with improved symptoms and changes in best corrected visual acuity (BCVA), respectively. Other outcomes included tear break up time (TBUT), Schirmer test, corneal fluorescein dye staining and number of visibly occluded meibomian gland (MG) orifices. RESULTS: The study population was 53.5 ± 11.1 years old and predominantly Chinese. For severity of symptom after 3 months of treatment, 78.3% Blephasteam(®) participants reported improvement compared to 45.5% warm towel participants (p = 0.023). The corresponding proportions for improvement in the frequency of symptoms were 82.6% and 50.0%, respectively (p = 0.020). The proportions of improvement of symptoms in EyeGiene(®) patients were not significantly different from warm towel intervention. At 1 month of treatment, the crude odds ratio of improvement of severity of irritation for Blephasteam(®) compared to control was 3.0 (95% CI 0.88-10.18). However, the odds ratio adjusted by age was 5.67 (1.30-24.66). The lid-warming treatments did not significantly change the TBUT, Schirmer test results or number of visibly occluded MGs in the study period. All treatment modalities did not worsen BCVA after 3 months. CONCLUSION: Blephasteam(®) is more effective than warm towel for MGD treatment, with warm towel and EyeGiene(®) being comparable effective. Older age might predict for treatment efficacy. All studied therapies were safe for visual acuity (VA) for 3 months of treatment.

Longitudinal changes in tear fluid lipidome brought about by eyelid-warming treatment in a cohort of meibomian gland dysfunction.

Meibomian gland dysfunction (MGD) is a leading cause of evaporative dry eye and ocular discomfort characterized by an unstable tear film principally attributed to afflicted delivery of lipids to the ocular surface. Herein, we elucidated longitudinal tear lipid alterations associated with disease alleviation and symptom improvement in a cohort of MGD patients undergoing eyelid-warming treatment for 12 weeks. Remarkably, eyelid-warming resulted in stark reductions in lysophospholipids (P < 0.001 for lyso-plasmalogen phosphatidylethanolamine, lysophosphatidylcholine, and lysophosphatidylinositol), as well as numerous PUFA-containing diacylglyceride species in tears, accompanied by significant increases in several PUFA-containing phospholipids. These changes in tear lipidomes suggest that eyelid-warming leads to diminished activity of tear phospholipases that preferentially target PUFA-containing phospholipids. In addition, treatment led to appreciable increases (P < 0.001) in O-acyl-ω-hydroxy-FAs (OAHFAs), which are lipid amphiphiles critical to the maintenance of tear film stability. Longitudinal changes in the tear lipids aforementioned also significantly (P < 0.05) correlated with reduced rate of ocular evaporation and improvement in ocular symptoms. The foregoing data thus indicate that excess ocular surface phospholipase activity detrimental to tear film stability could be alleviated by eyelid warming alone without application of steroids and identify tear OAHFAs as suitable markers to monitor treatment response in MGD.

Comparative analysis of two femtosecond LASIK platforms using iTRAQ quantitative proteomics.

PURPOSE: New femtosecond laser platforms may reduce ocular surface interference and LASIK-associated dry eye. This study investigated tear protein profiles in subjects who underwent LASIK using two femtosecond lasers to assess differences in protein expression. METHODS: This was a randomized interventional clinical trial involving 22 patients who underwent femtosecond laser refractive surgery with a contralateral paired eye design. Corneal flaps of 22 subjects were created by either Visumax or Intralase laser. Tear samples were collected preoperatively, and at 1 week and 3 months postoperatively using Schirmer's strips. Tear protein ratios were calculated relative to preoperative protein levels at baseline. The main outcome measures were the levels of a panel of dry eye protein markers analyzed using isobaric tagging for relative and absolute quantitation (iTRAQ) mass spectrometry. RESULTS: A total of 824 unique proteins were quantifiable. Tear protein ratios were differentially regulated between the eyes treated with different lasers. The secretoglobulins Lipophilin A (1.80-fold) and Lipophilin C (1.77) were significantly upregulated (P < 0.05) at 1 week postoperatively in Visumax but not in Intralase-treated eyes. At 1 week, orosomucoid1 was upregulated (1.78) in Intralase but not Visumax-treated eyes. In the same eyes, lysozyme, cathepsin B, and lipo-oxygenase were downregulated at 0.44-, 0.64-, and 0.64-folds, respectively. Transglutaminase-2 was downregulated in both groups of eyes. CONCLUSIONS: Different laser platforms induce distinct biological responses in the cornea and ocular surface, which manifests as different levels of tear proteins. This study has implications for surgical technology and modulation of wound healing responses. (ClinicalTrials.gov number, NCT01252654.).

Extensive characterization of human tear fluid collected using different techniques unravels the presence of novel lipid amphiphiles.

The tear film covers the anterior eye and the precise balance of its various constituting components is critical for maintaining ocular health. The composition of the tear film amphiphilic lipid sublayer, in particular, has largely remained a matter of contention due to the limiting concentrations of these lipid amphiphiles in tears that render their detection and accurate quantitation tedious. Using systematic and sensitive lipidomic approaches, we validated different tear collection techniques and report the most comprehensive human tear lipidome to date; comprising more than 600 lipid species from 17 major lipid classes. Our study confers novel insights to the compositional details of the existent tear film model, in particular the disputable amphiphilic lipid sublayer constituents, by demonstrating the presence of cholesteryl sulfate, O-acyl-ω-hydroxyfatty acids, and various sphingolipids and phospholipids in tears. The discovery and quantitation of the relative abundance of various tear lipid amphiphiles reported herein are expected to have a profound impact on the current understanding of the existent human tear film model.

Lipidomic analysis of human tear fluid reveals structure-specific lipid alterations in dry eye syndrome.

As current diagnostic markers for dry eye syndrome (DES) are lacking in both sensitivity and specificity, a pressing concern exists to develop activity markers that closely align with the principal axes of disease progression. In this study, a comprehensive lipidomic platform designated for analysis of the human tear lipidome was employed to characterize changes in tear lipid compositions from a cohort of 93 subjects of different clinical subgroups classified based on the presence of dry eye symptoms and signs. Positive correlations were observed between the tear levels of cholesteryl sulfates and glycosphingolipids with physiological secretion of tears, which indicated the possible lacrimal (instead of meibomian) origin of these lipids. Notably, we found wax esters of low molecular masses and those containing saturated fatty acyl moieties were specifically reduced with disease and significantly correlated with various DES clinical parameters such as ocular surface disease index, tear breakup time, and Schirmer's I test (i.e., both symptoms and signs). These structure-specific changes in tear components with DES could potentially serve as unifying indicators of disease symptoms and signs. In addition, the structurally-specific aberrations in tear lipids reported here were found in patients with or without aqueous deficiency, suggesting a common pathology for both DES subtypes.

Contributions of ocular surface components to matrix-metalloproteinases (MMP)-2 and MMP-9 in feline tears following corneal epithelial wounding.

PURPOSE: This study investigated ocular surface components that contribute to matrix-metalloproteinase (MMP)-2 and MMP-9 found in tears following corneal epithelial wounding. METHODS: Laboratory short-haired cats underwent corneal epithelial debridement in one randomly chosen eye (n = 18). Eye-flush tears were collected at baseline and during various healing stages. Procedural control eyes (identical experimental protocol as wounded eyes except for wounding, n = 5) served as controls for tear analysis. MMP activity was analyzed in tears using gelatin zymography. MMP staining patterns were evaluated in ocular tissues using immunohistochemistry and used to determine MMP expression sites responsible for tear-derived MMPs. RESULTS: The proMMP-2 and proMMP-9 activity in tears was highest in wounded and procedural control eyes during epithelial migration (8 to 36 hours post-wounding). Wounded eyes showed significantly higher proMMP-9 in tears only during and after epithelial restratification (day 3 to 4 and day 7 to 28 post-wounding, respectively) as compared to procedural controls (p<0.05). Tears from wounded and procedural control eyes showed no statistical differences for pro-MMP-2 and MMP-9 (p>0.05). Immunohistochemistry showed increased MMP-2 and MMP-9 expression in the cornea during epithelial migration and wound closure. The conjunctival epithelium exhibited highest levels of both MMPs during wound closure, while MMP-9 expression was reduced in conjunctival goblet cells during corneal epithelial migration followed by complete absence of the cells during wound closure. The immunostaining for both MMPs was elevated in the lacrimal gland during corneal healing, with little/no change in the meibomian glands. Conjunctival-associated lymphoid tissue (CALT) showed weak MMP-2 and intense MMP-9 staining. CONCLUSIONS: Following wounding, migrating corneal epithelium contributed little to the observed MMP levels in tears. The major sources assessed in the present study for tear-derived MMP-2 and MMP-9 following corneal wounding are the lacrimal gland and CALT. Other sources included stromal keratocytes and conjunctiva with goblet cells.

Application of intrinsic time-scale decomposition (ITD) to EEG signals for automated seizure prediction.

Intrinsic time-scale decomposition (ITD) is a new nonlinear method of time-frequency representation which can decipher the minute changes in the nonlinear EEG signals. In this work, we have automatically classified normal, interictal and ictal EEG signals using the features derived from the ITD representation. The energy, fractal dimension and sample entropy features computed on ITD representation coupled with decision tree classifier has yielded an average classification accuracy of 95.67%, sensitivity and specificity of 99% and 99.5%, respectively using 10-fold cross validation scheme. With application of the nonlinear ITD representation, along with conceptual advancement and improvement of the accuracy, the developed system is clinically ready for mass screening in resource constrained and emerging economy scenarios.

Comparison of corneal sensitivity, tear function and corneal staining following laser in situ keratomileusis with two femtosecond laser platforms.

PURPOSE: To evaluate longitudinal changes in corneal sensitivity, tear function, and corneal staining in patients who underwent laser in situ keratomileusis (LASIK) using two different femtosecond lasers. METHODS: In a prospective, randomized clinical trial, contralateral eyes of 45 patients underwent flap creation by either VisuMax or IntraLase™ femtosecond laser. Corneal sensitivity, tear break up time (TBUT), Schirmer's test, and corneal fluorescein staining were assessed preoperatively and at 1 week, 1 month, and 3 months postoperatively. RESULTS: There were no statistical differences in any clinical outcome measure between the two femtosecond lasers (P > 0.05), although there was a trend towards slightly lower reductions for corneal sensitivity and TBUT in VisuMax-operated eyes. Overall, corneal sensitivity was significantly reduced at 1 week (P < 0.05), 1 month (P < 0 .001), and 3 months (P < 0.001) postoperatively. A significantly greater reduction of corneal sensitivity was noted in eyes with a myopic spherical equivalent of -6.00 diopters (D) to -11.25 D as compared with eyes that had a relatively lower level of myopia of less than -6.00 D (P < 0.001). TBUT and Schirmer's test values were significantly diminished at 1 week postoperatively (P < 0.04). Overall, corneal staining was significantly increased at 1 week postoperatively (P < 0.001). The level of myopia did not significantly affect postoperative changes in TBUT, Schirmer's test values, or corneal staining (P > 0.05). CONCLUSION: This study showed that changes in corneal sensitivity, tear function, and corneal staining were statistically similar in LASIK using VisuMax and IntraLase femtosecond lasers for flap creation. However, the trend towards faster recovery of corneal sensitivity and TBUT observed in VisuMax-operated eyes may be attributable to improved technical specifications.

Repeatability of a new method for measuring tear evaporation rates.

PURPOSE: The purpose of this study was to evaluate the repeatability of tear evaporimetry based on infrared thermography in a clinical room setting and to test the effect of changing environmental humidity on ocular surface temperature (OST) and tear evaporation rates (TERs) in a controlled adverse environmental (CAE) chamber. METHODS: Twenty-six healthy participants were enrolled, of whom 16 underwent repeatability measurements in a clinical room and 10 were exposed to a constant temperature of 30°C with a humidity of 45 and 65% in a CAE. Participants were acclimatized to each condition for at least 20 minutes before OSTs were taken. Tear film breakup time was assessed in the CAE only. Number of blinks and OSTs were continuously measured for 20 seconds for the cornea, conjunctiva, and overall ocular surface with an infrared camera; corresponding TERs were calculated. RESULTS: The OSTs and TERs showed acceptable strength of agreement between the first and second measurements. The coefficients of repeatability were 0.4°C for OST and 6.0 W m for TER. An increase in chamber humidity (from 45 to 65%) increased OST (p < 0.05). The TER was not changed significantly (p > 0.05). The tear film breakup time and number of blinks were not significantly affected by different humidity conditions. CONCLUSIONS: This technique has acceptable repeatability and has potential to document individual tear evaporation changes with time where humidity may differ by less than 20%.

Detection of meibomian glands and classification of meibography images.

Computational methods are presented that can automatically detect the length and width of meibomian glands imaged by infrared meibography without requiring any input from the user. The images are then automatically classified. The length of the glands are detected by first normalizing the pixel intensity, extracting stationary points, and then applying morphological operations. Gland widths are detected using scale invariant feature transform and analyzed using Shannon entropy. Features based on the gland lengths and widths are then used to train a linear classifier to accurately differentiate between healthy (specificity 96.1%) and unhealthy (sensitivity 97.9%) meibography images. The user-free computational method is fast, does not suffer from inter-observer variability, and can be useful in clinical studies where large number of images needs to be analyzed efficiently.

Application of empirical mode decomposition (emd) for automated detection of epilepsy using EEG signals.

Epilepsy is a global disease with considerable incidence due to recurrent unprovoked seizures. These seizures can be noninvasively diagnosed using electroencephalogram (EEG), a measure of neuronal electrical activity in brain recorded along scalp. EEG is highly nonlinear, nonstationary and non-Gaussian in nature. Nonlinear adaptive models such as empirical mode decomposition (EMD) provide intuitive understanding of information present in these signals. In this study a novel methodology is proposed to automatically classify EEG of normal, inter-ictal and ictal subjects using EMD decomposition. EEG decomposition using EMD yields few intrinsic mode functions (IMF), which are amplitude and frequency modulated (AM and FM) waves. Hilbert transform of these IMF provides AM and FM frequencies. Features such as spectral peaks, spectral entropy and spectral energy in each IMF are extracted and fed to decision tree classifier for automated diagnosis. In this work, we have compared the performance of classification using two types of decision trees (i) classification and regression tree (CART) and (ii) C4.5. We have obtained the highest average accuracy of 95.33%, average sensitivity of 98%, and average specificity of 97% using C4.5 decision tree classifier. The developed methodology is ready for clinical validation on large databases and can be deployed for mass screening.

Choice of artificial tear formulation for patients with dry eye: where do we start?

Dry eye is prevalent in many parts of the world. As a result, ophthalmologists and other health care professionals, such as optometrists and general practitioners, often help these patients manage their symptoms. The most common form of treatment for management of dry eye is over-the-counter tear lubricants. A number of tear lubricant formulations are available that vary by their mechanism of action. This article suggests simple guidelines on how lubricants can be selected for patients with mild to moderate dry eye. Side effects of lubricants, such as burning on instillation because of mismatches of eye drop with tear acidity, are also discussed.

Associations of systemic diseases, smoking and contact lens wear with severity of dry eye.

PURPOSE: Systemic diseases, smoking, ocular surgeries and contact lens wear have been linked with dry eye but it is not known if these factors are also associated with severity of dry eye. A cross-sectional investigation was conducted on the effect of various systemic and ocular conditions with respect to the severity of dry eye in Asian patients. METHODS: Prospective recruitment of consecutive new referral patients from a dry eye clinic was performed. Medical history, dry eye symptoms and clinical assessment were coded in a standardised form and analysed. RESULTS: Out of 510 patients (25% men), mean ± S.D. age 53.0 ± 14.1 years, 25 had previous diagnosis of rheumatoid arthritis, 30 had diabetic mellitus, 41 had thyroid disease, and 33 were current smokers; 23 and 41 patients had previous LASIK and cataract surgery respectively and 90 were current contact lenses wearers. A previous diagnosis of rheumatoid arthritis was associated with more severe superior corneal fluorescein staining (OR = 11.2, 95% CI 4.6-27.4). CONCLUSION: Generally, with the exception of rheumatoid arthritis, there were no associations between dry eye severity and systemic diseases, smoking, previous ocular surgeries and contact lens wear. Dry eye patients with rheumatoid arthritis tend to have more severe ocular surface damage in the superior cornea.

Nuclear Factor-κB: central regulator in ocular surface inflammation and diseases.

The nuclear factor-κB (NF-κB) is a key transcription factor pathway that is responsible for many key biological processes, such as inflammation, apoptosis, stress response, corneal wound healing, angiogenesis, and lymphangiogenesis. Numerous recent studies have investigated NF-κB in the context of ocular surface disorders, including chemical injury, ultraviolet radiation-induced injury, microbial infections, allergic eye diseases, dry eye, pterygium, and corneal graft rejection. The purpose this article is to summarize key findings with regard to the pathways regulating NF-κB and processes governed by the NF-κB pathway. In the innate defense system, NF-κB is involved in signaling from the toll-like receptors 2, 3, 4, 5 and 7, which are expressed in conjunctival, limbal, and corneal epithelial cells. These determine the ocular responses to infections, such as those caused by Pseudomonas aeruginosa, Staphylococcus aureus, adenovirus, and herpes simplex-1 virus. Natural angiogenic inhibitors enhance NF-κB, and this may occur through the mitogen-activated protein kinases and peroxisome proliferator-activated receptor γ. In alkali injury, inhibition of NF-κB can reduce corneal angiogenesis, suggesting a possible therapeutic strategy. The evaluation of NF-κB inhibitors in diseases is also discussed, including emodin, besifloxacin, BOL-303242-X (mapracorat), thymosin-ß4, epigallocatechin gallate, Perilla frutescens leaf extract and IKKß-targeting short interfering RNA.

A preliminary study of changes in tear film proteins in the feline eye following nictitating membrane removal.

OBJECTIVE: To investigate the influence of nictitating membrane (third eyelid) removal on selected proteins in feline tears. ANIMAL STUDIED: Domestic short-haired cats (7-17 months; 2.6-5.2 kg) were used. PROCEDURES: Eye-flush tears were collected periodically for up to 18 weeks from both eyes of animals with nictitating membranes removed, but nictitating gland left intact, (n = 4) or with nictitating membranes intact (n = 4). Tear comparisons were based on total protein content (TPC) using micro bicinchoninic acid assay, immunoglobulin A (IgA), and matrix-metalloproteinase (MMP)-9 measurements using sandwich enzyme-linked immunosorbent assay (ELISA) and tear gelatinase activity using gelatin zymography. Expression of MMP-2 and -9 in nictitating membranes removed at baseline (week 0) and eyes collected at 18 weeks were also investigated in histological sections using immunoperoxidase for visualization. RESULTS: Nictitating membrane removal did not significantly change TPC and MMP-9 in tears within the first 4 weeks. MMP-9 was not detected by ELISA in tears from eyes without nictitating membranes from week 5 onwards. IgA (%IgA of TPC) data varied between animals. Gelatin zymography showed increased MMP-2 and -9 activity in tears from eyes without nictitating membranes at week 1 and a decrease following week 2 post-surgery. MMP-2 and -9 were immunolocalised to conjunctival goblet cells of removed nictitating membranes and to the conjunctival epithelium, respectively. After 18 weeks, the distribution of MMPs in tissue was comparable between eyes with and without nictitating membranes. CONCLUSIONS: Based on this preliminary study, nictitating membrane removal appeared to cause long-term changes in expression of tear proteins, including reduced MMP-9 expression.

Validation of the flush method as an alternative to basal or reflex tear collection.

PURPOSE: To validate the more easily applicable "flush" tear collection technique as a viable alternative to basal and reflex tear collection. MATERIALS AND METHODS: Total protein content (TPC) and immunoglobulin A (IgA) concentrations were determined in the basal, reflex, and flush tears of 16 healthy non-contact lens wearers. The overall protein profile was established using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and mass spectrometry (MS). RESULTS: Collection-rates were 4.6 ± 6.7 µl/min, 13.9 ± 11.1 µl/min, and 25.7 ± 12.4 µl/min for the basal, reflex, and flush tears, respectively. TPC was 7.14 ± 2.22 mg/mL, 6.01 ± 2.11 mg/mL, and 3.79 ± 1.51 mg/ mL for basal, reflex, and flush tears, respectively, with flush tears being significantly less concentrated than basal (p = 0.001) and reflex (p = 0.008). IgA concentration was 1.04 ± 0.29 mg/ mL, 0.64 ± 0.26 mg/mL, and 0.65 ± 0.23 mg/mL for basal, reflex, and flush tears, respectively, with basal tears being significantly more concentrated (p < 0.001). As a percentage of TPC, IgA represented 19.8 ± 14.9%, 11.4 ± 3.9%, and 19.8 ± 8.7% for basal, reflex, and flush, respectively. The flush was not significantly different to basal (p = 1.00) but significantly greater than reflex (p = 0.02). SDS-PAGE showed the same tear profiles for basal and flush tears. MS identified the most abundant proteins in all tear types. CONCLUSIONS: The flush method allows much faster collection than basal secretion sampling but returns essentially the same spectrum of proteins in similar proportions. This behavior is confirmation that the flush technique has utility as a more convenient alternative to basal tear sampling in studies involving composition analysis.

A comparison of basal and eye-flush tears for the analysis of cat tear proteins.

PURPOSE: To identify a rapid and effective tear collection method providing sufficient tear volume and total protein content (TPC) for analysis of individual proteins in cats. METHODS: Domestic adult short-haired cats (12-37 months; 2.7-6.6 kg) were used in the study. Basal tears without stimulation and eye-flush tears after instillation of saline (10 µl) were collected using microcapillary tubes from animal eyes either unwounded control or wounded with 9-mm central epithelial debridement giving four groups with n = 3. Tear comparisons were based on total time and rate for tear collection, TPC using micro bicinchoninic acid (BCA), tear immunoglobulin A (IgA), total matrix-metalloproteinase (MMP)-9 concentration using sandwich enzyme-linked immunosorbent assay (ELISA) and MMP-9 activity. RESULTS: Eye-flush tears were collected significantly faster than basal tears in wounded eyes with higher rates for tear collection in unwounded control and wounded eyes. TPC was significantly lower in eye-flush tears compared to basal tears. The relative proportion of tear IgA normalized to TPC (% IgA of TPC) was not significantly different between basal and eye-flush tears. In unwounded control eyes, MMP-9 was slightly higher in eye-flush than in basal tears; activity of MMP-9 in both tear types was similar. In wounded eyes, eye-flush tears showed highest MMP-9 levels and activity on Day 1, which subsequently decreased to Day 7. MMP-9 activity in basal tears from wounded eyes did not display changes in expression. CONCLUSIONS: Eye-flush tears can be collected rapidly providing sufficient tear volume and TPC. This study also indicates that eye-flush tears may be more suitable than basal tears for the analysis of MMPs following corneal wounding.