Morphological characteristics of Meibomian Glands and their Influence on Dry Eye disease in contact lens wearers.

PURPOSE: Meibomian glands (MG) are now easily imaged via clinical meibography machines. The purpose of this work was to explore the utility of the known MG morphology metrics for predicting dry eye disease (DED) in contact lens (CL) wearers. METHODS: Successful and previous CL wearers were recruited. DED was diagnosed if the participant's worst eye had a reduced tear meniscus height (TMH) of <0.2 mm or non-invasive tear break-up time (NITBUT) of <10 s and a Standardized Patient Evaluation of Eye Dryness (SPEED) score >5.0. Meibography was performed and images were subjectively graded by two examiners for the following MG characteristics: distorted, tortuous, hooked, abnormal gap, overlapping, fluffy areas, tadpoling, thinned, thickened, ghost, no extension to lid margin, shortened and dropout (atrophy). DED diagnostic ability of each metric was determined with receiver operating characteristic (ROC) analysis. RESULTS: A total of 112 participants were recruited, with 18.8% having DED and 60.7% being female. The only MG morphology metrics that were marginally predictive of DED were thickened upper eyelid MGs (p = 0.046), thickened mean upper plus lower eyelid MGs (p = 0.007), and atrophy of upper eyelid MGs (p = 0.043); however, none of these metrics reached a meaningful area under the curve in ROC analysis (all <0.70). CONCLUSION: While abnormal MG morphology is likely suggestive of DED in CL wearers, none of the MG morphology metrics evaluated alone in this study had clinically meaningful predictive value for detecting DED in this group of current and previous CL wearers.

Impact of meibomian gland width on successful contact lens use.

PURPOSE: To evaluate meibomian gland (MG) width and determine its impact on successful contact lens (CL) use and ocular health. METHODS: A five-site study was conducted by recruiting 18- to 45-year-old subjects who had dropped out of CLs because of discomfort. CL dropouts were compared to age- and sex-matched successful CL wearers. Right eyes were evaluated for tear break-up time, tear meniscus height, MG expressibility, meibum quality, and meibography. Central MG widths were evaluated with a custom MATLAB program. RESULTS: CL dropouts (n = 56) and successful CL (n = 56) wearers had similar grades for upper (p = 1.0) and lower (p = 0.22) MG atrophy, upper (p = 0.07) and lower (p = 0.89) MG tortuosity, and upper (p = 0.92) and lower (p = 0.97) MG widths. Upper eyelid MG widths were narrower than lower eyelid MG widths (p = 0.03). Upper and lower MG tortuosity (p < 0.001) and widths (p = 0.03) were associated, but not atrophy (p = 0.42). Lower eyelid MG widths were associated with MG expressibility (p = 0.01), but MG widths were not with any other factors. CONCLUSIONS: Successful CL wear does not appear to be clinically influenced by MG width or other measures of MG structural integrity. Lower eyelid MGs were wider than upper eyelid MGs and narrower lower eyelid MGs were associated with worse MG expressibility, suggesting that narrower MGs may produce abnormal meibum. Data also suggests that MG factors of both eyelids should be evaluated in practice.

Clinical factors associated with contact lens dropout.

PURPOSE: Contact lens (CL) dropout is estimated to be approximately equal to the number of new wearers per year, resulting in virtually no growth in the global CL market. The purpose of this study was to determine ocular and CL factors associated with CL dropout. METHODS: This five-site study recruited subjects 18-45 years of age who had ceased CL wear within the past 6-12 months due to discomfort. Dropout subjects were compared to age- and sex-matched currently successful CL wearers. Each subject was administered a symptoms survey and a study-specific survey that queried general CL history and compliance. Clinical testing included non-invasive tear break-up time, tear meniscus height, blepharitis assessment, meibum quality and expression, and meibography. RESULTS: A total of 56 matched-pairs were recruited. Dry eye was found to significantly increase a subject's odds of dropping out of CLs. The odds of dropping out of CLs was also significantly increased with each worsening grade of upper or lower eyelid meibomian gland (MG) plugging, upper eyelid meibum quality, and upper eyelid MG tortuosity. No other factors analyzed increased a subject's odds of dropping out of CLs. CONCLUSIONS: CL dropout may be precipitated by underlying dry eye symptoms, though most dry eye signs, with the exception of MG structure and function, had minimal predictive value for CL dropout. Nevertheless, evidence suggests that practitioners should screen for and educate CL patients about the importance of maintaining healthy MGs, which may potentially allow them to maintain comfortable CL use and increase their CL longevity.

A Randomized Trial to Evaluate the Effect of Toric Versus Spherical Contact Lenses on Vision and Eyestrain.

OBJECTIVES: To compare the effect of toric versus spherical soft contact lenses on objective measures of visual performance using visual acuity and electromyography of the orbicularis oculi muscle. METHODS: Current soft contact lens wearers with -0.75 to -1.75 D astigmatism in each eye were binocularly fitted with toric (1-Day ACUVUE MOIST for astigmatism) and spherical (1-Day ACUVUE MOIST) contact lenses in random order. After each fitting and at 1-week follow-up, high- and low-contrast visual acuities were measured. Electromyography was used to objectively evaluate eyestrain. Linear mixed models were used to assess differences between toric and spherical contact lenses. RESULTS: The mean age (±SD) of the 60 participants was 27.5±5.0 years, spherical refractive error was -3.68±2.01 D, and cylinder was -1.28±0.36 D. High- and low-contrast visual acuities with toric lenses were better than with spherical lenses at both fitting (toric high-contrast: -0.065±0.078 and low-contrast: 0.133±0.103 vs. spherical high-contrast: 0.001±0.104 and low-contrast: 0.224±0.107) and follow-up (toric high-contrast: -0.083±0.087 and low-contrast: 0.108±0.107 vs. spherical high-contrast: -0.015±0.095 and low-contrast: 0.211±0.104) (all P<0.0001). Electromyography-measured eyestrain was less with toric versus spherical contact lenses at fitting (least-square ratio of toric over spherical=0.72; P=0.0019) but not at follow-up (ratio=0.86; P=0.11). CONCLUSION: These results suggest that toric contact lenses provided improved objective measures of vision in a low-to-moderate astigmatic population.

Efficacy of Toric Contact Lenses in Fitting and Patient-Reported Outcomes in Contact Lens Wearers.

OBJECTIVES: To assess whether patient-reported measures are improved with soft toric contact lenses (TCLs) compared with soft spherical contact lenses (SCLs) and whether clinical time needed to fit TCL is greater than SCL. METHODS: Habitual contact lens wearers with vertexed spherical refraction +4.00 to +0.25 D or -0.50 to -9.00 D and cylinder -0.75 to -1.75 DC were randomly assigned to be binocularly fitted into a TCL or SCL, and masked to treatment assignment. Time to successful fit was recorded. After 5 days, the National Eye Institute Refractive Error Quality of Life Instrument (NEI-RQL-42) and modified Convergence Insufficiency Symptom Survey (CISS) were completed. After washout, subjects were fit into the alternative lens design (TCL or SCL). Outcomes were evaluated using linear mixed models for the time to fit and CISS score, generalized linear model for the successful fit, and Wilcoxon tests for the NEI-RQL-42. RESULTS: Sixty subjects (71.7% women, mean age [±SD] = 27.5±5.0 years) completed the study. The mean time to fit the TCL was 10.2±4.3 and 9.0±6.5 min for the SCL (least square [LS] mean difference (TCL-SCL)=1.2, P=0.22). Toric contact lens scored better than SCL in global NEI-RQL-42 score (P=0.006) and the clarity of vision (P=0.006) and satisfaction with correction subscales (P=0.006). CISS showed a 15% reduction in symptoms (LS mean difference [TCL-SCL]=-2.20, P=0.02). CONCLUSION: TCLs are a good option when trying to improve the vision of patients with low-to-moderate astigmatism given the subjective improvements in outcomes.

Effect of Buffer Conditions and Organic Cosolvents on the Rate of Strain-Promoted Azide-Alkyne Cycloaddition.

We investigate the effect of buffer identity, ionic strength, pH, and organic cosolvents on the rate of strain-promoted azide-alkyne cycloaddition with the widely used DIBAC cyclooctyne. The rate of reaction between DIBAC and a hydrophilic azide is highly tolerant to changes in buffer conditions but is impacted by organic cosolvents. Thus, bioconjugation reactions using DIBAC can be carried out in the buffer that is most compatible with the biomolecules being labeled, but the use of organic cosolvents should be carefully considered.

Inter-examiner reliability in meibomian gland dysfunction assessment.

PURPOSE: We evaluated inter-examiner reliability in grading of clinical variables associated with meibomian gland dysfunction (MGD) in real-time examination versus a graded digital image. METHODS: Meibography grading of meibomian gland atrophy and acini appearance, and slit-lamp grading of lid debris and telangiectasias were conducted on 410 post-menopausal women. Meibography and slit-lamp photos were captured digitally and saved for analysis by a masked examiner. Gland atrophy was graded as a proportion of partial glands in the lower lid, and acini appearance by the presence/absence of grape-like clusters. Lid debris and telangiectasias were graded based on severity and quantity from the same image, respectively. Observed agreement and weighted kappas (κ(w)) with 95% confidence intervals (CI) determined the degree of inter-examiner reliability between grading of these clinical variables in real-time examination and digital photographs using a multiple-point categorical scale. RESULTS: Observed agreement was determined for telangiectasias (40.6%), lid debris (50.9%), gland dropout (42.8%), and acini appearance (54.5%). Inter-examiner reliability for the four clinical outcomes ranged from fair agreement for acini appearance (κ(w) = 0.23, 95% CI = 0.14-0.32) and lid debris (κ(w) = 0.24, 0.16-0.32) to moderate agreement for gland dropout (κ(w) = 0.50, 0.40-0.59) and telangiectasias (κ(w) = 0.47, 0.39-0.55). Conclusions. Gland dropout and potentially lid telangiectasia grading from a photograph are more representative of grading in a real-time examination compared to acini appearance and lid debris. Alternative grading scales and/or clinical variables associated with MGD should be addressed in future studies.

Evaluation of extractants and precipitants in tear film proteomic analyses.

PURPOSE: To determine the efficiency of several protein extraction or precipitation treatments used in proteomic analyses. METHODS: Tear samples were taken from each eye of 40 normal subjects using glass microcapillaries. Tear volume was measured followed by storage at -86°C. Lotrafilcon B contact lenses were fitted and worn for 14 days, followed by removal and storage at -86°C. Tear samples from each eye within a subject were randomly assigned to either one of four chemical treatments (acetone, trichloroacetic acid, urea, and trifluoroacetic acid/acetonitrile [TFA/ACN]) or no chemical treatment in groups of 10. Contact lens samples were subjected to the same treatments as tear samples for each subject, with a second treatment preceding the first. Protein concentrations were quantified by Bradford assay. RESULTS: For tear samples, a significant reduction in total protein was observed when subjected to any of the four treatments studied compared with those samples left untreated. A positive relationship was noted between protein concentration and tear volume for treated, untreated, and combined tear samples. For contact lens samples, there was a significant reduction in the amount of deposited protein removed when comparing acetone, trichloroacetic acid, and urea with TFA/ACN. A second extraction from contact lenses assigned to the urea and TFA/ACN groups yielded a significant amount of additional protein compared with the amount removed initially. CONCLUSIONS: Tear samples subjected to any of the evaluated chemical treatments provided significantly less protein than untreated samples. For contact lenses, TFA/ACN extraction provided the highest yield of available protein out of the four treatments evaluated.