CLEAR - Evidence-based contact lens practice.

Evidence-based contact lens -->practice involves finding, appraising and applying research findings as the basis for patient management decisions. These decisions should be informed by the strength of the research study designs that address the question, as well as by the experience of the practitioner and the preferences and environment of the patient. This reports reviews and summarises the published research evidence that is available to inform soft and rigid contact lens history and symptoms taking, anterior eye health examination (including the optimised use of ophthalmic dyes, grading scales, imaging techniques and lid eversion), considerations for contact lens selection (including the ocular surface measurements required to select the most appropriate lens parameter, lens modality and material selection), evaluation of lens fit, prescribing (teaching self-application and removal, adaptation, care regimen and cleaning instructions, as well as -->minimising risks of lens wear through encouraging compliance) and an aftercare routine.

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.

Assessment of a practitioner's perception of scleral contact lens complications.

PURPOSE: The purpose of this survey was to better understand scleral lens (SL) practitioners' fitting preferences and minor SL complications and their subsequent treatments. METHOD: Practitioners who attended the 2017 Global Specialty Lens Symposium were asked to complete an electronic questionnaire that was created by the investigators, a survey that asked practitioners about their SL fitting experience and preferences, their patients' experience with poor SL wetting, SL fogging, ocular symptoms (redness, pain/discomfort, dryness), and blurred central and side vision, and how the practitioners treated these conditions. RESULTS: This study analyzed data from 164 SL practitioners. The practitioners had been in practice for 16.3 ± 13.4 years, had been fitting SL for 5.5 ± 5.0 years, and fit 7.4 ± 7.1 SL/month. Practitioners preferred a SL with a final central corneal clearance of ∼200 µm and an overall diameter between 15.1 mm to 16.5 mm. Poor SL wetting (90.8% of practitioners documented condition), SL fogging (84.8%), blurred central vision (40.2%), ocular redness (34.8%), ocular dryness (24.4%), ocular pain/discomfort (20.7%), and blurred side vision (12.8%) were encountered by the practitioners. Practitioners preferred treating poor wetting and fogging with lens removal, cleaning, and reapplication, blurred central vision with a lens power change, blurred side (peripheral) vision, ocular redness, and ocular pain with a lens parameter change, and dryness with artificial tears. CONCLUSIONS: Most SL practitioners preferred a SL central corneal clearance of ∼200 µm, and they occasionally encountered SL-related complications in their practice, which they treated similarly to corneal gas permeable CLs.

Psychometric Analysis of the SPEED Questionnaire and CLDEQ-8.

Purpose: This study reports on the ability of the Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire to detect dry eye (DE) symptoms in contact lens (CL) and non-CL wearers. Methods: The SPEED questionnaire was administered to all subjects while the Contact Lens Dry Eye Questionnaire-8 (CLDEQ-8) was only administered to CL wearers. Tear meniscus heights (TMH) were measured, and the phenol red thread (PRT) test was conducted. These tests along with self-reported DE were used to identify subjects with dry eye disease (DED). Rasch analysis was performed to evaluate the questionnaires for measurement precision and unidimensionality, and the scores from these Rasch analyses were used to understand their ability to predict measures of DED. Results: We enrolled 284 subjects (150 CL and 134 non-CL wearers). Mean subject age was 39.4 ± 14.2 years. Rasch analysis yielded a multidimensional short form of the SPEED questionnaire (8-items) and a unidimensional short form of the CLDEQ-8 (4-item). Scores from both questionnaires were significantly associated with self-reported DE in CL and non-CL wearers. Scores of the 8-item SPEED questionnaire were associated with DED status in non-CL wearers but not in CL wearers while 4-item CLDEQ scores were associated with DED status in CL wearers. TMH or PRT were not associated with either questionnaire in CL or non-CL wearers. Conclusions: The 8-item SPEED questionnaire demonstrated adequate measurement precision with evidence of quantifying multiple symptoms categories while the 4-item CLDEQ-8 primarily quantified DE symptoms. Questionnaire scores were associated with self-reported DE, which suggests that they may have utility in both populations analyzed.

MyD88 Deficiency Protects Against Dry Eye-Induced Damage.

Purpose: Dry eye disease (DED) is a multifactorial disease associated with ocular surface inflammation. Toll-like receptors (TLRs) are integral in the initiation of inflammatory signaling. Therefore, we evaluated the effect of TLR-deficiency on dry eye-related ocular surface damage and inflammation using a mouse model of experimental dry eye (EDE). Methods: C57BL/6 wild-type (WT), MyD88-/-, and IL-1R-/- mice were exposed to EDE conditions for 5 days. Tear production was measured by phenol red thread test and ocular surface damage assessed with fluorescein staining. Corneal homogenates were obtained for matrix metalloproteinase (MMP) and cytokine expression analysis by Luminex assay and quantitative PCR. In addition, whole eyes and eyelids were dissected and goblet cells and Meibomian glands were imaged, respectively. Results: Following 5 days of EDE, WT mice had extensive ocular surface staining, while MyD88-/- mice had no increased staining above non-EDE conditions. Similarly, MyD88-/- mice did not have increased corneal MMP-2, 3, or 8 concentrations, as seen with WT mice. MyD88-deficiency also resulted in decreased corneal cytokine levels. In addition, MyD88-/- mice had significantly lower conjunctival goblet cell counts compared with both WT (EDE) and IL-1R-/- (non-EDE) mice. However, there was no difference in Meibomian gland morphology between WT, IL-1R-/-, and MyD88-/- mice. Conclusions: These studies demonstrate the importance of TLR signaling in dry eye development. Mice lacking TLR signaling, MyD88-/-, were protected from EDE-induced ocular surface damage and inflammatory mediator expression, warranting further investigation into TLR inhibition as a potential therapeutic for DED.

Comparison of subjective grading of lid wiper epitheliopathy with a semi-objective method.

PURPOSE: To validate a semi-objective method of grading lid wiper epitheliopathy (LWE) compared to subjective assessment. METHODS: Twenty upper and 20 lower eyelid margins of patients with LWE were photographed after instillation of fluorescein and lissamine green. The images were graded by two observers using a 0-3 grading scale for height (%) and width (mm) of the lid staining. The images were also processed using custom designed software in MATLAB. After manual delineation of the staining area, width and perpendicular height were automatically measured throughout the selected area. The height as a proportion of the lid margin width and width measures were then categorized into the same bins as in the grading scale. RESULTS: Repeatability of the image analysis system showed a mean difference (95% limits of agreement) between repeats of -0.01mm (0.03 and -0.05mm) for LWE height, 0.04mm (1.16 and -1.08mm) for LWE width, and -0.11mm2 (0.32 and -0.53mm2) for LWE area. The mean difference (95% limits of agreement) between image analysis and human grading for LWE height was -0.84 grades (0.54 and -2.21 grades), for LWE width was 0.31 grades (1.22 and -0.59 grades), and for the final grade (mean height and width) was -0.26 (0.44 and -0.96 grades) (all p<0.001). CONCLUSION: Human observers tend to overestimate the height and underestimate the width of LWE staining. Lid wiper region is not well defined, thus, it might be a difficult process for human observers to judge the stained region as a proportion of the lid wiper total region.

Influence of Meibomian Gland Expression Methods on Human Lipid Analysis Results.

PURPOSE: To compare the lipid composition of human meibum across three different meibum expression techniques. METHODS: Meibum was collected from five healthy non-contact lens wearers (aged 20-35 years) after cleaning the eyelid margin using three meibum expression methods: cotton buds (CB), meibomian gland evaluator (MGE) and meibomian gland forceps (MGF). Meibum was also collected using cotton buds without cleaning the eyelid margin (CBn). Lipids were analyzed by chip-based, nano-electrospray mass spectrometry (ESI-MS). Comparisons were made using linear mixed models. RESULTS: Tandem MS enabled identification and quantification of over 200 lipid species across ten lipid classes. There were significant differences between collection techniques in the relative quantities of polar lipids obtained (P<.05). The MGE method returned smaller polar lipid quantities than the CB approaches. No significant differences were found between techniques for nonpolar lipids. No significant differences were found between cleaned and non-cleaned eyelids for polar or nonpolar lipids. CONCLUSION: Meibum expression technique influences the relative amount of phospholipids in the resulting sample. The highest amounts of phospholipids were detected with the CB approaches and the lowest with the MGE technique. Cleaning the eyelid margin prior to expression was not found to affect the lipid composition of the sample. This may be a consequence of the more forceful expression resulting in cell membrane contamination or higher risk of tear lipid contamination as a result of reflex tearing.

Intersubject and Interday Variability in Human Tear and Meibum Lipidomes: A Pilot Study.

PURPOSE: Our aim was to quantitate day-to-day changes in the tear and meibum lipid profile of individual subjects in a pilot study of healthy humans. METHODS: Matched tear and meibum samples were obtained from four subjects on three consecutive days. Quantitative lipid profiles of human basal tears and meibum were compared using multivariate analysis by principal components. RESULTS: Substantial differences in the lipid profile between subjects were observed, while lipid profiles were steady across the three consecutive days of sampling. Multivariate principal component analysis demonstrated that lysophosphatidylcholine was the largest variant lipid class between subjects in tears, while wax esters comprised the most variation between subjects in meibum secretions. CONCLUSION: Interday variability is shown to be much smaller than interpatient variability, suggesting that tears and meibum subjects both have unique profiles in humans.

A comparison of patient matched meibum and tear lipidomes.

PURPOSE: To quantify the molecular lipid composition of patient-matched tear and meibum samples and compare tear and meibum lipid molecular profiles. METHODS: Lipids were extracted from tears and meibum by bi-phasic methods using 10:3 tert-butyl methyl ether:methanol, washed with aqueous ammonium acetate, and analyzed by chip-based nanoelectrospray ionization tandem mass spectrometry. Targeted precursor ion and neutral loss scans identified individual molecular lipids and quantification was obtained by comparison to internal standards in each lipid class. RESULTS: Two hundred and thirty-six lipid species were identified and quantified from nine lipid classes comprised of cholesterol esters, wax esters, (O-acyl)-ω-hydroxy fatty acids, triacylglycerols, phosphatidylcholine, lysophosphatidylcholine, phosphatidylethanolamine, sphingomyelin, and phosphatidylserine. With the exception of phospholipids, lipid molecular profiles were strikingly similar between tears and meibum. CONCLUSIONS: Comparisons between tears and meibum indicate that meibum is likely to supply the majority of lipids in the tear film lipid layer. However, the observed higher mole ratio of phospholipid in tears shows that analysis of meibum alone does not provide a complete understanding of the tear film lipid composition.