Changes in corneal epithelial irregularity following treatment with artificial tears.

SIGNIFICANCE: Dry eye sufferers have a highly irregular corneal epithelial surface compared with those without dry eye. This study demonstrated that corneal epithelial thickness irregularity can be significantly reduced after as little as 48 hours following treatment with regular use of topical ocular lubricants. PURPOSE: This study aimed to compare changes in corneal epithelial thickness irregularity factor (EIF) and ocular symptoms in a population with symptoms of dry eye before and up to 4 weeks after treatment with two commercially available lubricating eye drops versus saline. METHODS: We conducted a prospective single-center, investigator-masked, randomized, parallel-group dispensing study. Participants with moderate to severe symptoms of dry eye (Ocular Surface Disease Index score >23 at baseline) were enrolled and randomly assigned to receive either 0.15% hyaluronic acid + hydroxypropyl guar, 0.2% hyaluronic acid, or saline (16 in each group). Corneal epithelial thickness measurements were obtained along vertical and horizontal CASIA SS-1000 Optical Coherence Tomography scans at baseline and after 48 hours, 2 weeks, and 4 weeks. The Ocular Surface Disease Index questionnaire was administered at baseline, 2 weeks, and 4 weeks. RESULTS: Forty-eight participants (male-to-female ratio, 17:31) completed the study. Horizontal EIF was significantly lower at all follow-up visits compared with baseline (p=0.001), but there were no significant differences between study eye drops (p=0.34). No significant difference in vertical EIF was observed over time (p=0.32) or between eye drops (p=0.08). Ocular symptoms significantly improved after 2 and 4 weeks of treatment compared with baseline (p<0.001), but no differences were observed between eye drops (p=0.46). CONCLUSIONS: All treatments were effective for reducing EIF along the horizontal meridian 48 hours after initiation of treatment, and improvements were maintained for 4 weeks. Improvements in ocular symptoms were observed with all study treatments.

Human tear metabolites associated with nucleoside-signalling pathways in bacterial keratitis.

OBJECTIVE: The study aimed to profile and quantify tear metabolites associated with bacterial keratitis using both untargeted and targeted metabolomic platforms. METHODS: Untargeted metabolomic analysis using liquid-chromatography-Q Exactive-HF mass-spectrometry explored tear metabolites significantly associated with bacterial keratitis (n = 6) compared to healthy participants (n = 6). Differential statistics and principal component analysis determined meaningful metabolite differences between cases and controls. Purines and nucleosides were further quantified and compared between 15 cases and 15 controls in the targeted metabolomic platform using TSQ quantum access triple quadrupole mass spectrometry. Compound quantification was done by plotting the calibration curves and the difference in the compound levels was evaluated using the Wilcoxon rank-sum test. RESULTS: In the untargeted analysis, 49 tear metabolites (27 upregulated and 22 downregulated) were differentially expressed between cases and controls. The untargeted analysis indicated that the purine metabolism pathway was the most affected by bacterial keratitis. Metabolite quantification in the targeted analysis further confirmed the upregulation of xanthine (P = 0.02) and downregulation of adenine (P < 0.0001), adenosine (P < 0.0001) and cytidine (P < 0.0001) in the tears of participants with bacterial keratitis compared to that of healthy participants. CONCLUSIONS: Bacterial keratitis significantly changes the tear metabolite profile, including five major compound classes such as indoles, amino acids, nucleosides, carbohydrates, and steroids. This study also indicates that tear fluids can be used to map the metabolic pathways and uncover metabolic markers associated with bacterial keratitis. Conceivably, the inhibition of nucleoside synthesis may contribute to the pathophysiology of bacterial keratitis because nucleosides are required for maintaining cellular energy homeostasis and immune adaptability.

Culture of primary human meibomian gland cells from surgically excised eyelid tissue.

Meibomian gland dysfunction is one of the most common ocular diseases, with therapeutic treatment being primarily palliative due to our incomplete understanding of meibomian gland (MG) pathophysiology. To progress in vitro studies of human MG, this study describes a comprehensive protocol, with detailed troubleshooting, for the successful isolation, cultivation and cryopreservation of primary MG cells using biopsy-size segments of human eyelid tissue that would otherwise be discarded during surgery. MG acini were isolated and used to establish and propagate lipid-producing primary human MG cells. The primary cell viability during culture procedure was maintained through the application of Rho-associated coiled-coil containing protein kinase inhibitor (Y-27632, 10 µM) and collagen I from rat tails. Transcriptomic analysis of differentiated primary human MG cells confirmed cell origin and revealed high-level expression of many lipogenesis-related genes such as stearoyl-CoA desaturase (SCD), ELOVL Fatty Acid Elongase 1 (ELOVL1) and fatty acid synthase (FASN). Primary tarsal plate fibroblasts were also successfully isolated, cultured and cryopreserved. Established primary human MG cells and tarsal plate fibroblasts presented in this study have potential for applications in 3D models and bioengineered tissue that facilitate research in understanding of MG biology and pathophysiology.

Diurnal changes and topographical distribution of ocular surface epithelial dendritic cells in humans, and repeatability of density and morphology assessment.

PURPOSE: Dendritic cells (DC) play a crucial role in ocular surface defence. DC can be visualised in vivo by confocal microscopy but have not yet been fully characterised in humans. This study investigated the diurnal variation, topographical distribution and repeatability of DC density and morphology measurements. METHODS: In vivo confocal microscopy (IVCM) was conducted on 20 healthy participants (mean age 32.7 ± 6.4 years, 50% female) at baseline and repeated after 30 minutes, 2, 6 and 24 h. Images were captured at the corneal centre, inferior whorl, corneal periphery, limbus and bulbar conjunctiva. DC were counted manually, and their morphology was assessed for cell body size, presence of dendrites, and presence of long and thick dendrites. Mixed-model analysis, non-parametric analyses, Bland and Altman plots, coefficient of repeatability (CoR) and kappa were used. RESULTS: There were no significant changes in DC density (p ≥ 0.74) or morphology (p > 0.07) at any location over the 24-h period. The highest DC density was observed at the corneal limbus followed by the peripheral cornea (p < 0.001), with the lowest density at the corneal centre, inferior whorl and bulbar conjunctiva. Most DC at the corneal periphery, limbus and bulbar conjunctiva had larger cell bodies compared with the corneal centre (p ≤ 0.01), and the presence of long dendrites was observed mostly at non-central locations. Day-to-day CoR for DC density ranged from ±28.1 cells/mm2 at the corneal centre to ±56.4 cells/mm2 at the limbus. Day-to-day agreement of DC morphology determined by kappa ranged from 0.5 to 0.95 for cell body size, 0.60 to 0.95 for presence of dendrites, and 0.55 to 0.80 for the presence of long dendrites at various locations. CONCLUSIONS: No diurnal changes are apparent in corneal or conjunctival DC. Substantial topographical differences exist in DC density and morphology. IVCM provides good repeatability of DC density and acceptable agreement of DC morphology.

Impact of Microplastics on the Ocular Surface.

Plastics are synthetic materials made from organic polymers that are ubiquitous in daily living and are especially important in the healthcare setting. However, recent advances have revealed the pervasive nature of microplastics, which are formed by degradation of existing plastic products. Although the impact on human health has yet to be fully characterised, there is increasing evidence that microplastics can trigger inflammatory damage, microbial dysbiosis, and oxidative stress in humans. Although there are limited studies investigating their effect on the ocular surface, studies of microplastics on other organs provide some insights. The prevalence of plastic waste has also triggered public outcry, culminating in the development of legislation aimed at reducing microplastics in commercial products. We present a review outlining the possible sources of microplastics leading to ocular exposure, and analyse the possible mechanisms of ocular surface damage. Finally, we examine the utility and consequences of current legislation surrounding microplastic regulation.

Analysis of sex steroids in human tears using LC-MS and GC-MS: Considerations and developments to improve method sensitivity and accuracy.

Sex steroids play a role in regulation of tear film function and may exert their action locally at the ocular surface. However, measurement of sex steroids in tears is difficult due to small-volume tear samples and very low concentrations of the hormones. This short communication highlights what has been achieved to date in the analysis of tear sex steroids using ultra-performance LC-MS (UPLC-MS) as previously published, and reports further and more recent investigations toward optimising mass spectrometry method sensitivity and accuracy. The published UPLC-MS method successfully measured progesterone, androsterone glucuronide and 5α-androstane-3α,17ß-diol in pooled basal tears of postmenopausal women, and fourteen sex steroid standards in methanol. Limitations included sub-optimal limits of detection (LOD) and lower limits of quantification (LLOQ) for some analytes (particularly oestrogens), exclusion of sample matrix effects and no use of internal standards. This update reports on further experiments carried out to improve sensitivity and accuracy. Sample matrix effects, internal standard spiking, and derivatisation with dansyl chloride and oximes were investigated. Dansylation significantly improved the LOD and LLOQ of oestrogens and their metabolites, by a factor of 10 for oestradiol and a factor of 5 for oestrone, but sensitivity of this updated method is not sufficient however for analysis of these oestrogens in human tears. Using gas chromatography-mass spectrometry (GC-MS) as an alternative technique to LC-MS, improved sensitivity for derivatised oestradiol is reported. This work demonstrates the need to develop higher sensitivity methods and points researchers towards specific MS ionisation techniques for future analysis of sex steroids in tears, in order to progress current understanding of the role of sex steroids in tear function and dry eye.

The incidence of falls after first and second eye cataract surgery: a longitudinal cohort study.

OBJECTIVE: To compare fall incidence, and visual acuity and refractive status, before surgery and after first and second eye cataract surgery. DESIGN, SETTING: Prospective observational study in eight tertiary referral ophthalmology clinics in public hospitals in Sydney, Melbourne, and Perth. PARTICIPANTS: People aged 65 years or more referred for bilateral age-related cataract surgery during 2013-16, followed for maximum of 24 months after study entry or until six months after second eye surgery, whichever was shorter. MAIN OUTCOME MEASURES: Primary outcome: age- and sex-adjusted incidence of falls. SECONDARY OUTCOMES: visual acuity and refractive error. RESULTS: The mean age of the 409 included participants was 75.4 years (SD, 5.4 years); 220 were women (54%). Age- and sex-adjusted fall incidence prior to surgery was 1.17 (95% CI, 0.95-1.43) per year, 0.81 (95% CI, 0.63-1.04) per year after first eye surgery, and 0.41 (95% CI, 0.29-0.57) per year after second eye surgery. For the 118 participants who underwent second eye surgery and participated in all follow-up visits, age- and sex-adjusted incidence before (0.80 [95% CI, 0.55-1.15] falls per year) and after first eye surgery (0.81 [95% CI, 0.57-1.15] falls per year) was similar, but was lower after second eye surgery (0.32 [95% CI 0.21-0.50] falls per year). Mean habitual binocular visual acuity (logMAR) was 0.32 (SD, 0.21) before surgery, 0.15 (SD, 0.17) after first eye surgery, and 0.07 (SD, 0.15) after second eye surgery. CONCLUSIONS: First eye surgery substantially improves vision in older people with cataract, but second eye surgery is required to minimise fall incidence. Timely cataract surgery for both eyes not only optimises vision in older people with cataract, but also reduces their risk of injury from falls.

Multiple things going on at the same time: determinants of appropriate primary diabetic eyecare delivery.

PURPOSE: A recent nationwide medical record audit of optometry practices has identified an evidence-to-practice gap in primary diabetic eyecare delivery. This study aimed to explore the determinants (barriers and enablers) to appropriate diabetic eyecare delivery in Australia. METHODS: A qualitative study involving focus-group discussions and interviews of a purposeful sample of Australian optometrists was conducted. Participants were asked about the perceived barriers to adherence to four underperforming clinical indicators related to primary diabetic eyecare identified by the recent national optometry practice audit. The Theoretical Domain Framework was used for thematic analysis and coding salience to identify key behavioural determinants. RESULTS: Optometrists participated in eight focus groups (n = 27) and individual interviews (n = 4). The most salient barriers were related to Environmental resources (e.g., limited chair time); Beliefs about consequences (e.g., lack of perceived importance); Knowledge (e.g., poor understanding); Professional role/identity (e.g., the perceived role of optometry in care process); Social influences (e.g., the influence of senior optometrists) and Intentions (e.g., apathy). Key enablers were Environmental resources (e.g., electronic record system and practice aids); Knowledge (e.g., keeping up with knowledge/professional development); reinforcements (e.g., fear of legal actions) and behavioural regulations (e.g., self-monitoring/audit). CONCLUSIONS: This study shows that the evidence-to-practice gap in primary diabetic eyecare delivery in Australia can be attributed in part to several interconnected factors related to optometrists' individual capability and motivation as well as the social and practice environment within which they sit. These behavioural determinants will inform the design of an intervention to improve the appropriateness of primary diabetic eyecare delivery.

Epidemiology, Microbiology, and Genetics of Contact Lens-Related and Non-Contact Lens-Related Infectious Keratitis.

ABSTRACT: Infectious keratitis is a rare but severe condition associated with a range of ocular and systemic predisposing conditions, including ocular trauma, prior surgery, surface disease, and contact lens (CL) wear. This review explores the epidemiology of infectious keratitis, specifically the differences in disease incidence and risk factors, causative organism profile and virulence characteristics and host microbiome, genetics, gene expression, proteomics, and metabolomic characteristics in CL-related and non-CL-related diseases. Differences exist in the epidemiology, demographics, causative organisms, and their virulence characteristics in CL-related and non-CL-related diseases, and there is less evidence to support differences between these groups of individuals in the ocular surface microbiome, genetics, and pathways of disease. Genetic variations, however, in the host immune profile are implicated in both the onset and severity of infectious keratitis in CL and non-CL wearers. As technologies in metabolomics, proteomics, and genomics improved to be better able to process small-volume samples from the ocular surface, there will be improved understanding of the interplay between the CL, ocular surface, host immune profile, and the microbial environment. This may result in a more personalized approach in the management of disease to reduce disease severity.

Subjective Responses to Various Filling Solutions in the Posterior Fluid Reservoir of Miniscleral Lenses at Application.

PURPOSE: To compare the effect of the use of different lubrication eye drops and nonpreserved saline for the application of miniscleral contact lenses (CLs) on subjective experience during 6 hr of lens wear. METHODS: Experienced soft CL wearers aged 18 to 45 years (inclusive) were enrolled in this prospective, randomized, double-masked, three arm comparison cross-over study. Subjects were custom fitted with KATT 16.5 mm diameter miniscleral lenses, ordered to their prescription. Subjects attended visits on three separate days and were randomized to receive instillation of an HP-guar/nanoemulsion drop or an HP-guar/sodium hyaluronate (HA) eye drop into the miniscleral lens before filling with saline or filling with saline alone (control). Subjective responses were collected up to 6 hr postapplication. Generalized linear mixed models with multinomial distribution and cumulative logit link were used to compare the rate at which responses improved post-CL application for the different treatments. RESULTS: Twenty-four participants completed the study. Dryness symptoms were more likely to improve at a slower rate postlens application with saline alone compared with the addition of HP-guar/nanoemulsion (P=0.005) or HP-guar/HA (P=0.049) before lens application. Furthermore, the addition of HP-guar/nanoemulsion was more effective than saline alone in improving symptoms of fluctuating vision (P=0.011), grittiness/burning/stinging (P=0.001), and foreign body sensation (P=0.006) more quickly. CONCLUSIONS: The use of postlens lubrication may be useful in enhancing adaptation to miniscleral lenses.

Semi-quantification of lipids in human meibomian gland epithelial cells using dual staining microplate assays.

Two spectrophotometric microplate assays with dual staining for either fluorescent Nile red (NR) plus 4,6-diamidino-2-phenylindole (DAPI) or non-fluorescent Oil red O (ORO) plus Crystal violet (CV) were applied and optimised to evaluate the lipid producing capacity of immortalised human meibomian gland epithelial cells (iHMGEC). Cells were treated with rosiglitazone (Rosi, 10-50 µM), a known lipid producing inducer for iHMGEC, and were analysed for lipids using the NR-DAPI and ORO-CV microplate assays. The lipid producing capacity of iHMGEC after each treatment was determined by normalising lipid quantity (measured with NR or ORO) to cell number (measured with DAPI or CV). The dye concentrations of NR 1 µg/mL, DAPI 5 µg/mL, ORO 0.3% (v/v) and CV 0.5% (v/v), provided optimal linearity and coverage of signals over a range of cell densities (corresponding to 10-100% cell confluence). Both NR-DAPI and ORO-CV showed a dose-dependent effect of Rosi on lipid production in iHMGEC, consistent with the results reported previously using traditional microscopic imaging methods. The microplate assays offer a rapid, high throughput and objective measurement of the amount of lipids in iHMGEC (and potentially other lipid-producing cells) and can be used for screening the effects of biological agents or incubation changes on lipid production in cells in future studies.

Development of antibiotic resistance in the ocular Pseudomonas aeruginosa clone ST308 over twenty years.

Corneal infection caused by a bacteria Pseudomonas aeruginosa is common cause of ocular morbidity. Increasing antibiotic resistance by ocular P. aeruginosa is an emerging concern. In this study the resistome of ocular isolates of Pseudomonas aeruginosa clone ST308 isolated in India in 1997 (PA31, PA32, PA33, PA35 and PA37) and 2018 (PA198 and PA219) were investigated. All the isolates of ST308 had >95% nucleotide similarity. The isolates from 2018 had larger genomes, coding sequences, accessory and pan genes compared to the older isolates from 1997. The 2018 isolate PA219 was resistant to all antibiotics except polymyxin B, while the 2018 isolate PA198 was resistant to ciprofloxacin, levofloxacin, gentamicin and tobramycin. Among the isolates from 1997, five were resistant to gentamicin, tobramycin and ciprofloxacin, four were resistant to levofloxacin while two were resistant to polymyxin B. Twenty-four acquired resistance genes were present in the 2018 isolates compared to 11 in the historical isolates. All isolates contained genes encoding for aminoglycoside (aph(6)-Id, aph(3')-lIb, aph(3″)-Ib), beta-lactam (blaPAO), tetracycline (tet(G)), fosfomycin (fosA), chloramphenicol (catB7), sulphonamide (sul1), quaternary ammonium (qacEdelta1) and fluoroquinolone (crpP) resistance. Isolate PA198 possessed aph(3')-VI, rmtD2, qnrVC1, blaOXA-488, blaPME-1, while PA219 possessed aadA1, rmtB, qnrVC1, aac(6')-Ib-cr, blaTEM-1B, blaVIM-2, blaPAO-1, mph(E), mph(A), msr(E). In both recent isolates qnrVC1 was present in Tn3 transposon. In 219 blaTEM-1 was carried on a transposon and blaOXA-10 on a class 1 integron. There were no notable differences in the number of single nucleotide polymorphisms, but recent isolates carried more insertions and deletions in their genes. These findings suggest that genomes of P. aeruginosa ocular clonal strains with >95% nucleotide identity isolated twenty years apart had changed over time with the acquisition of resistance genes. The pattern of gene mutations also varied with more insertions and deletions in their chromosomal genes which confer resistance to antibiotics.

Effect of Water Exposure on Contact Lens Storage Case Contamination in Soft Lens Wearers.

SIGNIFICANCE: Water exposure during contact lens wear can transfer pathogenic microorganisms to the eye, causing ocular complications. This study determined that water exposure is prevalent among lens wearers and is independently associated with higher case contamination. Contact lens compliance education to minimize water exposure should be reenforced by contact lens organizations and practitioners. PURPOSE: Given the increasing association between water exposure and contact lens disease, this study aimed to explore the effect of water exposure and storage case contamination in soft contact lens users. METHODS: A total of 165 daily soft lens wearers completed a self-administered questionnaire on contact lens hygiene. Lens cases were collected, and microbial analysis was conducted using an adenosine triphosphate assay (for overall microbial bioburden) and limulus amebocyte lysate assay (for endotoxin levels). The lens hygiene (excellent, >35; moderate, 28 to 35; poor, <28) and water contact (≤1, good; >1, poor) scores measured the compliance and water exposure during lens wear, respectively. Multiple regression determined the association between water behaviors and case contamination. RESULTS: The average (standard deviation) age of participants was 28 (13.5) years (18 to 78 years), and 65% were female. The average overall microbial bioburden of storage cases was 3.10 (0.98) log colony-forming unit/mL (1.09 to 5.94 log colony-forming unit/mL). Forty-five percent of participants reported showering, 49.7% reported swimming while wearing lenses (65.4% of whom swam without goggles), 27.8% used wet hands to handle lenses, and 17.5% used tap water to rinse storage cases. Showering with lenses significantly increased the risk of higher storage case bioburden (P = .001), whereas using wet hands (P = .01) doubled the risk of higher case endotoxin levels (odds ratio, 2.41; confidence interval 1.19 to 4.86). CONCLUSIONS: Water contact behavior while wearing lenses is prevalent among soft lens wearers and is associated with higher case contamination. Practitioners may improve contact lens education to reduce water exposure and case contamination to reduce the risk of lens-related adverse events.

Factors Affecting Microbial Contamination on the Back Surface of Worn Soft Contact Lenses.

SIGNIFICANCE: The results of this study demonstrate that Smart Touch Technology packaging, which is designed to reduce and simplify contact lens handling before insertion, is effective in reducing the frequency of bacterial contamination of the back surface of contact lenses after short-term wear. PURPOSE: The purpose of this study was to investigate the effect of lens packaging type, chelating agent, and finger contamination on microbial contamination on the back surface of worn soft contact lenses. METHODS: Twenty-five subjects completed each contralateral lens wear comparison in this randomized study: Smart Touch Technology versus conventional blister packaging for (1) silicone hydrogel lenses with ethylenediaminetetraacetic acid (EDTA) and (2) hydrogel lenses without EDTA in the packaging, and (3) silicone hydrogel lenses without EDTA versus hydrogel lenses with EDTA both in Smart Touch Technology packaging. Participants washed hands, underwent finger swabs, and inserted the lenses. After 45 minutes, lenses were removed aseptically and the posterior lens surfaces cultured. RESULTS: Thirty-eight subjects (average age, 30.9 ± 12.5 years) participated in this study. Overall, the level of back surface contamination was low for both lens materials, ranging from 0 to 43 colony-forming unit (CFU)/lens for the silicone hydrogel and 0 to 17 CFU/lens for the hydrogel lenses. The proportion of lenses with zero back surface contamination ranged from 16 to 64% for silicone hydrogel lenses and 28 to 64% for hydrogel lenses. Contact lenses from conventional packaging containing EDTA had 3.38 times increased risk (95% confidence interval [CI], 1.02 to 11.11; P = .05) of contamination being present compared with lenses from Smart Touch packaging with EDTA. Contact lenses from conventional packaging without EDTA had 3.4 times increased risk (95% CI, 1.02 to 11.36; P = .05) of contamination being present compared with Smart Touch packaging without EDTA, and silicone hydrogel lenses had a 6.28 times increased risk (95% CI, 1.65 to 23.81; P = .007) of contamination being present compared with hydrogels. The median (interquartile range) number of bacteria isolated from fingers used to perform lens insertion after handwashing but before lens insertion was not significantly different between the silicone hydrogel and hydrogel lenses (63.7 [204.2] vs. 59 [84.5], P = .09). Finger contamination was not significantly associated with lens contamination in the presence or absence of EDTA. CONCLUSIONS: Smart Touch Technology packaging was effective in reducing the proportion of contaminated lenses. Although silicone hydrogel lenses were more likely to be contaminated, the presence of EDTA ameliorated this effect. Finger contamination was not associated with lens contamination.

American Academy of Optometry Microbial Keratitis Think Tank.

SIGNIFICANCE: Think Tank 2019 affirmed that the rate of infection associated with contact lenses has not changed in several decades. Also, there is a trend toward more serious infections associated with Acanthamoeba and fungi. The growing use of contact lenses in children demands our attention with surveillance and case-control studies. PURPOSE: The American Academy of Optometry (AAO) gathered researchers and key opinion leaders from around the world to discuss contact lens-associated microbial keratitis at the 2019 AAO Annual Meeting. METHODS: Experts presented within four sessions. Session 1 covered the epidemiology of microbial keratitis, pathogenesis of Pseudomonas aeruginosa, and the role of lens care systems and storage cases in corneal disease. Session 2 covered nonbacterial forms of keratitis in contact lens wearers. Session 3 covered future needs, challenges, and research questions in relation to microbial keratitis in youth and myopia control, microbiome, antimicrobial surfaces, and genetic susceptibility. Session 4 covered compliance and communication imperatives. RESULTS: The absolute rate of microbial keratitis has remained very consistent for three decades despite new technologies, and extended wear significantly increases the risk. Improved oxygen delivery afforded by silicone hydrogel lenses has not impacted the rates, and although the introduction of daily disposable lenses has minimized the risk of severe disease, there is no consistent evidence that they have altered the overall rate of microbial keratitis. Overnight orthokeratology lenses may increase the risk of microbial keratitis, especially secondary to Acanthamoeba, in children. Compliance remains a concern and a significant risk factor for disease. New insights into host microbiome and genetic susceptibility may uncover new theories. More studies such as case-control designs suited for rare diseases and registries are needed. CONCLUSIONS: The first annual AAO Think Tank acknowledged that the risk of microbial keratitis has not decreased over decades, despite innovation. Important questions and research directions remain.

Facilitators and barriers to the delivery of eye care by optometrists: a systematic review using the theoretical domains framework.

PURPOSE: Evidence-based practice is fundamental to providing quality care, patient satisfaction and judicious use of limited healthcare resources. However, variability in evidence-based eye care delivery has been reported. Given the important role of optometrists in delivering primary eye care, a better understanding of the barriers and facilitators to providing optometric care is required. This systematic review aimed to identify determinants (barriers and facilitators) of eye care delivery by optometrists and interventions that may improve eye care delivery. RECENT FINDINGS: PubMed, MEDLINE, EMBASE, CINAHL, SCOPUS, PsychINFO, ProQuest and Web of Science were searched for studies reporting barriers and facilitators to eye care delivery published between 1999 and 2020. The Theoretical Domains Framework (TDF) was used to analyse data (quotations, interpretive summaries, survey result) with barriers and facilitators coded to one or more of the 14 domains, and used to identify the key behavioural domains influencing eye care delivery based on frequency of coding, elaboration and stated importance in the study. Influential domains were mapped to the Behaviour Change Wheel to identify potential interventions to improve eye care delivery. Of the 802 studies retrieved from the search, 30 were included. Frequently identified barriers were time constraints, resources and equipment issues, patient factors, lack of awareness, skill proficiency deficits and negative attitudes and beliefs. Frequently identified facilitators were adequate time, resources and equipment, education, skill proficiency and understanding the relevancy of the eye care provided. The key TDF domains influencing eye care delivery were 'environmental context and resources' (time, resources, equipment issues, patient factors), 'knowledge' (awareness issues), 'skills' (skills proficiency) and 'belief about consequences' (beliefs and relevancy). Intervention functions that may improve eye care delivery were education, training, restriction, environmental restructuring, enablement, persuasion and modelling. SUMMARY: The barriers and facilitators identified in this review were diverse and located at both the practitioner and organisational levels. Four TDF domains were found to be influential determinants of eye care practice. Intervention functions identified in this study can be used to improve the appropriateness of primary eye care delivery.

Quality of 2019 American optometric association clinical practice guideline for diabetic eye care.

PURPOSE: The 2019 American Optometric Association (AOA) clinical practice guideline intends to assist optometrists in providing evidence-based eye care for people with diabetes. This technical report evaluated the methodological and reporting quality of the guideline. METHODS: Four independent reviewers appraised the 2014 and 2019 versions of the AOA's guideline using the AGREE II instrument. Average scaled scores across the six domains of the AGREE II and an overall independent score were calculated based on the formula provided. RESULTS: The 2019 guideline scored high (range: 75-93%) in all domains except for the domain of applicability (34%). In the domain of rigour of development, significant improvements were noted in the 2019 guideline (median score: 7.0, interquartile range (IQR): 6.0-7.0) compared to the 2014 guideline (median: 5.0, IQR: 4.0-6.0) (p < 0.0001). The appraisal of the guideline also identified room for further improvements, especially in relation to implementing the guideline. CONCLUSION: The overall and domain specific quality of the AOA 2019 guideline was high, however, improvement in its applicability domain is required. The findings of this study will aid uptake of the guideline and inform improvement efforts for other international optometric guidelines.

Alteration of the pattern of regenerative corneal subbasal nerves after laser in-situ keratomileusis surgery.

PURPOSE: Corneal nerves exhibit high plasticity, which allows successful reinnervation after nerve damage caused by laser in-situ keratomileusis (LASIK) surgery. This study aimed to examine corneal subbasal nerve orientation during regeneration after LASIK. METHODS: This study involved 20 healthy, myopic subjects who had undergone bilateral Femto-LASIK 12-16 months prior with a superior hinge position. The corneal subbasal nerve plexus at the central, mid-temporal and mid-superior cornea on the right eye were imaged using in vivo confocal microscopy. Global nerve fibre orientation (indicating the overall pattern) and variation of nerve fibre orientation (indicating the consistency of the orientation) was determined using customised MATLAB™ software (www.mathworks.com/products/matlab.html). Differences in nerve orientation variables between groups were examined using the Mann-Whitney U test. Linear mixed models with Bonferroni adjustment were conducted to examine differences between corneal regions, and over time, after LASIK. RESULTS: There were no differences between post-LASIK and control groups in global nerve orientation at any of the examined corneal regions. The post-LASIK subjects had a greater variation of nerve orientation at the central (p = 0.007) and temporal (p = 0.049) cornea than the controls. There was a difference in global nerve fibre orientation between corneal regions (p < 0.001) in the controls but not in the post-LASIK group. The variation of nerve fibre orientation was higher at the central, compared to the temporal and superior cornea after LASIK (p < 0.001), although there were no differences between corneal regions in controls. CONCLUSIONS: Our results demonstrate that there was an increased variability in the corneal subbasal innervation patterns following LASIK when compared to controls.

iCareTrack: measuring the appropriateness of eyecare delivery in Australia.

PURPOSE: To meet the needs of an ageing population and optimise health expenditure, delivery of care should be based on evidence. However, the level of evidence-based care delivered to patients with eye conditions is rarely assessed. This study thus aimed to determine the percentage of eyecare encounters at which a sample of adult Australians received appropriate care (i.e., eyecare in line with evidence-based or consensus-based guidelines). METHODS: A cross-sectional retrospective review of optometry practice records was conducted using random stratified (by state) sampling in mainland Australia. Eighty-five clinical indicators were developed from evidence-based clinical practice guideline recommendations and refined by panels of experts using a modified Delphi process. Healthcare records of patients 18 years and over were examined against these indicators, representing appropriate care for three common eye conditions (preventative eyecare, glaucoma, and diabetic eyecare). Encounters occurred in optometry practices that were selected to be representative of the socioeconomic profile of Australian practices. The primary outcome measure was percentage compliance of eyecare delivery against the clinical indicators. RESULTS: From 426 optometry practices contacted by mail or telephone, 90 (21%) replied, 46 proved eligible and 42 were included in the study and visited for data collection. From these 1260 patient records were reviewed. Appropriate eyecare was received by Australian patients at an average of 71% (95%CI 70%, 73%) of eligible encounters. The percentage of appropriateness of eyecare at the condition level for preventative, glaucoma and diabetic eyecare was 81% (95%CI 79%, 83%), 63% (95%CI 61%, 64%), and 69% (95%CI 66%, 73%), respectively. Appropriateness of eyecare delivery was lowest for the domains of history taking and physical examination for all eye conditions. CONCLUSIONS: There were pockets of excellence but consistent delivery of appropriate eyecare needs improvement, and gaps in eyecare delivery should be addressed.

The risk of vision loss in contact lens wear and following LASIK.

PURPOSE: To compare the risk of vision loss following contemporary laser-assisted in situ keratomileusis (LASIK) with different types and modality of use of contact lenses. METHODS: Data from a previously published study were used to derive the incidence of vision loss (≥ 2 line loss of best corrected spectacle acuity) following microbial keratitis for different contact lens types and wearing modality, stratified by duration of lens wear. A literature search on vision loss following LASIK was performed between 2003 and 2019. The prevalence of vision loss at six months post-surgery was captured from clinical trials published after 2003. A proportion meta-analysis was applied to derive the prevalence of vision loss following LASIK. A least-squares fitting of cumulative vision loss (P, /10 000 wearers) over time (t, years) using an exponential model estimated the years of contact lens wear to which the risk of vision loss with LASIK was equivalent. RESULTS: Vision loss following LASIK occurred in 66 (95% confidence interval [CI] 34-108) per 10 000 wearers. As a conservative estimate based on the lower confidence interval of the estimated equivalent years of contact lens wear, daily wear contact lenses and extended overnight silicone wear hydrogel contact lens need to be worn for 103 (95% [CI] 103-391) and 25 (95% [CI] 25-79) years respectively, to equal the rate of vision loss equivalent to a one-off LASIK procedure. CONCLUSIONS: The risk of vision loss to the individual is low with either contact lens wear or refractive surgery. Contact lens wear does not pose a higher risk of vision loss than LASIK surgery for the most common wear modalities.