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Clinical Relevance: Traditionally, refraction is performed, and spectacles are manufactured in in 0.25D-steps. Trial and spectacle lenses manufactured in smaller increments may allow for a more accurate refraction and prescribed spectacles., Background: To determine whether refraction in 0.05D-steps improves the proportion of eyes achieving achieve duochrome equality, and whether spectacles prescribed in 0.05D-steps offer any vision benefits, compared to 0.25D-steps., Methods: Myopic young adults were enrolled into two prospective studies conducted at different sites. Study 1 comprised 66 participants (refracted under cycloplegia) while Study 2 comprised 51 participants (not cyclopleged). A standard refraction was performed in both studies and a trial frame and trial lenses were used to determine the spherical endpoint of duochrome equality (0.25D-steps first then 0.05D-steps). In Study 2, the cylindrical component was refined in 0.05D-steps before the spherical endpoint in 0.05D-steps. Monocular high-contrast-visual-acuity (HCVA) was measured while wearing the final refractions. Participants in Study 2 wore spectacles manufactured in 0.25D and 0.05D-steps for 7 days each in a randomized, double-masked study. Both spectacles appeared identical. Outcome measures assessed on dispensing and after 7 days of wear comprised monocular acuity-based measurements (HCVA, low-contrast-visual-acuity, vanishing-optotype-acuity, contrast-sensitivity) and subjective ratings. The Quality-of-Vision questionnaire and subjective preference were assessed after 7 days., Results:     Both studies showed a higher proportion of eyes achieved duochrome equality ( P < 0.001) and better average monocular HCVA ( P ≤ 0.006) in 0.05D-steps. Study 2 showed 0.05D-step spectacles provided better average results for all monocular acuity-based measurements ( P < 0.006) and were preferred by 65% ( P = 0.04) of participants after 7 days ( P = 0.04). There were no differences between spectacles for any other measures ( P > 0.1)., Conclusions: Refraction performed, and spectacles manufactured in 0.05D-steps for this study improved average acuity-based outcomes and were preferred by most participants to spectacles in traditional 0.25D-steps.

Myopia has significantly risen in East and Southeast Asia, and the pathological outcomes of this condition, such as myopic maculopathy and optic neuropathy linked to high myopia, have emerged as leading causes of irreversible vision loss. Addressing this issue requires strategies to reduce myopia prevalence and prevent progression to high myopia. Encouraging outdoor activities for schoolchildren and reducing near-work and screen time can effectively prevent myopia development, offering a safe intervention that promotes healthier habits. Several clinical approaches can be employed to decelerate myopia progression, such as administering low-dose atropine eye drops (0.05%), utilizing orthokeratology lenses, implementing soft contact lenses equipped with myopia control features, and incorporating spectacle lenses with aspherical lenslets. When choosing an appropriate strategy, factors such as age, ethnicity, and the rate of myopia progression should be considered. However, some treatments may encounter obstacles such as adverse side effects, high costs, complex procedures, or limited effectiveness. Presently, low-dose atropine (0.05%), soft contact lenses with myopia control features, and orthokeratology lenses appear as promising options for managing myopia. The measures mentioned above are not necessarily mutually exclusive, and researchers are increasingly exploring their combined effects. By advocating for a personalized approach based on individual risk factors and the unique needs of each child, this review aims to contribute to the development of targeted and effective myopia prevention strategies, thereby minimizing the impact of myopia and its related complications among school-aged children in affected regions., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Tariq, Mobeen, Wang, Lin, Bao, Liu and Gao.)

Introduction: A hallmark of photoreceptor degenerations is progressive, aberrant remodeling of the surviving retinal neurons and glia following photoreceptor loss. The exact relationship between neurons and glia remodeling in this late stage of retinal degeneration, however, is unclear. This study assessed this by examining Müller cell dysfunction via glutamine synthetase immunoreactivity and its spatial association with retinal neuron subpopulations through various cell markers., Methods: Aged Rd1 mice retinae (P150 - P536, n = minimum 5 per age) and control heterozygous rd1 mice retinae (P536, n = 5) were isolated, fixed and cryosectioned. Fluorescent immunolabeling of glutamine synthetase was performed and retinal areas quantified as having low glutamine synthetase immunoreactivity if proportion of labeled pixels in an area was less than two standard deviations of the mean of the total retina. Other Müller cell markers such as Sox9 and Glial fibrillary acidic protein along with neuronal cell markers Calbindin, Calretinin, recoverin, Protein kinase C-α, Glutamic acid decarboxylase 67, and Islet-1 were then quantified within areas of low and normal synthetase immunoreactivity., Results: Glutamine synthetase immunoreactivity was lost as a function of age in the rd1 mouse retina (P150 - P536). Immunoreactivity of other Müller cell markers, however, were unaffected suggesting Müller cells were still present in these low glutamine synthetase immunoreactive regions. Glutamine synthetase immunoreactivity loss affected specific neuronal populations: Type 2, Type 8 cone, and rod bipolar cells, as well as AII amacrine cells based on reduced recoverin, protein kinase Ca and parvalbumin immunoreactivity, respectively. The number of cell nuclei within regions of low glutamine synthetase immunoreactivity was also reduced suggesting possible neuronal loss rather than reduced cell marker immunoreactivity., Conclusion: These findings further support a strong interplay between glia-neuronal alterations in late-stage degeneration and highlight a need for future studies and consideration in intervention development., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Reynisson, Kalloniatis, Fletcher, Shivdasani and Nivison-Smith.)

Purpose: To examine the effect of hydroxypropyl-guar nanoemulsion (HP-Guar nanoemulsion, Alcon Laboratories Ltd, Fort Worth, TX, USA) versus saline (0.9% sodium chloride; Pfizer Inc., Bentley WA Australia) on the comfort and tear film properties of people with dry eye disease both in the short-term (up to 2 h post-drop instillation) and longer-term (after 4 weeks of 4-times daily use), and to examine the effect on tear inflammatory markers after 4 weeks., Methods: This was a prospective, investigator-masked, randomised, cross-over dispensing study. Twenty participants with dry eye disease (5 males: 15 females) with average age 46.9 ± 14.4 (range 26 to 70) years were randomized to either HP-Guar nanoemulsion, or saline eye drops. Ocular symptoms, lipid layer thickness, tear evaporation, tear osmolarity and non-invasive break-up time were measured pre-drop instillation, 1 h and 2 h post-eye drop instillation, and after 4-weeks of 4-times daily drop use. Tear inflammatory mediators were measured pre-drop instillation and after 4-weeks. After 4-weeks, patients had a 4-week washout period and then crossed over to the alternate drop., Results: With HP-Guar nanoemulsion, participants reported less grittiness/burning/stinging 1 h post eye drop instillation compared to baseline (79.5 ± 23.3 vs. 66.8 ± 27.7, p = 0.02); less dryness 1 h and 2 h post eye drop instillation compared to baseline (77.8 ± 23.0 and 76.2 ± 23.7 vs. 61.0 ± 27.1 respectively, p < 0.01 for both); and greater overall satisfaction 1 h post drop instillation and after 4 weeks of daily use compared to baseline (80.4 ± 21.6 and 83.4 ± 16.6 vs. 68.6 ± 26.0 respectively, p ≤ 0.011 for both). With saline, participants reported less dryness after 4 weeks of daily use compared to baseline (74.2 ± 23.8 vs. 60.2 ± 24.0, p < 0.01). For HP-Guar nanoemulsion, average lipid layer thickness was significantly thicker 2 h post drop-instillation (79.5 ± 21.7 nm) compared to baseline (63.7 ± 18.9 nm) and the 4-week assessment (62.4 ± 23.1 nm, p < 0.01 for both). For saline, average lipid layer thickness was significantly thicker at 1 h and 2 h post eye drop instillation (76.0 ± 23.8 nm and 80.4 ± 24.8 nm) compared to baseline (61.0 ± 15.6 nm, p < 0.01 for both). There was no difference in inflammatory mediators or other tear variables between drops or visits., Conclusion: HP-Guar nanoemulsion was more effective for improving a range of subjective dry eye symptoms both in the short and long-term compared to saline. Both HP-Guar nanoemulsion and saline transiently increased lipid layer thickness., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

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., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2021 Contact Lens Association of Ophthalmologists.)

Background: Falls in older people have become a major public health concern worldwide, but a comprehensive assessment of the burden of falls for older people in mainland China has not been done. We aimed to investigate the burden of falls among older people at the national and subnational level in mainland China, and explore the trends from 1990 to 2019, using data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019., Method: Using data from GBD 2019, we estimated the burden of falls among people aged 60 years and older by sex and age group in terms of incidence, mortality, and disability-adjusted life-year (DALY) rates and assessed these indicators at the subnational level in 31 geographical units (hereafter called provinces). We investigated the overall trend in the burden of falls across these 31 provinces from 1990 to 2019, and assessed the change in the burden of falls by sex, age group (60-64, 65-69, 70-74, 75-79, and ≥80 years), and province between 1990 and 2019., Findings: In 2019, in mainland China, the incidence rate of falls among people aged 60 years and older was 3799·4 (95% uncertainty interval [UI] 3062·4-4645·0) new falls per 100 000 population, and 39·2 deaths (21·8-48·8) per 100 000 population and 1238·9 DALYs (920·5-1553·2) per 100 000 population were due to falls. We found no significant difference in the burden of falls between males and females. The incidence, mortality, and DALY rates of falls for people aged 80 years and older were significantly higher than those in the other age groups, except for incidence rate, which was non-significantly different between the age 75-79 years group and the oldest age group. Large variations in the incidence and DALY rates of falls were observed across 31 provinces. Although between 1990 and 2019 we found no significant changes in overall mortality due to falls in all provinces and in DALY rates for 23 provinces (DALY rates significantly decreased in two provinces and increased in six provinces), we found large increases in the incidence rate of falls in both males (percentage change between 1990 and 2019: 82·9% [67·4-100]) and females (77·0% [63·3-91·8]). The percentage change in incidence rate of falls between 1990 and 2019 varied from 50·0% (42·2-59·5) for people aged 60-64 years to 123·8% (105·4-141·9) for people aged 80 years and older. All provinces had significant increases in the incidence rate of falls between 1990 and 2019, with Sichuan having the greatest increase (148·5% [125·5-171·4]) and Jilin the smallest increase (14·7% [3·6-26·1])., Interpretation: Between 1990 and 2019, the incidence rate of falls increased substantially in older adults across mainland China, whereas the rates of mortality and DALY of falls among older people remained relatively stable, suggesting improvements in outcomes of falls. Nevertheless, falls remain an ongoing health burden for older people in mainland China, and there is an urgent need to introduce system-wide, integrated, and cost-effective measures to protect and support older people to minimise their risks and combat an increasing absolute burden as the population continues ageing., Funding: Bill & Melinda Gates Foundation., Competing Interests: Declaration of interests We declare no competing interests., (Copyright © 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Diabetic retinopathy (DR) complications can be prevented with regular screening and timely access to an ophthalmologist for treatment. But there are patient and health system barriers that can impact access to DR services. This study aims to identify enablers and barriers for accessing public DR eye care services in a low socio-economic urban area of Australia. We conducted a qualitative study using semi-structured interviews for patients with diabetes aged 35 years and older attending public ophthalmology services. Interviews were analyzed to identify themes and subthemes; and the COM-B framework was used to interpret the complex behavioral mechanisms, including capability, opportunity, and motivation factors, to explain adherence to DR eye care. Three main themes and 7 sub-themes relating to patient experiences of DR care were derived. Patients were found to be passive actors in their DR eye care, but patients trusted clinicians and were determined to maintain their vision and quality of life. The barriers and facilitators of care related to the health system (service availability and recall-reminder systems) and patient experiences (choices, knowledge, and fear). The findings of this study will guide patient-centered initiatives to target and improve access to DR care. Strategies should focus on improving communication between eye care providers, and communication with patients to empower them to become more active players in healthcare decisions., Competing Interests: Declaration of Conflicting Interests: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2021.)

Contact lenses in the future will likely have functions other than correction of refractive error. Lenses designed to control the development of myopia are already commercially available. Contact lenses as drug delivery devices and powered through advancements in nanotechnology will open up further opportunities for unique uses of contact lenses. This review examines the use, or potential use, of contact lenses aside from their role to correct refractive error. Contact lenses can be used to detect systemic and ocular surface diseases, treat and manage various ocular conditions and as devices that can correct presbyopia, control the development of myopia or be used for augmented vision. There is also discussion of new developments in contact lens packaging and storage cases. The use of contact lenses as devices to detect systemic disease has mostly focussed on detecting changes to glucose levels in tears for monitoring diabetic control. Glucose can be detected using changes in colour, fluorescence or generation of electric signals by embedded sensors such as boronic acid, concanavalin A or glucose oxidase. Contact lenses that have gained regulatory approval can measure changes in intraocular pressure to monitor glaucoma by measuring small changes in corneal shape. Challenges include integrating sensors into contact lenses and detecting the signals generated. Various techniques are used to optimise uptake and release of the drugs to the ocular surface to treat diseases such as dry eye, glaucoma, infection and allergy. Contact lenses that either mechanically or electronically change their shape are being investigated for the management of presbyopia. Contact lenses that slow the development of myopia are based upon incorporating concentric rings of plus power, peripheral optical zone(s) with add power or non-monotonic variations in power. Various forms of these lenses have shown a reduction in myopia in clinical trials and are available in various markets., (Crown Copyright © 2021. Published by Elsevier Ltd. All rights reserved.)

Contact lenses are widely prescribed in clinical practice with multiple applications and advantages. However, contact lenses can be associated with various complications which range from innocuous to severe. Clinicians thus not only need to possess the ability to prescribe the most appropriate contact lenses for each individual patient but also be able to recognise and manage any associated complications. This review examines the existing literature on the management of corneal infiltrative events associated with soft contact lenses, including microbial keratitis, particularly in the context of practising in Australia. The definitions and diagnosis of corneal infiltrative events, as well as the current understanding of their aetiologies, will be explored. The various aspects of a successful management will be discussed, including the applications of therapeutic agents such as antimicrobial and anti-inflammatory agents, the role of microbiological investigations, and strategies to improve long-term prognosis. The currently available evidence supporting management options will be presented, highlighting the relative abundance of high-level evidence on management protocols, antimicrobial selection and treatment duration for microbial keratitis; and the relative paucity of studies and trials for sterile corneal infiltrative events, despite this condition being much more commonly encountered in clinical practice.

Background: Water exposure during contact lens wear has been associated with contact lens disease including microbial keratitis and sterile corneal infiltrates. Despite the documented risks, water exposure is common amongst lens wearers. This study aimed to determine the effect of water education in the form of "no-water" lens case stickers on water-contact behaviours and storage case contamination., Methods: In a prospective, masked, randomised controlled trial, 200 daily lens wearers were randomised to either receive a storage case with a "no-water" sticker (test) or without a "no-water" sticker (control). Both groups received written compliance information. Participants completed a self-administered lens hygiene questionnaire at baseline and after 6 weeks. Microbial analysis of used storage cases, collected at both study visits, was conducted using ATP and limulus amebocyte lysate (LAL) assays for overall microbial contamination and endotoxin levels, respectively. A one-way ANCOVA and multiple logistic regression determined the change in water-contact behaviours and storage case contamination over time., Results: A total of 188 lens wearers completed both study visits; 128 females and 60 males; average age 29 ± 13 (range 18-78 years); 95 test and 93 control participants. After 6 weeks, the overall water exposure score and endotoxin levels reduced significantly in the test group compared with the control group (p < 0.05). There were no significant changes in individual water-contact behaviours or overall storage case contamination., Conclusion: A no-water infographic on the contact lens case improved overall water-contact behaviours and reduced storage case endotoxin. Refining the messaging may be beneficial in future to improve other aspects of compliance.

While countries are in a hurry to obtain SARS-CoV-2 vaccine, we are concerned with the availability of vaccine and whether a vaccine will be available to all in need. We predicted three possible scenarios for vaccine distributions and urge an international united action on the worldwide equitable access. In case the international community does not reach a consensus on how to distribute the vaccine to achieve worldwide equitable access, we call for a distribution plan that includes the employees in international transportation industries and international travelers to halt the disease transmission and promote the recovery of the global economy., Competing Interests: Conflict of interest: The authors declare no competing financial interests., (© 2021 Zhuo Yu et al., published by De Gruyter.)

Purpose: To ascertain the safety of soft contact lens (SCL) wear in children through a retrospective chart review including real-world clinical practice settings., Methods: The study reviewed clinical charts from 963 children: 782 patients in 7 US eye care clinics and 181 subjects from 2 international randomised clinical trials (RCTs). Subjects were first fitted while 8-12 years old with various SCL designs, prescriptions and replacement schedules, and observed through to age 16. Clinical records from visits with potential adverse events (AEs) were electronically scanned and reviewed to consensus by an Adjudication Panel., Results: The study encompassed 2713 years-of-wear and 4611 contact lens visits. The cohort was 46% male, 60% were first fitted with daily disposable SCLs, the average age at first fitting was 10.5 years old, with a mean of 2.8 ± 1.5 years-of-wear of follow-up observed. There were 122 potential ocular AEs observed from 118/963 (12.2%) subjects; the annualised rate of non-infectious inflammatory AEs was 0.66%/year (95% CI 0.39-1.05) and 0.48%/year (0.25-0.82) for contact lens papillary conjunctivitis. After adjudication, two presumed or probable microbial keratitis (MK) cases were identified, a rate of 7.4/10 000 years-of-wear (95% CI 1.8-29.6). Both were in teenage boys and one resulted in a small scar without loss of visual acuity., Conclusion: This study estimated the MK rate and the rate of other inflammatory AEs in a cohort of SCL wearers from 8 through to 16 years of age. Both rates are comparable to established rates among adults wearing SCLs., (© 2020 The Authors. Ophthalmic and Physiological Optics published by John Wiley & Sons Ltd on behalf of College of Optometrists.)

Human platelet products have emerged as an alternative treatment for a range of ocular surface diseases such as dry eye and corneal ulceration. With significant therapeutic potential and increasing popularity, this study aimed to conduct a systematic review to detail the various production methods involved in generating platelet-derived products, compare and analyze clinical findings across available studies, and disseminate the relative advantages, limitations, and challenges of using platelet products to treat ocular surface disease. Thirty-eight clinical studies were identified, excluding studies conducted in animals and non-English language. Studies reported clinical outcomes, which included ocular surface disease index, best-corrected visual acuity, and corneal fluorescein staining. Most clinical studies reported improved patient signs and symptoms with an increasing variety of human platelet products including platelet rich plasma eye drops, human platelet lysate and platelet gels. However, due to variations in production methods, and study designs as well as confusing terminology, it was suggested that characterization of platelet products is needed for proper evaluation across studies., Competing Interests: The authors report no conflicts of interest for this work., (© 2020 You et al.)

Purpose: Pigmented ocular lesions are commonly encountered by eye-care professionals, and range from benign to sight or life-threatening. After identifying a lesion, the primary care professional must establish the likely diagnosis and decide either to reassure, to monitor or to refer. The increasing use of ocular imaging technologies has contributed to an increase in the detection rate of pigmented lesions and a higher number of referrals, which may challenge existing pathways of health-care delivery. Specialist services may be over-burdened by referring all patients with pigmented lesions for an opinion, while inter-optometric referrals are underutilised. The aim of this study was to describe the referral patterns of pigmented lesions to an optometry led intermediate-tier collaborative care clinic., Methods: We performed a retrospective review of patient records using the list of patients examined at Centre for Eye Health (CFEH) for an initial or follow up pigmented lesion assessment between the 1/7/2013 and the 30/6/2016. Analysis was performed on: patient demographic characteristics, the referrer's tentative diagnosis, CFEH diagnosis and recommended management plan., Results: Across 182 patient records, the primary lesion prompting referral was usually located in the posterior segment: choroidal naevus (105/182, 58%), congenital hypertrophy of the retinal pigment epithelium (CHRPE; 11/182, 6%), chorioretinal scarring (10/182, 5%) or not specified (52/182, 29%). Referrals described a specific request for ocular imaging in 25 instances (14%). The number of cases with a non-specific diagnosis was reduced after intermediate-tier care assessment (from 29% to 10%), while the number of diagnoses with less common conditions rose (from 2% to 21%). There was a 2% false positive referral rate to intermediate-tier care and a first visit discharge rate of 35%. A minority required on-referral to an ophthalmologist (22/182, 12%), either for unrelated incidental ocular findings, or suspicious choroidal naevi. Conditions most amenable to optometric follow up included: 1) chorioretinal scarring, 2) choroidal naevus, and 3) CHRPE., Conclusions: Intermediate-tier optometric eye-care in pigmented lesions (following opportunistic primary care screening) has the potential to reduce the number of cases with non-specific diagnoses and to increase those with less common diagnoses. The majority of cases seen under this intermediate-tier model required only ongoing optometric surveillance., (© 2017 The Authors. Ophthalmic and Physiological Optics published by John Wiley & Sons Ltd on behalf of College of Optometrists.)

The purpose of this study was to investigate the release of the anti-myopia drugs atropine sulfate and pirenzepine dihydrochloride from commercially available soft contact lenses. Standard ultraviolet (UV) absorbance-concentration curves were generated for atropine and pirenzepine. Ten commercially available contact lenses, including four multifocal lenses, were loaded by soaking in atropine or pirenzepine solutions at two different concentrations (10 mg/mL and 1 mg/mL). The release of the drugs into phosphate-buffered saline was determined over the course of 24 hours at 34°C using UV absorbance. Materials with surface charge released the greatest amount of atropine when loaded with either concentration when compared to the other lens types ( p <0.05), releasing upward of 1.026±0.035 mg/lens and 0.979±0.024 mg/lens from etafilcon A and ocufilcon A, respectively. There were no significant differences in the amount of atropine or pirenzepine released from the multifocal and non-multifocal lenses made from the same lens materials. Narafilcon A material demonstrated prolonged release of up to 8 hours when loaded with pirenzepine, although the overall dose delivered from the lens into the solution was among the lowest of the materials investigated. The rest of the lenses reached a plateau within 2 hours of release, suggesting that they were unable to sustain drug release into the solution for long periods of time. Given that no single method of myopia control has yet shown itself to be completely effective in preventing myopia progression, a combination of optical and pharmaceutical devices comprising a drug delivering contact lens presents a novel solution that warrants further investigation., Competing Interests: Disclosure The authors report no conflicts of interest and have no proprietary interest in any of the materials mentioned in this article.

The subcommittee reviewed the prevalence, incidence, risk factors, natural history, morbidity and questionnaires reported in epidemiological studies of dry eye disease (DED). A meta-analysis of published prevalence data estimated the impact of age and sex. Global mapping of prevalence was undertaken. The prevalence of DED ranged from 5 to 50%. The prevalence of signs was higher and more variable than symptoms. There were limited prevalence studies in youth and in populations south of the equator. The meta-analysis confirmed that prevalence increases with age, however signs showed a greater increase per decade than symptoms. Women have a higher prevalence of DED than men, although differences become significant only with age. Risk factors were categorized as modifiable/non-modifiable, and as consistent, probable or inconclusive. Asian ethnicity was a mostly consistent risk factor. The economic burden and impact of DED on vision, quality of life, work productivity, psychological and physical impact of pain, are considerable, particularly costs due to reduced work productivity. Questionnaires used to evaluate DED vary in their utility. Future research should establish the prevalence of disease of varying severity, the incidence in different populations and potential risk factors such as youth and digital device usage. Geospatial mapping might elucidate the impact of climate, environment and socioeconomic factors. Given the limited study of the natural history of treated and untreated DED, this remains an important area for future research., (Copyright © 2017 Elsevier Inc. All rights reserved.)