A genome-scale metabolic model of Cupriavidus necator H16 integrated with TraDIS and transcriptomic data reveals metabolic insights for biotechnological applications.

Exploiting biological processes to recycle renewable carbon into high value platform chemicals provides a sustainable and greener alternative to current reliance on petrochemicals. In this regard Cupriavidus necator H16 represents a particularly promising microbial chassis due to its ability to grow on a wide range of low-cost feedstocks, including the waste gas carbon dioxide, whilst also naturally producing large quantities of polyhydroxybutyrate (PHB) during nutrient-limited conditions. Understanding the complex metabolic behaviour of this bacterium is a prerequisite for the design of successful engineering strategies for optimising product yields. We present a genome-scale metabolic model (GSM) of C. necator H16 (denoted iCN1361), which is directly constructed from the BioCyc database to improve the readability and reusability of the model. After the initial automated construction, we have performed extensive curation and both theoretical and experimental validation. By carrying out a genome-wide essentiality screening using a Transposon-directed Insertion site Sequencing (TraDIS) approach, we showed that the model could predict gene knockout phenotypes with a high level of accuracy. Importantly, we indicate how experimental and computational predictions can be used to improve model structure and, thus, model accuracy as well as to evaluate potential false positives identified in the experiments. Finally, by integrating transcriptomics data with iCN1361 we create a condition-specific model, which, importantly, better reflects PHB production in C. necator H16. Observed changes in the omics data and in-silico-estimated alterations in fluxes were then used to predict the regulatory control of key cellular processes. The results presented demonstrate that iCN1361 is a valuable tool for unravelling the system-level metabolic behaviour of C. necator H16 and can provide useful insights for designing metabolic engineering strategies.

Required Gene Set for Autotrophic Growth of Clostridium autoethanogenum.

The majority of the genes present in bacterial genomes remain poorly characterized, with up to one-third of those that are protein encoding having no definitive function. Transposon insertion sequencing represents a high-throughput technique that can help rectify this deficiency. The technology, however, can only be realistically applied to those species in which high rates of DNA transfer can be achieved. Here, we have developed a number of approaches that overcome this barrier in the autotrophic species Clostridium autoethanogenum by using a mariner-based transposon system. The inherent instability of such systems in the Escherichia coli conjugation donor due to transposition events was counteracted through the incorporation of a conditionally lethal codA marker on the plasmid backbone. Relatively low frequencies of transformation of the plasmid into C. autoethanogenum were circumvented through the use of a plasmid that is conditional for replication coupled with the routine implementation of an Illumina library preparation protocol that eliminates plasmid-based reads. A transposon library was then used to determine the essential genes needed for growth using carbon monoxide as the sole carbon and energy source. IMPORTANCE Although microbial genome sequences are relatively easily determined, assigning gene function remains a bottleneck. Consequently, relatively few genes are well characterized, leaving the function of many as either hypothetical or entirely unknown. High-throughput transposon sequencing can help remedy this deficiency, but is generally only applicable to microbes with efficient DNA transfer procedures. These exclude many microorganisms of importance to humankind either as agents of disease or as industrial process organisms. Here, we developed approaches to facilitate transposon insertion sequencing in the acetogen Clostridium autoethanogenum, a chassis being exploited to convert single-carbon waste gases CO and CO2 into chemicals and fuels at an industrial scale. This allowed the determination of gene essentiality under heterotrophic and autotrophic growth, providing insights into the utilization of CO as a sole carbon and energy source. The strategies implemented are translatable and will allow others to apply transposon insertion sequencing to other microbes where DNA transfer has until now represented a barrier to progress.

Supervisor experiences of extended clinical placements in optometry: a mixed methods study.

BACKGROUND: In Australia, optometry students have traditionally undertaken their clinical training in short-block rotations at University-led teaching clinics in metropolitan locations. Demand for clinical placements is growing as the number of optometry students steadily increases. As such, universities and clinical education providers must look for more diverse methods of student placement. Extended clinical placements in community-based settings are one alternative: a model similar to the longitudinal clerkships in medicine. This study aimed to explore the experience of extended clinical placements from the perspective of the optometrists who supervised students. It also sought to determine whether there were differences in views between metropolitan and rural practitioners. METHODS: This mixed methods study included a survey and interviews with optometrists who had previously supervised Deakin University optometry students on an extended 26-week (2 x 13-weeks) clinical placement. Lines of enquiry focused on; the benefits and challenges associated with extended placements; areas for improvement; duration of the placement; and willingness to supervise further students. Interviews were transcribed verbatim and analysed using Braun and Clarke's 6 step method of thematic analysis with a qualitative descriptive approach. RESULTS: Supervisors felt that hosting a student prompted greater reflective practice and critical appraisal of clinical decisions. The extended nature of the placement was thought to foster greater immersion in the clinical setting and community for the students and establish a stronger relationship between supervisor and student. Supervisors recognised the importance of role-modelling and mentoring the next generation of optometrists however noted that taking on a student was a sizeable commitment. Willingness to host a student was not dependent on the supervisor's location (rural vs metropolitan) p = 0.57. However, interviews uncovered motivations that were unique to supervisors residing in rural locations, such as succession planning. CONCLUSION: Overall, supervisors were positive about the value of student extended clinical placement in optometry and felt that it was a fulfilling and professionally beneficial experience. Lack of time and financial remuneration were the key downsides highlighted. Schools of optometry might carefully consider engaging in discussion about the duration of such placements, but 26 weeks was considered appropriate by supervisors.

Student perspectives of extended clinical placements in optometry: a qualitative study.

BACKGROUND: The number of students enrolled in health courses at Australian universities is rising, increasing demand for clinical placements. Optometry students have historically undertaken clinical training in short-block rotations at university-led teaching clinics in metropolitan locations. This is changing, with some optometry programs adopting extended placements. These placements are conducted in community-based practices, with many incorporating a rural component to the training. This study explored factors which influence placement success and satisfaction from the perspective of optometry students. METHODS: Nine focus groups were undertaken with 42 final year optometry students upon completion of a 26-week placement (of which at least half was undertaken in a non-metropolitan area, or area where a shortage of optometrists has been identified). Focus groups were audio recorded and transcribed verbatim. Thematic analysis was conducted according to Braun and Clarke's 6 step method. RESULTS: Four key themes were identified during analysis. 'Changing identity', related to how the students grew both personally and professionally, with the extended placement being considered the vital component that allowed students to begin thinking of themselves as clinicians. The theme 'Dealing with complex dynamics and circumstances' predominantly described instances where the student-supervisor relationship was strained, resulting in high levels of anxiety made worse by a perceived lack of university support. 'Optometrist under instruction', related to students feeling that the placement was an ideal opportunity to trial the everyday reality of work without the obligation of an ongoing commitment or employment contract. Finally, the theme 'Rural practice is more rewarding', was about a chance to seek different experiences, meet new people and challenge themselves professionally. CONCLUSION: While the majority of students enjoyed their placement and felt that it was the key component of their training that equipped them for future practice, it is clear that universities and placement providers must provide both students and supervisors thorough and explicit guidance covering placement expectations. Furthermore, student support systems should be embedded into placement programs to ensure where issues arise, they are dealt with promptly and successfully. It is vital that ongoing professional development and pedagogical training for supervisors underpins continued accreditation.

3-Substituted Quinolines as RORγt Inverse Agonists.

We have previously reported the syntheses of a series of 3,6-disubstituted quinolines as modulators of the retinoic acid receptor-related orphan receptor gamma t (RORγt). These molecules are potent binders but are high molecular weight and they exhibited poor solubility at pH 2 and pH 7. This manuscript details our efforts at improving physical chemical properties for this series of compounds by increasing the diversity at the 3-position (i.e. introducing heteroatoms and lowering the molecular weight). These efforts have led to molecules which are potent binders with improved solubility.

A novel conjugal donor strain for improved DNA transfer into Clostridium spp.

Clostridium encompasses species which are relevant to human and animal disease as well as species which have industrial potential, for instance, as producers of chemicals and fuels or as tumour delivery vehicles. Genetic manipulation of these target organisms is critical for advances in these fields. DNA transfer efficiencies, however, vary between species. Low efficiencies can impede the progress of research efforts. A novel conjugal donor strain of Escherichia coli has been created which exhibits a greater than 10-fold increases in conjugation efficiency compared to the traditionally used CA434 strain in the three species tested; C. autoethanogenum DSM 10061, C. sporogenes NCIMB 10696 and C. difficile R20291. The novel strain, designated 'sExpress', does not methylate DNA at Dcm sites (CCWGG) which allows circumvention of cytosine-specific Type IV restriction systems. A robust protocol for conjugation is presented which routinely produces in the order of 105 transconjugants per millilitre of donor cells for C. autoethanogenum, 106 for C. sporogenes and 102 for C. difficile R20291. The novel strain created is predicted to be a superior conjugal donor in a wide range of species which possess Type IV restriction systems.

Identification and structure activity relationships of quinoline tertiary alcohol modulators of RORγt.

A high-throughput screen of the ligand binding domain of the nuclear receptor retinoic acid-related orphan receptor gamma t (RORγt) employing a thermal shift assay yielded a quinoline tertiary alcohol hit. Optimization of the 2-, 3- and 4-positions of the quinoline core using structure-activity relationships and structure-based drug design methods led to the discovery of a series of modulators with improved RORγt inhibitory potency and inverse agonism properties.

6-Substituted quinolines as RORγt inverse agonists.

We identified 6-substituted quinolines as modulators of the retinoic acid receptor-related orphan receptor gamma t (RORγt). The synthesis of this class of RORγt modulators is reported, and optimization of the substituents at the quinoline 6-position that produced compounds with high affinity for the receptor is detailed. This effort identified molecules that act as potent, full inverse agonists in a RORγt-driven cell-based reporter assay. The X-ray crystal structures of two full inverse agonists from this chemical series bound to the RORγt ligand binding domain are disclosed, and we highlight the interaction of a hydrogen-bond acceptor on the 6-position substituent of the inverse agonist with Glu379:NH as a conserved binding contact.

Effect of Masking on Subjective Responses to Daily Disposable Contact Lenses.

PURPOSE: To explore the effect of masking on subjective responses when wearing daily disposable (DD) contact lenses. METHODS: In an adaptation phase, habitual wearers of Manufacturer-A (MFA) (n = 43) and Manufacturer-B (MFB) (n = 53) wore MFA-brand 1 or MFB-brand 1 DDs, respectively, for 30 days, open-label. Subjects were then randomly assigned to one of two experiments. Each experiment included two, 3-day crossover phases. An enhanced version of MFA and MFB lenses (MFA-brand 2 and MFB-brand 2) were worn contralaterally to evaluate potential differences in masking result between manufacturers. Experiment 1: subjects were fully masked to lens and packaging (FM) then unmasked (UM). Experiment 2: subjects were FM then partially masked using an over-label (PM). Comfort ratings (0-100) were recorded for each lens daily and preference between lenses was recorded on day 3 for each crossover phase. The mean difference between 0-100 ratings or preference when FM or PM versus UM for the same lens was considered a measurement of the effect associated with masking. The purpose of the study was withheld from subjects to minimize bias. RESULTS: The effect associated with masking for habitual wearers of MFA and MFB lenses was less than 1 out of 100 (0 ± 2.5) in both experiments. Fifty-eight subjects (60%) expressed no preference when FM. This decreased to 29 (30%) when UM or PM (proportion test, p < 0.001). Approximately half the subjects had a change in lens preference when they were UM or PM, primarily in favor of their habitual lens manufacturer. CONCLUSIONS: Masking did not have a measurable impact on 0-100 ratings with the DD lenses used in this study but did have an impact on lens preference. Subjects were more likely to express a preference when they handled the lenses and were exposed to the lens packaging and, in some cases, able to read the lens brand and lens manufacturer.

Temporal changes in contact lens comfort over a day of wear.

PURPOSE: Contact lens discomfort continues to be reported as the primary reason for soft lens discontinuation, regardless of new modalities and materials. The purpose of this analysis of comfort related data from a series of clinical studies was to review whether there was a difference between symptomatic and asymptomatic habitual lens wearers' comfort responses over the course of the day. METHODS: Data from five independent non-dispensing clinical studies were pooled and analysed. Participants in these studies were assigned to one of two groups depending on whether they were classified as symptomatic or asymptomatic contact lens wearers according to a modified Subjective Evaluation of Symptoms of Dryness (SESOD) questionnaire. Masked participants were randomised to wear either a hydrogel or a silicone hydrogel contact lens and their ocular comfort was rated using a visual analogue scale on insertion and 2-hourly during an 8-hour period of a single lens wearing day. RESULTS: Data from 103 participants were used, 58 in the symptomatic group and 45 in the asymptomatic group as determined by the SESOD questionnaire. There was no effect of lens material on comfort (p = 0.43). However, there was a significant interaction between symptoms and time. The difference in mean comfort between the symptomatic and asymptomatic group was significant at each time point (p < 0.05). However, comfort did not vary significantly over the day for the asymptomatic group (p = 0.87), whereas, there was a significant decline in mean comfort ratings for the symptomatic group from 84.6 ± 13.2 (S.D.) at insertion to 73.0 ± 18.5 at 8 hours (p < 0.001). CONCLUSIONS: In our study, changes in contact lens comfort over a day were independent of lens material but not symptoms. Symptomatic lens wearers reported a progressive decrease in comfort, whereas asymptomatic wearers did not. Therefore, asymptomatic wearers should not be used when measuring contact lens comfort in clinical studies. The exclusion of asymptomatic lens wearers would likely increase the sensitivity of comfort ratings as a measure in contact lens research.

Whole genome sequence and manual annotation of Clostridium autoethanogenum, an industrially relevant bacterium.

BACKGROUND: Clostridium autoethanogenum is an acetogenic bacterium capable of producing high value commodity chemicals and biofuels from the C1 gases present in synthesis gas. This common industrial waste gas can act as the sole energy and carbon source for the bacterium that converts the low value gaseous components into cellular building blocks and industrially relevant products via the action of the reductive acetyl-CoA (Wood-Ljungdahl) pathway. Current research efforts are focused on the enhancement and extension of product formation in this organism via synthetic biology approaches. However, crucial to metabolic modelling and directed pathway engineering is a reliable and comprehensively annotated genome sequence. RESULTS: We performed next generation sequencing using Illumina MiSeq technology on the DSM10061 strain of Clostridium autoethanogenum and observed 243 single nucleotide discrepancies when compared to the published finished sequence (NCBI: GCA_000484505.1), with 59.1 % present in coding regions. These variations were confirmed by Sanger sequencing and subsequent analysis suggested that the discrepancies were sequencing errors in the published genome not true single nucleotide polymorphisms. This was corroborated by the observation that over 90 % occurred within homopolymer regions of greater than 4 nucleotides in length. It was also observed that many genes containing these sequencing errors were annotated in the published closed genome as encoding proteins containing frameshift mutations (18 instances) or were annotated despite the coding frame containing stop codons, which if genuine, would severely hinder the organism's ability to survive. Furthermore, we have completed a comprehensive manual curation to reduce errors in the annotation that occur through serial use of automated annotation pipelines in related species. As a result, different functions were assigned to gene products or previous functional annotations rejected because of missing evidence in various occasions. CONCLUSIONS: We present a revised manually curated full genome sequence for Clostridium autoethanogenum DSM10061, which provides reliable information for genome-scale models that rely heavily on the accuracy of annotation, and represents an important step towards the manipulation and metabolic modelling of this industrially relevant acetogen.

Visual Performance of a Multifocal Contact Lens versus Monovision in Established Presbyopes.

PURPOSE: To compare subjective and objective visual performance of the Air Optix Aqua Multifocal lens to monovision in a group of subjects requiring a medium level of reading-addition power. METHODS: Fifty participants with reading additions between 1.25 and 2.00 diopters (inclusive) were randomized into a prospective, crossover clinical trial. They wore monovision and multifocals for 2 weeks in a randomized order. High- and low-contrast logMAR (logarithm of the minimum angle of resolution) acuity and stereopsis were measured at the beginning and end of each period. During each phase, participants performed specific tasks followed by subjective rating surveys and also completed satisfaction rating surveys on days 3, 7, and 12; all were transferred in real time using BlackBerry smartphones. A general rating survey was completed at the dispensing and 2-week visits. RESULTS: Forty-nine participants completed the study (mean age, 52 years). Distance and near high- and low-contrast acuities were significantly better (p < 0.05) with monovision at all visits. High-contrast intermediate acuity was only better (p < 0.05) with multifocals after 2 weeks. Stereopsis was equivalent after 2 weeks, but better (p < 0.05) with multifocals at dispensing. Subjective ratings were generally equivalent between modalities although there was a trend for multifocals to be rated higher for focus changing and driving, whereas monovision tended to be rated higher for near tasks. For both corrections, the satisfaction survey showed no significant change between days 3, 7, and 12, and the general survey showed that comfort was maintained but subjective vision ratings decreased significantly over the 2 weeks. Twenty-five participants (51%) preferred multifocals, 18 (37%) preferred monovision, and the remaining 6 (12%) declared both unacceptable. CONCLUSIONS: In this cohort, distance and near acuities were better with monovision, whereas the subjective ratings tended to favor the Air Optix Aqua Multifocal, with the exception of near performance. Preference was statistically similar between both corrections, with a trend toward preferring the multifocal.

Comparison between live and photographed slit lamp grading of corneal staining.

PURPOSE: To compare live and photographic (still) grades of corneal staining of the same eyes and the repeatability of grading between two investigators. METHODS: Thirty patients were recruited to participate in a contact lens study, and their level of corneal staining was graded by two investigators in situ (live images), using slit lamp biomicroscopy. Digital still images of the corneal staining were also captured during the study visits. An independent observer selected 105 of the still images graded by investigator 1 and another 105 images graded by investigator 2 and presented them to the original investigator in a random order, on three separate occasions. Grading was performed at the time of the live grading and the three still image sessions, using the Centre for Contact Lens Research corneal staining scale that combines grades of both extent and type to provide an overall "global staining score" from 0 to 10,000 for corneal staining. A comparison was made between live and still grades as well as the intrainvestigator repeatability for the multiple grading of the still images. RESULTS: The mean (±SD) of corneal staining grades recorded for the same eyes examined live and then later on three occasions was 1795 (±1083) and 714 (±974), respectively, for participants examined by investigator 1 (p < 0.001) and 1854 (±1075) and 461 (±411) for those examined by investigator 2 (p < 0.001). There was a significant difference over the three repeated still grading sessions for each investigator (p < 0.001), although there was a high degree of consistency among the three still grading sessions for each of the investigators: the intraclass correlation for investigator 1 was 0.91 (confidence interval, 0.87 to 0.93) and that for investigator 2 was 0.82 (confidence interval, 0.77 to 0.87). DISCUSSION: Digital still image grading of corneal staining significantly underrepresented the amount of corneal staining observed through a slit lamp. Clinical investigators graded corneal staining with a high degree of consistency.

Trends in US Contact Lens Prescribing 2002 to 2014.

PURPOSE: To document contact lens prescribing patterns in the United States between 2002 and 2014. METHODS: A survey of contact lens prescribing trends was conducted each year between 2002 and 2014, inclusive. Randomly selected contact lens practitioners were asked to provide information relating to 10 consecutive contact lens fits between January and March each year. RESULTS: Over the 13-year survey period, 1650 survey forms were received from US practitioners representing details of 7702 contact lens fits. The mean (±SD) age of lens wearers was 33.6 (±15.2) years, of whom 65.2% were female. Rigid lens new fits decreased from 13.0% in 2002 to 9.4% in 2014. Across this period, silicone hydrogels have replaced mid water contact lens hydrogels as the soft lens material of choice. Toric lenses represented about 25 to 30% of all soft lens fits. Multifocal soft lenses are generally preferred to monovision. Daily disposable lens fits have recently increased, and in 2014, they represented 27.1% of all soft lens fits. Most lenses are prescribed on 1 to 2 weekly or monthly lens replacement regimen. Extended wear remains a minority lens wearing modality. The vast majority of those wearing reusable lenses use multipurpose lens care solutions. Lenses are mostly worn 7 d/wk. CONCLUSIONS: This survey has revealed prescribing trends and preferences in the United States over the past 13 years.

Clinical performance of three silicone hydrogel daily disposable lenses.

PURPOSE: To determine the clinical performance of DAILIES TOTAL1 (DT1), Clariti 1Day (C1D), and 1-DAY ACUVUE TruEye (AVTE) silicone hydrogel daily disposable contact lenses (SiHy DDCLs). METHODS: Eligible participants, subdivided into asymptomatic and symptomatic groups, wore each SiHy DDCLs for three consecutive days. Each participant attended three visits (on day 1 at 0 hours; on days 1 and 3 after 8 hours of wear) per lens type. The order of lens wear was randomized, with at least 1 day washout between lenses. Lens-related performance was evaluated by assessing lens surface deposits, wettability, pre-lens noninvasive tear breakup time, lens movement, and centration; ocular response assessments included conjunctival redness, corneal staining, and conjunctival staining and indentation. RESULTS: Fifty-one asymptomatic and 53 symptomatic participants completed the study. For all visits, the mean noninvasive tear breakup time was about 1 second longer with DT1 than with C1D and AVTE (p < 0.01). Overall, the wettability of all three lenses was good; however, DT1 was graded marginally better than the other lenses (both p < 0.01). On day 3, eyes wearing AVTE had significantly more dehydration-induced corneal staining compared with DT1 (AVTE, 24%; DT1, 11%; p < 0.01). After 8 hours, conjunctival staining was different between lenses (greatest with C1D and least with DT1; all p < 0.01). Conjunctival indentation was more prevalent with the C1D lenses (n = 70) compared with DT1 (n = 1; p < 0.01) and AVTE (n = 11; p < 0.01). There were no differences between asymptomatic and symptomatic lens wearers for any of the clinical parameters (all p > 0.05). CONCLUSIONS: Each of the three SiHy DDCLs performed well. Noninvasive tear breakup time was longest and wettability was greater with DT1. C1D had the most conjunctival staining conjunctival indentation. There was no difference between asymptomatic and symptomatic wearers with regard to ocular response and contact lens-related parameters. These results suggest that SiHy DDCLs may be an excellent contact lens modality for the symptomatic patient.

Optometrists who leave the profession in Australia: 2011 to 2019.

CLINICAL RELEVANCE: The number, demographics, registration status and geographic distribution of optometrists in Australia who do not renew their registration is reported. BACKGROUND: The size of the optometry workforce in Australia is determined by the number of new entrants to the profession and the number of optometrists leaving it. Limited attention has been paid to the latter. METHODS: A dataset obtained from the Australian Health Practitioner Registration Agency about registered optometrists during the period 1 January 2011 to 31 December 2019 was analysed. It included registrants' first year of registration, gender, year of birth (in five-year bands), optometry qualification; and annual collection of registration type and postcode of principal place of practice. RESULTS: Data for 6,595 registrants were analysed. Over the study period, 626 optometrists left the register. When those leaving the register were examined by year of birth bands, two main groups emerged - optometrists aged in their fifties or older, and optometrists who were under forty years of age and disproportionately male. Registration type had a significant effect on whether a registrant left or remained on the register (p < 0.05). Those holding Non-practising Registration or Limited Registration were more likely to leave the register. Registrants with an optometry qualification from an overseas institution, including from New Zealand, were more likely to leave the register (p < 0.05). Optometrists whose registration was not endorsed were more likely to leave the register (p < 0.05). No significant difference was found when the geographic location of optometrists who left the register was compared with those who remained. CONCLUSION: Optometrists who left the register fell into two main groups - late-career and early-career. An unanticipated finding was that younger optometrists who left the register were disproportionately male. What motivates optometrists in Australia to leave the register is worthy of future research.

International trends in rigid contact lens prescribing (2000-2023): An update.

PURPOSE: Rigid contact lenses have an important role in contact lens practice. The purpose of this work is to update earlier surveys by describing global trends in rigid lens fitting between 2000-2023. METHOD: An annual contact lens prescribing survey was sent to eye care practitioners in up to 71 countries between 2000 and 2023. Data relating to 342,500 fits undertaken in 20 countries returning reliable longitudinal data were analysed in respect of rigid lens fitting, defined as the fitting of any design of a contact lens manufactured in a rigid material. RESULTS: Overall, rigid lens prescribing increased slightly over time, from 14.2 % of lens fits in 2000 to 15.2 % in 2023 (p < 0.0001). However, post-hoc analysis shows that the change over time is best described as a decline between 2000 and 2012, followed by a steady increase subsequently. There were significant differences in rigid lens prescribing between countries (p < 0.0001). The difference between the percentage of males fitted with rigid lenses, as a proportion of all contact lenses (12.7 %), and females (12.0 %) is significant (p < 0.0001), although not clinically meaningful. Rigid lens wearers are older at fitting than soft lens wearers (38.7 vs 31.3 years, respectively) (p < 0.0001). Analysis of 5,994 rigid lens fits prescribed currently (2019-2023) were categorised as: corneal sphere - 30 %; scleral and corneo-scleral - 28 %; corneal myopia control/orthokeratology - 21 %; and corneal complex (including toric, multifocal and monovision) - 16 %. CONCLUSION: There has been a slight increase in rigid lens fitting during the second decade of this century. This increase is apparently due to a 'repurposing' of rigid lenses, with the growth of scleral/corneo-scleral and myopia control/orthokeratology lens fits essentially replacing conventional spherical corneal lens fits.

International trends in daily disposable contact lens prescribing (2000-2023): An update.

PURPOSE: Daily disposable contact lenses offer numerous benefits in terms of ocular health and wearer convenience. The purpose of this work is to update earlier surveys by describing global trends in daily disposable lens fitting between 2000 and 2023. METHOD: An annual contact lens prescribing survey was sent to eye care practitioners in up to 71 countries between 2000 and 2023, inclusive. Data relating to 265,106 daily wear soft lens fits undertaken in 20 countries returning reliable longitudinal data were analysed in respect of daily disposable lens fitting. RESULTS: Overall, daily disposable lens prescribing increased over time, from 17.1 % of daily wear soft lens fits in 2000 to 46.7 % in 2023 (p < 0.0001). There were significant differences between countries in daily disposable lens prescribing (p < 0.0001), and between the percentage of males fitted with daily disposable lenses, as a proportion of all daily wear soft lenses (37.2 %), compared to females (35.2 %) (p < 0.0001). Daily disposable lens wearers are slightly younger at fitting than reusable soft lens wearers (31.0 vs 31.2 years, respectively) (p < 0.0001), although this difference is not clinically meaningful. Analysis of 50,240 daily wear soft lenses fitted recently (2019-2023) were found to be prescribed for the following replacement frequencies: daily - 47 %; monthly - 42 %; 1-2 weekly - 9 %; and ≥3 monthly - 2 %. CONCLUSION: There has been a substantial increase in daily disposable lens fitting throughout the first 24 years of this century. The gradual nature of this increase is commensurate with the staged introduction of daily disposable lens designs and expanded parameter ranges over the survey period.

International survey of rigid contact lens fitting.

PURPOSE: To determine the extent of rigid contact lens fitting worldwide and to characterize the associated demographics and fitting patterns. METHODS: Survey forms were sent to contact lens fitters in up to 40 countries between January and March every year for five consecutive years (2007 to 2011). Practitioners were asked to record data relating to the first 10 contact lens fits or refits performed after receiving the survey form. Survey data collected between 1996 and 2011 were also analyzed to assess rigid lens fitting trends in seven nations during this period. RESULTS: Data were obtained for 12,230 rigid and 100,670 soft lens fits between 2007 and 2011. Overall, rigid lenses represented 10.8% of all contact lens fits, ranging from 0.2% in Lithuania to 37% in Malaysia. Compared with soft lens fits, rigid lens fits can be characterized as follows: older age (rigid, 37.3 ± 15.0 years; soft, 29.8 ± 12.4 years); fewer spherical and toric fits; more bifocal/multifocal fits; less frequent replacement (rigid, 7%; soft, 85%); and less part-time wear (rigid, 4%; soft, 10%). High-Dk (contact lens oxygen permeability) (36%) and mid-Dk (42%) materials are predominantly used for rigid lens fitting. Orthokeratology represents 11.5% of rigid contact lens fits. There has been a steady decline in rigid lens fitting between 1996 and 2011. CONCLUSIONS: Rigid contact lens prescribing is in decline but still represents approximately 10% of all contact lenses fitted worldwide. It is likely that rigid lenses will remain as a viable, albeit increasingly specialized, form of vision correction.

Comfort response of three silicone hydrogel daily disposable contact lenses.

PURPOSE: To evaluate subjective ocular comfort across the day with three silicone hydrogel daily disposables (SHDDs) in a group of adapted lens wearers. METHODS: Masked subjects (asymptomatic or symptomatic of end-of-day (EOD) dryness with habitual lenses) wore three SHDDs: DAILIES TOTAL1 (DT1), Clariti 1day (C1D), or 1-DAY ACUVUE TRUEYE (AVTE), each for 3 days. On day 2, wearing time (WT) and comfort ratings after insertion, at 4, 8, and 12 hours, and at EOD were recorded. Because not all subjects wore lenses for 12 hours, comfort was analyzed across the day (up to 8 hours, 8 to 12 hours), and a new variable ("cumulative comfort" [CC]) was calculated for EOD. RESULTS: One hundred four subjects completed the study (51 asymptomatic, 53 symptomatic). The two groups had different WTs (mean WT, 14.0 and 12.7 hours, respectively; p < 0.001). Ocular comfort was rated higher in the asymptomatic group throughout the day (p < 0.001). One hundred four subjects wore all three SHDDs for at least 8 hours, whereas 74 (45 asymptomatic, 29 symptomatic) subjects wore them for 12 hours or longer. Comfort ratings were higher with DT1 (least square means [LSM] = 91.0) than with C1D (LSM = 86.5; p < 0.001) and AVTE (LSM = 87.7; p = 0.011) for the first 8 hours and lower with C1D compared with DT1 (p = 0.012) from 8 to 12 hours. Mean EOD (± SD) comfort with the C1D lens was 72 ± 21, lower than both DT1 (mean, 79 ± 17; p = 0.001) and AVTE (mean, 78 ± 21; p = 0.010). Mean CC was higher in the asymptomatic group (mean, 1261 ± 59) compared with that in the symptomatic group (mean, 1009 ± 58; p < 0.001) and higher for DT1 (mean, 1184 ± 258) than C1D (mean, 1094 ± 318; p = 0.002) and AVTE (mean, 1122 ± 297; p = 0.046). CONCLUSIONS: All three SHDDs had average WTs of 12 hours or longer for 1 day. Comfort during the first 12 hours was highest with DT1 (similar to AVTE between 8 and 12 hours) and lowest with C1D. End-of-day comfort was lowest with C1D, and CC was highest for DT1. Cumulative comfort may be a valuable new metric to assess ocular comfort during the day.