Stimulus characteristics of a novel air-based multiple stimulus aesthesiometer.

PURPOSE: To identify the stimulus airflow characteristics and confirm the consistency of a novel air jet-based aesthesiometer capable of producing and applying multiple stimuli separated either by time and/or by space. METHODS: A novel aesthesiometer (Dolphin Aesthesiometer) was designed around a micro-blower under software management. Two nozzle attachments assisted in airflow control (flexible tube 1.6 mm diameter; brass tube 0.5 mm diameter). Four studies that tested the characteristics of the airflow and stimulus consistency were completed: (i) airflow pattern/trajectory, (ii) airflow surface dispersion, (iii) force of airflow across a range of stimulus strengths and (iv) thermal effects on the ocular surface. RESULTS: Stimulus characteristic studies revealed: (i) airflow is coherent within the expected test distance range for the instrument, and spread rate is constant irrespective of stimulus strength; (ii) airflow dispersion occurs upon encountering a surface and dispersion increases with increasing airflow rate; (iii) a consistent and small force (10-4 N) is applied by the airflow and (iv) repeatable thermal effects occur in relation to the airflow, and the mode of stimulation of the Dolphin aesthesiometer is predominantly thermal in nature. CONCLUSIONS: These studies confirm the repeatability and consistency of the novel instrument. The device is suitable for measuring corneal sensitivity. The availability of additional air jets allows the application of multiple stimuli to facilitate corneal summation investigations.

Features and influences on the normal tear evaporation rate.

Tear evaporation is a normal physiological phenomenon that has an important role in regulating blink activity and tear production. An altered tear evaporation rate (TER) is a defining characteristic of evaporative dry eye disease (DED), and the measurement of tear evaporation is a useful clinical test for diagnosis. Reported values for a normal TER cover a broad range, which may be due to the influence of ocular, environmental, and systemic factors. For improved disease diagnosis, a fuller understanding of the normal TER range is essential. This paper reports on a literature review of the current knowledge of these normal influences on TER.

Comparison of Javal-Schiøtz keratometer, Orbscan IIz and Pentacam topographers in evaluating anterior corneal topography.

CLINICAL RELEVANCE: Inter-instrument variation in anterior corneal shape (ACS) measurement has a consequence for ocular clinical practice. BACKGROUND: To consider inter-instrument variability in keratometry measurements across the ACS and to explore instrument protocols for determining ACS keratometric analogues (KAs). METHODS: Mean keratometry/KAs of the right eye were recorded using Javal-Schiøtz keratometer (J-S), Orbscan IIz and Pentacam from 124 subjects (78 females; mean ± SD age: 24.71 ± 6.61 years). Mean radii of curvature were obtained for 1-mm wide annular zones extending up to 6 mm (horizontally) and 4 mm (vertically) from the apex for Orbscan and Pentacam. Zonal mean radius of curvature was calculated by averaging keratometry values for all measured points within the zone. RESULTS: KA (mean ± SD): Horizontal: Orbscan (7.80 ± 0.31 mm) and J-S (7.82 ± 0.29 mm) were not significantly different (p = 0.072). Pentacam (7.86 ± 0.29 mm) was significantly flatter than J-S (p < 0.001) and Orbscan (p < 0.001). Vertical: Orbscan (7.64 ± 0.31 mm) was significantly steeper than J-S (7.67 ± 0.29 mm, p < 0.005) and Pentacam (7.70 ± 0.29 mm, p < 0.001). Pentacam was significantly flatter than J-S (p < 0.001) and significant flatter than Orbscan across the entire profile (1-4 mm zones horizontal and vertical, p < 0.001).                        LoAs (CI): J-S/Orbscan: ±0.75 mm (0.05-0.18); J-S/Pentacam: ±0.72 mm (0.01-0.12); Pentacam/Orbscan: ±0.16 mm (0.04-0.08). There was a +0.03 mm positive bias for Orbscan compared to J-S, +0.06 mm positive bias for Orbscan compared to Pentacam and -0.03 mm negative bias for Pentacam compared to J-S. CONCLUSIONS: Algorithms used by Orbscan and Pentacam to solve the peripheral paraxial ray problem produce significantly different KAs. Instrument-specific KAs cannot be used inter-changeably between instruments. Differences in KA between instruments are not significant for ocular surgery, but may influence rigid contact lens fitting. Pentacam measures flatter than Orbscan and J-S.

Interdisciplinary collaborative working on surgical ward rounds: reality or rhetoric? A systematic review.

Daily surgical ward rounds shape the quality of postoperative care and contribute to positive patient outcomes. Despite their importance, strategies to facilitate and promote deliberate interdisciplinary collaboration within surgical ward rounds have not been comprehensively investigated. This paper systematically reviews the literature to identify what is known from existing publications about interdisciplinary working on surgical ward rounds. Pubmed, Embase, CINAHL, Scopus, and Web of Science were searched from database inception until May 2021 for studies involving interdisciplinary surgical ward rounds. Also, journal hand searches were undertaken. All potential abstracts and papers were screened independently by two reviewers to determine inclusion. All included papers were assessed for methodological quality using the accepted quality criteria outlined in the BEME No. 1 guide. A modified Kirkpatrick model was employed to analyze and synthesize the included studies. The search identified 1765 studies. Reviews of 861 abstracts resulted in the retrieval of 124 articles for full-text screening. Thirty-two papers met the inclusion/exclusion criteria. The levels of research evidence were low with 11 papers scoring either grade 4 (results are clear and very likely to be true) or grade 5 (results are unequivocal) in accordance with the BEME No. 1 guide. These 11 studies had three foci (1) full teams managing specific medical conditions through deliberate interdisciplinary collaboration on ward rounds (n = 5); (2) suggestions on the best format for interdisciplinary collaboration on ward rounds (n = 3); and, (3) the roles of specific disciplines in a collaborative surgical round (n = 3). Physicians, intensivists, and pediatricians embrace the benefits of interdisciplinary working to facilitate the improvement of communication, collaboration, and patient safety. Yet, persistent hierarchies within surgical wards act as a barrier often preventing allied health professionals from speaking up, thus perpetuating intra disciplinary siloed behaviors. This barrier contributes to a dearth of research evidence to facilitate interdisciplinary collaborative intentionality in surgical ward rounds and surgical education. Given the high-risk nature of surgery, interdisciplinary collaboration is a critical component for patient safety. Our findings serve as a call to action to address the rhetoric of interdisciplinary collaboration on surgical ward rounds. An evidence-base is required to design, educate for and implement interdisciplinary collaborative opportunities in surgical wards so this critical aspect of patient care becomes a reality.

Applying Patient and Public Involvement in preclinical research: A co-created scoping review.

BACKGROUND: Patient and Public Involvement (PPI) in research aims to improve the quality, relevance and appropriateness of research. PPI has an established role in clinical research where there is evidence of benefit, and where policymakers and funders place continued emphasis on its inclusion. However, for preclinical research, PPI has not yet achieved the same level of integration. As more researchers, including our team, aim to include PPI in preclinical research, the development of an evidence-based approach is important. Therefore, this scoping review aimed to identify and map studies where PPI has been used in preclinical research and develop principles that can be applied in other projects. METHODS: A scoping review was conducted to search the literature in Medline (PubMed), EMBASE, CINAHL, PsycInfo and Web of Science Core Collection to identify applied examples of preclinical PPI. Two independent reviewers conducted study selection and data extraction separately. Data were extracted relating to PPI in terms of (i) rationale and aims, (ii) approach used, (iii) benefits and challenges, (iv) impact and evaluation and (v) learning opportunities for preclinical PPI. Findings were reviewed collaboratively by PPI contributors and the research team to identify principles that could be applied to other projects. RESULTS: Nine studies were included in the final review with the majority of included studies reporting PPI to improve the relevance of their research, using approaches such as PPI advisory panels and workshops. Researchers report several benefits and challenges, although evidence of formal evaluation is limited. CONCLUSION: Although currently there are few examples of preclinical research studies reporting empirical PPI activity, their findings may support those aiming to use PPI in preclinical research. Through collaborative analysis of the scoping review findings, several principles were developed that may be useful for other preclinical researchers. PATIENT OR PUBLIC CONTRIBUTION: This study was conducted as part of a broader project aiming to develop an evidence base for preclinical PPI that draws on a 5-year preclinical research programme focused on the development of advanced biomaterials for spinal cord repair as a case study. A PPI Advisory Panel comprising seriously injured rugby players, clinicians, preclinical researchers and PPI facilitators collaborated as co-authors on the conceptualization, execution and writing of this review, including refining the findings into the set of principles reported here.

Factors influencing the delivery of telerehabilitation for stroke: A systematic review.

OBJECTIVE: Despite the available evidence regarding effectiveness of stroke telerehabilitation, there has been little focus on factors influencing its delivery or translation from the research setting into practice. There are complex challenges to embedding telerehabilitation into stroke services and generating transferable knowledge about scaling up and routinising this service model. This review aimed to explore factors influencing the delivery of stroke telerehabilitation interventions, including platforms, technical requirements, training, support, access, cost, usability and acceptability. METHODS: MEDLINE, EMBASE, CINAHL, Web of Science and Cochrane Library and Central Registry of Clinical Trials were searched to identify full-text articles of randomised controlled trials (RCTs) and protocols for RCTs published since a Cochrane review on stroke telerehabilitation services. A narrative synthesis was conducted, providing a comprehensive description of the factors influencing stroke telerehabilitation intervention delivery. RESULTS: Thirty-one studies and ten protocols of ongoing studies were included. Interventions were categorised as synchronous telerehabilitation (n = 9), asynchronous telerehabilitation (n = 11) and tele-support (n = 11). Telephone and videoconference were the most frequently used modes of delivery. Usability and acceptability with telerehabilitation were high across all platforms, although access issues and technical challenges may be potential barriers to the use of telerehabilitation in service delivery. Costs of intervention delivery and training requirements were poorly reported. CONCLUSIONS: This review synthesises the evidence relating to factors that may influence stroke telerehabilitation intervention delivery at a crucial timepoint given the rapid deployment of telerehabilitation in response to the COVID-19 pandemic. It recommends strategies, such as ensuring adequate training and technical infrastructure, shared learning and consistent reporting of cost and usability and acceptability outcomes, to overcome challenges in embedding and routinising this service model and priorities for research in this area.

Self-regulatory learning theory as a lens on how undergraduate and postgraduate learners respond to feedback: A BEME scoping review: BEME Guide No. 66.

INTRODUCTION: Little is known of processes by which feedback affects learners to influence achievement. This review maps what is known of how learners interact with feedback, to better understand how feedback affects learning strategies, and to explore enhancing and inhibiting factors. METHODS: Pilot searching indicated a wide range of interpretations of feedback and study designs, prompting the use of scoping methodology. Inclusion criteria comprised: (i) learners (undergraduate, postgraduate, continuing education) who regularly receive feedback, and (ii) studies that associated feedback with subsequent learner reaction. The screening was performed independently in duplicate. Data extraction and synthesis occurred via an iterative consensus approach. Self-regulatory learning theory (SRL) was used as the conceptual framework. RESULTS: Of 4253 abstracts reviewed, 232 were included in the final synthesis. Understandings of feedback are diverse; a minority adopt recognised definitions. Distinct learner responses to feedback can be categorized as cognitive, behavioural, affective, and contextual with complex, overlapping interactions. Importantly emotional responses are commonplace; factors mediating them are pivotal in learner recipience. CONCLUSION: Feedback benefits learners most when focussed on learner needs, via engagement in bi-directional dialogue. Learner emotions must be supported, with the construction of positive learner-teacher relationships. A developmental agenda is key to learner's acceptance of feedback and enhancing future learning.

CLEAR - Effect of contact lens materials and designs on the anatomy and physiology of the eye.

This paper outlines changes to the ocular surface caused by contact lenses and their degree of clinical significance. Substantial research and development to improve oxygen permeability of rigid and soft contact lenses has meant that in many countries the issues caused by hypoxia to the ocular surface have largely been negated. The ability of contact lenses to change the axial growth characteristics of the globe is being utilised to help reduce the myopia pandemic and several studies and meta-analyses have shown that wearing orthokeratology lenses or soft multifocal contact lenses can reduce axial length growth (and hence myopia). However, effects on blinking, ptosis, the function of Meibomian glands, fluorescein and lissamine green staining of the conjunctiva and cornea, production of lid-parallel conjunctival folds and lid wiper epitheliopathy have received less research attention. Contact lens wear produces a subclinical inflammatory response manifested by increases in the number of dendritiform cells in the conjunctiva, cornea and limbus. Papillary conjunctivitis is also a complication of all types of contact lenses. Changes to wear schedule (daily disposable from overnight wear) or lens materials (hydrogel from SiHy) can reduce papillary conjunctivitis, but the effect of such changes on dendritic cell migration needs further study. These changes may be associated with decreased comfort but confirmatory studies are needed. Contact lenses can affect the sensitivity of the ocular surface to mechanical stimulation, but whether these changes affect comfort requires further investigation. In conclusion, there have been changes to lens materials, design and wear schedules over the past 20+ years that have improved their safety and seen the development of lenses that can reduce the myopia development. However, several changes to the ocular surface still occur and warrant further research effort in order to optimise the lens wearing experience.

Comparative Analysis of Tear Proteins in Keratoconic Scleral Lens Wearers with Variation in Limbal Clearance.

SIGNIFICANCE: Cytokine and protease analysis revealed relative changes in the post-lens tear film of scleral lenses with low and high limbal clearances. Results from this study indicate that midperipheral lens fit is an important fitting feature that can impact the inflammatory response of a keratoconic eye. PURPOSE: The purpose of this study was to investigate changes in levels of inflammatory mediators in the post-lens tear film of keratoconic scleral lens wearers with varying limbal clearance designs. METHODS: Twenty-two keratoconic eyes were fitted with two sets of scleral lenses that were consistent in lens diameter and central sagittal depth but varied in limbal clearance by approximately 50 µm. Lenses were worn in a randomly assigned order for a 2-week period each. At each follow-up visit, immediately after lens removal, tear samples were collected with a microcapillary tube (10 µL, 0.5 mm in diameter) from the bowl of the inverted scleral lens. Tear cytokine and protease analysis was performed using a multiplex electrochemiluminescent array (Meso Scale Discovery, Rockville, MD) instrument. Levels of interleukins 1, 6, and 8; tumor necrosis factor α; and matrix metalloproteinases 1 and 9 were compared and analyzed. RESULTS: Levels of interleukin 1ß, tumor necrosis factor α, and matrix metalloproteinase 1 increased with high limbal clearance (P = .01, .006, and .02, respectively). No change in interleukins 6 and 8 levels was found (P > .05). A decrease in matrix metalloproteinase 9 was noted in post-lens tear film of scleral lenses with high limbal clearance (P = .10). DISCUSSION: Relative changes in the cytokine and protease levels were found when comparing low and high limbal clearance, indicating that the midperipheral lens fit is an important feature that can impact the inflammatory response of the keratoconic eye.

Development of a national stroke audit in Ireland: scoping review protocol.

Introduction Recent advances in stroke management and care have resulted in improved survival and outcomes. However, providing equitable access to acute care, rehabilitation and longer-term stroke care is challenging. Recent Irish evidence indicates variation in stroke outcomes across hospitals, and a need for continuous audit of stroke care to support quality improvement. The aim of this project is to develop a core minimum dataset for use in the new Irish National Audit of Stroke (INAS), which aims to improve the standard of stroke care in Ireland. This paper outlines the protocol for conducting a scoping review of international practice and guidelines in auditing acute and non-acute stroke care. Objective Identify data items that are currently collected by stroke audits internationally, and identify audit guidelines that exist for recommending inclusion of content in stroke audit datasets. Methods and analysis This scoping review will be conducted in accordance with the Preferred Reporting Items for Systematic Reviews extension for Scoping Reviews (PRISMA-ScR). We will search the following databases: Medline Ovid; Embase; CINAHL EBSCOHost. Grey literature will also be searched for relevant materials, as will relevant websites. Study selection and review will be carried out independently by two researchers, with discrepancies resolved by a third. Data charting and synthesis will involve sub-dividing relevant sources of evidence, and synthesising data into three categories: i) acute stroke care; ii) non-acute stroke care; and iii) audit data collection procedures and resourcing. Data will be charted using a standardised form specific to each category. Consultation with knowledge users will be conducted at all stages of the scoping review. Discussion This scoping review will contribute to a larger project aimed at developing an internationally benchmarked stroke audit tool that will be used prospectively to collect data on all stroke admissions in Ireland, encompassing both acute and non-acute data items.

Objective and Subjective Evaluation of Clinical Performance of Scleral Lens with Varying Limbal Clearance in Keratoconus.

SIGNIFICANCE: This study evaluates how limbal clearance (LC) may impact the clinical performance of scleral lenses based on subjective response on comfort and ocular responses. Limbal zone designs in scleral lenses might affect the integrity of the limbal epithelial tissue as a result of a combined hypoxic and compression-related etiology. PURPOSE: This study aimed to investigate the clinical performance and ocular and subjective responses to the wear of scleral lenses having varying LC. METHODS: Lenses with varying LC with a difference of 50 µm were fitted on and compared among keratoconic participants. The lenses were worn during a 2-week period. Visual analog scales concerning subjective comfort were completed. Ocular surface findings including hyperemia, limbal staining, and corneal swelling were compared. RESULTS: Participants reported greater comfort achieved with high LC. No difference in limbal and bulbar hyperemia was found (P > .05). Corneal response to scleral lens wear with both low and high LCs seems to result in similar perilimbal staining and negative corneal staining. An increase in corneal pachymetric values was noted at the central and peripheral cornea, with no difference between low- and high-LC lenses (all, P < .05). Quadrant-specific analysis indicated that all meridians at both 6 and 8 mm were increased for the low-LC lenses (all, P < .05) and only the temporal region for the high-LC lenses (P = .02). CONCLUSIONS: Limbal clearance may play an important role in subjective performance in scleral lenses but does not impact the degree of hyperemia in either the limbal or bulbar region. Although low LC might result in more compression-related changes to ocular surface, high LC is associated with greater comfort and greater edematous changes. Limbal zone designs in scleral lenses might affect the integrity of the limbal epithelial tissue as a result of a combined hypoxic and compression-related etiology.

Relationship Between the Degree of Iris Pigmentation and Corneal Sensitivity to a Cooling Stimulus.

PURPOSE: To explore the relationship between the degree of iris pigmentation and corneal sensitivity threshold (CST) on a variety of different ethnicities, using the air-jet noncontact corneal aesthesiometer and by applying a consistent method of subject iris pigmentation classification. METHODS: A total of 200 subjects (mean age 23.7 ± 3.1 years, 127 women) participated in this clinical cross-sectional study: 100 whites, 40 Asians, 40 Chinese, and 20 Afro-Caribbeans. CST was assessed within the central cornea using a noncontact corneal aesthesiometer, and the degree of iris pigmentation of each subject was noted according to the Seddon method using a set of graded photographs of iris pigmentation (grades 1-5). Inclusion criteria were absence of ocular disease including dry eye, no contact lens wear, and no use of artificial tears. Statistical testing between ethnicities was made by the pairwise t test with Holm adjustment, and a linear model was set up to analyze the effects of ethnicity and iris grade. RESULTS: A moderate trend for increasing CST with increasing iris pigmentation grade for all ethnicities was observed (R = 0.46; P < 0.0001), with CST changing from 0.66 ± 0.16 mbars for grade 1, 0.74 ± 0.18 mbars for grade 2, 0.86 ± 0.31 mbars for grade 3, 0.85 ± 0.32 mbars for grade 4, and 1.08 ± 0.40 mbars for grade 5. This correlation was stronger within the white group, representing the only ethnicity with all iris pigmentation grades (R = 0.50; P < 0.0001). CONCLUSIONS: There is a moderate relationship between corneal sensitivity and the degree of iris pigmentation, with sensitivity increasing as iris pigmentation decreases. This relationship is stronger within whites.

Atomic force microscopy analysis of the effect of plasma treatment on gas permeable contact lens surface topography.

PURPOSE: Using atomic force microscopy (AFM) to investigate anterior surface topography (AST) in worn and unworn, plasma surface-treated (PST) and untreated (UT) gas permeable (GP) lenses, and influence of surface topography on in vivo comfort. METHODS: GP lens AST evaluated with AFM in tapping mode, using an uncoated, 40 nm symmetric tip (sampling frequency: 300 kHz), at five randomised locations, over a 100µm2 area, to produce mean average roughness (Ra) and root mean square (RMS) values for each sample. Four unworn lenses (two PST, two UT) were examined (Quasar/Boston EO material). Twenty worn lenses (ten PST, ten UT) of same design and material as unworn lenses collected after 3 months lens wear. General wearing comfort reported by visual analogue scale (VAS) at 3 months visit. For sample preparation, two worn UT GP lenses were divided into four segments; each segment underwent a different lens rinse and drying method. RESULTS: Unworn: UT lenses had significantly higher mean RMS and Ra values compared to PST (Mann-Whitney, p < 0.05). Worn: UT Median RMS values were significantly higher than PST (Mann-Whitney, p < 0.05). Comfort: no correlation found between general comfort and RMS or Ra scores. Sample preparation: Method 4 (purified, distilled water rinse/nitrogen gas dry) produced optimum median RMS and Ra values. CONCLUSIONS: Unworn PST GP lenses had lower Ra and RMS values compared with unworn UT GP lenses. After 3 months wear, PST lenses had smoother surface topographies than UT lenses. No relationship was found between surface topography and lens wear comfort. Sample preparation protocol directly impacts AFM results.

Ocular Impression-Taking-Which Material Is Best?

OBJECTIVES: To assess the efficacy and effect on clinical signs of a polyvinylsiloxane (Tresident; Shütz Dental Group GmbH, Germany) compared with an irreversible hydrocolloid (Orthoprint; Zhermack SpA, Badia Polesine, Italy) for ocular impression-taking. METHODS: Twenty subjects were recruited (13 female and 7 male), with mean age 31.1±4.6 years (SD) (range 25.8-39.7). Subjects attended for 2 sessions, each of 1-hr duration, on 2 separate days. Each session was scheduled at the same time on each day. At each visit, the subject underwent an ocular impression procedure, using either Tresident or Orthoprint, in random order and to one eye only. Investigator 2 was blind to this assignment. Two experienced practitioners conducted the study, investigator 1 performed the ocular impression procedures and investigator 2 observed and assessed the clinical signs: logMAR visual acuity, ocular surface staining, tear break-up time (TBUT), and ocular hyperemia. RESULTS: Visual acuity was unaffected by either material; TBUT was marginally disrupted by both materials, but was not clinically significant according to published criteria; ocular redness increased with both materials; and corneal staining was significantly greater after Orthoprint impression. Less redness and clinically insignificant staining after impression-taking, with fewer clinical complications, was found after use of Tresident. CONCLUSIONS: Tresident offers a quicker, more effective, and clinically viable method of obtaining ocular impression topography compared with the traditional Orthoprint, and Orthoprint causes significantly more superficial punctuate staining of the corneal epithelium than Tresident.

Corneal Sensitivity After Ocular Surgery.

The cornea is densely innervated with free nerve endings to provide a high level of sensitivity to foreign bodies or noxious substances. They also provide trophic support to the tissues of the cornea and facilitate their repair and replacement. Any reduction in the function of the nerve endings through disease, contact lens wear, or surgery may lead to corneal disease, damage, or reduced healing. Assessment of the corneal nerve function can be made by the use of specialized instruments (aesthesiometers) that stimulate the corneal nerves using different modalities-mechanical, chemical, and thermal. Each modality assesses the function of a different cohort of corneal nerve type. Ocular surgery, particularly corneal surgery, can produce significant damage to the corneal innervation. However, for the majority of surgical procedures, corneal sensation eventually returns to preoperative levels, given enough time. The principal exceptions to this are penetrating keratoplasty, epikeratophakia, and cryo-keratomileusis, where sensation rarely returns to normal. For all types of surgery, the pattern of corneal sensation loss and recovery depends on the type, depth, and extent of incision because these influence the number of nerve fibers severed, and on the healing response of the patient.

Lid-parallel conjunctival fold (LIPCOF) morphology imaged by optical coherence tomography and its relationship to LIPCOF grade.

PURPOSE: Lid-parallel conjunctival folds (LIPCOF) are a well-accepted clinical sign in dry eye diagnosis. Commonly, LIPCOF is classified by grading the number of folds observed by slit-lamp microscope. This study investigated the relationship between subjective grading scale and LIPCOF morphology imaged by optical coherence tomography (OCT). METHODS: Temporal and nasal LIPCOF of 42 subjects (mean age 27.3 ± 8.4 (SD) years; 13 M, 29 F) were observed and classified by an experienced optometrist using the Pult LIPCOF grading scale (0: no permanent, lid-parallel conjunctival fold; 1: one fold; 2: two folds, 3: three or more folds). Additionally, LIPCOF cross-sectional area (LIPCOF-A) and fold count (LIPCOF-C), as imaged by OCT (Cirrus HD; Carl Zeiss Meditec, Jena, Germany), were analysed with ImageJ 1.50 (http://rsbweb.nih.gov/ij). Correlations between subjective grading and LIPCOF-A and LIPCOF-C were analysed by Spearman correlation, differences between subjective grading and LIPCOF-C were analysed by Wilcoxon test. RESULTS: For temporal and nasal sectors, mean subjective LIPCOF grade was 1.43 ± 0.86 grade units and 0.57 ± 0.80 grade units, mean LIPCOF-C was 1.67 ± 0.82 folds and 0.69 ± 0.78 folds, and mean LIPCOF-A was 0.0676 ± 0.0236mm2 and 0.0389 ± 0.0352 mm2, respectively. Subjective temporal and nasal LIPCOF grade was significantly correlated to LIPCOF-C (r = 0.610, p < 0.001 and r = 0.645, p < 0.001, respectively), and to LIPCOF-A (r = 0.612, p < 0.001 and r = 0.583, p < 0.001, respectively). LIPCOF-C was not statistical different to subjective LIPCOF grade (p = 0.07 and p = 0.239; temporal and nasal sectors, respectively). CONCLUSIONS: OCT allows for better imaging of finer details of LIPCOF morphology, and especially of LIPCOF area. OCT evaluation of LIPCOF area correlated well with subjective grading and appears to be a promising objective method for LIPCOF classification.

Comparison of meibomian gland dropout using two infrared imaging devices.

PURPOSE: To measure the degree of meibomian gland (MG) dropout in the lower eyelid determined by analysis of images obtained from the LipiView II (LVII) and the Keratograph 5M (K5M). METHODS: The inferior eyelid of each participant was imaged in a random order using both devices. All images were subjectively assessed by a single-masked investigator to determine the extent of MG loss using the Arita 4-point meiboscore grading scale. The images were also semi-objectively analyzed with ImageJ to calculate the percentage of MG dropout, by tracing around the non-glandular area and the total exposed area of the lower lid. RESULTS: Twenty participants (mean age 37 years, range 23-60, 60% female) completed the study. A significant difference in meiboscore (mean ±â€¯SD) was obtained between the LVII and the K5M (1.43 ±â€¯0.78 vs. 1.90 ±â€¯0.81, Z = 3.25, p = 0.001). The meiboscore 95% limit of agreement (LOA) ranged from -1.88 to +0.93. A significant difference was found with mean ImageJ percentage dropout between the LVII and the K5M (31.5% vs 43.4%, t = -4.8, p = 0.00003). The percentage dropout 95% LOA ranged from -42.79% to +19.06%. CONCLUSIONS: LVII images had significantly lower meiboscores and less percentage MG dropout. Varying amounts of dropout were observed between the devices due the amount of eyelid that was typically everted and because of differences in image quality. These results indicate that these devices should not be used interchangeably to evaluate MG dropout.

Immediate effect of a tear enhancer and meibomian gland expression on the corneal surface and whole eye higher order aberrations / Efecto inmediato de las lágrimas artificiales y de la expresión de las glándulas de Meibomio sobre las aberraciones de alto orden de la superficie corneal y totales

Purpose: To investigate changes in higher order ocular aberrations (HOA) induced by the administration of 0.15% sodium hyaluronate tear enhancer (TE) and meibomian gland expression (ME) on the tear film of normal subjects. Methods: HOA values were obtained from the corneal surface (CS) and whole eye (WE), using a corneal topographer and Shack-Hartmann aberrometer, from both eyes of 50 subjects (25 females, mean age ± sd 32.5 ± 11.0 years, and 25 males, 33.88 ± 11.2 years) for two pupil sizes (3 and 6 mm) in a dark environment. One drop of Blink ContactsTM (Abbott Medical Optics) was instilled into the right eye and HOA measurements repeated after 30 s. After 1h, the meibomian glands of the left lower eyelid were gently squeezed and HOA measurements repeated after 30s. Results: There was no significant difference for CS and WE root mean square (RMS) HOAs between right and left eyes before (both pupil sizes) and after TE use or ME (3 mm pupil). For 6mm pupil, TE use significantly reduced the WE RMS HOA (p < 0.05, mean ± sd) for Z40 (0.297 ± 0.136 to 0.053 ± 0.069), and Z55 (0.221 ± 0.372 to 0.098 ± 0.121) while ME significantly increased CS RMS HOA (p < 0.05, mean ± sd) for Z3-3 (0.799 ± 1.178 to 1.302±1.991) and Z44 (0.594±1.184 to 0.988 ± 1.463). In general, the change in HOA was significantly correlated with the initial value before TE use or ME (p < 0.05). Conclusion: There were no detectable differences between right and left eyes. For the 6mm pupil, the tear enhancer tended to improve optical performance of the WE and meibomian gland expression tended to reduce the optical performance at the CS

Objetivo: Estudiar los cambios de las aberraciones oculares de alto orden (HOA) inducidas por la aplicación de las lágrimas artificiales con 0,15% de hialuronato sódico y la expresión de las glándulas de Meibomio (ME) en la película lagrimal en sujetos normales. Métodos: Se obtuvieron los valores de HOA de la superficie corneal (SC) y de la totalidad del ojo, utilizando un topógrafo corneal y un aberrómetro Shack-Hartmann, de ambos ojos de 50 sujetos (25 mujeres, edad media ± DE 32,5 ± 11 años, y 25 varones, 33,88 ± 11,2 años) para dos tamaños de pupila (3 y 6 mm) en un entorno oscuro. Se instiló una gota de Blink ContactsTM (Abbott Medical Optics) en el ojo derecho, repitiéndose las mediciones de HOA transcurridos 30 segundos. Al cabo de 1 hora, se presionaron suavemente las glándulas de Meibomio del párpado inferior del ojo izquierdo y se repitieron las mediciones de HOA al cabo de 30 segundos. Resultados: No se produjo diferencia significativa en el error cuadrático médio (RMS) de HOA de la superficie corneal y la totalidad del ojo entre los ojos derecho e izquierdo (ambos tamaños de pupila) antes o después del uso de las lágrimas artificiales o ME (pupila de 3 mm). Para pupilas de 6mm, el uso de lágrimas artificiales redujo significativamente el RMS de HOA de la totalidad del ojo (p< 0,05, media ± DE) para Z04 (de 0,297 ± 0,136 a 0,053 ± 0,069), y Z55 (de 0,221 ± 0,372 a 0,098 ± 0,121) mientras que ME incrementó significativamente el RMS de HOA (p < 0,05, media ± DE) para Z−33 (de 0,799 ± 1,178 a 1,302 ± 1,991) y Z44 (de 0,594 ± 1,184 a 0,988 ± 1,463). En general, el cambio de HOA guardó una correlación significativa con el valor inicial antes del uso de lágrimas artificiales o ME (p < 0,05). Conclusión: No se observaron diferencias detectables entre los ojos derecho e izquierdo. Para la pupila de 6 mm, la lágrima artificial tendió a mejorar el rendimiento óptico de la totalidad del ojo, y la expresión de las glándulas de Meibomio tendió a reducir el rendimiento óptico de la superficie corneal

Effects of ambient humidity on the Cochet-Bonnet aesthesiometer.

PURPOSE: The Cochet-Bonnet (COBO) aesthesiometer is the current standard in corneal sensitivity assessment. This study investigates the influence of ambient room humidity levels on the stimulus force exerted by the instrument. METHODS: A COBO instrument (Luneau Opthalmologie) with 0.12 mm nominal nylon filament diameter was placed in an environment chamber (Electro-tech systems Inc. PA, USA) at 25 °C and relative humidity (%RH) set to either 20-80%, in 10% steps. After 12 h in the chamber at a chosen %RH level, the instrument was removed and exerted force measured by pressing the nylon filament onto the plate of an analytical microbalance (Mettler-Toledo AB265; precision ±0.0001 g) at a perpendicular angle, by a predetermined amount. Exerted force onto the microbalance was recorded in grams for a specified filament length. Procedure was repeated for filament lengths 10-60 mm, in 5 mm steps. The instrument was returned to the chamber and procedure repeated 5 times, before repeating at the next %RH setting (random order). Measurements at each filament lengths were compared using one-way ANOVA and post-hoc Tukey's range test. A p-value < 0.05 denoted statistical significance. RESULTS: Significant differences in exerted force were observed with alteration in %RH levels for each filament length (all p < 0.001). Exerted force decreased significantly with an increase in %RH for all filament lengths, with the average force decreasing by 15% with each 10% rise in %RH. CONCLUSIONS: This study confirms previous suggestions that the rigidity of the COBO nylon filament is affected by ambient room humidity levels, with implications on the stimulus force delivered by the instrument. A conversion table is provided for converting filament lengths to pressure for a range of relative humidity levels.

Immediate effect of a tear enhancer and meibomian gland expression on the corneal surface and whole eye higher order aberrations.

PURPOSE: To investigate changes in higher order ocular aberrations (HOA) induced by the administration of 0.15% sodium hyaluronate tear enhancer (TE) and meibomian gland expression (ME) on the tear film of normal subjects. METHODS: HOA values were obtained from the corneal surface (CS) and whole eye (WE), using a corneal topographer and Shack-Hartmann aberrometer, from both eyes of 50 subjects (25 females, mean age±sd 32.5±11.0 years, and 25 males, 33.88±11.2 years) for two pupil sizes (3 and 6mm) in a dark environment. One drop of Blink Contacts™ (Abbott Medical Optics) was instilled into the right eye and HOA measurements repeated after 30s. After 1h, the meibomian glands of the left lower eyelid were gently squeezed and HOA measurements repeated after 30s. RESULTS: There was no significant difference for CS and WE root mean square (RMS) HOAs between right and left eyes before (both pupil sizes) and after TE use or ME (3mm pupil). For 6mm pupil, TE use significantly reduced the WE RMS HOA (p<0.05, mean±sd) for Z40 (0.297±0.136 to 0.053±0.069), and Z55 (0.221±0.372 to 0.098±0.121) while ME significantly increased CS RMS HOA (p<0.05, mean±sd) for Z3-3 (0.799±1.178 to 1.302±1.991) and Z44 (0.594±1.184 to 0.988±1.463). In general, the change in HOA was significantly correlated with the initial value before TE use or ME (p<0.05). CONCLUSION: There were no detectable differences between right and left eyes. For the 6mm pupil, the tear enhancer tended to improve optical performance of the WE and meibomian gland expression tended to reduce the optical performance at the CS.