Publications by authors named "James S Wolffsohn"

200 Publications

Fast versus gradual adaptation of soft monthly contact lenses in neophyte wearers.

Cont Lens Anterior Eye 2021 May 22:101469. Epub 2021 May 22.

Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.

Aim: To determine if a gradual adaptation period is necessary for neophytes when fitted with modern hydrogel or silicone hydrogel reusable disposable contact lenses.

Method: Across four sites, 74 neophytes (18-28 years) were randomly assigned to a reusable lens cleaned nightly with Opti-Free® Puremoist® multi-purpose contact lens solution: Proclear® (hydrogel) or Biofinity® (silicone hydrogel) and an adaptation schedule: fast (10 h wear from the first day) or gradual (4 h on the first day, increasing their wear time by 2 h on each subsequent day until they had reached 10 h). Masked investigators graded ocular surface physiology and non-invasive tear breakup time (NIBUT) and a range of comfort, vision and lens handling subjective ratings (0-100 visual analogue scales) were recorded at the baseline visit and after 10 h of lens wear, 4-6 days and 12-14 days after lens fitting. Subjective scores were also repeated after 7 days.

Results: There was no difference (p > 0.05) in ocular surface physiology or NIBUT between fast and gradual adaptation groups at any time point in either lens type with the exception of increased corneal staining (p = 0.019) in the silicone hydrogel fast adaptation group after 4-6 days, but was similar by 12-14 days. Subjective scores were also similar across the visits and lens types with the exception of 'lens awareness' (p = 0.019) which was less in the gradual versus the fast adaptation silicone hydrogel lens group at 12-14 days.

Conclusion: There seems to be no clinical benefit for recommending a gradual adaptation period in new wearers fitted with modern soft reusable disposable contact lenses. The findings of this work add to a growing body of evidence suggesting that such advice is unnecessary in regular soft contact lens wear, which has important ramifications for the initial clinical management of these patients.
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http://dx.doi.org/10.1016/j.clae.2021.101469DOI Listing
May 2021

Comparison of Keratoconus Cone Location of Different Topo/tomographical Parameters.

Curr Eye Res 2021 May 17. Epub 2021 May 17.

Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran.

Purpose: To compare the corneal cone location on different maps and instruments and their agreements with elevation maps.

Methods: In 90 left eyes with bilateral keratoconus, the apex of cone location was determined based on the maximum simulated keratometry (Kmax) location on the anterior sagittal curvature map by Pentacam HR, the maximum curvature on the mean curvature map by ATLAS 9000, most elevated point of the island of positive elevation relative to the best fit sphere on the front and back corneal elevation maps by Pentacam HR, and thinnest point on the thickness map by Pentacam HR and Orbscan, and the thinnest points on pachymetry and epithelial thickness maps by RTVue OCT.

Results: There was a significant difference among the location on different maps along the x- and y- axes (p< 0.001). The lowest agreement with the cone apex on both front and back elevation maps was for the anterior sagittal curvature map and the highest agreement for the Pentacam thickness map. The majority of keratoconus cone apexes were displaced in the inferotemporal direction on the different maps except for the epithelial thickness maps.

Conclusions: Despite the variability between different devices and methods; the thickness map on the Pentacam HR showed the highest correlation with the front and back elevation maps, while the RTVue epithelial thickness map showed the poorest correlation. Based on this study, epithelial thickness maps and anterior curvature maps should be utilized with caution to determine the location of the cone.
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http://dx.doi.org/10.1080/02713683.2021.1931343DOI Listing
May 2021

Demographic and lifestyle risk factors of dry eye disease subtypes: A cross-sectional study.

Ocul Surf 2021 May 15;21:58-63. Epub 2021 May 15.

Optometry and Vision Sciences, College of Health and Life Sciences, Aston University, Birmingham, UK; Department of Ophthalmology, New Zealand National Eye Centre, The University of Auckland, New Zealand. Electronic address:

Purpose: To evaluate demographic and lifestyle factors associated with aqueous deficient and evaporative dry eye disease.

Methods: A total of 1125 general public visitors (707 females, mean ± SD age, 33 ± 21, range 5-90 years) at the Royal Society Summer Science Exhibition were recruited in a cross-sectional study. A demographic and lifestyle factor questionnaire was administered, and dry eye symptomology (DEQ-5 score), ocular surface characteristics (conjunctival hyperaemia, and infrared meibography), and tear film parameters (tear meniscus height, non-invasive breakup time, and lipid layer grade) were evaluated for the left eye of each participant within a single session. The diagnostic criteria for dry eye disease subtypes were adapted from the rapid non-invasive dry eye assessment algorithm.

Results: Overall, 428 (38%) participants fulfilled the diagnostic criteria for dry eye disease, 161 (14%) with aqueous deficient dry eye disease, and 339 (30%) with evaporative dry eye disease. Multivariate logistic regression demonstrated that advancing age, female sex, reduced sleep duration, higher psychological stress, and poorer self-perceived health status were independently associated with aqueous deficient dry eye disease (all p < 0.05). Significant risk factors for evaporative dry eye disease included advancing age, East and South Asian ethnicity, contact lens wear, increased digital device screen exposure, higher psychological stress, and poorer self-perceived health status (all p < 0.05).

Conclusions: Both subtypes of dry eye disease were associated with several unique and shared demographic and lifestyle factors. The findings of this study could inform future research design investigating the utility of targeted screening and risk factor modification for the prevention and management of dry eye disease.
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http://dx.doi.org/10.1016/j.jtos.2021.05.001DOI Listing
May 2021

Clinical practice patterns in the management of dry eye disease: A TFOS international survey.

Ocul Surf 2021 May 6;21:78-86. Epub 2021 May 6.

Department of Ophthalmology, New Zealand National Eye Centre, The University of Auckland, New Zealand.

Purpose: To examine clinical management and prescribing patterns for dry eye disease (DED), in relation to severity and subtype, by eye care practitioners across the globe.

Methods: An online, anonymous cross-sectional survey (on Qualtrics) translated into 14 languages was distributed to eye care practitioners across the globe. The survey included six questions around the management of DED, in relation to severity and subtype.

Result: The survey was completed by 1139 eyecare professionals (37% ophthalmologists and 58% optometrists) from 51 countries. Management varied significantly by continent and country (p < 0.01). The most commonly recommended management approaches, internationally, included general advice (87%), low (85%) and high (80%) viscosity-enhancing unpreserved lubricants and lid wipes/scrubs (81%). Some treatments were prescribed largely independently of severity (e.g. artificial tears and nutritional supplements) while oral antibiotics, punctal occlusion, topical anti-inflammatory/immunosuppressants, secretagogues, biologics, therapeutic contact lenses and surgical approaches were prescribed by more practitioners as severity increased. Essential fatty acids, lipid sprays/drops, lid hygiene, warm compresses, intense pulsed light therapy and antibiotics (topical or oral) were more commonly recommended for evaporative DED, while punctal occlusion, therapeutic contact lenses, secretagogues and biologics were more commonly recommended for aqueous deficient DED.

Conclusions: DED management differs across continents and countries. A wide range of management strategies are utilised at each severity level and between subtypes. The survey results enable clinicians to benchmark their practice to that of their peers, indicate where further research is required to optimise patient management and inform industry on how best to target product development.
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http://dx.doi.org/10.1016/j.jtos.2021.04.011DOI Listing
May 2021

Patient-reported experience of dry eye management: An international multicentre survey.

Cont Lens Anterior Eye 2021 Apr 30:101450. Epub 2021 Apr 30.

Optometry and Vision Science, College of Health and Life Sciences, Aston University, Birmingham, UK. Electronic address:

Purpose: To explore the journey taken by patients in a range of different countries to manage their dry eye symptoms.

Method: Members of the general public who responded positively to the question "Do your eyes ever feel dry?" completed a questionnaire describing their demographics, the impact of their symptomology, the advice they have received and the management options they have tried. The Ocular Surface Disease Index (OSDI) questionnaire was also completed.

Results: A total of 916 individuals (Canada = 235, Mexico = 127, New Zealand = 157, Taiwan = 246, UK = 151) of similar age distribution (median 38 years, IQR: 27-50) completed the survey. The reported duration of symptoms was longest in Canada (median 4 years, range 2-10) and least in Taiwan (2 years, range 1-3; p < 0.001), and similar trends were observed for symptom severity (p = 0.001). However, there was no statistically significant difference between countries with respect to the impact of symptoms on quality of life (median 3/10; p = 0.08). Less than half of the individuals in any country had consulted with a health professional. About half had tried a treatment for their dry eye symptoms, with artificial tears being the most common treatment, followed by warm compresses, and both therapies were rated as reasonably effective (median 5-7/10).

Conclusion: Many people with dry eye symptoms are not consulting health care professionals who can confirm the diagnosis, exclude differential diagnoses, and offer a wide range of treatments targeted at the dry eye subtype.
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http://dx.doi.org/10.1016/j.clae.2021.101450DOI Listing
April 2021

IMI 2021 Reports and Digest - Reflections on the Implications for Clinical Practice.

Invest Ophthalmol Vis Sci 2021 Apr;62(5)

Department of Ophthalmology and Visual Science, Tokyo Medical and Dental University, Tokyo, Japan.

The International Myopia Institute's (IMI) mission is to advance research, education, and management of myopia to decrease future vision impairment and blindness associated with increasing myopia. Its approach is to bring together scientists, clinicians, policymakers, government members, and educators into the field of myopia to stimulate collaboration and sharing of knowledge. The latest reports are on pathologic myopia, the impact of myopia, risk factors for myopia, accommodation and binocular vision in myopia development and progression, and the prevention of myopia and its progression. Together with the digest updating the 2019 International Myopia Institute white papers using the research published in the last 18 months, these evidence-based consensus white papers help to clarify the imperative for myopia control and the role of environmental modification initiatives, informing an evidence-based clinical approach. This guidance includes who to treat and when to start or stop treatment, and the advantages and limitations of different management approaches.
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http://dx.doi.org/10.1167/iovs.62.5.1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8083124PMC
April 2021

IMI Accommodation and Binocular Vision in Myopia Development and Progression.

Invest Ophthalmol Vis Sci 2021 Apr;62(5)

School of Optometry, Aston University, Birmingham, United Kingdom.

The role of accommodation in myopia development and progression has been debated for decades. More recently, the understanding of the mechanisms involved in accommodation and the consequent alterations in ocular parameters has expanded. This International Myopia Institute white paper reviews the variations in ocular parameters that occur with accommodation and the mechanisms involved in accommodation and myopia development and progression. Convergence is synergistically linked with accommodation and the impact of this on myopia has also been critiqued. Specific topics reviewed included accommodation and myopia, role of spatial frequency, and contrast of the task of objects in the near environment, color cues to accommodation, lag of accommodation, accommodative-convergence ratio, and near phoria status. Aspects of retinal blur from the lag of accommodation, the impact of spatial frequency at near and a short working distance may all be implicated in myopia development and progression. The response of the ciliary body and its links with changes in the choroid remain to be explored. Further research is critical to understanding the factors underlying accommodative and binocular mechanisms for myopia development and its progression and to guide recommendations for targeted interventions to slow myopia progression.
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http://dx.doi.org/10.1167/iovs.62.5.4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8083074PMC
April 2021

IMI Prevention of Myopia and Its Progression.

Invest Ophthalmol Vis Sci 2021 Apr;62(5)

School of Optometry, Aston University, Birmingham, United Kingdom.

The prevalence of myopia has markedly increased in East and Southeast Asia, and pathologic consequences of myopia, including myopic maculopathy and high myopia-associated optic neuropathy, are now some of the most common causes of irreversible blindness. Hence, strategies are warranted to reduce the prevalence of myopia and the progression to high myopia because this is the main modifiable risk factor for pathologic myopia. On the basis of published population-based and interventional studies, an important strategy to reduce the development of myopia is encouraging schoolchildren to spend more time outdoors. As compared with other measures, spending more time outdoors is the safest strategy and aligns with other existing health initiatives, such as obesity prevention, by promoting a healthier lifestyle for children and adolescents. Useful clinical measures to reduce or slow the progression of myopia include the daily application of low-dose atropine eye drops, in concentrations ranging between 0.01% and 0.05%, despite the side effects of a slightly reduced amplitude of accommodation, slight mydriasis, and risk of an allergic reaction; multifocal spectacle design; contact lenses that have power profiles that produce peripheral myopic defocus; and orthokeratology using corneal gas-permeable contact lenses that are designed to flatten the central cornea, leading to midperipheral steeping and peripheral myopic defocus, during overnight wear to eliminate daytime myopia. The risk-to-benefit ratio needs to be weighed up for the individual on the basis of their age, health, and lifestyle. The measures listed above are not mutually exclusive and are beginning to be examined in combination.
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http://dx.doi.org/10.1167/iovs.62.5.6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8083117PMC
April 2021

IMI 2021 Yearly Digest.

Invest Ophthalmol Vis Sci 2021 Apr;62(5)

College of Optometry, University of Houston, Houston, Texas, United States.

Purpose: The International Myopia Institute (IMI) Yearly Digest highlights new research considered to be of importance since the publication of the first series of IMI white papers.

Methods: A literature search was conducted for articles on myopia between 2019 and mid-2020 to inform definitions and classifications, experimental models, genetics, interventions, clinical trials, and clinical management. Conference abstracts from key meetings in the same period were also considered.

Results: One thousand articles on myopia have been published between 2019 and mid-2020. Key advances include the use of the definition of premyopia in studies currently under way to test interventions in myopia, new definitions in the field of pathologic myopia, the role of new pharmacologic treatments in experimental models such as intraocular pressure-lowering latanoprost, a large meta-analysis of refractive error identifying 336 new genetic loci, new clinical interventions such as the defocus incorporated multisegment spectacles and combination therapy with low-dose atropine and orthokeratology (OK), normative standards in refractive error, the ethical dilemma of a placebo control group when myopia control treatments are established, reporting the physical metric of myopia reduction versus a percentage reduction, comparison of the risk of pediatric OK wear with risk of vision impairment in myopia, the justification of preventing myopic and axial length increase versus quality of life, and future vision loss.

Conclusions: Large amounts of research in myopia have been published since the IMI 2019 white papers were released. The yearly digest serves to highlight the latest research and advances in myopia.
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http://dx.doi.org/10.1167/iovs.62.5.7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8088231PMC
April 2021

Validation of the Spanish version of the Low Vision Quality of Life Questionnaire.

J Optom 2021 Apr 17. Epub 2021 Apr 17.

Ophthalmology Unit, Hospital de la Esperanza, MAR Health Park, Barcelona, Spain; Institut Català de la Retina, Barcelona, Spain; Universitat Internacional de Catalunya, Barcelona, Spain.

Purpose: To validate the Spanish Low Vision Qualify of Life (SLVQOL) questionnaire, a quality of life instrument specifically designed for patients with visual impairment, and evaluate its psychometric properties.

Methods: The study included 170 visually impaired patients and 195 healthy subjects. Participants were administered the SLVQOL, the NEI VFQ-25, and the EQ 5D-5L questionnaires. Reliability, test-retest reproducibility, feasibility, and construct validity of the SLVQOL were assessed. The Generalized Partial Credit Model was used to fit the data and the performance of each item was characterized using category response curves and item information.

Results: The reliability of the SLVQOL was 0.981 (95% CI: 0.978-0.985). Test-retest reproducibility was good (ρ=0.864, P<.001). A cut-off point of 105 or 106 was optimal to detect visual impairment, with a sensitivity of 95.4% and a specificity of 91.8%. Construct validity was shown by the corresponding convergence or divergence correlations between the score of the SLVQOL and its dimensions and the overall and partial scores of the NEI VFQ-25 and the EQ 5D-5L. Item response theory analysis showed discrimination and information parameters ranging from 0.539 to 3.063 and from -1.894 to 1.074, respectively.

Conclusion: The SLVQOL was able to quantitatively assess and identify differences in the quality of life among patients with visual impairment and normal subjects. The evaluated psychometric properties suggest that this tool has excellent validity, internal consistency, and reproducibility, but may benefit from a reduction of the number of items.
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http://dx.doi.org/10.1016/j.optom.2021.01.004DOI Listing
April 2021

Effect of Eye Spray Phospholipid Concentration on the Tear Film and Ocular Comfort.

Eye Contact Lens 2021 Apr 2. Epub 2021 Apr 2.

Optometry and Vision Sciences Research Group (H.P., F.S.K., S.T.H., J.S.W.), College of Health and Life Sciences, Aston University, Birmingham, United Kingdom; Dr. Heiko Pult-Optometry and Vision Research (H.P.), Weinheim, Germany; and School of Biomedical & Life Sciences (H.P.), Cardiff University, Cardiff, United Kingdom.

Objectives: To evaluate the effect of eye spray phospholipid concentration on symptoms and tear film stability.

Methods: High-concentration (Tears Again, Optima Pharma GmbH, Hallbergmoos, Germany) and low-concentration (Ocuvers, Innomedis AG, Germany) phospholipid eye sprays were sprayed onto the closed eyelids of 30 subjects (33.2±1.8 years; 20 women) in a multicentered, prospective, crossover study. Ocular comfort (visual analog scale) and noninvasive tear film stability (NIBUT) of each eye were evaluated before application (along with the Ocular Surface Disease Index), 10 min after application, and 30 min after application.

Results: Comfort (high concentration: 68.5±16.4 vs. low concentration: 70.7±14.5 phospholipid) and NIBUT (high concentration: 11.5±4.6 sec vs. low concentration: 11.2±6.0 sec phospholipid) were not different (P>0.3) between sprays before application, but comfort (by 12 points, P=0.001) and NIBUT (by 5 sec, P=0.016) were significantly better with a high-concentration phospholipid spray at both 10 min and 30 min time points than those with the low-concentration phospholipid spray.

Conclusions: The liposomal eye spray with higher concentration of phospholipids significantly improved ocular comfort and tear film stability in contrast to the eye spray with lower concentration of phospholipids, hence practitioners need to choose an appropriate eye spray to maximize the patient benefit.
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http://dx.doi.org/10.1097/ICL.0000000000000788DOI Listing
April 2021

CLEAR - Evidence-based contact lens practice.

Cont Lens Anterior Eye 2021 Apr 25;44(2):368-397. Epub 2021 Mar 25.

School of Optometry and Vision Science, UNSW Sydney, Australia.

Evidence-based contact lens -->practice involves finding, appraising and applying research findings as the basis for patient management decisions. These decisions should be informed by the strength of the research study designs that address the question, as well as by the experience of the practitioner and the preferences and environment of the patient. This reports reviews and summarises the published research evidence that is available to inform soft and rigid contact lens history and symptoms taking, anterior eye health examination (including the optimised use of ophthalmic dyes, grading scales, imaging techniques and lid eversion), considerations for contact lens selection (including the ocular surface measurements required to select the most appropriate lens parameter, lens modality and material selection), evaluation of lens fit, prescribing (teaching self-application and removal, adaptation, care regimen and cleaning instructions, as well as -->minimising risks of lens wear through encouraging compliance) and an aftercare routine.
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http://dx.doi.org/10.1016/j.clae.2021.02.008DOI Listing
April 2021

CLEAR - Contact lens complications.

Cont Lens Anterior Eye 2021 Apr 25;44(2):330-367. Epub 2021 Mar 25.

School of Optometry, Aston University, Birmingham, UK.

Contact lens-related complications are common, affecting around one third of wearers, although most are mild and easily managed. Contact lenses have well-defined anatomical and physiological effects on the ocular surface and can result in other consequences due to the presence of a biologically active material. A contact lens interacts with the tear film, ocular surface, skin, endogenous and environmental microorganisms, components of care solutions and other antigens which may result in disease specific to contact lens wear, such as metabolic or hypersensitivity disorders. Contact lens wear may also modify the epidemiology or pathophysiology of recognised conditions, such as papillary conjunctivitis or microbial keratitis. Wearers may also present with intercurrent disease, meaning concomitant or pre-existing conditions unrelated to contact lens wear, such as allergic eye disease or blepharitis, which may complicate the diagnosis and management of contact lens-related disease. Complications can be grouped into corneal infection (microbial keratitis), corneal inflammation (sterile keratitis), metabolic conditions (epithelial: microcysts, vacuoles, bullae, tight lens syndrome, epithelial oedema; stromal: superficial and deep neovascularisation, stromal oedema [striae/folds], endothelial: blebs, polymegethism/ pleomorphism), mechanical (corneal abrasion, corneal erosion, lens binding, warpage/refractive error changes; superior epithelial arcuate lesion, mucin balls, conjunctival epithelial flaps, ptosis, discomfort), toxic and allergic disorders (papillary conjunctivitis, solution-induced corneal staining, incomplete neutralisation of peroxide, Limbal Stem Cell Deficiency), tear resurfacing disorders/dry eye (contact lens-induced dry eye, Meibomian gland dysfunction, lid wiper epitheliopathy, lid parallel conjunctival folds, inferior closure stain, 3 and 9 o'clock stain, dellen, dimple veil) or contact lens discomfort. This report summarises the best available evidence for the classification, epidemiology, pathophysiology, management and prevention of contact lens-related complications in addition to presenting strategies for optimising contact lens wear.
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http://dx.doi.org/10.1016/j.clae.2021.02.010DOI Listing
April 2021

CLEAR - Anatomy and physiology of the anterior eye.

Cont Lens Anterior Eye 2021 Apr 25;44(2):132-156. Epub 2021 Mar 25.

School of Optometry, Aston University, Birmingham, UK; Department of Ophthalmology, New Zealand National Eye Centre, The University of Auckland, New Zealand.

A key element of contact lens practice involves clinical evaluation of anterior eye health, including the cornea and limbus, conjunctiva and sclera, eyelids and eyelashes, lacrimal system and tear film. This report reviews the fundamental anatomy and physiology of these structures, including the vascular supply, venous drainage, lymphatic drainage, sensory innervation, physiology and function. This is the foundation for considering the potential interactions with, and effects of, contact lens wear on the anterior eye. This information is not consistently published as academic research and this report provides a synthesis from all available sources. With respect to terminology, the report aims to promote the consistent use of nomenclature in the field, and generally adopts anatomical terms recommended by the Federative Committee for Anatomical Terminology. Techniques for the examination of the ocular surface are also discussed.
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http://dx.doi.org/10.1016/j.clae.2021.02.009DOI Listing
April 2021

Contact Lens Evidence-Based Academic Reports (CLEAR).

Cont Lens Anterior Eye 2021 Apr 25;44(2):129-131. Epub 2021 Mar 25.

School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia.

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http://dx.doi.org/10.1016/j.clae.2021.02.011DOI Listing
April 2021

Visual Performance of Center-distance Multifocal Contact Lenses Fit Using a Myopia Control Paradigm.

Optom Vis Sci 2021 03;98(3):272-279

The Ocular Surface Institute, University of Houston College of Optometry, Houston, Texas.

Purpose: The purpose of this study was to examine the visual performance of center-distance MFCLs in nonpresbyopic adults under different illumination and contrast conditions compared with a single-vision contact lens (SVCL).

Methods: Twenty-five adult subjects were fit with three different lenses (CooperVision Biofinity D MFCL +2.50 add, Visioneering Technologies NaturalVue MFCL, CooperVision Biofinity sphere). Acuity and reading performance were evaluated.

Results: A statistically significant difference in high-contrast distance acuity was observed (Biofinity, -0.18 ± 0.06; Biofinity MFCL, -0.14 ± 0.08; NaturalVue MFCL, -0.15 ± 0.03; repeated-measures [RM] ANOVA, P = .02). Under mesopic, high-contrast conditions, MFCLs performed worse than SVCLs (Biofinity, -0.05 ± 0.091; Biofinity MFCL, +0.03 ± 0.09; NaturalVue MFCL, +0.05 ± 0.091; RM-ANOVA, P < .0001). Under low-contrast conditions, MFCLs performed one line worse in photopic lighting and two lines worse under mesopic conditions (RM-ANOVA, P < .0001). Glare reduced acuity by 0.5 logMAR for all lenses (RM-ANOVA, P < .001). A statistically significant difference in near acuity was observed (RM-ANOVA, P = .02), but all lenses achieved acuity better than -0.1 logMAR (Biofinity, -0.16 ± 0.06; Biofinity MFCL, -0.17 ± 0.04; NaturalVue MFCL, -0.13 ± 0.08). Reading performance in words per minute (wpm) was worse with MFCLs (Biofinity MFCL, 144 ± 22 wpm; NaturalVue MFCL, 150 ± 28 wpm) than with SVCLs (156 ± 23 wpm; RM-ANOVA, P = .02) regardless of letter size (RM-ANOVA, P = .13). No difference in acuity between the MFCLs was detected (RM-ANOVA: all, P > .05).

Conclusions: Multifocal contact lenses perform similarly to SVCLs for high-contrast targets and display reduced low-contrast acuity and reading speed. Practitioners should recognize that high-contrast acuity alone does not describe MFCL visual performance.
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http://dx.doi.org/10.1097/OPX.0000000000001665DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8007064PMC
March 2021

Association between dry eye disease, self-perceived health status, and self-reported psychological stress burden.

Clin Exp Optom 2021 Mar 3:1-6. Epub 2021 Mar 3.

Department of Ophthalmology, New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand.

: Dry eye disease is a common chronic ocular condition, which is acknowledged to have adverse impacts on quality of life and work productivity.: The wide-reaching impacts of dry eye disease on mental health and quality of life have received growing attention in recent years. The purpose of this study was therefore to investigate the relationship between dry eye disease, self-perceived health status, and self-reported psychological stress burden.: Three hundred and twelve community residents (178 females, 134 males; mean ± SD age, 38 ± 21 years) with no major systemic, ophthalmic, or psychiatric conditions (other than dry eye disease), were recruited in a cross-sectional study. Self-perceived health status and self-reported psychological stress burden were assessed, and dry eye symptomology, ocular surface characteristics, and tear film quality were evaluated for each participant within a single clinical session, in accordance with the global consensus recommendations of the Tear Film and Ocular Surface Society Dry Eye Workshop II reports.: Multivariate regression analysis, adjusted for age, sex, ethnicity, and contact lens wear, demonstrated that improved self-perceived health status was associated with decreased odds of dry eye disease, aqueous tear deficiency and meibomian gland dysfunction (all p < 0.05). Increased self-reported psychological stress burden was positively associated with dry eye disease, aqueous tear deficiency and meibomian gland dysfunction (all p ≤ 0.01).: Dry eye disease is associated with poorer self-perceived health status and greater self-reported psychological stress burden. The findings of this study highlight the wide-reaching impacts of dry eye disease, and the importance of minimising the impacts of the condition with optimised management and actioning inter-disciplinary referral for affected patients where necessary.
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http://dx.doi.org/10.1080/08164622.2021.1887580DOI Listing
March 2021

Evaluation of tear meniscus height using different clinical methods.

Clin Exp Optom 2021 Mar 2:1-6. Epub 2021 Mar 2.

Höhere Fachschule für Augenoptik Köln (Cologne School of Optometry), Cologne, Germany.

: The height of the tear meniscus (TMH) is a generally accepted method to evaluate tear film volume, especially in dry eye diagnoses and management.: The purpose of this study was to evaluate the ability of different methods to measure tear meniscus height accurately and repeatably.: Lower TMH of 20 volunteers (26.8 ± 5.6 years) was measured by two observers (OI and OII) using optical coherence tomography (OCT), slitlamp microscope image analysis, and with a reticule at low (8x) and high (32x) magnification. TMH was also evaluated by both observers by comparing TMH to thickness of the lid margin (lid-ratio; grade 0: TMH 1/2 lid margin thickness; grade 1: 1/3; grade 2: 1/4; grade 3: 1/5; grade 4: 1/6) and to the number of eyelashes fitting in the tear meniscus. Differences between observers were analysed by paired-t-test. Differences between OCT-TMH and other methods were analysed by ANOVA, and inter-observer repeatability by intra-class-correlation-coefficient (ICC). The ability to predict OCT-TMH was calculated by receiver operative characteristic (ROC) curve analysis.: There was no significant difference between OI and OII in all methods except of the eyelash-count-method (p = 0.008). For OI, TMH measured using a reticule at 8x (0.20 ± 0.05 mm) was significantly lower than OCT-TMH (0.24 ± 0.07 mm) (p = 0.032) but not at 32x (0.22 ± 0.01 mm; p = 0.435). TMH evaluated by the image software of the slitlamp (0.20 ± 0.05 mm) was significantly lower than OCT-TMH (p = 0.022). The lid-ratio-method and eyelash-count-method resulted in grades of 2.35 ± 1.22 and 2.85 ± 0.81, respectively. ROC analyses showed that only the 8x and the 32x magnification method could discriminate between normal and abnormal OCT-TMH. OCT had the best repeatability (ICC = 0.88; p < 0.001) followed by reticule using 32x magnification (ICC = 0.70; p = 0.004).: The most reliable method to measure TMH was OCT followed by slitlamp using a reticule. TMH cannot be reliably evaluated by comparing it against lid margin thickness or number of eyelashes.
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http://dx.doi.org/10.1080/08164622.2021.1878854DOI Listing
March 2021

Dry eye disease is associated with retinal microvascular dysfunction and possible risk for cardiovascular disease.

Acta Ophthalmol 2021 Feb 11. Epub 2021 Feb 11.

Vascular Research Laboratory, Ophthalmic Research Group, College of Health and life Sciences, Aston University, Birmingham, UK.

Purpose: To explore the presence of microvascular endothelial dysfunction as a measure for early cardiovascular disease in individuals diagnosed with dry eye disease (DED) as compared to age-matched normal controls.

Methods: Systemic blood pressure, Body Mass Index, intraocular pressure, blood levels of glucose (GLUC), triglycerides, cholesterol (CHOL), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C)] as well as retinal and peripheral microvascular function were assessed in twenty-five 35-50 year olds with diagnosed with DEDa (using the TFOS DEWS II criteria) and 25 age and sex-matched controls.

Results: After controlling all the influential covariates, individuals diagnosed with DED exhibited significant lower retinal artery baseline (p = 0.027), artery maximum diameter (p = 0.027), minimum constriction (p = 0.039) and dilation amplitude (p = 0.029) than controls. In addition, the time to reach the vein maximum diameter was significantly longer in the DED patients than in normal controls (p = 0.0052). Only in individuals diagnosed with DED, artery maximum constriction correlated statistically significantly and positively with HDL-C blood levels (p = 0.006). Similarly, artery slope correlated positively with T-CHOL and LDL-C (p = 0.006 & 0.011 respectively). Additionally, artery baseline diameter and maximum constriction were significantly and negatively correlated to T-CHOL/HDL-C ratio (p = 0.032 and p = 0.013 respectively) in DED individuals only.

Conclusions: Individuals with positive diagnosis of DED exhibit abnormal retinal microvascular function and possible higher risk for CVD.
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http://dx.doi.org/10.1111/aos.14782DOI Listing
February 2021

Design considerations for the ideal low vision aid: insights from de-brief interviews following a real-world recording study.

Ophthalmic Physiol Opt 2021 03 2;41(2):266-280. Epub 2021 Feb 2.

Optometry and Vision Science, Aston University, Birmingham, UK.

Purpose: Low Vision Aids (LVAs) can have a transformative impact on people living with sight loss, yet the everyday requirements for developing such devices remain poorly understood and defined. This study systematically explored LVA requirements through a structured de-brief interview following a real-world self-recording study. The purpose of this work was to define the actual needs of those living with sight loss so that low vision services can better address them in future.

Methods: Thirty-two visually impaired volunteers with varying levels of previous LVA experience participated in a de-brief interview centred around a structured questionnaire. The de-brief followed a one-week real-world study during which participants used recoding spectacles to capture and narrate all situations in which they would use a 'perfect sight aid'. Content and thematic analyses were used to analyse interviews which had the purpose of contextualising these recordings and exploring requirements around psychological, functional and design factors.

Results: Participants reported that 46% of tasks which they had recorded were most important to them. Of these tasks, 82% were encountered frequently. Few tasks emerged as very important across many participants, the remaining tasks reflecting individual lifestyles or circumstances. Every participant used at least one LVA in their everyday life and 72% identified further coping strategies. Current LVAs identified as consistently poor were distance LVAs, with all other devices receiving mixed or only positive feedback. Around two-thirds of participants would prefer LVA use on an ad-hoc / quick access basis rather than over long periods of time, and just over half would prefer to carry it rather than wearing it all day. Lack of consistency in these responses illustrated potentially different user clusters with divergent design needs. Two-thirds of participants emphasised the desire for a discreet LVA that does not attract attention. However, since half of all participants felt self-conscious in public or in front of other people when wearing the small recording spectacles, this may not be technically achievable.

Conclusions: There is a substantial opportunity for new LVAs to address visual needs that traditional devices and coping strategies cannot support. Functional, psychological and design factors require careful consideration for future LVAs to be relevant and widely adopted.
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http://dx.doi.org/10.1111/opo.12778DOI Listing
March 2021

Modifiable lifestyle risk factors for dry eye disease.

Cont Lens Anterior Eye 2021 Jan 21:101409. Epub 2021 Jan 21.

Department of Ophthalmology, New Zealand National Eye Centre, The University of Auckland, New Zealand; Ophthalmic Research Group, School of Life and Health Sciences, Aston University, Birmingham, United Kingdom. Electronic address:

Purpose: To examine the association between modifiable lifestyle factors and dry eye disease.

Methods: Three hundred and twenty-two community residents (186 females, 136 males; mean ± SD age, 41 ± 22 years) with no major systemic or ophthalmic conditions (other than dry eye disease) were recruited in a cross-sectional study. A lifestyle factor questionnaire was administered, and dry eye symptomology, ocular surface characteristics, and tear film quality were evaluated for each participant within a single clinical session, in accordance with the global consensus recommendations of the TFOS DEWS II reports.

Results: A total of 111 (34 %) participants fulfilled the TFOS DEWS II diagnostic criteria for dry eye disease. Multivariate regression analysis demonstrated that advancing age, female sex, East Asian ethnicity, and increased digital screen exposure time were positive risk factors for dry eye disease (all p < 0.05), while increased caffeine consumption was a protective factor (p = 0.04).

Conclusions: Increased digital screen exposure time and reduced caffeine consumption were modifiable lifestyle factors associated with higher odds of dry eye disease. These findings might contribute to informing the design of future prospective research investigating the efficacy of preventative intervention and risk factor modification strategies.
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http://dx.doi.org/10.1016/j.clae.2021.01.004DOI Listing
January 2021

Developing evidence-based guidance for the treatment of dry eye disease with artificial tear supplements: A six-month multicentre, double-masked randomised controlled trial.

Ocul Surf 2021 Apr 2;20:62-69. Epub 2021 Jan 2.

Optometry and Vision Science Research Group, Aston University, Birmingham, UK.

Purpose: To assess the six-month therapeutic profiles of lipid and non-lipid-based artificial tear supplements in managing dry eye disease (DED).

Methods: Ninety-nine participants fulfilling the TFOS DEWS II diagnostic criteria for DED (64% females; mean ± SD age, 44 ± 16 years) were enrolled in a prospective, multicentre, double-masked, parallel group, randomised controlled trial. Participants instilled lipid-based nanoemulsion drops or non-lipid-based aqueous drops for six months, at least four times daily. Symptomology, tear film and ocular surface characteristics were assessed at Days 0, 30, 60, 90, 120, 150 and 180.

Results: Sustained reductions in OSDI, DEQ-5, and SANDE symptom scores from baseline were observed from Day 30 onwards in both groups (all p < 0.05) and decreased superior lid wiper epitheliopathy grades from Day 60 onwards (all p ≤ 0.01). Improvements in non-invasive tear film breakup time, and sodium fluorescein and lissamine green staining scores followed from Day 120 onwards in both groups (all p < 0.05). Tear lipid layer grades increased from Day 90 onwards only with the lipid-based drops, and with significantly greater improvement in those with suboptimal lipid layer thickness at baseline (grade ≤3; p = 0.02). By Day 180, 19% of participants no longer fulfilled the diagnostic criteria for DED.

Conclusions: Over a six-month treatment period, improvements in dry eye symptomology preceded tear film and ocular surface changes with regular use of both lipid and non-lipid-based artificial tear supplements. Both formulations addressed most mild-to-moderate forms of aqueous deficient and evaporative DED, while evaporative cases benefitted preferentially from lipid-based supplementation. This represents a first step towards mapping DED therapeutic strategies according to disease subtype and severity.
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http://dx.doi.org/10.1016/j.jtos.2020.12.006DOI Listing
April 2021

Effect of meibomian gland morphology on functionality with applied treatment.

Cont Lens Anterior Eye 2021 Jan 1:101402. Epub 2021 Jan 1.

Ophthalmic Research Group, School of Life & Health Sciences, Aston University, Birmingham, B4 7ET, United Kingdom. Electronic address:

Purpose: To determine how Meibomian gland (MG) morphology affects MG function by means of gland expression with the effect of treatment.

Methods: Fifteen patients (aged 31.6 ± 13.1 years) from a dry eye clinic diagnosed with MG dysfunction had their 365 lower lid MGs visualised with a slit-lamp biomicroscopy. Using infrared meibography (Oculus K5m), MG length, width and tortuosity were objectively measured. Each MG was expressed and the meibum graded (0=clear fluid, 1=cloudy fluid, 2= particulate fluid, 3=inspissated, or 4 = no expression) to determine its functionality. Participants had functionality repeated each time following a sequence of a warm compress, debridement, and forcible expression after 5 min.

Results: Just over 10 % of complete length MGs gave clear expression, while about 5% did not express at all, with most expressed meibum being particulate in nature. In contrast, the majority of partial length glands gave inspissated expression (38 %), with 32 % not expressing at all. No MG of <10 % length expressed. MG gland length was correlated with gland expression (r=-0.507, p < 0.001) and MG tortuosity (r=-0.129, p < 0.001), but not MG width (r=-0.090, p = 0.167). Regardless of MG length, warm compress increased the quality of expression (p < 0.002). Debridement further improved expression in partial MGs (p = 0.003), but not forcible expression (p = 0.529).

Conclusions: Length is the key functional morphology metric of lower lid MGs. Warm compress and massage increase the quality of expression in all, but the shortest glands and patients with partial length glands also benefit from debridement.
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http://dx.doi.org/10.1016/j.clae.2020.12.065DOI Listing
January 2021

Clinical significance of contact lens related changes of ocular surface tissue observed on optical coherence images.

Cont Lens Anterior Eye 2020 Dec 5:101388. Epub 2020 Dec 5.

Höhere Fachschule für Augenoptik Köln, Cologne School of Optometry, Cologne, Germany; Optometry and Vision Science Research Group, Aston University, Birmingham, United Kingdom. Electronic address:

Purpose: To investigate the relationship between the real contact lens imprint into the conjunctival tissue, observed by optical coherence tomography (OCT) and conjunctival staining and contact lens wearing comfort.

Methods: 17 participants (mean age = 26.6 SD ± 3.6 years; 7 females) were fitted with three different contact lenses base curves of the same silicone hydrogel custom lens type (Visell 50; Hecht Contactlinsen, Au, Germany) in a randomised order. One lens was optimally fitted according to the manufacturer's recommendation, one fitted 0.4 mm flatter and one fitted 0.4 mm steeper. After 4 h of lens wear the contact lens edge in the area of the conjunctiva was imaged nasally and temporally using OCT (Optovue iVue SD-OCT). To correct the artefact due to optical distortion with OCT, the imprint of all worn lenses was measured on a glass plate afterwards. Conjunctival staining in the limbal region after 4 h of lens wear was classified using the CCLRU Grading Scale. Comfort scoring was based on visual analog scales from 0 (very poor) to 100 (excellent).

Results: The mean conjunctival imprint of all contact lens edges was 32.0 ± 8.1 μm before and 7.3 ± 6.5 μm after distortion correction of the OCT images. The distortion corrected conjunctival imprint with the 0.4 mm steeper lens (11.5 ± 6.2 μm) was statistically significantly greater compared to the optimally fitted lens (6.5 ± 5.9 μm) (One-way ANOVA followed Tukey-test; p = 0.017) and greater compared to the 0.4 mm flatter lens (3.9 ± 5.3 μm) (p < 0.001). There was no statistically significant difference between the optimally fitted lens and the 0.4 mm flatter lens (p = 0.209). The nasally measured imprint (11.4 ± 9.0 μm) was significantly greater than the temporally measured (3.3 ± 7.6 μm) (p < 0.001). There was no statistically significant correlation between the amount of conjunctival imprint and the graded conjunctival staining (p = 0.346) or the wearer's comfort (p = 0.735).

Conclusions: Contact lens edges imaged by OCT exhibited displacement artefacts. The observed conjunctival imprints are a combination of real conjunctival compression and artefacts. A deeper imprint of the contact lens into the conjunctiva caused by a steeper base curve was not related to clinically significant staining or changes in comfort after 4 h of lens wear. The observed differences between nasal and temporal imprint are likely to be caused by variations of conjunctival thickness and the shape of the underlying sclera.
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http://dx.doi.org/10.1016/j.clae.2020.11.008DOI Listing
December 2020

Contact lens wear and care in Spain during the COVID-19 pandemic.

Cont Lens Anterior Eye 2020 Nov 11:101381. Epub 2020 Nov 11.

Vision and Hearing Sciences Research Centre, Anglia Ruskin University, Cambridge, UK. Electronic address:

Aim: To establish contact lens wear and care practices during the COVID-19 pandemic in Spain.

Method: A 58-item anonymous online survey was distributed during the period 30th April to 10th May via Qualtrics. The survey explored: a) demographic characteristics (age, sex, general health and where they were living during lockdown), b) changes in their contact lens use during lockdown, c) hygiene and contact lens compliance and d) concerns associated with contact lens wear and ways to support wearers during the pandemic.

Results: Two hundred and sixty responses were analysed (38.8 ± 11.4 years old, 75% female). Three-quarters of participants reported that they were self-isolating or rigorously following social distancing advice. Sixty-seven percent of participants reported using their contact lenses less during the pandemic. Respondents were found to be compliant with handwashing prior to inserting and removing contact lenses (in both cases 97% doing this 'most times' or 'every time'). However, only 44 % complied with the '20 s rule' and 48 % used a shared towel to dry their hands. A higher proportion of hydrogen peroxide users replaced the lens case monthly compared to multi-purpose users (64% vs.49%; p < 0.001). Twenty-four percent admitted wearing lenses whilst showering and 16% did not consider ceasing lens wear if feeling unwell with flu/cold symptoms.

Conclusion: Eye care practitioners should continue to educate contact lens wearers to ensure safe contact lens wear to minimise the chance of developing contact lens related complications during the pandemic. Modifiable factors that need particular attention in Spain include: handwashing for at least 20s before lens handling, drying hands with single use paper towels, including a rub-and-rinse step for reusable lenses, lens case cleaning and renewal, avoidance of water exposure and when to cease lens wear during the pandemic.
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http://dx.doi.org/10.1016/j.clae.2020.11.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7657612PMC
November 2020

Social Media Listening to Understand the Lived Experience of Presbyopia: Systematic Search and Content Analysis Study.

J Med Internet Res 2020 09 21;22(9):e18306. Epub 2020 Sep 21.

Novartis Business Services, Product Lifecycle Services, Hyderabad, India.

Background: Presbyopia is defined as the age-related deterioration of near vision over time which is experienced in over 80% of people aged 40 years or older. Individuals with presbyopia have difficulty with tasks that rely on near vision. It is not currently possible to stop or reverse the aging process that causes presbyopia; generally, it is corrected with glasses, contact lenses, surgery, or the use of a magnifying glass.

Objective: This study aimed to explore how individuals used social media to describe their experience of presbyopia with regard to the symptoms experienced and the impacts of presbyopia on their quality of life.

Methods: Social media sources including Twitter, forums, blogs, and news outlets were searched using a predefined search string relating to symptoms and impacts of presbyopia. The data that were downloaded, based on the keywords, underwent manual review to identify relevant data points. Relevant posts were further manually analyzed through a process of data tagging, categorization, and clustering. Key themes relating to symptoms, impacts, treatment, and lived experiences were identified.

Results: A total of 4456 social media posts related to presbyopia were identified between May 2017 and August 2017. Using a random sampling methodology, we selected 2229 (50.0%) posts for manual review, with 1470 (65.9%) of these 2229 posts identified as relevant to the study objectives. Twitter was the most commonly used channel for discussions on presbyopia compared to forums and blogs. The majority of relevant posts originated in Spain (559/1470, 38.0%) and the United States (426/1470, 29.0%). Of the relevant posts, 270/1470 (18.4%) were categorized as posts written by individuals who have presbyopia, of which 37 of the 270 posts (13.7%) discussed symptoms. On social media, individuals with presbyopia most frequently reported experiencing difficulty reading small print (24/37, 64.9%), difficulty focusing on near objects (15/37, 40.5%), eye strain (12/37, 32.4%), headaches (9/37, 24.3%), and blurred vision (8/37, 21.6%). 81 of the 270 posts (30.0%) discussed impacts of presbyopia-emotional burden (57/81, 70.4%), functional or daily living impacts (46/81, 56.8%), such as difficulty reading (46/81, 56.8%) and using electronic devices (21/81, 25.9%), and impacts on work (3/81, 3.7%).

Conclusions: Findings from this social media listening study provided insight into how people with presbyopia discuss their condition online and highlight the impact of presbyopia on individuals' quality of life. The social media listening methodology can be used to generate insights into the lived experience of a condition, but it is recommended that this research be combined with prospective qualitative research for added rigor and for confirmation of the relevance of the findings.
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http://dx.doi.org/10.2196/18306DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7536603PMC
September 2020

Near visual function measured with a novel tablet application in patients with astigmatism.

Clin Exp Optom 2021 Jan;104(1):42-47

Optometry and Vision Science Research Group, Aston University , Birmingham, UK.

Clinical Relevance: While the clinical focus of performance metrics is traditionally based on visual acuity, research from the field of visual impairment has demonstrated that metrics such as reading speed and critical print size correlate much more strongly with subjective patient reported outcomes and assessed ability in real-world tasks.

Background: More recently, digital device use has increasingly replaced many paper-based tasks. Therefore, this study aimed to assess the correlation between standard acuity/contrast metrics and functional reading ability compared to real-world performance on an iPad-based reading task with astigmatic patients corrected wearing toric and mean spherical equivalent contact lenses.

Methods: Thirty-four adult participants, with -0.75 to -1.50-D of refractive astigmatism, were enrolled in a double-masked cross-over study and fitted with toric and spherical equivalent contact lenses, in random order. A digital application was developed to assess zoom, contrast modifications, the distance at which the tablet was held, blink rate, and time to complete the reading task. High and low contrast near logMAR visual acuity were measured along with reading performance (critical print size and optimal reading speed).

Results: The amount participants chose to increase tablet font size (zoom) was correlated with their high-contrast visual acuity with toric correction (r = 0.434, p = 0.010). With best sphere correction, zoom was associated with reading speed (r = -0.450, p = 0.008) and working distance (r = 0.522, p = 0.002). Text zoom was also associated with horizontal (toric: r = 0.898, p < 0.001; sphere: r = 0.880, p < 0.001) and vertical scrolling (toric: r = 0.857, p < 0.001; sphere: r = 0.846, p < 0.001). There was a significant negative association between the selection of text contrast and zoom (toric: r = -0.417, p = 0.0141; sphere: r = -0.385, p = 0.025).

Conclusion: Real-world task performance allows more robust assessment of visual function than standard visual metrics alone. Digital technology offers the opportunity to better understand the impact of different vision correction options on real-world task performance.
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http://dx.doi.org/10.1111/cxo.13138DOI Listing
January 2021

Integration of paper microfluidic sensors into contact lenses for tear fluid analysis.

Lab Chip 2020 11 18;20(21):3970-3979. Epub 2020 Sep 18.

Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.

In this article, using the integration of paper microfluidics within laser-inscribed commercial contact lenses, we demonstrate the multiplexed detection of clinically relevant analytes including hydrogen ions, proteins, glucose, nitrites and l-ascorbic acid, all sampled directly from model tears. In vitro measurements involved the optimization of colorimetric assays, with readouts collected, stored and analyzed using a bespoke Tears Diagnostics smartphone application prototype. We demonstrate the potential of the device to perform discrete measurements either for medical diagnosis or disease screening in the clinic or at the point-of-care (PoC), with future applications including monitoring of ocular infections, uveitis, diabetes, keratopathies and assessing oxidative stress.
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http://dx.doi.org/10.1039/d0lc00438cDOI Listing
November 2020

Corneoscleral Topography Measured with Fourier-based Profilometry and Scheimpflug Imaging.

Optom Vis Sci 2020 09;97(9):766-774

Ophthalmic Research Group, Life and Health Sciences, Aston University, Birmingham, United Kingdom.

Significance: Precise measurement of corneoscleral topography makes a valuable contribution to the understanding of anterior eye anatomy and supports the fitting process of contact lenses. Sagittal height data, determined by newer noninvasive techniques, are particularly useful for initial scleral lens selection.

Purpose: The purpose of this study was to investigate the agreement and repeatability of Fourier-based profilometry and Scheimpflug imaging, in the measurement of sagittal height and toricity of the corneoscleral region.

Methods: Minimal (Minsag), maximal (Maxsag) sagittal height, toricity (Maxsag - Minsag), and the maximum possible measurement zone diameter of 38 subjects were compared using the Eye Surface Profiler (ESP; Eagle Eye, Houten, the Netherlands) and the corneoscleral profile module of the Pentacam (Oculus, Wetzlar, Germany) at two different sessions. Correlations between the instruments were analyzed using the Pearson coefficient. Differences between sessions and instruments were analyzed using Bland-Altman and paired t tests.

Results: For an equal chord length, the measurement with Pentacam was significantly greater for Minsag (344 μm; 95% confidence interval [CI], 322 to 364 μm; P < .001) and significantly greater for Maxsag (280 μm; 95% CI, 256 to 305 μm; P < .001), but significantly smaller for toricity (-63 μm; 95% CI, -95 to -31 μm; P < .001). Maximum possible measurement zone diameter with ESP (16.4 ± 1.3 mm) was significantly greater than with Pentacam (14.8 ± 1.1 mm) (P < .001). Repeated measurements from session 1 and session 2 were not significantly different for Pentacam and ESP (P = .74 and P = .64, respectively). The 95% CIs around differences indicate good repeatability for Pentacam (mean difference, -0.9 μm; 95% CI, -6.7 to 4.8 μm) and ESP (4.6 μm; -22.4 to 31.6).

Conclusions: Although both instruments deliver useful data especially for the fitting of scleral and soft contact lenses, the sagittal height and the toricity measurements cannot be considered as interchangeable.
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http://dx.doi.org/10.1097/OPX.0000000000001572DOI Listing
September 2020

Effect of Scleral Lens Oxygen Permeability on Corneal Physiology.

Optom Vis Sci 2020 09;97(9):669-675

Ophthalmic Research Group, Aston University, Birmingham, United Kingdom.

Significance: This randomized, masked, crossover clinical study identifies that ≥125 Dk materials should be used for scleral lens daily wear if disruption to corneal oxygen is to be minimized.

Purpose: Modern scleral lens use has increased and has proven to be successful where other types and materials have previously failed. Although the required oxygen permeability has been modeled, this has not been established clinically.

Methods: Fifteen masked participants aged 20.7 ± 2.3 years (10 female) were bilaterally fitted with five different scleral lenses (65, 100, 125, 163, and 180+ Dk) of the same shape profile and one soft silicone hydrogel lens compared with no lens wear on separate occasions in a randomized order. A masked researcher measured corneal thickness and fluid reservoir depth, corneal curvature, objective bulbar and limbal redness, corneal biomechanics, and ocular surface oxygen consumption before and after 8 hours of wear. In addition, comfort scores were obtained using a visual analog scale.

Results: Scleral lenses with oxygen permeability of 65 Dk resulted in greater corneal thickness (1.37 ± 1.25%) after 8 hours of wear versus ≥100 Dk materials (0.58 ± 0.99%; F = 17.215, P < .001) because of stromal thickening; edema with ≥100 Dk materials was associated with fluid reservoir depth (r = 0.231, P = .05). Fluid reservoir depth decreased similarly with all oxygen-permeable lenses from 325.6 ± 99.1 μm to 174.2 ± 100.8 μm after 8 hours of wear (F = 0.961, P = .44). Oxygen consumption reduced with ≤125 Dk lenses (χ = 604.196, P < .001). Soft and scleral lens wear had no effect on corneal curvature, corneal biomechanics, or ocular hyperemia (P > .05). Soft lenses were more comfortable than all the scleral lenses (P < .05), and the 180+ Dk lenses had the best comfort among the sclerals (P < .05).

Conclusions: A ≥125 Dk is advised for safe scleral lens daily wear. Scleral lens wear leads to an increase in corneal thickness, regardless of lens-material oxygen permeability because of the fluid reservoir depth.
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http://dx.doi.org/10.1097/OPX.0000000000001557DOI Listing
September 2020