BCLA CLEAR presbyopia: Mechanism and optics.

With over a billion adults worldwide currently affected, presbyopia remains a ubiquitous, global problem. Despite over a century of study, the precise mechanism of ocular accommodation and presbyopia progression remains a topic of debate. Accordingly, this narrative review outlines the lenticular and extralenticular components of accommodation together with the impact of age on the accommodative apparatus, neural control of accommodation, models of accommodation, the impact of presbyopia on retinal image quality, and both historic and contemporary theories of presbyopia.

BCLA CLEAR Presbyopia: Definitions.

Presbyopia is often the first sign of ageing experienced by humans. Standardising terminology and adopting it across the BCLA CLEAR Presbyopia reports, improves consistency in the communication of the evidence-based understanding of this universal physiological process. Presbyopia can be functionally and psychologically debilitating, especially for those with poor access to eyecare. Presbyopia was defined as occurring when the physiologically normal age-related reduction in the eye's focusing range reaches a point that, when optimally corrected for far vision, the clarity of vision at near is insufficient to satisfy an individual's requirements. Accommodation is the change in optical power of the eye due to a change in crystalline lens shape and position, whereas pseudo-accommodation is the attainment of functional near vision in an emmetropic or far-corrected eye without changing the refractive power of the eye. Other definitions specific to vision and lenses for presbyopia were also defined. It is recommended that these definitions be consistently adopted in order to standardise future research, clinical evaluations and education.

Utility of artificial intelligence-based large language models in ophthalmic care.

PURPOSE: With the introduction of ChatGPT, artificial intelligence (AI)-based large language models (LLMs) are rapidly becoming popular within the scientific community. They use natural language processing to generate human-like responses to queries. However, the application of LLMs and comparison of the abilities among different LLMs with their human counterparts in ophthalmic care remain under-reported. RECENT FINDINGS: Hitherto, studies in eye care have demonstrated the utility of ChatGPT in generating patient information, clinical diagnosis and passing ophthalmology question-based examinations, among others. LLMs' performance (median accuracy, %) is influenced by factors such as the iteration, prompts utilised and the domain. Human expert (86%) demonstrated the highest proficiency in disease diagnosis, while ChatGPT-4 outperformed others in ophthalmology examinations (75.9%), symptom triaging (98%) and providing information and answering questions (84.6%). LLMs exhibited superior performance in general ophthalmology but reduced accuracy in ophthalmic subspecialties. Although AI-based LLMs like ChatGPT are deemed more efficient than their human counterparts, these AIs are constrained by their nonspecific and outdated training, no access to current knowledge, generation of plausible-sounding 'fake' responses or hallucinations, inability to process images, lack of critical literature analysis and ethical and copyright issues. A comprehensive evaluation of recently published studies is crucial to deepen understanding of LLMs and the potential of these AI-based LLMs. SUMMARY: Ophthalmic care professionals should undertake a conservative approach when using AI, as human judgement remains essential for clinical decision-making and monitoring the accuracy of information. This review identified the ophthalmic applications and potential usages which need further exploration. With the advancement of LLMs, setting standards for benchmarking and promoting best practices is crucial. Potential clinical deployment requires the evaluation of these LLMs to move away from artificial settings, delve into clinical trials and determine their usefulness in the real world.

Assessing the utility of ChatGPT as an artificial intelligence-based large language model for information to answer questions on myopia.

PURPOSE: ChatGPT is an artificial intelligence language model, which uses natural language processing to simulate human conversation. It has seen a wide range of applications including healthcare education, research and clinical practice. This study evaluated the accuracy of ChatGPT in providing accurate and quality information to answer questions on myopia. METHODS: A series of 11 questions (nine categories of general summary, cause, symptom, onset, prevention, complication, natural history, treatment and prognosis) were generated for this cross-sectional study. Each question was entered five times into fresh ChatGPT sessions (free from influence of prior questions). The responses were evaluated by a five-member team of optometry teaching and research staff. The evaluators individually rated the accuracy and quality of responses on a Likert scale, where a higher score indicated greater quality of information (1: very poor; 2: poor; 3: acceptable; 4: good; 5: very good). Median scores for each question were estimated and compared between evaluators. Agreement between the five evaluators and the reliability statistics of the questions were estimated. RESULTS: Of the 11 questions on myopia, ChatGPT provided good quality information (median scores: 4.0) for 10 questions and acceptable responses (median scores: 3.0) for one question. Out of 275 responses in total, 66 (24%) were rated very good, 134 (49%) were rated good, whereas 60 (22%) were rated acceptable, 10 (3.6%) were rated poor and 5 (1.8%) were rated very poor. Cronbach's α of 0.807 indicated good level of agreement between test items. Evaluators' ratings demonstrated 'slight agreement' (Fleiss's κ, 0.005) with a significant difference in scoring among the evaluators (Kruskal-Wallis test, p < 0.001). CONCLUSION: Overall, ChatGPT generated good quality information to answer questions on myopia. Although ChatGPT shows great potential in rapidly providing information on myopia, the presence of inaccurate responses demonstrates that further evaluation and awareness concerning its limitations are crucial to avoid potential misinterpretation.

New insights in presbyopia: impact of correction strategies.

Presbyopia occurs when the physiologically normal age-related reduction in the eyes focusing range reaches a point, when optimally corrected for distance vision, that the clarity of vision at near is insufficient to satisfy an individual's requirements. Hence, it is more about the impact it has on an individual's visual ability to function in their environment to maintain their lifestyle than a measured loss of focusing ability. Presbyopia has a significant impact on an individual's quality of life and emotional state. While a range of amelioration strategies exist, they are often difficult to access in the developing world and prescribing is generally not optimal even in developed countries. This review identified the need for a standardised definition of presbyopia to be adopted. An appropriate battery of tests should be applied in evaluating presbyopic management options and the results of clinical trials should be published (even if unsuccessful) to accelerate the provision of better outcomes for presbyopes.

Effect of peripheral defocus on axial growth and modulation of refractive error in children with anisohyperopia.

PURPOSE: To establish whether axial growth and refractive error can be modulated in anisohyperopic children by imposing relative peripheral hyperopic defocus (RPHD) using multifocal soft contact lenses. METHODS: This study is a prospective, controlled paired-eye study with anisohyperopic children. Axial growth and refractive error were observed without intervention for the first 6 months of the 3-year trial with participants wearing single vision spectacles. Then, participants wore a centre-near, multifocal, soft contact lens (+2.00 D add) in their more hyperopic eye for 2 years, with a single vision contact lens worn in the fellow eye if required. The 'centre-near' portion of the contact lens in the more hyperopic eye corrected distance refractive error while the 'distance' portion imposed hyperopic defocus in the peripheral retina. Participants reverted to single vision spectacles for the final 6 months. RESULTS: Eleven participants, mean age of 10.56 years (SD 1.43; range 8.25-13.42), completed the trial. No increase in axial length (AL) was found during the first 6 months in either eye (p > 0.99). Axial growth across the 2-year intervention period was 0.11 mm (SEM 0.03; p = 0.06) in the test eye versus 0.15 mm (SEM 0.03; p = 0.003) in the control eye. AL was invariant during the final 6 months in both eyes (p > 0.99). Refractive error was stable during the first 6 months in both eyes (p = 0.71). Refractive error change across the 2-year intervention period was -0.23 D (SEM 0.14; p = 0.32) in the test eye versus -0.30 D (SEM 0.14; p = 0.61) in the control eye. Neither eye demonstrated a change in refractive error during the final 6 months (p > 0.99). CONCLUSIONS: Imposing RPHD using the centre-near, multifocal, contact lens specified here did not accelerate axial growth nor reduce refractive error in anisohyperopic children.

Ciliary Muscle Dimension Changes With Accommodation Vary in Myopia and Emmetropia.

Purpose: The purpose of this study was to determine whether accommodation-induced changes in ciliary muscle dimensions vary between emmetropes and myopes, and the effect of the image analysis method. Methods: Seventy adults aged 18 to 27 years consisted of 25 people with emmetropia (spherical equivalent refraction [SER] +0.21 ± 0.36 diopters [D]) and 45 people with myopia (-2.84 ± 1.72 D). There were 23 people with low myopia (>-3 D) and 22 people with moderate myopia (-3 to -6 D). Right eye ciliary muscles were imaged (Visante OCT; Carl Zeiss Meditec) at 0 D and 6 D demands. Measures included ciliary muscle length (CML), ciliary muscle curved length (CMLarc), maximum ciliary muscle thickness (CMTmax), CMT1, CMT2, and CMT3 (fixed distances 1-3 mm from the scleral spur), CM25, CM50, and CM75 (proportional distances 25%-75%). Linear mixed model analysis determined effects of refractive groups, race, and demand on dimensions. Significance was set at P < 0.05. Results: Myopic eyes had greater CML and CMLarc nasally than emmetropic eyes. Myopic eyes had thicker muscles than emmetropic eyes at nasal positions, except CM25 and CMT3, and at CM75 temporally. During accommodation and only nasally, CML reduced in emmetropic and myopic eyes, and CMLarc reduced in myopic eyes only. During accommodation, both nasally and temporally, muscles thickened anteriorly (CMT1 and CM25) and thinned posteriorly (CMT3 and CM75) except for temporal CM75. Moderate myopic eyes had greater temporal CMLarc than low myopic eyes, and the moderate myopes had thicker muscles both nasally and temporally using fixed and proportional distances. Conclusions: People with myopia had longer and thicker ciliary muscles than people with emmetropia. During accommodation, the anterior muscle thickened and the curved nasal muscle length shortened, more in myopic than in emmetropic eyes. The fixed distance method is recommended for repeat measures in the same individual. The proportional distance method is recommended for comparisons between refractive groups.

The effect of peripheral defocus on axial growth and modulation of refractive error in hyperopes.

PURPOSE: To establish whether axial growth and refractive error can be modulated in hyperopic children by imposing relative peripheral hyperopic defocus using multifocal soft contact lenses. METHODS: A prospective controlled study with hyperopic participants allocated to a control or test group. Control group participants were corrected with single vision spectacles and changes to axial length and refractive error were followed for 3 years. For the test group, axial growth and post-cycloplegic refractive error were observed with participants wearing single vision spectacles for the first 6 months of the trial and then corrected with centre-near multifocal soft contact lenses with a 2.00 D add for 2 years. The central 'near' portion of the contact lens corrected distance refractive error while the 'distance' portion imposed hyperopic defocus. Participants reverted to single vision spectacles for the final 6 months of the study. RESULTS: Twenty-two participants, mean age 11.13 years (SD 1.72) (range 8.33-13.92), completed the trial. Axial length did not change during the first 6 months in either group (p = 1.00). Axial growth across the 2-year intervention period was 0.17 mm (SEM 0.04) (p < 0.0005) in the test group versus 0.06 mm (SEM 0.07) (p = 0.68) in the control group. Axial length was invariant during the final 6 months in either group (p = 1.00). Refractive error was stable during the first 6 months in both groups (p = 1.00). Refractive error change across the 2-year intervention period was -0.26 D (SEM 0.14) (p = 0.38) in the test group versus -0.01 D (SEM 0.09) (p = 1.00) in the control group. Neither the test (p = 1.00) nor control (p = 0.63) group demonstrated a change in refractive error during the final 6 months. CONCLUSIONS: The rate of axial growth can be accelerated in children with hyperopia using centre-near multifocal soft contact lenses.

The efficacy of multifocal soft contact lenses for the alleviation of asthenopic symptoms in myopes with accommodative lag.

PURPOSE: To evaluate the efficacy of multifocal soft contact lenses to reduce asthenopic symptoms in myopes with accommodative lag. METHODS: Twenty-four myopic participants, aged 18-35 years, with mean spherical equivalent (MSE) of ≤ -0.75D, were recruited in a randomised, double-blind crossover study. All participants were existing contact lens wearer with near orthophoria or esophoria, presenting with subjective asthenopic symptoms at baseline [Convergence Insufficiency Symptom Survey (CISS) score ≥ 21] and a lag of accommodation ≥ +0.75 D. All participants were initially fitted with single vision contact lenses for a one month period. Participants were then randomly assigned 1:1 to wear low add or high add multifocal soft contact lenses for a further month. After this period, the groups were reversed. Data were collected at baseline and following one month's wear of each lens. Change in CISS score was evaluated as the primary outcome measure, while secondary outcome measures were changes in accommodative lag and heterophoria status. RESULTS: Baseline CISS score was (mean ± SD) 25.04 ± 4.58. Post-intervention scores were as follows: single vision: 24.46 ± 4.59, low add: 12.17 ± 6.89, high add: 13.71 ± 7.23. Both low add and high add multifocal soft contact lens wear was associated with an improvement in CISS score compared to baseline CISS and single vision (all p < 0.01). No significant difference was found between the CISS score for the baseline CISS and single vision (p = 1.00). No significant difference was found in lag of accommodation between lens conditions (all p > 0.05), however, there was an exophoric shift in near heterophoria between single vision and both multifocal contact lenses (low add: (mean difference 1.33 Δ, p = 0.02; high add: mean difference 1.23 Δ, p = 0.02) but not between habitual spectacle or any other modality (all p > 0.05). CONCLUSIONS: The use of multifocal soft contact lenses for a one-month period was associated with reduced severity of asthenopic symptoms in pre-presbyopic myopes with accommodative lag. Whilst improvement of symptoms does not appear to be mediated by a significant reduction in accommodative lag, changes in heterophoria may play a role in reducing asthenopic symptoms.

Characterisation and Modelling of an Artificial Lens Capsule Mimicking Accommodation of Human Eyes.

A synthetic material of silicone rubber was used to construct an artificial lens capsule (ALC) in order to replicate the biomechanical behaviour of human lens capsule. The silicone rubber was characterised by monotonic and cyclic mechanical tests to reveal its hyper-elastic behaviour under uniaxial tension and simple shear as well as the rate independence. A hyper-elastic constitutive model was calibrated by the testing data and incorporated into finite element analysis (FEA). An experimental setup to simulate eye focusing (accommodation) of ALC was performed to validate the FEA model by evaluating the shape change and reaction force. The characterisation and modelling approach provided an insight into the intrinsic behaviour of materials, addressing the inflating pressure and effective stretch of ALC under the focusing process. The proposed methodology offers a virtual testing environment mimicking human capsules for the variability of dimension and stiffness, which will facilitate the verification of new ophthalmic prototype such as accommodating intraocular lenses (AIOLs).

An Artificial Lens Capsule with a Lens Radial Stretching System Mimicking Dynamic Eye Focusing.

Presbyopia is a common eye disorder among aged people which is attributed to the loss of accommodation of the crystalline lens due to the increasing stiffness. One of the potential techniques to correct presbyopia involves removing the lens substance inside the capsule and replacing it with an artificial lens. The development of such devices, e.g., accommodating intraocular lenses (AIOLs), relies on the understanding of the biomechanical behaviour of the lens capsule and the essential design verification ex vivo. To mimic the eye's dynamic focusing ability (accommodation), an artificial lens capsule (ALC), from silicone rubber accompanied by a lens radial stretching system (LRSS) was developed. The ALC was manufactured to offer a dimension and deforming behaviour replicating the human lens capsule. The LRSS was calibrated to provide a radial stretch simulating the change of diameter of capsules during accommodating process. The biomechanical function of the ALC was addressed by studying its evolution behaviour and reaction force under multiaxial stretch from the LRSS. The study highlighted the convenience of this application by performing preliminary tests on prototypes of ophthalmic devices (e.g., AIOLs) to restore accommodation.

IMI Accommodation and Binocular Vision in Myopia Development and Progression.

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.

Accommodative dynamics and attention: the influence of manipulating attentional capacity on accommodative lag and variability.

PURPOSE: There is evidence that attention can modulate ocular dynamics, but its effects on accommodative dynamics have yet to be fully determined. We investigated the effects of manipulating the capacity to focus on task-relevant stimuli, using two levels of dual-tasking (arithmetic task) and auditory feedback, on the accommodative dynamics at three different target distances (500, 40 and 20 cm). METHODS: The magnitude and variability of the accommodative response were objectively measured in 20 healthy young adults using the Grand Seiko WAM-5500 autorefractor. In randomised order, participants fixated on a Maltese cross while 1) performing an arithmetic task with two levels of complexity (low and high mental load); 2) being provided with two levels of auditory feedback (low and high feedback); and 3) without performing any mental task or receiving feedback (control). Accommodative and pupil dynamics were monitored for 90 seconds during each of the 15 trials (5 experimental conditions x 3 target distances). RESULTS: The lag of accommodation was sensitive to the attentional state (p = 0.001), where a lower lag of accommodation was observed for the high feedback condition compared to the control (corrected p-value = 0.009). The imposition of mental load while fixating on a distant target led to a greater accommodative response (corrected p-value = 0.010), but no effects were found for the near targets. There was a main effect of the experimental manipulation on the accommodative variability (p < 0.001), with the use of auditory feedback improving the accuracy of the accommodative system. CONCLUSIONS: Our data show that accommodative dynamics is affected by varying the capacity to focus on task-relevant stimuli, observing an improvement in accommodative stability and response with auditory feedback. These results highlight an association between attention and ocular dynamics and provide new insight into the control of accommodation.

Long-term efficacy and safety of solifenacin in pediatric patients aged 6 months to 18 years with neurogenic detrusor overactivity: results from two phase 3 prospective open-label studies.

INTRODUCTION: The standard recommended treatment for neurogenic detrusor overactivity (NDO) is clean intermittent catheterization combined with an antimuscarinic agent. However, the adverse systemic side-effects of oxybutynin, the most widely used agent, are of concern. OBJECTIVE: To evaluate the efficacy and safety of solifenacin in pediatric patients with NDO, aged 6 months-<5 years and 5-<18 years. STUDY DESIGN: Two open-label, baseline-controlled, phase 3 studies were conducted in pediatric patients with NDO. Patients were treated with sequential doses of solifenacin oral suspension (pediatric equivalent doses 2.5-10 mg) for 12 weeks to determine each patient's optimal dose, followed by a fixed dose ≥40-week treatment period. Primary efficacy endpoint was change from baseline in maximum cystometric capacity (MCC) after 24 weeks. Secondary endpoints included bladder compliance, bladder volume until first detrusor contraction (>15 cmH2O), number of overactive detrusor contractions (>15 cmH2O), maximum catheterized volume (MCV)/24 h, and incontinence episodes/24 h. Safety parameters were treatment-emergent adverse events (TEAEs), serious adverse events, laboratory variables, vital signs, electrocardiograms, and ocular accommodation and cognitive function assessments. RESULTS: After 24 weeks, MCC had significantly increased compared with baseline in patients aged 6 months -<5 years and 5-<18 years (37.0 ml and 57.2 ml, respectively; P < 0.001; Fig.). Improvement was also observed after 52 weeks' treatment. Significant changes were observed from baseline to week 24 in all secondary endpoints in both age groups: increase in bladder compliance, increase in bladder volume to first detrusor contraction as a percentage of expected bladder capacity, reduction in the number of overactive detrusor contractions, increase in MCV, and decreased incontinence episodes. TEAEs were mostly mild or moderate, and there were no new drug-related TEAEs compared with adult studies. Age-related improvements were noted in ocular accommodation and cognitive function. DISCUSSION: These long-term multicenter investigations demonstrated the efficacy and safety of solifenacin in pediatric patients with NDO. The observed increases in MCC were clinically relevant and demonstrated that an increase in fluid volume can be accommodated in the bladder prior to reaching intravesical pressures that endanger kidney function and/or are associated with leakage or discomfort. Solifenacin was well tolerated with low incidences of constipation and dry mouth (typically associated with antimuscarinics), central nervous system-related side-effects, and facial flushing. CONCLUSION: Solifenacin was effective and well tolerated in pediatric patients with NDO, aged 6 months-<18 years, suggesting that it is a viable alternative to oxybutynin, the current standard of care. STUDIES ARE REGISTERED AT CLINICALTRIALS.GOV: NCT01981954 and NCT01565694.

Effects of Optical Correction Method on the Magnitude and Variability of Accommodative Response: A Test-retest Study.

SIGNIFICANCE: The present study addresses the accommodative response and its dependence on the type of optical correction used. The results are discussed relative to their possible implications for myopia progression and visual fatigue. PURPOSE: The accommodative response has been investigated owing to its possible relationship with the onset and progression of myopia and visual fatigue. This study explored the influence of wearing soft contact lenses in comparison with spectacles in terms of magnitude and variability of accommodation. In addition, we analyzed the intersession and intermethod repeatability. METHODS: Dynamic accommodative response was recorded during 30-second epochs, at five different distances (50, 40, 33, 25, and 20 cm), in 21 individuals (mean refractive error ± SD, -0.79 ± 1.39 D) while wearing either soft contact lenses or spectacles on two different days. To assess repeatability, a second identical intervention was conducted. RESULTS: Higher lags of accommodation were obtained with the use of soft contact lenses in comparison with the spectacle condition (P = .04, partial η [ηp] = 0.204), and similarly, a higher variability of accommodation at near distances was found during the soft contact lens measurement (P < .001, ηp = 0.647). There was a strong intersession repeatability at all the distances tested for both optical correction methods. CONCLUSIONS: The higher accommodative lag and fluctuations found while wearing soft contact lenses in comparison with spectacles may help to understand the mechanisms underlying myopia progression and asthenopia. These findings may be also considered when testing the accommodative response in research settings. Our test-retest design confirmed that there is a very good intersession repeatability for all the distances in both optical correction methods.

Presbyopia: Effectiveness of correction strategies.

Presbyopia is a global problem affecting over a billion people worldwide. The prevalence of unmanaged presbyopia is as high as 50% of those over 50 years of age in developing world populations, due to a lack of awareness and accessibility to affordable treatment, and is even as high as 34% in developed countries. Definitions of presbyopia are inconsistent and varied, so we propose a redefinition that states "presbyopia occurs when the physiologically normal age-related reduction in the eye's focusing range reaches a point, when optimally corrected for distance vision, that the clarity of vision at near is insufficient to satisfy an individual's requirements". Strategies for correcting presbyopia include separate optical devices located in front of the visual system (reading glasses) or a change in the direction of gaze to view through optical zones of different optical powers (bifocal, trifocal or progressive addition spectacle lenses), monovision (with contact lenses, intraocular lenses, laser refractive surgery and corneal collagen shrinkage), simultaneous images (with contact lenses, intraocular lenses and corneal inlays), pinhole depth of focus expansion (with intraocular lenses, corneal inlays and pharmaceuticals), crystalline lens softening (with lasers or pharmaceuticals) or restored dynamics (with 'accommodating' intraocular lenses, scleral expansion techniques and ciliary muscle electrostimulation); these strategies may be applied differently to the two eyes to optimise the range of clear focus for an individual's task requirements and minimise adverse visual effects. However, none fully overcome presbyopia in all patients. While the restoration of natural accommodation or an equivalent remains elusive, guidance is given on presbyopic correction evaluation techniques.

Effect of Peripheral Defocus on Axial Eye Growth and Modulation of Refractive Error in Hyperopes: Protocol for a Nonrandomized Clinical Trial.

BACKGROUND: Hyperopia occurs due to insufficient ocular growth and a failure to emmetropize in childhood. In anisohyperopia, it is unclear why one eye may remain hyperopic while the fellow eye grows toward an emmetropic state. Animal studies have shown that manipulating peripheral defocus through optical means while simultaneously providing correct axial focus can either discourage or encourage axial eye growth to effectively treat myopia or hyperopia, respectively. Myopia progression and axial eye growth can be significantly reduced in children and adolescents through the use of multifocal contact lenses. These contact lenses correct distance central myopia while simultaneously imposing relative peripheral myopic defocus. The effect of correcting distance central hyperopia while simultaneously imposing relative peripheral hyperopic defocus is yet to be elucidated in humans. OBJECTIVE: The objective of our study is to understand the natural progression of axial eye growth and refractive error in hyperopes and anisohyperopes and to establish whether axial eye growth and refractive error can be modified using multifocal contact lenses in hyperopes and anisohyperopes. METHODS: There are 3 elements to the program of research. First, the natural progression of axial eye growth and refractive error will be measured in spectacle-wearing hyperopic and anisohyperopic subjects aged between 5 and <20 years. In other words, the natural growth of the eye will be followed without any intervention. Second, as a paired-eye control study, anisohyperopes aged between 8 and <16 years will be fitted with a center-near multifocal design contact lens in their more hyperopic eye and a single-vision contact lens in the fellow eye if required. The progression of axial eye growth and refractive error will be measured and compared. Third, subjects aged between 8 and <16 years with similar levels of hyperopia in each eye will be fitted with center-near multifocal design contact lenses in each eye; the progression of axial eye growth and refractive error in these subjects will be measured and compared with those of subjects in the natural progression study. RESULTS: Recruitment commenced on 6 June 2016 and was completed on 8 April 2017. We estimate the data collection to be completed by April 2020. CONCLUSIONS: This trial will establish whether axial eye growth can be accelerated in children with hyperopia by imposing relative peripheral hyperopic defocus using center-near multifocal contact lenses. TRIAL REGISTRATION: ClinicalTrials.gov NCT02686879; https://clinicaltrials.gov/ct2/show/NCT02686879 (Archived by Webcite at http://www.webcitation.org/71o5p3fD2). REGISTERED REPORT IDENTIFIER: RR1-10.2196/9320.

Optical Coherence Tomography Reveals Sigmoidal Crystalline Lens Changes during Accommodation.

This study aimed to quantify biometric modifications of the anterior segment (AS) during accommodation and to compare them against changes in both accommodative demand and response. Thirty adults, aged 18-25 years were rendered functionally emmetropic with contact lenses. AS optical coherence tomography (AS-OCT) images were captured along the 180° meridian (Visante, Zeiss Meditec, Jena, Germany) under stimulated accommodative demands (0-4 D). Images were analysed and lens thickness (LT) was measured, applying a refractive index correction of 1.00. Accommodative responses were also measured sequentially through a Badal optical system fitted to an autorefractor (Shin Nippon NVision-K 5001, Rexxam, Japan). Data were compared with Dubbelman schematic eye calculations. Significant changes occurred in LT, anterior chamber depth (ACD), lens centroid (i.e., ACD + LT/2), and AS length (ASL = ACD + LT) with accommodation (all p < 0.01). There was no significant change in CT with accommodation (p = 0.81). Measured CT, ACD, and lens centroid values were similar to Dubbelman modelled parameters, however AS-OCT overestimated LT and ASL. As expected, the accommodative response was less than the demand. Interestingly, up until approximately 1.5 D of response (2.0 D demand), the anterior crystalline lens surface appears to be the primary correlate. Beyond this point, the posterior lens surface moves posteriorly resulting in an over-all sigmoidal trajectory. he posterior crystalline lens surface demonstrates a sigmoidal response with increasing accommodative effort.

Effect of contact lens surface properties on comfort, tear stability and ocular physiology.

AIM: Retrospective analysis of different contact lens wearing groups suggests lens surface lubricity is the main factor influencing contact lens comfort. However, the examined commercially available contact lenses differ in material and design as well as surface properties. Hence this study isolates the contribution of lens surface properties using an ultra-thin coating technology. METHODS: Nineteen habitual contact lens wearers (21.6±1.7years) wore formofilcon B soft monthly disposable contact lenses with and without coating technology modified surface properties for a month each in a randomised double-masked cross-over study. OBJECTIVE NON-INVASIVE: breakup time (NIKBUT), NIKBUT average and ocular redness (Jenvis grading scale) were evaluated (Keratograph 5M) after 1 week and 1 month of wear. Symptoms were assessed using the Contact Lens Dry Eye Questionnaire (CLDEQ-8); perceived vision quality and subjective lens comfort at insertion, mid-day and end of the day were rated with four Visual Analog Scales. RESULTS: Perceived visual quality (F=5.049,p=0.037), contact lens dry eye symptoms (F=14.408,p=0.001) and subjective lens comfort (F=28.447,p<0.001) were better for coated compared to uncoated lenses. The surface coating postponed the lens dewetting (F=8.518,p=0.009) and increased the pre-lens tear film stability (F=5.626,p=0.029), but bulbar (F=0.340,p=0.567) and limbal (F=0.110,p=0.744) redness were similar for both contact lenses. No parameter changed significantly between a weeks' and months' wear (p>0.05). Lens surface wettability and ocular redness were not correlated to changes in symptoms (p>0.05). CONCLUSION: As previously hypothesised, enhancing the physical surface properties of a soft contact lens improves subjectively rated wearer comfort, which, in turn, should result in reduced contact lens discontinuation.