Design and development of a noninvasive ocular pressure estimator.

SIGNIFICANCE: A snapshot intraocular pressure (IOP) is ineffective in identifying the IOP peak and fluctuation, especially during sleep. Because IOP variability plays a significant role in the progression of glaucoma, monitoring the IOP, especially during sleep, is essential to capture the dynamic nature of IOP. PURPOSE: We aimed to design an ocular pressure estimator (OPE) that can reliably and accurately measure the IOP noninvasively over closed-eyelid condition. METHODS: Ocular pressure estimator works on the principle that the external pressure applied by raising the IOP of the eyeball is transmitted through a compressible septum to the pressure sensor, thus recording the IOP. A fluid-filled pouch with a pressure sensor was placed over a rubber glove mimicking the eyelid (septum), covering the cornea of enucleated goat eyeballs. A pressure-controlled setup was connected to a goat cadaver eye, which was validated by a rebound tonometer. Cannulation of eyeballs through the lower limbus had the least difference from the control setup values documented using rebound tonometer, compared with cannulation through the optic nerve. Intraocular pressures ranging from 3 to 30 mmHg was induced, and the outputs recorded using OPE were amplified and recorded for 10 minutes (n = 10 eyes). We stratified the randomization of the number of times and the induced pressures. RESULTS: The measurements recorded were found to be linear when measured against an IOP range of 3 to 30 mmHg. The device has excellent reliability (intraclass correlation coefficient, 0.998). The repeatability coefficient and coefficient of variations were 4.24 (3.60 to 4.87) and 8.61% (7.33 to 9.90), respectively. The overall mean difference ± SD between induced IOP and the OPE was 0.22 ± 3.50 (95% confidence interval, -0.35 to 0.79) mmHg across all IOP ranges. CONCLUSIONS: Ocular pressure estimator offers a promising approach for reliably and accurately measuring IOP and its fluctuation noninvasively under a condition mimicking a closed eye.

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.

Relationship between Diurnal Variation in Intraocular Pressure and Central Corneal Power.

SIGNIFICANCE: Relationship between intraocular pressure (IOP) change and central corneal curvature is complicated by measurement techniques and corneal biomechanical parameters. Findings from this study indicate that it is worthwhile to observe the association between diurnal change in IOP and corneal power. PURPOSE: This study aimed to investigate the relationship between the diurnal change in IOP and central corneal power among eyes with and without myopia. METHODS: Sixty healthy eyes of 24 emmetropes and 36 myopes were recruited for this cross-sectional study. Both anterior and posterior central corneal powers of the steep (Ks), flat (Kf), mean meridian (Km), best-fit spheres, and central corneal thickness were recorded followed by the IOP (Goldmann-correlated IOP [IOPg] and corneal-compensated IOP) and corneal biomechanics (corneal hysteresis and corneal resistance factor). Measurements were obtained every 3 hours from 9.30 am to 6.30 pm . Linear-mixed model was used to determine the relationship between the change in IOP and the associated change in corneal measurements (adjusted for age, sex, refractive error, central corneal thickness, and biomechanics) among the myopic and nonmyopic eyes. RESULTS: Group mean, amplitude of change, and the diurnal change in IOPg were (mean ± standard deviation) 15.14 ± 2.50, 3.33 ± 1.44, and 1.81 ± 1.25 mmHg, respectively. Overall, an IOP increase was associated with a decrease in the adjusted anterior corneal powers. Myopic eyes were associated with a decrease of 0.04 D (95% confidence interval [CI], 0.07 to 0.01 D; P = .02) in Ks and 0.03 D (95% CI, 0.06 to 0.001 D; P = .047) in Kf per mmHg increase in IOP, whereas for emmetropes, per mmHg increase in IOP only flattened the Kf by 0.03 D (95% CI, 0.06 to 0.004 D; P = .02). CONCLUSIONS: Change in anterior corneal power was inversely related to the change in IOPg, with myopic and nonmyopic eyes reporting a significant but differential impact of IOP. Clinicians must keep in mind the impact of large IOP fluctuation on the anterior corneal power.

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.

Small Peptidic Ionophore for Calcium Transport.

Synthetic calcium transporters are few despite their potential biological significance. Herein, we report small alanine-derived peptides containing pyridyl-triazole motifs for inducing calcium selectivity. The peptides are decorated with hydrophobic alkyl chains to facilitate membrane insertion. The most efficient peptide scaffold has an EC50 value of 0.09 mol % and functions as a calcium carrier.

Agreement and Repeatability of Corneal Thickness and Radius among Three Different Corneal Measurement Devices.

SIGNIFICANCE: Corneal refractive surgery screening, orthokeratology, and contact lens fitting require accurate estimation of the corneal thickness and curvature. We found that any of the imaging devices used in this study can be used to image a healthy myopic cornea, which is essential to screen for corneal ectasia. PURPOSE: This study aimed to compare agreement and repeatability of corneal thickness and radius measurements obtained using Scheimpflug imaging (Pentacam HR), swept-source optical coherence tomography (Casia SS-1000), and Placido-Scheimpflug tomography (Topographic Modeling System, version 5 [TMS-5]). METHODS: Sixty eyes of 60 subjects with myopia were measured with Casia, TMS-5, and Pentacam for their central corneal thickness (CCT), thinnest corneal thickness, central corneal radius of the steep meridian (Ks), central corneal radius of the flat meridian (Kf), mean central corneal radius (Km), and anterior and posterior best-fit spheres. Two readings were obtained from each instrument. Central corneal thickness was also measured with ultrasound pachymetry. Intraclass correlation coefficient, repeatability coefficient, and coefficient of variation were calculated. RESULTS: Repeatability coefficient, coefficient of variation, and intraclass correlation coefficient of CCT among the instruments ranged between 2.48 and 12.79, 0.17 and 0.86, and 0.98 and 1.00, respectively. Mean CCT measurements were similar between Casia, TMS-5, Pentacam, and ultrasound pachymetry (P = .13). Intraclass range of correlation for agreement was 0.95 to 0.99 for CCT among instruments. The range of 95% limits of agreement (LoAs) for ultrasound CCT was narrowest with Casia (31.94 µm). Casia-TMS-5 displayed a narrow range of 95% LoA for CCT (12.14 to -12.44), thinnest corneal thickness (12.31 to -11.31), and Ks (0.56 to -0.53), whereas Casia-Pentacam showed a narrow range of 95% LoA for Kf (0.56 to -0.42), Km (0.41 to -0.27), and anterior best-fit sphere (0.03 to -0.07). A significant difference in posterior best-fit sphere measurements was noted among all instruments (P = .01). CONCLUSIONS: Casia, TMS-5, and Pentacam can be used interchangeably to measure corneal thickness and radius measurement in healthy eyes. Casia had the best agreement with ultrasound pachymeter CCT and exhibited the highest repeatability.

Longitudinal Evaluation of the Structural and Functional Changes Associated with Glaucoma in Myopia.

SIGNIFICANCE: This study ascertains that myopia is a risk factor for glaucoma progression among eyes with primary open angle glaucoma. Myopic eyes with primary open angle glaucoma may benefit from measurement and incorporation of axial length information into clinical decision making. PURPOSE: The purpose of this study was to estimate the rate of change in retinal nerve fiber layer (RNFL) thickness and the rate of change in visual field of glaucoma patients with and without myopia. METHODS: We conducted a prospective, observational cohort study where we analyzed 245 eyes of 135 glaucoma patients followed for a mean period of 6.08 years. All the subjects had RNFL imaging and standard automated perimetry performed for both eyes in the same visit every 4 months for at least 60 months. RESULTS: The rate of change of average RNFL thickness and visual field index (VFI) was -0.29 µm/y (95% confidence interval, -1.80 to +1.23 µm/y) and -0.30%/y (95% confidence interval, -2.24 to +1.64%/y), respectively, after adjusting for age, axial length, IOP, baseline RNFL thickness, signal strength, and correlation between fellow eyes. Axial length, as a continuous variable, was not associated with the rates of change of average RNFL thickness and VFI. However, high myopic eyes with axial lengths of ≥26.0 and ≥26.5 mm had an average rate of change of RNFL thickness of 0.15 and 0.16 µm/y faster than eyes with axial lengths of less than 26 and 26.5 mm, respectively. Similarly, myopic eyes with an axial length of ≥26.5 mm were associated with a 0.21%/y faster rate of VFI reduction. CONCLUSIONS: Both RNFL and visual field progression rates are faster in myopic glaucomatous eyes with an axial length of ≥26.5 mm than in eyes <26.5 mm. However, the small difference that supports high myopia as a risk factor for progression does not indicate the clinical importance or significance of axial length.

Homocysteine & its metabolite homocysteine-thiolactone & deficiency of copper in patients with age related macular degeneration - A pilot study.

BACKGROUND & OBJECTIVES: Age related macular degeneration (ARMD) is a leading cause of blindness, particularly in persons above 60 yr of age. Homocysteine is implicated in many ocular diseases including ARMD. This study was undertaken to assess the status and relationship between plasma homocysteine, homocysteine - thiolactone, homocysteinylated protein and copper levels in patients with ARMD. METHODS: A total of 16 patients with ARMD and 16 age-matched controls were recruited for the study. Plasma glutathione, homocysteine, homocysteine - thiolactone and extent of homocysteine conjugation with proteins, copper and thiobarbituric acid reactive substances were measured. RESULTS: Homocysteine levels were elevated with increase in homocysteine-thiolactone, thiobarbituric acid reactive substances and a decrease of glutathione. The levels of homocysteinylated protein were elevated in ARMD. The elevated homocysteine, homocysteine-thiolactone correlated with the decrease in copper level. INTERPRETATION & CONCLUSIONS: Elevated homocysteine and its metabolite homocysteine-thiolactone and decreased levels of copper may play an important role in the pathogenesis of ARMD.

Circumventing aglycon transfer en route to the synthesis of pentasaccharide thioglycoside donor for the chain extension of Plesiomonas shigelloides strain 302-73 (serotype O1) repeating unit.

Herein we report a chemical synthesis of a pentasaccharide thioglycoside repeating unit of Plesiomonas shigelloides Strain 302-73 (Serotype O1), as a chain extension unit. In our synthetic endeavor we encountered multiple aglycon transfer reactions during glycosylations. This problem was obviated by employing a PMP group as a transient protecting group.

An Insight into Knowledge, Perspective, and Practices of Indian Optometrists towards Childhood Myopia.

The current understanding of clinical approaches and barriers in managing childhood myopia among Indian optometrists is limited. This research underscores the necessity and relevance of evidence-based practice guidelines by exploring their knowledge, attitude, and practice towards childhood myopia. A self-administered internet-based 26-item survey was circulated online among practicing optometrists in India. The questions assessed the demographics, knowledge, self-reported clinical practice behavior, barriers, source of information guiding their management, and extent of adult caregiver engagement for childhood myopia. Of 393 responses, a significant proportion of respondents (32.6-92.4%) were unaware of the ocular complications associated with high myopia, with less than half (46.5%) routinely performing ocular biometry in clinical practice. Despite the growing awareness of emerging myopia management options, the uptake remains generally poor, with single-vision distance full-correction spectacles (70.3%) being the most common mode of vision correction. Barriers to adopting optimal myopia care are medicolegal concerns, absence of clinical practice guidelines, and inadequate consultation time. Own clinical experience and original research articles were the primary sources of information supporting clinical practice. Most (>70%) respondents considered involving the adult caregiver in their child's clinical decision-making process. While practitioners' awareness and activity of newer myopia management strategies are improving, there is plenty of scope for its enhancement. The importance of evidence-based practice guidelines and continuing education on myopia control might help practitioners enhance their clinical decision-making skills.

The influence of the environment and lifestyle on myopia.

BACKGROUND: Myopia, commonly known as near-sightedness, has emerged as a global epidemic, impacting almost one in three individuals across the world. The increasing prevalence of myopia during early childhood has heightened the risk of developing high myopia and related sight-threatening eye conditions in adulthood. This surge in myopia rates, occurring within a relatively stable genetic framework, underscores the profound influence of environmental and lifestyle factors on this condition. In this comprehensive narrative review, we shed light on both established and potential environmental and lifestyle contributors that affect the development and progression of myopia. MAIN BODY: Epidemiological and interventional research has consistently revealed a compelling connection between increased outdoor time and a decreased risk of myopia in children. This protective effect may primarily be attributed to exposure to the characteristics of natural light (i.e., sunlight) and the release of retinal dopamine. Conversely, irrespective of outdoor time, excessive engagement in near work can further worsen the onset of myopia. While the exact mechanisms behind this exacerbation are not fully comprehended, it appears to involve shifts in relative peripheral refraction, the overstimulation of accommodation, or a complex interplay of these factors, leading to issues like retinal image defocus, blur, and chromatic aberration. Other potential factors like the spatial frequency of the visual environment, circadian rhythm, sleep, nutrition, smoking, socio-economic status, and education have debatable independent influences on myopia development. CONCLUSION: The environment exerts a significant influence on the development and progression of myopia. Improving the modifiable key environmental predictors like time spent outdoors and engagement in near work can prevent or slow the progression of myopia. The intricate connections between lifestyle and environmental factors often obscure research findings, making it challenging to disentangle their individual effects. This complexity underscores the necessity for prospective studies that employ objective assessments, such as quantifying light exposure and near work, among others. These studies are crucial for gaining a more comprehensive understanding of how various environmental factors can be modified to prevent or slow the progression of myopia.

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.

Association of sunlight exposure with visual impairment in an Indian fishing community.

Purpose: Indian fishermen belong to a marginalized population and are continuously exposed to extreme occupational hazards and sunlight. A high prevalence of visual impairment (VI) is reported in the coastal fishing community. We aimed to investigate the association between VI and sunlight exposure measurement (SEM). Methods: In this cross-sectional observational study, 270 eyes of 135 participants were enrolled from a coastal fishing village. Participants underwent a comprehensive ophthalmic examination, which included best-corrected visual acuity (BCVA), and anterior and posterior segment examination. Ocular Surface Disease Index (OSDI) and SEM questionnaire were administered to estimate the level of dry eye and ultraviolet-B (UV-B) exposure, respectively. VI was defined as presenting visual acuity worse than 6/12 (logarithm of the minimum angle of resolution [logMAR] > 0.3). Results: The mean age and spherical equivalent were 50.56 ± 11.72 years (range: 18-80 years) and 0.36 ± 1.68 diopters (D) (range: -7.0 to +3.0 D), respectively. Age, SEM, OSDI, fishing as an occupation, and cataract were significantly associated with higher odds of VI in univariate analysis. Refraction, gender, education level, smoking status, amblyopia, systematic, and other ocular diseases were not significantly associated with VI. In the multivariate analysis, age, SEM, and presence of cataract remained significantly associated with a higher risk for VI. The area under the receiver operating characteristic curve values for age and SEM scores demonstrate a fair index of discrimination for the detection of VI. Conclusion: SEM level is directly associated with a higher risk of VI among fishermen. The fishing community might benefit from regular eye examinations and awareness about the harmful effects of sunlight exposure and preventive measures.

A Duration-Dependent Interaction Between High-Intensity Light and Unrestricted Vision in the Drive for Myopia Control.

Purpose: To evaluate the duration-dependent and synergetic impact of high-intensity light (HL) and unrestricted vision (UnV) on lens-induced myopia (LIM) development in chickens. Methods: Myopia was induced in one eye in chicks (10 groups, n = 126) from day 1 posthatching (D1) until day 8 (D8) using -10 diopter (D) lenses. Fellow eyes remained uncovered as controls. Nine groups were exposed daily to 2, 4, or 6 hours of HL (15,000 lux), UnV (removal of -10 D lens), or both (HL + UnV). One group served as the LIM group without any interventions. Ocular axial length (AL), refractive error, and choroidal thickness were measured on D1, D4, and D8. Outcome measures are expressed as interocular difference (IOD = experimental eye - control eye) ± SEM. Results: By D8, LIM increased AL (0.36 ± 0.04 mm), myopic refraction (-9.02 ± 0.37 D), and choroidal thinning (-90.27 ± 16.44 µm) in the LIM group (all, P < 0.001). Compared to the LIM group, exposure to 2, 4, or 6 hours of HL, UnV, or HL + UnV reduced myopic refraction in a duration-dependent manner, with UnV being more effective than HL (P < 0.05). Only 6 hours of HL + UnV (not 2 or 4 hours) prevented LIM and was more effective than UnV (P = 0.004) or HL (P < 0.001) in reducing myopic refraction and more effective than HL (P < 0.001) in reducing axial elongation. Conclusions: Daily exposure to 2, 4, or 6 hours of HL, UnV, or HL + UnV reduced lens-induced myopic refraction in a duration-dependent manner in chickens. Only 6 hours of HL + UnV completely stopped LIM development. The synergetic effect of HL and UnV is dependent on the duration of the interventions.

Physical activity, time spent outdoors, and near work in relation to myopia prevalence, incidence, and progression: An overview of systematic reviews and meta-analyses.

Myopia has reached epidemic levels in recent years. Stopping the development and progression of myopia is critical, as high myopia is a major cause of blindness worldwide. This overview aims at finding the association of time spent outdoors (TSO), near work (NW), and physical activity (PA) with the incidence, prevalence, and progression of myopia in children. Literature search was conducted in PubMed, Scopus, Cumulative Index to Nursing and Allied Health Literature, Cochrane Database of Systematic Reviews, ProQuest, and Web of Science databases. Systematic reviews (SR) and meta-analyses (MA) on the TSO, NW, and PA in relation to myopia were reviewed. Methodological nature of qualified studies were evaluated utilizing the Risk of Bias in Systematic Review tool. We identified four SRs out of which three had MA, which included 62 unique studies, involving >1,00,000 children. This overview found a protective trend toward TSO with a pooled odds ratio (OR) of 0.982 (95% confidence interval (CI) 0.979-0.985, I2 = 93.5%, P < 0.001) per extra hour of TSO every week. A pooled OR 1.14 (95% CI 1.08-1.20) suggested NW to be related to risk of myopia. However, studies associating myopia with NW activities are not necessarily a causality as the effect of myopia might force children to indoor confinement with more NW and less TSO. PA presented no effect on myopia. Though the strength of evidence is less because of high heterogeneity and lack of clinical trials with clear definition, increased TSO and reduced NW are protective against myopia development among nonmyopes.

Total Synthesis of the All-Rare Sugar-Containing Pentasaccharide Repeating Unit of the O-Polysaccharide of Plesiomonas shigelloides Strain 302-73 (Serotype O1).

First total synthesis of the conjugation-ready pentasaccharide repeating unit of Plesiomonas shigelloides strain 302-73 (serotype O1) is reported. The complex target pentasaccharide is composed of all-rare amino sugars such as orthogonally functionalized d-bacillosamine, l-fucosamine, and l-pneumosamine linked through four consecutive α-linkages. The poor nucleophilicity of axial 4-OH of l-fucosamine and stereoselective glycosylations are the key challenges in the total synthesis, which was completed via a longest linear sequence of 27 steps in 3% overall yield.