Atropine Differentially Modulates ECM Production by Ocular Fibroblasts, and Its Ocular Surface Toxicity Is Blunted by Colostrum

The role of atropine in myopia control: insights into choroidal and scleral mechanisms

In this study, we investigate the inhibitory effects of atropine on the progression of experimental myopia by targeting the functions of the choroid and sclera and exploring its potential therapeutic mechanisms. Form deprivation myopia (FDM) was induced in C57BL/6 mice, with treatment groups receiving atropine. We assessed the effects on ocular morphology, extracellular matrix (ECM) protein expression, choroidal and scleral thickness, and choroidal vascular index (CVI) through histopathology, immunofluorescence, and quantitative quantitative polymerase chain reaction (qPCR). In vitro, mouse scleral fibroblasts (MSFs) were treated with Na2S2O4 to induce hypoxia, followed by atropine treatment. Atropine treatment significantly reduced axial elongation and ECM remodeling in FDM mice, as indicated by a decrease in collagen volume fraction. It restored choroidal and scleral thickness and increased CVI, suggesting improved microcirculation. Atropine also modulated ECM protein expression and reduced the hypoxia marker Hypoxia-Inducible Factor-1α (HIF-1α). In vitro, atropine protected MSFs from hypoxia-induced damage, preserved cytoskeletal integrity, and modulated key signaling pathways, including P53 and β-catenin. These findings suggest that atropine holds promise for controlling myopia progression by improving choroidal microcirculation, reducing scleral hypoxia, and regulating ECM remodeling, supporting its therapeutic application in myopia management.

The Short-term Effect of Atropine 0.1% on the Axial Length and Choroid of Children Treated for Myopia Progression Prevention, Measured by Optical Coherence Tomography Angiography

PURPOSE

To investigate the short-term effect of atropine to better understand its mechanism of action in myopia prevention. The current study investigates whether atropine's effect on the axial length arises from an increase in choroidal thickness using swept-source optical coherence tomography angiography (OCTA).

METHODS

Twenty-five myopic children (25 eyes) (9 boys and 16 girls; mean age: 11.8 years, range: 7 to 15 years) were enrolled following documented myopia progression and axial length increase in the preceding 6 months. Using swept-source OCTA, choroidal thickness and choroidal stromal volume (CSV) were measured at baseline and after 1 month of daily atropine 0.1% use. Axial length measurements were taken on the same days.

RESULTS

Following 1 month of daily atropine 0.1% instillation, choroidal thickness increased from 284.24 ± 65.05 to 308.04 ± 70.65 µm (Δ 22.41 ± 4.20 µm, P < .01), CSV increased from 11.88 ± 5.20 to 12.96 ± 5.86 mm3 (Δ 1.08 ± 1.02 mm3, P < .01), and axial length decreased from 25.37 ± 1.21 to 25.33 ± 1.21 mm (Δ 0.044 ± 0.016 mm, P < .05). The CSV and choroidal thickness increase show a negative correlation with the axial length decrease of -0.462 and -0.374, respectively, demonstrating a weak to moderate correlation.

CONCLUSIONS

One month of daily atropine 0.1% eye drop administration results in an acute decrease in axial length concurrent with an increase in choroidal thickness and CSV. A direct cause-and-effect relationship between these two parameters is plausible. [J Pediatr Ophthalmol Strabismus. 20XX;X(X):XXXXXX.].

Rapid myopization of the fellow eye in anisometropic amblyopia treated with 1% atropine: a case report

BACKGROUND

High anisometropia is often accompanied by amblyopia. One percent atropine penalization is an important treatment for anisometropic amblyopia and is as effective as occlusion therapy. On the other hand, 1% atropine had the strongest effect on controlling refractive error and axial length (AL) changes in myopic patients.

CASE PRESENTATION

A female child was diagnosed with anisometropia at the age of two. Cycloplegic retinoscopy examination revealed refraction of + 2.5 diopters the right eye and -8.5/-1.5 × 120 diopters the left eye, and full correction spectacles and patching therapy were prescribed for the child. Anisometropic amblyopia was then diagnosed because the best corrected vision acuity in highly myopic eyes is 20/100. Owing to poor compliance, visual acuity recovery in the amblyopic eye was unsatisfactory, and 1% atropine was applied two times per week for the fellow (right) eye. Since then, the fellow eye has experienced rapid myopization, with the refractive error increasing to -7.5/-1.25 × 15 diopterswithin five years. In addition, the visual acuity of the amblyopic (left) eye has improved gradually to 20/20, although the refraction status has remained stable.

CONCLUSIONS

In this report, a high anisometropic amblyopia patient underwent rapid myopization in the fellow eye with constant use of 1% atropine, in contrast to the stable refraction status of the amblyopic eye.

Effects of atropine on choroidal hemodynamics and VEGFA and HIF-1α expression in form-deprivation myopia guinea pigs

We investigated the mechanism of action of atropine in myopia control by examining its effect on choroidal hemodynamics. Blood flow was evaluated using indocyanine green (ICG) fluorescence and molecular variation during the development of form-deprivation myopia (FDM) and atropine treatment in guinea pigs. Guinea pigs were divided randomly into the normal control (NC), FDM, and FDM + 1% atropine (ATR) groups, and evaluated by spherical equivalent refractive error (SE) and axial length (AL). Choroidal hemodynamic parameters were measured via ICG fluorescence imaging including the maximal ICG fluorescence intensity (Imax), rising time (Trising), blood flow index (BFI), and mean transit time (MTT). Additionally, the expression in the choroid-RPE complex of choroidal vascular endothelial growth factor A (VEGFA) and HIF-1 α were assessed via Western blotting. Atropine inhibited the development of FDM, with effects of FD on both SE and AL being reduced. ICG fluorescence hemodynamic wide-field maps and time-series curves revealed that the atropine significantly accelerated choroidal blood flow, with reduced Trising and MTT, while increasing Imax, BFI and the number of lobulated choriocapillaris structures compared with the FDM group. In terms of molecular markers, atropine inhibited the effect of FDM, increasing VEGFA levels and reducing HIF-1α expression. These findings suggest that atropine improved choroidal hemodynamics and changed vascular markers, potentially contributing to its role in inhibiting the progression of myopia in the FDM model.

Oxygen, the Paradox of Life and the Eye

Oxidative stress, caused by the formation of free radicals, such as reactive oxygen species (ROS), leads to cell and tissue degradation, contributing to various diseases and aging. While oxygen is essential for aerobic organisms, it inevitably causes oxidative stress. Antioxidants protect against damage from free radicals, and oxidative stress arises when an imbalance occurs between free radical production and antioxidant defenses. However, when investigating whether an excess of antioxidants, almost eliminating oxidative stress, could benefit aging and disease susceptibility, it was observed that a basic level of oxidative stress appears necessary to maintain the correct homeostasis of tissues and organs and life in general. Therefore, this review aimed to compile the most significant and recent papers characterizing and describing the dual role of oxygen as a molecule essential for life and as a precursor of oxidative stress, which can be detrimental to life. We conducted targeted searches in PubMed and Google browsers to gather all relevant papers. We then focused on the eye, an organ particularly vulnerable due to its high metabolic activity combined with direct exposure to light and environmental pollutants, which produces a substantial number of free radicals (mainly ROS). We present a curated selection of relevant literature describing the main ocular pathologies of the posterior and anterior segments of the eye, highlighting oxidative stress as a significant contributing factor. Additionally, we report how endogenous and exogenous antioxidants can mitigate the development and progression of these diseases. Finally, we consider a frequently overlooked aspect: the balance between oxidants and antioxidants in maintaining the homeostatic equilibrium of tissues and organs. It is widely recognized that when oxidants overwhelm antioxidants, oxidative stress occurs, leading to negative consequences for the organism's homeostasis. However, we emphasize that a similarly dangerous situation can arise when the presence of antioxidants overwhelms the production of free radicals, drastically reducing their amount and adversely affecting aging and longevity. Unfortunately, no specific studies have addressed this particular situation in the eye.

Short-term effects of ophthalmic topical 0.01% atropine on the ocular surface, pupil size, and subsequent subjective quality of vision in young myopic Chinese adults

Background

Daily use of low concentrations of atropine is recommended for children undergoing myopia control therapy. While the benefits of controlling myopia progression have been confirmed, the potential unwanted side effects on the ocular surface, pupil size, and quality of vision following the administration of 0.01% atropine have not been investigated.

Objective

This single-arm, self-control study aimed to investigate the short-term effects of 0.01% atropine topical eye drop (He Eye Hospital Co., Ltd., Shenyang, China) on pupil size and subjective quality of vision in participants with myopia. Each 3 mL vial of eye drops contains atropine (0.01%), sodium chloride (0.9%), and benzalkonium chloride (0.005%) in an aqueous solution.

Methods

Thirty-three adults (66 eyes) were recruited for the study. The mean age of the participants recruited for this study was 24.91 ± 3.36 years. This study is registered with Clinical Trials.gov (NCT06071260). Assessments were performed at baseline and 10 h, 14 h, and 18 h following the administration of 0.01% topical atropine drop (TAD). Mesopic pupil diameter (MPD), photopic pupil diameter (PPD), higher order aberration (HOA), non-invasive tear breakup time (NITBUT), tear meniscus height (TMH), tear film lipid layer (TFLL), and Redness score (RS). Subjective assessments included the quality of vision (QoV) and the ocular surface disease index (OSDI) questionnaires.

Results

Following the use of 0.01% atropine, PPD significantly increased at all the time points (p < 0.001); MPD increased significantly at 10 h and 14 h (p < 0.001 and p < 0.05, respectively). A decrease in TMH and an increase in the OSDI questionnaire scores were observed up to 10 and 14 h, respectively, after using atropine (p < 0.001). Glare (p = 0.004 at 10 h and p = 0.003 at 14 h), blurred vision (p < 0.0001 at 10 h and p = 0.035 at 14 h), and focusing difficulties (p < 0.0001 at 10 h and p < 0.0001 at 14 h) were significantly higher at both 10 h and 14 h after using atropine. No significant changes were observed in the HOA, NITBUT, and RS scores (all p > 0.05) at all time points.

Conclusion

Decreased TMH, dry eye symptoms, and visual symptoms will likely persist overnight but often diminish within 18 h after using 0.01% atropine eye drops.

Collagen is crucial target protein for scleral remodeling and biomechanical change in myopia progression and control

In recent decades, the prevalence of myopia has been on the rise globally, attributed to changes in living environments and lifestyles. This increase in myopia has become a significant public health concern. High myopia can result in thinning of the sclera and localized ectasia of the posterior sclera, which is the primary risk factor for various eye diseases and significantly impacts patients' quality of life. Therefore, it is essential to explore effective prevention strategies and programs for individuals with myopia. Collagen serves as the principal molecule in the extracellular matrix (ECM) of scleral tissue, consisting of irregular collagen fibrils. Collagen plays a crucial role in myopia progression and control. During the development of myopia, the sclera undergoes a thinning process which is primarily influenced by collagen expression decreased and remodeled, thus leading to a decrease in its biomechanical properties. Improving collagen expression and promoting collagen crosslinking can slow down the progression of myopia. In light of the above, improving collagen expression or enhancing the mechanical properties of collagen fibers via medication or surgery represents a promising approach to control myopia.

Five-year results of atropine 0.01% efficacy in the myopia control in a European population

AIMS

To evaluate the efficacy and safety of 0.01% atropine eye-drops in controlling myopia progression over 5 years.

METHODS

Experimental, analytical, prospective, randomised and longitudinal study, in 361 right eyes from 361 children randomised into the control group (177 eyes without treatment) and treatment group (184 eyes with 0.01% atropine eye-drops). Children assigned to the treatment group used 0.01% atropine once a day every night and the control group's children did not use any treatment or placebo. All the subjects completed an eye examination every 6 months for the 5 years of follow-up. The examination included subjective and objective refraction with cycloplegia, axial length (AL), keratometry and anterior chamber depth (ACD) to evaluate the efficacy of the treatment. It also included the anterior and posterior pole examination to evaluate the safety of the treatment.

RESULTS

The SE increased -0.63±0.42D in children after 5 years of treatment with 0.01% atropine, while in the control group the increase was -0.92±0.56D. AL increased 0.26±0.28 mm in the treatment group compared with 0.49±0.34 mm in the control group. Atropine 0.01% showed an efficacy of 31.5% and 46.9% in the control of the SE and AL increase, respectively. ACD and keratometry did not have significant changes between groups.

CONCLUSIONS

Atropine 0.01% is effective in slowing myopia progression in a European population. There were no side effects after 5 years of 0.01% atropine.

Eye Diseases: When the Solution Comes from Plant Alkaloids

Plants are an incredible source of metabolites showing a wide range of biological activities. Among these, there are the alkaloids, which have been exploited for medical purposes since ancient times. Nowadays, many plant-derived alkaloids are the main components of drugs used as therapy for different human diseases. This review deals with providing an overview of the alkaloids used to treat eye diseases, describing the historical outline, the plants from which they are extracted, and the clinical and molecular data supporting their therapeutic activity. Among the different alkaloids that have found application in medicine so far, atropine and pilocarpine are the most characterized ones. Conversely, caffeine and berberine have been proposed for the treatment of different eye disorders, but further studies are still necessary to fully understand their clinical value. Lastly, the alkaloid used for managing hypertension, reserpine, has been recently identified as a potential drug for ameliorating retinal disorders. Other important aspects discussed in this review are different solutions for alkaloid production. Given that the industrial production of many of the plant-derived alkaloids still relies on extraction from plants, and the chemical synthesis can be highly expensive and poorly efficient, alternative methods need to be found. Biotechnologies offer a multitude of possibilities to overcome these issues, spanning from genetic engineering to synthetic biology for microorganisms and bioreactors for plant cell cultures. However, further efforts are needed to completely satisfy the pharmaceutical demand.

Oral administration of caffeine metabolite 7-methylxanthine is associated with slowed myopia progression in Danish children

PURPOSE

Myopia is associated with an increased risk of permanent vision loss. The caffeine metabolite 7-methylxanthine (7-MX), licensed in Denmark since 2009 as a treatment to reduce the rate of childhood myopia progression, is the only orally administered therapy available. The purpose of the current study was to assess the rate of myopia progression in children taking 7-MX.

METHODS

Longitudinal cycloplegic refraction and axial length data for 711 myopic children from Denmark treated with varying doses of oral 7-MX (0-1200 mg per day) were analysed using linear mixed models.

RESULTS

The median age at baseline was 11.1 years (range 7.0 -15.0 years). Children were followed for an average of 3.6 years (range 0.9-9.1 years) and the average myopia progression was 1.34 dioptres (D) (range -6.50 to +0.75 D). Treatment with 7-MX was associated with a reduced rate of myopia progression (p<0.001) and axial elongation (p<0.002). Modelling suggested that, on average, an 11-year-old child taking 1000 mg 7-MX daily would develop -1.43 D of myopia over the next 6 years, compared with -2.27 D if untreated. Axial length in this child would increase by 0.84 mm over 6 years when taking a daily dose of 1000 mg of 7-MX, compared with 1.01 mm if untreated. No adverse effects of 7-MX therapy were reported.

CONCLUSIONS

Oral intake of 7-MX was associated with reduced myopia progression and reduced axial elongation in this sample of myopic children from Denmark. Randomised controlled trials are needed to determine whether the association is causal.

The Role of Atropine in Preventing Myopia Progression: An Update

Several approaches have been investigated for preventing myopia progression in children and teenagers. Among them, topical atropine has shown promising results and it is being adopted in clinical practice more and more frequently. However, the optimal formulation and treatment algorithm are still to be determined. We discuss the pharmacokinetic, pharmacodynamic, clinical, and tolerability profile revealed first by the multicenter, randomized ATOM 1 and 2 trials and, more recently, by the LAMP Study. Results from these trials confirmed the efficacy of low-concentration atropine with a concentration-dependent response. Although atropine at 0.025% and 0.05% concentrations has shown the most encouraging results in large-scale studies, these formulations are not yet commonplace in worldwide clinical practice. Moreover, their rebound effect and the possibility of reaching a stabilization effect have not been fully investigated with real-life studies. Thus, further larger-scale studies should better characterize the clinical efficacy of atropine over longer follow-up periods, in order to define the optimal dosage and treatment regimen.

Global Tendency and Frontiers of Research on Myopia From 1900 to 2020: A Bibliometrics Analysis

Background:

Myopia is one of the most common causes of vision impairment in children and adults and has become a public health priority with its growing prevalence worldwide. This study aims to identify and evaluate the global trends in myopia research of the past century and visualize the frontiers using bibliometric analysis.

Methods

The literature search was conducted on the Web of Science for myopia studies published between 1900 and 2020. Retrieved publications were analyzed in-depth by the annual publication number, prolific countries and institutions, core author and journal, and the number of citations through descriptive statistics. Collaboration networks and keywords burst were visualized by VOSviewer and CiteSpace. Myopia citation network was visualized using CitNetExplorer.

Results

In total, 11,172 publications on myopia were retrieved from 1900 to 2020, with most published by the United States. Saw SM, from the National University of Singapore, contributed the most publications and citations. Investigative Ophthalmology &amp; Visual Science was the journal with highest number of citations. Journal of Cataract and Refractive Surgery with the maximum number of publications. The top 10 cited papers mainly focused on the epidemiology of myopia. Previous research emphasized myopia-associated experimental animal models, while recent keywords include “SMILE” and “myopia control” with the stronger burst, indicating a shift of concern from etiology to therapy and coincided with the global increment of incidence. Document citation network was clustered into six groups: “prevalence and risk factors of myopia,” “surgical control of myopia,” “pathogenesis of myopia,” “optical interventions of myopia,” “myopia and glaucoma,” and “pathological myopia.”

Conclusions

Bibliometrics analysis in this study could help scholars comprehend global trends of myopia research frontiers better. Hundred years of myopia research were clustered into six groups, among which “prevalence and risk factors of myopia” and “surgical control of myopia” were the largest groups. With the increasing prevalence of myopia, interventions of myopia control are a potential research hotspot and pressing public health issue.

Comparative Efficiency of Lutein and Astaxanthin in the Protection of Human Corneal Epithelial Cells In Vitro from Blue-Violet Light Photo-Oxidative Damage

The aim of this study was to compare in vitro the protective and antioxidant properties of lutein and astaxanthin on human primary corneal epithelial cells (HCE-F). To this purpose, HCE-F cells were irradiated with a blue-violet light lamp (415–420 nm) at different energies (20 to 80 J/cm2). Lutein and astaxanthin (50 to 250 μM) were added to HCE-F right before blue-violet light irradiation at 50 J/cm2. Viability was evaluated by the CKK-8 assay while the production of reactive oxygen species (ROS) by the H2DCF-DA assay. Results have shown that the viability of HCE-F cells decreased at light energies from 20 J/cm2 to 80 J/cm2, while ROS production increased at 50 and 80 J/cm2. The presence of lutein or astaxanthin protected the cells from phototoxicity, with lutein slightly more efficient than astaxanthin also on the blunting of ROS, prevention of apoptotic cell death and modulation of the Nrf-2 pathway. The association of lutein and astaxanthin did not give a significant advantage over the use of lutein alone. Taken together, these results suggest that the association of lutein and astaxanthin might be useful to protect cells of the ocular surface from short (lutein) and longer (astaxanthin) wavelengths, as these are the most damaging radiations hitting the eye from many different LED screens and solar light.

Update and guidance on management of myopia. European Society of Ophthalmology in cooperation with International Myopia Institute

The prevalence of myopia is increasing extensively worldwide. The number of people with myopia in 2020 is predicted to be 2.6 billion globally, which is expected to rise up to 4.9 billion by 2050, unless preventive actions and interventions are taken. The number of individuals with high myopia is also increasing substantially and pathological myopia is predicted to become the most common cause of irreversible vision impairment and blindness worldwide and also in Europe. These prevalence estimates indicate the importance of reducing the burden of myopia by means of myopia control interventions to prevent myopia onset and to slow down myopia progression. Due to the urgency of the situation, the European Society of Ophthalmology decided to publish this update of the current information and guidance on management of myopia. The pathogenesis and genetics of myopia are also summarized and epidemiology, risk factors, preventive and treatment options are discussed in details.

Atropine in topical formulations for the management of anterior and posterior segment ocular diseases

INTRODUCTION

Atropine is an old-known drug which is gaining increasing attention due to the myriad of therapeutic effects it may trigger on eye structures. Nevertheless, novel applications may require more adequate topical formulations.

AREAS COVERED

This review aims to gather the existing knowledge about atropine and its clinical applications in the ophthalmological field when administered topically. Atropine ocular pharmacokinetics is paid a special attention, including recent evidences of the capability of the drug to access to the posterior segment. Ocular bioavailability and systemic bioavailability are counterbalanced. Finally, limitations of traditional dosage forms and potential advantages of under investigation delivery systems are analyzed.

EXPERT OPINION

Mydriasis and cyclopegia have been widely exploited for eye examination, management of anterior segment diseases, and more recently as antidotes of chemical weapons. Improved knowledge on drug receptors and related pathways explains atropine repositioning as an outstanding tool to prevent myopia. The ease with which atropine penetrates ocular tissues is a double edged sword, that is, while it ensures therapeutic levels in the posterior segment, the unspecific distribution causes a wide variety of untoward effects. The design of formulations that can selectively deliver atropine to the target tissue for each specific application is an urgent unmet need.

Effects of Single and Repeated Intravitreal Applications of Atropine on Choroidal Thickness in Alert Chickens

INTRODUCTION

Atropine, a muscarinic antagonist, is known since the 19th century to inhibit myopia development in children. One of its effects is that it stimulates choroidal thickening. Thicker choroids, in turn, have been linked to myopia inhibition. We used the atropine-stimulated choroidal response in the chicken to learn more about the time courses and amplitudes of the effects of atropine, as well as whether repeated applications lead to accumulation or desensitization.

METHODS

Intravitreal injections containing 250 µg atropine sulfate were performed in 1 eye around 10:00 in the morning, the fellow eye received vehicle. Chickens with bilateral vehicle injections served as controls. Choroidal thickness was measured over the day for every 2-3 h in alert animals, using spectral domain optical coherence tomography, with 3-5 independent measurements in each eye. Three experiments were done - (1) single injection and time course measured over 1 day, (2) single injection and time course measured over 4 days, and (3) daily injections and time course measured over 4 days for measuring the effects of atropine on vitreal, retinal, and choroidal dopamine, and 3,4-dihydroxyphenylacetic acid levels by using high-performance liquid chromatography with electrochemical detection.

RESULTS

Atropine induced an increase in choroidal thickness by about 60 percent, with a peak amplitude after about 2 h. The effect persisted only for a few hours and had nearly disappeared by evening. Initially, similar amounts of choroidal thickening were observed in vehicle-injected fellow eyes but recovery to baseline was faster. When atropine was injected daily for 4 days, choroids thickened every day with similar amplitudes and time courses, with no signs of either accumulation or desensitization effects. Interestingly, while dopamine release from the retina was stimulated by atropine and followed approximately, the time course of choroidal thickening, its tissue concentration dropped in the choroid.

CONCLUSIONS

Even at relatively high intravitreal doses, effects of atropine on choroidal thickness remained transient, similar to its effects on retinal dopamine. With repeated application every day, the diurnal patterns of choroidal thickening could be reproduced for 4 days with similar amplitudes and time courses. The transient nature of the effects of atropine on the choroid may be relevant for application protocols of atropine against myopia.