Differential Impact of 0.01% and 0.05% Atropine Eyedrops on Ocular Surface in Young Adults.

Purpose: To evaluate the effect of low-concentration (0.01% and 0.05%) atropine eyedrops on ocular surface characteristics in young adults. Methods: Twenty-six myopic students aged 18 to 30 years were randomly assigned to receive either 0.01% or 0.05% atropine once nightly for 14 days, followed by cessation, with a ≥14-day interval between each administration. Assessments were conducted one, two, seven, and 14 days after using atropine with corresponding timepoints after atropine cessation. Tear meniscus height and first and average noninvasive keratograph tear film breakup time (NIKBUT-first, NIKBUT-average) were measured using Keratograph 5M, whereas the objective scatter index (OSI) was measured by OQAS II devices; the ocular surface disease index (OSDI) score was also obtained. Results: The mean OSI peaked after two days of administration of 0.05% atropine (ß = 0.51, P = 0.001), accompanied by significant decreases in NIKBUT-first (ß = -7.73, P < 0.001) and NIKBUT-average (ß = -8.10, P < 0.001); the OSDI peaked after 14 days (ß = 15.41, P < 0.001). The above parameters returned to baseline one week after atropine discontinuation (all P > 0.05). NIKBUT-first and NIKBUT-average reached their lowest points after 14 days of 0.01% atropine administration (NIKBUT-first: ß = -4.46, P = 0.005; NIKBUT-average: ß = -4.42, P = 0.001), but those significant changes were diminished once atropine treatment stopped. Conclusions: Young adult myopes experienced a significant but temporary impact on the ocular surface with 0.05% atropine administration, whereas 0.01% atropine had a minimal effect. Translational Relevance: The investigation of the ocular surface effects of different concentrations of atropine may inform evidence-based clinical decisions regarding myopia control in young adults.

The effect of glycopyrrolate vs. atropine in combination with neostigmine on cardiovascular system for reversal of residual neuromuscular blockade in the elderly: a randomized controlled trial.

BACKGROUND: Glycopyrrolate-neostigmine (G/N) for reversing neuromuscular blockade (NMB) causes fewer changes in heart rate (HR) than atropine-neostigmine (A/N). This advantage may be especially beneficial for elderly patients. Therefore, this study aimed to compare the cardiovascular effects of G/N and A/N for the reversal of NMB in elderly patients. METHODS: Elderly patients aged 65-80 years who were scheduled for elective non-cardiac surgery under general anesthesia were randomly assigned to the glycopyrrolate group (group G) or the atropine group (group A). Following the last administration of muscle relaxants for more than 30 min, group G received 4 ug/kg glycopyrrolate and 20 ug/kg neostigmine, while group A received 10 ug/kg atropine and 20 ug/kg neostigmine. HR, mean arterial pressure (MAP), and ST segment in lead II (ST-II) were measured 1 min before administration and 1-15 min after administration. RESULTS: HR was significantly lower in group G compared to group A at 2-8 min after administration (P < 0.05). MAP was significantly lower in group G compared to group A at 1-4 min after administration (P < 0.05). ST-II was significantly depressed in group A compared to group G at 2, 3, 4, 5, 6, 7, 8, 9, 11, 13, 14, and 15 min after administration (P < 0.05). CONCLUSIONS: In comparison to A/N, G/N for reversing residual NMB in the elderly has a more stable HR, MAP, and ST-II within 15 min after administration.

Unveiling the antinociceptive mechanisms of Methyl-2-(4-chloro-phenyl)-5-benzoxazoleacetate: insights from nociceptive assays in mice.

OBJECTIVE: Methyl-2-(4-chloro- phenyl)-5-benzoxazoleacetate (MCBA), a synthetic benzoxazole derivative with established antipsoriatic efficacy, was investigated for potential antinociceptive effects. This study employs various nociceptive assays in mice to elucidate MCBA's antinociceptive mechanisms. MATERIALS AND METHODS: MCBA's antinociceptive potential was tested against various nociception models induced by formalin, glutamate, capsaicin, a transient receptor potential vanilloid 1 (TRPV1) receptor agonist, and phorbol 12-myristate 13-acetate, a protein kinase C (PKC) activator. It was then assessed using the hot plate test and examined within the acetic acid-induced writhing test. During the acetic acid-induced writhing test, MCBA was pre-challenged against selective receptor antagonists such as naloxone, caffeine, atropine, yohimbine, ondansetron, and haloperidol. It was also pre-challenged with ATP-sensitive potassium channel inhibitor (glibenclamide) to further elucidate its antinociceptive mechanism. RESULTS: The results showed that oral administration of MCBA led to a dose-dependent and significant inhibition (p < 0.05) of nociceptive effects across all evaluated models at doses of 60, 120, and 240 mg/kg. Moreover, the efficacy of MCBA's antinociceptive potential was significantly counteracted (p < 0.0001) by specific antagonists: (i) directed at adenosinergic, alpha-2 adrenergic, and cholinergic receptors using caffeine, yohimbine, and atropine, respectively; and (ii) targeting ATP-sensitive potassium channels, employing glibenclamide. Antagonists aimed at opioidergic and serotoninergic receptors (naloxone and ondansetron, respectively) had poor utility in inhibiting antinociceptive activity. Conversely, the dopaminergic receptor antagonist haloperidol potentiated locomotor abnormalities associated with MCBA treatment. CONCLUSIONS: MCBA-induced antinociception involves modulation of glutamatergic-, TRVP1 receptors- and PKC-signaling pathways. It impacts adenosinergic, alpha-2 adrenergic, and cholinergic receptors and opens ATP-sensitive potassium channels.

Safety and efficacy of cardioneuroablation for vagal bradycardia in a single arm prospective study.

Cardioneuroablation (CNA) is currently considered as a promising treatment option for patients with symptomatic bradycardia caused by vagotonia. This study aims to further investigate its safety and efficacy in patients suffering from vagal bradycardia. A total of 60 patients with vagal bradycardia who underwent CNA in the First Affiliated Hospital of Xinjiang Medical University from November 2019 to June 2022. Preoperative atropine tests revealed abnormal vagal tone elevation in all patients. First, the electroanatomic structures of the left atrium was mapped out by using the Carto 3 system, according to the protocol of purely anatomy-guided and local fractionated intracardiac electrogram-guided CNA methods. The upper limit of ablation power of superior left ganglion (SLGP) and right anterior ganglion (RAGP) was not more than 45W with an ablation index of 450.Postoperative transesophageal cardiac electrophysiological examination was performed 1 to 3 months after surgery. The atropine test was conducted when appropriate. Twelve-lead electrocardiogram, Holter electrocardiogram, and skin sympathetic nerve activity were reviewed at 1, 3, 6 and 12 months after operation. Adverse events such as pacemaker implantation and other complications were also recorded to analyze the safety and efficacy of CNA in the treatment of vagus bradycardia. Sixty patients were enrolled in the study (38 males, mean age 36.67 ± 9.44, ranging from 18 to 50 years old). None of the patients had a vascular injury, thromboembolism, pericardial effusion, or other surgical complications. The mean heart rate, minimum heart rate, low frequency, low/high frequency, acceleration capacity of rate, and skin sympathetic nerve activity increased significantly after CNA. Conversely, SDNN, PNN50, rMSSD, high frequency, and deceleration capacity of rate values decreased after CNA (all P < 0.05). At 3 months after ablation, the average heart rate, maximum heart rate, and acceleration capacity of heart rate remained higher than those before ablation, and the deceleration capacity of heart rate remained lower than those before ablation and the above results continued to follow up for 12 months after ablation (all P < 0.05). There was no significant difference in other indicators compared with those before ablation (all P > 0.05). The remaining 81.67% (49/60) of the patients had good clinical results, with no episodes of arrhythmia during follow-up. CNA may be a safe and effective treatment for vagal-induced bradycardia, subject to confirmation by larger multicenter trials.

Evaluation and estimation of diuretic activity of the linalyl acetate in the rats.

This study aimed to explore the diuretic activity of linalyl acetate (LA). LA is an essential oil, it is an integral phyto-constituent of various plants. In this study, acute and chronic diuretic activities were explored by measuring the levels of different electrolytes and pH in the urine of experimental rats. Rats were divided into five groups. The control group was given 10 mg/kg normal saline, the treated group was given 10 mg/kg furosemide, and the remaining 3 groups received different doses of LA including 25, 50, and 75 mg/kg through intraperitoneal route, to determine its diuretic potential. Urine volume for acute diuretic activity was measured for 6 hours however for chronic diuretic activity was measured for 6 days. For a comparative study of LA with a control group and treated group with reference drug, diuretic index was used. Moreover, the underlying mechanism of the diuretic activity was also explored by comparing atropine, L-NAME, and indomethacin. The results of each group with 6 rats in each group were obtained by ± standard error of the mean of every group. Analysis of Variance (ANOVA) was used for statistical analysis. Results revealed that the LA 75 mg/kg dose showed comparable results as of furosemide. Moreover, this study revealed the involvement of muscarinic receptors to produce diuresis in comparison with atropine with very little involvement of prostanoids and no effect on NO pathway induced by indomethacin and L-NAME respectively. It is concluded that LA possess anti-diuretic potential. Muscarinic receptors might be involved in producing diuretic effects.

Occurrence and health risk assessment of tropane alkaloids in cereal foods consumed in Korea.

Tropane alkaloids (TA) are natural toxins found in certain plants, including cereals, of which atropine and scopolamine are the main species of concern due to their acute toxicity. This study aimed to determine the occurrence of TA in cereal foods and assess the potential health risks associated with their consumption in Korea. TA levels were analyzed in 80 raw and 71 processed cereal samples, which were distributed throughout Korea in 2021, using ultra-performance liquid chromatography-tandem mass spectrometry. At least one of the six TA species, namely atropine, scopolamine, pseudotropine, tropinone, scopine, and 6-hydroxytropinone, was detected in 10 out of the 151 samples at levels ranging from 0.12 to 88.10 µg kg-1. Dietary exposure (mean, 0.23 ng kg-1 bw day-1) to atropine and scopolamine in the Korean population was estimated to be low across all age groups. This is despite considering worst-case scenarios using the total concentrations of atropine and scopolamine in a millet sample, both of which were detected, and 95th percentile consumption for consumers of millet only. Both the hazard index and margin of exposure methods indicated that the current levels of TA exposure from millet consumption were unlikely to pose significant health risks to the Korean population.

Myopia control: Seeing beyond efficacy.

SIGNIFICANCE: The availability of a range of effective myopia control modalities enables the clinician to exercise judgment when discussing the treatment plan with the patient and their parents. This article outlines important considerations beyond efficacy.Clinically meaningful myopia control may be attained with some spectacle lenses, select soft contact lenses, some concentrations of atropine, and overnight orthokeratology. Given that satisfactory efficacy can be achieved with a range of modalities, other factors should be considered when deciding upon the best intervention for a given child. Four key factors-compliance, quality of vision, quality of life, and safety-are discussed in this review. Compliance directly impacts efficacy regardless of the modality and is the most important consideration, as it is influenced by quality of vision and comfort. Daily disposal myopia control contact lenses and overnight orthokeratology are generally associated with high compliance, provide better vision-related quality of life than spectacles, and carry a very low risk when used appropriately. A further benefit of overnight orthokeratology is the elimination of a need for optical correction during the day.

LC-MS/MS determination of atropine toxicity: Pre-analytical effect of blood collection tube and analytical matrix.

Atropine (ATR) intoxication is a recurrent case in emergency departments. The diagnosis is dependent on clinical evaluation and is supported by analytical assessment. The assay is limited by the rapid degradation/metabolism of ATR into TRP as well as the preanalytical factors impairing correct detection and diagnosis. In this study, an HPLC-MS/MS method was optimized for the simultaneous determination of ATR and TRP. The effect of analytical matrix and the impact of blood-collection tube type on the ATR analytical signal were investigated. Separation was achieved using water: 0.01% formic acid acidified methanol (40: 60, v/v) as a mobile phase and Inertsil® C18 column (5 µm; 4.6*150 mm) as a stationary phase. The retention-times were 2.6 and 6.5 min for ATR and TRP, respectively. A chromatographic shift (0.4 min) in ATR peak, but not TRP, was observed in biological samples from neat ones. The best analytical signal was observed when heparinized blood collection tubes were employed. The method was linear, accurate and precise in the ATR toxicity range enabling the detection of ATR intoxication down to a concentration of 0.1 ng/mL by applying a simple sample clean-up procedure. In conclusion, an HPLC-MS/MS method for the simultaneous determination of ATR and TRP is presented. The method highlights the chromatographic shift of ATR peak in biological samples that may induce false-negative detection and poses TRP as an alternative toxicological marker for ATR toxicity. Meanwhile the study recommends heparin tubes for blood-sample collection.

Hypertensive emergency secondary to atropine / Emergencia hipertensiva secundaria a atropina

Atropine, a competitive antagonist of acetylcholine muscarinic receptors, is commonly used to treat severe bradycardia by blocking parasympathetic activity. We present a rare case of hypertensive emergency following atropine administration, with only one previous report in the literature. A 78-year-old woman with essential hypertension and hypercholesterolemia was admitted to the cardiac intensive care unit for non-ST segment elevation myocardial infarction. During coronary angiography, an occlusion of the right coronary artery was identified. While removing the diagnostic catheter through the right radial artery, the patient experienced intense pain and discomfort, accompanied by a vasovagal reflex characterized by bradycardia and hypotension. Intravenous atropine (0.5mg) was administered, leading to a rapid rise in heart rate with frequent ventricular ectopy. Subsequently, a progressive and exaggerated elevation in arterial blood pressure occurred, peaking at 294/121mmHg approximately 10min after atropine administration. The patient developed hypertensive acute pulmonary edema, successfully treated with intravenous nitroglycerine (10mg) and furosemide (60mg). Blood pressure normalized after approximately 14min. The exact mechanism of atropine-induced hypertensive emergency remains unknown. While hypertensive emergencies with atropine are exceedingly rare, healthcare professionals should be aware of this potential effect and be prepared for prompt intervention.(AU)

La atropina, un antagonista competitivo de los receptores muscarínicos de acetilcolina, se utiliza comúnmente para tratar la bradicardia severa al bloquear la actividad parasimpática. Presentamos un caso raro de emergencia hipertensiva después de la administración de atropina, con solo un informe previo en la literatura. Una mujer de 78 años con hipertensión esencial e hipercolesterolemia fue ingresada en la unidad de cuidados intensivos cardíacos por infarto agudo de miocardio sin elevación del segmento ST. Durante la angiografía coronaria, se identificó una oclusión de la arteria coronaria derecha. Mientras se retiraba el catéter diagnóstico a través de la arteria radial derecha, la paciente experimentó un intenso dolor y malestar, acompañado de un reflejo vasovagal caracterizado por bradicardia e hipotensión. Se administró atropina intravenosa (0,5 mg), lo que provocó un rápido aumento de la frecuencia cardíaca con frecuente ectopia ventricular. Posteriormente, ocurrió una elevación progresiva y exagerada de la presión arterial, alcanzando un máximo de 294/121 mmHg aproximadamente 10 minutos después de la administración de atropina. La paciente desarrolló edema pulmonar agudo hipertensivo, tratado con éxito con nitroglicerina intravenosa (10 mg) y furosemida (60 mg). La presión arterial se normalizó después de aproximadamente 14 minutos. El mecanismo exacto de la emergencia hipertensiva inducida por atropina sigue siendo desconocido. Aunque las emergencias hipertensivas con atropina son excepcionalmente raras, los profesionales de la salud deben estar al tanto de este efecto potencial y estar preparados para intervenir rápidamente.(AU)

Using big data to understand interest in myopia.

SIGNIFICANCE: Popularity of publicly searched myopia terminologies is reported, for example, myopia control over myopia management and myopia over nearsighted or shortsighted. Insights are also provided for searches on specific myopia control interventions. The findings offer an evidence-based starting point for public messaging and communications by clinicians, policymakers, and other industry leaders. PURPOSE: Public understanding of myopia can be difficult to ascertain for clinicians. Although small-scale studies provide valuable snapshots of data, findings tend to be population-specific and thus difficult to extrapolate to global audiences. In this study, big data were used to provide a more comprehensive depiction of global market interest in myopia. METHODS: Google Trends data were used to analyze searches relating to myopia between January 2004 and August 2023. Data extracted were related to use of the terms myopia control and myopia management, with further searches executed for common myopia control interventions: orthokeratology, contact lenses, atropine, and glasses. Analysis into the search interest of other refractive error states, hyperopia and astigmatism, was also undertaken along with alternative terms that may be used to describe myopia. Where relevant, search trends were considered worldwide, by country, and over time. RESULTS: Myopia was a more popular search term than common layman alternatives such as nearsighted or shortsighted. Myopia control was found to be more popular than myopia management, and of the specific myopia interventions, atropine was most popular. Compared with astigmatism and hyperopia, relative search volumes were greatest for myopia, on average accounting for approximately 50% of the relative search volume at the country level. CONCLUSIONS: The differences identified in both popularity of myopia-related search terms and specific interventions may provide the basis for improvements in public messaging and facilitate patient-practitioner communication.

Hypertensive emergency secondary to atropine.

Atropine, a competitive antagonist of acetylcholine muscarinic receptors, is commonly used to treat severe bradycardia by blocking parasympathetic activity. We present a rare case of hypertensive emergency following atropine administration, with only one previous report in the literature. A 78-year-old woman with essential hypertension and hypercholesterolemia was admitted to the cardiac intensive care unit for non-ST segment elevation myocardial infarction. During coronary angiography, an occlusion of the right coronary artery was identified. While removing the diagnostic catheter through the right radial artery, the patient experienced intense pain and discomfort, accompanied by a vasovagal reflex characterized by bradycardia and hypotension. Intravenous atropine (0.5mg) was administered, leading to a rapid rise in heart rate with frequent ventricular ectopy. Subsequently, a progressive and exaggerated elevation in arterial blood pressure occurred, peaking at 294/121mmHg approximately 10min after atropine administration. The patient developed hypertensive acute pulmonary edema, successfully treated with intravenous nitroglycerine (10mg) and furosemide (60mg). Blood pressure normalized after approximately 14min. The exact mechanism of atropine-induced hypertensive emergency remains unknown. While hypertensive emergencies with atropine are exceedingly rare, healthcare professionals should be aware of this potential effect and be prepared for prompt intervention.

Cardiovascular responses and the role of the neurohumoral cardiac regulation during digestion in the herbivorous lizard Iguana iguana.

Carnivorous reptiles exhibit an intense metabolic increment during digestion, which is accompanied by several cardiovascular adjustments responsible for meeting the physiological demands of the gastrointestinal system. Postprandial tachycardia, a well-documented phenomenon in these animals, is mediated by the withdrawal of vagal tone associated with the chronotropic effects of non-adrenergic and non-cholinergic (NANC) factors. However, herbivorous reptiles exhibit a modest metabolic increment during digestion and there is no information about postprandial cardiovascular adjustments. Considering the significant impact of feeding characteristics on physiological responses, we investigated cardiovascular and metabolic responses, as well as the neurohumoral mechanisms of cardiac control, in the herbivorous lizard Iguana iguana during digestion. We measured oxygen consumption rate (O2), heart rate (fH), mean arterial blood pressure (MAP), myocardial activity, cardiac autonomic tone, fH/MAP variability and baroreflex efficiency in both fasting and digesting animals before and after parasympathetic blockade with atropine followed by double autonomic blockade with atropine and propranolol. Our results revealed that the peak of O2 in iguanas was reached 24 h after feeding, accompanied by an increase in myocardial activity and a subtle tachycardia mediated exclusively by a reduction in cardiac parasympathetic activity. This represents the first reported case of postprandial tachycardia in digesting reptiles without the involvement of NANC factors. Furthermore, this withdrawal of vagal stimulation during digestion may reduce the regulatory range for short-term fH adjustments, subsequently intensifying the blood pressure variability as a consequence of limiting baroreflex efficiency.

The role of vasoactive intestinal peptide (VIP) in atropine-related inhibition of the progression of myopia.

OBJECTIVE: This study aimed to investigate the potential involvement of vasoactive intestinal polypeptide (VIP) in myopia development and its contribution to the mechanism of action of the anti-myopia drug, atropine. METHODS: Thirty-three-week-old guinea pigs were randomly divided into normal control (NC, n = 10), monocularly form-deprived (FDM, n = 10), and FDM treated with 1% atropine (FDM + AT, n = 10) groups. The diopter and axial length were measured at 0, 2, and 4 weeks. Guinea pig eyeballs were removed at week four, fixed, and stained for morphological changes. Immunohistochemistry (IHC) and in situ hybridization (ISH) were performed to evaluate VIP protein and mRNA levels. RESULTS: The FDM group showed an apparent myopic shift compared to the control group. The results of the H&E staining were as follows: the cells of the inner/outer nuclear layers and retinal ganglion cells were disorganized; the choroidal thickness (ChT), blood vessel lumen, and area were decreased; the sclera was thinner, with disordered fibers and increased interfibrillar space. IHC and ISH revealed that VIP's mRNA and protein expressions were significantly up-regulated in the retina of the FDM group. Atropine treatment attenuated FDM-induced myopic shift and fundus changes, considerably reducing VIP's mRNA and protein expressions. CONCLUSIONS: The findings of elevated VIP mRNA and protein levels observed in the FDM group indicate the potential involvement of VIP in the pathogenesis and progression of myopia. The ability of atropine to reduce this phenomenon suggests that this may be one of the molecular mechanisms for atropine to control myopia.

Anti-rheumatic colchicine phytochemical exhibits potent antiviral activities against avian and seasonal Influenza A viruses (IAVs) via targeting different stages of IAV replication cycle.

BACKGROUND: The continuous evolution of drug-resistant influenza viruses highlights the necessity for repurposing naturally-derived and safe phytochemicals with anti-influenza activity as novel broad-spectrum anti-influenza medications. METHODS: In this study, nitrogenous alkaloids were tested for their viral inhibitory activity against influenza A/H1N1 and A/H5N1 viruses. The cytotoxicity of tested alkaloids on MDCK showed a high safety range (CC50 > 200 µg/ml), permitting the screening for their anti-influenza potential. RESULTS: Herein, atropine sulphate, pilocarpine hydrochloride and colchicine displayed anti-H5N1 activities with IC50 values of 2.300, 0.210 and 0.111 µg/ml, respectively. Validation of the IC50 values was further depicted by testing the three highly effective alkaloids, based on their potent IC50 values against seasonal influenza A/H1N1 virus, showing comparable IC50 values of 0.204, 0.637 and 0.326 µg/ml, respectively. Further investigation suggests that colchicine could suppress viral infection by primarily interfering with IAV replication and inhibiting viral adsorption, while atropine sulphate and pilocarpine hydrochloride could directly affect the virus in a cell-free virucidal effect. Interestingly, the in silico molecular docking studies suggest the abilities of atropine, pilocarpine, and colchicine to bind correctly inside the active sites of the neuraminidases of both influenza A/H1N1 and A/H5N1 viruses. The three alkaloids exhibited good binding energies as well as excellent binding modes that were similar to the co-crystallized ligands. On the other hand, consistent with in vitro results, only colchicine could bind correctly against the M2-proton channel of influenza A viruses (IAVs). This might explicate the in vitro antiviral activity of colchicine at the replication stage of the virus replication cycle. CONCLUSION: This study highlighted the anti-influenza efficacy of biologically active alkaloids including colchicine. Therefore, these alkaloids should be further characterized in vivo (preclinical and clinical studies) to be developed as anti-IAV agents.

Low-dose atropine 0.01% for the treatment of childhood myopia: a pan-India multicentric retrospective study.

OBJECTIVE: The objective of this study was to assess the efficacy of low-dose atropine 0.01% in controlling myopia progression among Indian children over a 2-year period. METHODS: This retrospective study, conducted across 20 centres in India, monitored the progression of myopia over 2 years after initiating treatment with 0.01% atropine eye drops. This included children between 6 and 14 years with baseline myopia ranging from -0.5 D to -6 D, astigmatism≤-1.5 D, anisometropia ≤ -1 D and documented myopia progression of ≥0.5 D in the year prior to starting atropine. Subjects with any other ocular pathologies were excluded. RESULTS: A total of 732 children were included in the data analysis. The mean age of the subjects was 9.3±2.7 years. The mean myopia progression at baseline (1 year before starting atropine) was -0.75±0.31 D. The rate of myopia progression was higher in younger subjects and those with higher baseline myopic error. After initiating atropine, myopia progression significantly decreased to -0.27±0.14 D at the end of the first year and -0.24±0.15 D at the end of the second year (p<0.001). Younger children (p<0.001) and higher baseline myopia (p<0.001) was associated with greater myopia progression and poor treatment response (p<0.001 for both). CONCLUSION: Low-dose atropine (0.01%) effectively reduces myopia progression over 2 years in Indian children.

Assessing the rebound phenomenon in different myopia control treatments: A systematic review.

PURPOSE: To review the rebound effect after cessation of different myopia control treatments. METHODS: A systematic review that included full-length randomised controlled studies (RCTs), as well as post-hoc analyses of RCTs reporting new findings on myopia control treatments rebound effect in two databases, PubMed and Web of Science, was performed according to the PRISMA statement. The search period was between 15 June 2023 and 30 June 2023. The Cochrane risk of bias tool was used to analyse the quality of the selected studies. RESULTS: A total of 11 studies were included in this systematic review. Unifying the rebound effects of all myopia control treatments, the mean rebound effect for axial length (AL) and spherical equivalent refraction (SER) were 0.10 ± 0.07 mm [-0.02 to 0.22] and -0.27 ± 0.2 D [-0.71 to -0.03] after 10.2 ± 7.4 months of washout, respectively. In addition, spectacles with highly aspherical lenslets or defocus incorporated multiple segments technology, soft multifocal contact lenses and orthokeratology showed lower rebound effects compared with atropine and low-level light therapy, with a mean rebound effect for AL and SER of 0.04 ± 0.04 mm [0 to 0.08] and -0.13 ± 0.07 D [-0.05 to -0.2], respectively. CONCLUSIONS: It appears that the different treatments for myopia control produce a rebound effect after their cessation. Specifically, optical treatments seem to produce less rebound effect than pharmacological or light therapies. However, more studies are required to confirm these results.

Effects on radius of curvature and refractive power of the cornea and crystalline lens by atropine 0.01% eye drops.

PURPOSE: The morphological changes in the cornea and crystalline lens have not been closely evaluated after the administration of atropine 0.01%. This study aims to evaluate the radii of curvature and refractive power of the cornea and lens in myopic eyes during atropine 0.01% treatment. METHODS: Children aged 6-14 years with myopia <-6.0 D were randomized to receive atropine 0.01% once nightly with single vision lenses or simply wear single vision lenses. Ocular biometric parameters were measured using the IOLMaster 700 biometry and the radii of corneal and lenticular curvature were simulated using a customized program. RESULTS: At the 9-month visit, 69 atropine-treated eyes and 50 control eyes were included in the final analyses. In atropine-treated eyes, the posterior corneal surface steepened (-0.05 ± 0.13 mm) and the anterior lenticular surface flattened (0.20 ± 0.69 mm) significantly within 3-6 months, whereas the posterior corneal surface and anterior lenticular surface gradually flattened (0.07 ± 0.23 and 0.32 ± 0.80 mm respectively) in the control eyes over 9 months. The difference in the change of corneal refractive power was significant between groups (-0.03 ± 0.18 D vs. 0.11 ± 0.24 D, p = 0.001), while that in the change of lenticular refractive power was statistically insignificant (0.01 ± 0.92 D vs. -0.22 ± 0.86 D, p = 0.161). CONCLUSIONS: The administration of atropine 0.01% exhibited a clinically short and subtle impact on the cornea and lens, which may shed light on new targets of action for atropine in inhibiting myopia.