Presbyopia: a New Potential Pharmacological Treatment

Presbyopia occurs after 40 years of age in humans with a progressive loss of accommodation. Accommodation depends on the contraction of the ciliary muscle and iris, lens changes and convergence.  The parasympathetic system regulates the degree of ciliary muscle and iris contraction necessary to modify the shape and position of the lens and its stimulation is effective through the activation of muscarinic receptors that are present in both structures. The hypothesis proposed here suggests the correction of accommodation in emmetropic presbyopic patients using a pharmacological treatment that includes a cholinergic agent combined with non-steroidal anti-inflammatory drugs (NSAIDs). This drug combination can restore near vision without affecting distance vision. It is important to note that the pharmaceutical form used was devoid of any inflammatory or other collateral effects

Presbyopia: a New Potential Pharmacological Treatment

Presbyopia occurs after 40 years of age in humans with a progressive loss of accommodation. Accommodation depends on the contraction of the ciliary muscle and iris, lens changes and convergence.  The parasympathetic system regulates the degree of ciliary muscle and iris contraction necessary to modify the shape and position of the lens and its stimulation is effective through the activation of muscarinic receptors that are present in both structures. The hypothesis proposed here suggests the correction of accommodation in emmetropic presbyopic patients using a pharmacological treatment that includes a cholinergic agent combined with non-steroidal anti-inflammatory drugs (NSAIDs). This drug combination can restore near vision without affecting distance vision. It is important to note that the pharmaceutical form used was devoid of any inflammatory or other collateral effects

Overview of pharmacological treatments for presbyopia

Background: Presbyopia is the normal progressive waning of accommodation with loss of the visual ability to focus on objects residing at different distances. Presbyopia exacts a cost in quality of life and professional efficiency of many people over 40 years of age. Presbyopia is likely to be 1 of the main pressing visual concerns of the 21st century, given that life expectancy is increasing, resulting in an aging population. This review aimed to address the 3 strategies of the pharmacological treatment for presbyopia. Methods: A review on PubMed/MEDLINE, Google Scholar, and Clinicaltrials.gov was performed to investigate the English literature on pharmacological treatment for presbyopia from beginning-of-year 2012 to September 30, 2020. Results: In addition to the treatment of presbyopia with glasses or contact lenses, new surgical strategies have been developed, some of which have been successful. However, during the last decade, a new, promising, non-invasive option for treating presbyopia has emerged: the pharmacological approach. Many researchers have developed 3 different lines of investigation from different assumptions, on a pharmacological basis. The first consisted of producing miosis, to take advantage of a pharmacologically induced pinhole effect, increasing depth-of-focus, and thus improving uncorrected near visual acuity. The second aimed to rehabilitate accommodation binocularly to enable good vision at all distances. Finally, the third approach attempted to rehabilitate lost elasticity in the human crystalline lens. Conclusions: None of the 3 discussed pharmacological strategies for treating presbyopia, prescribed globally, but patients of restoring accommodation strategy can adhere locally, where they are sold so far as master prescriptions

Developmental Changes in Accommodation Evidenced by an Ultrabiomicroscopy Procedure in Patients of Different Ages

We demonstrate that changes in the behaviour of the contractile ciliary muscle accompanied by augmented rigidity of the lens are the most important aspects in the loss of accommodation. With ultrabiomicroscopy (UBM), we demonstrated that the performance of the ciliary muscle is diminished and accompanied by rigidity of the lens. Both lens thickness and trabecular-ciliary process distance (TCPD) were the parameters that showed major alterations with the loss of accommodation in patients of different ages. The results indicated that the differences between these parameters in farsightedness and nearsightedness in the different groups of patients were positively correlated

Developmental Changes in Accommodation Evidenced by an Ultrabiomicroscopy Procedure in Patients of Different Ages

We demonstrate that changes in the behaviour of the contractile ciliary muscle accompanied by augmented rigidity of the lens are the most important aspects in the loss of accommodation. With ultrabiomicroscopy (UBM), we demonstrated that the performance of the ciliary muscle is diminished and accompanied by rigidity of the lens. Both lens thickness and trabecular-ciliary process distance (TCPD) were the parameters that showed major alterations with the loss of accommodation in patients of different ages. The results indicated that the differences between these parameters in farsightedness and nearsightedness in the different groups of patients were positively correlated

Fasting conditions: Influence of water intake on clinical chemistry analytes

Introduction: Currently available recommendations regarding fasting requirements before phlebotomy do not specify any maximum water intake volume permitted during the fasting period. The aim was to study the effects of 300 mL water intake 1 h before phlebotomy on specific analytes. Materials and methods: Blood was collected from 20 women (median age (min-max): 24 (22 - 50) years) in basal state (T0) and 1 h after 300 mL water intake (T1). Glucose, total proteins (TP), urea, creatinine, cystatin C, total bilirubin (BT), total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides (Tg), uric acid (UA), high-sensitivity C-reactive protein, gamma-glutamyl transferase (GGT), aspartate-aminotransferase (AST), alanine-aminotransferase and lactate-dehydrogenase (LD) were studied. Results were analyzed using Wilcoxon test. Mean difference (%) was calculated for each analyte and was further compared with reference change value (RCV). Only mean differences (%) higher than RCV were considered clinically significant. Results: Significant differences (median T0 vs median T1, P) were observed for TP (73 vs 74 g/L, 0.001); urea (4.08 vs 4.16 mmol/L, 0.010); BT (12 vs 13 μmol/L, 0.021); total cholesterol (4.9 vs 4.9 mmol/L, 0.042); Tg (1.05 vs 1.06 mmol/L, 0.002); UA (260 vs 270 μmol/L, 0.006); GGT (12 vs 12 U/L, 0.046); AST (22 vs 24 U/L, 0.001); and LD (364 vs 386 U/L, 0.001). Although the differences observed were statistically significant, they were not indicative of clinically significant changes. Conclusions: A water intake of 300 mL 1 h prior to phlebotomy does not interfere with the analytes studied in the present work

Coffee intake one hour prior to phlebotomy produces no clinically significant changes in routine biochemical test results

IntroductionAlthough current guidelines recommend not drinking coffee prior to phlebotomy, our hypothesis is that drinking coffee does not affect the clinical interpretation of biochemical and haematological test results. Materials and methodsTwenty-seven volunteers were studied in basal state (T0) and 1h after (T1) drinking coffee. Routine haematological (Sysmex-XN1000 analyser) and biochemistry parameters (Vitros 4600 analyser) were studied. Results were compared using the Wilcoxon test (P < 0.05). A clinical change was considered when mean percent difference (MD%) was higher than the reference change value (RCV). ResultsCoffee intake produced statistically, but not clinically, significant: i) increases in haemoglobin (P = 0.009), mean cell haemoglobin concentration (P = 0.044), neutrophils (P = 0.001), albumin (P = 0.001), total protein (P = 0.000), cholesterol (P = 0.025), high density lipoprotein cholesterol (P = 0.007), uric acid (P = 0.011), calcium (P = 0.001), potassium (P = 0.010), aspartate aminotransferase (P = 0.001), amylase (P = 0.026), and lactate dehydrogenase (P = 0.001), and ii) decreases in mean cell volume (P = 0.002), red cell distribution width (P = 0.001), eosinophils (P = 0.002), and lymphocytes (P = 0.001), creatinine (P = 0.001), total bilirubin (P = 0.012), phosphorus (P = 0.001), magnesium (P = 0.007), and chloride (P = 0.001). ConclusionDrinking a cup of coffee 1 hour prior to phlebotomy produces no clinically significant changes in routine biochemical and haematological test results

Avaliação do desempenho analítico do três métodos de quantificação de hemoglobina A1c

El laboratorio debe garantizar la exactitud de los resultados de HbA1c cumpliendo con los requisitos analíticos internacionales de calidad, cada vez más estrictos, y asegurar que una variación de HbA1c de 0,5 puntos porcentuales (%-NGSP) o más entre dos controles consecutivos de un paciente diabético se deba a una variación clínica y no a una variación analítica. En este trabajo se evaluó el desempeño analítico de tres métodos comerciales para HbA1c: Inmunoturbidimétrico, Enzimático y Cromatográfico de Intercambio Catiónico. Para tal fin, se procesaron por cada método distintos controles comerciales de HbA1c, con trazabilidad al método de referencia IFCC, determinándose en cada caso Coeficiente de Variación Total, Bias, Error Total, Valor de Referencia del Cambio y cambio clínico significativo de HbA1c en el punto crítico 7,0 %-NGSP. En las condiciones analíticas de este trabajo, solamente el método Inmunoturbidimétrico tuvo un desempeño analítico aceptable, permitiendo atribuir un cambio de 0,5 %-NGSP a una variación clínica significativa del paciente. Frente a las recomendaciones internacionales sobre el uso de HbA1c en el control y diagnóstico de diabetes, es indiscutible la importancia de elegir un método que satisfaga los requerimientos analíticos mínimos de calidad para asegurar la utilidad clínica del resultado de HbA1c.The laboratory must guarantee the accuracy of HbA1c results meeting the increasingly strict international analytical quality standards and assuring that an HbA1c variation of 0.5 percentage points (%-NGSP) or more between two consecutive controls of a diabetic patient is due to a clinical variation and not to an analytical variation. In this paper, the analytical performance of three commercial methods for HbA1c: Immunoturbidimetric, Chromatographic and Enzymatic Cation Exchange, were evaluated. For this purpose, commercial con- trols with assigned values traceable to the IFCC reference method for HbA1c were processed. For each methodology, total Coefficient of Variation (CV%), Bias%, Total Error (TE%), Change Reference Value and Clinically Significant Change (CSC) at the critical point of HbA1c 7.0%-NGSP were determined. Within the analytical conditions of this study, only the immunoturbidimetric method had an acceptable analytical performance, allowing attribute a change in 0.5%-NGSP to a significant clinical variation. Faced with international recommendations on the use of HbA1c on control and diagnosis of diabetes, the importance of choosing a method that meets the minimum analytical quality requirements to ensure the clinical utility of HbA1c result is undeniable.O laboratório deve garantir a precisão dos resultados da HbA1c cumprindo com os requisitos analíticos internacionais de qualidade cada vez mais exigentes e garantir que uma variação de HbA1c de 0,5 pontos percentuais (% - NGSP) ou mais entre duas verificações consecutivas de um doente diabético seja devido a uma variação clínica e não a uma variação analítica. Neste trabalho foi avaliado o desempenho analítico de três métodos comerciais para HbA1c: imunoturbidimétrico, enzimático e cromatográfico de intercâmbio catiônico. Para esse fim, foram processados diversos controles comerciais de HbA1c por cada método, com rastreabilidade ao método de referência IFCC, determinando em cada caso Quociente de Variação Total, Bias, Erro Total, Valor de Referência da Alteração e Alteração Clinicamente Significativa de HbA1c no ponto crítico 7,0%-NGSP. Nas condições de análise deste estudo, apenas o método imunoturbidimétrico teve um desempenho analítico aceitável, permitindo atribuir uma alteração de 0,5%-NGSP a uma variação clínica significativa do paciente. Perante as recomendações internacionais sobre o uso da HbA1c no controle e diagnóstico da diabetes, é inegável a importância de escolher um método que atenda os requisitos analíticos mínimos de qualidade de análise para garantir a utilidade clínica do resultado HbA1c.Fil: Unger, Gisela. Universidad Nacional del Sur; ArgentinaFil: Ruiz, Gustavo. Laboratorio Privado Dr. Ruiz; ArgentinaFil: Milano, Pablo Gustavo. Consejo Nacional de Investigaciones Cientí­ficas y Técnicas. Centro Científico Tecnológico Bahí­a Blanca. Instituto de Investigaciones Bioquí­micas Bahí­a Blanca (i); ArgentinaFil: Benozzi, Silvia. Universidad Nacional del Sur; ArgentinaFil: Pennacchiotti, Graciela Laura. Universidad Nacional del Sur; Argentina. Hospital Municipal Dr. Lucero de Bahía Blanca; Argentin