ascorbic-acid and Glaucoma

There is currently a lack of high-quality research on the best dietary recommendations for patients with early glaucoma or at high risk for glaucoma. This meta-analysis aims to clarify the relationship between vitamin intake and glaucoma risk. Electronic databases, including PubMed, EMbase, ScienceDirect, Cochrane Database, Clinicaltrials.gov, and Google Scholar, were searched for publications indexed as of September 18, 2021. Data were expressed as odds ratios (ORs) with 95% confidence intervals (CIs). The I

Topics: Ascorbic Acid; Glaucoma; Humans; Odds Ratio; Vitamin A; Vitamins

Since the retina continuously receives light to enable vision, reactive oxygen species (ROS) are easily generated in neural retina. The oxidative stress induced by ROS may be involved in the onset and progression of blinding aging diseases such as age-related macular degeneration, diabetic retinopathy, and glaucoma. Although supply of antioxidants to the retina is important to maintain the redox homeostasis in neural retina, the blood-retinal barrier (BRB) is created by complex tight-junctions of retinal capillary endothelial cells and retinal pigment epithelial cells to prevent the free diffusion of substances. The BRB is equipped with several membrane transporters to supply nutrients and essential molecules including antioxidants and drugs which exhibit antiaging effect to the retina from the circulating blood. In this review, the transporter-mediated retinal distribution of key endogenous compounds and drugs, such as vitamin C, l-cystine and gabapentin, is introduced for antiaging of the retina.

Topics: Animals; Antioxidants; Ascorbic Acid; Blood-Retinal Barrier; Cystine; Diabetic Retinopathy; Endothelial Cells; Gabapentin; Glaucoma; Homeostasis; Humans; Macular Degeneration; Oxidation-Reduction; Oxidative Stress; Rats; Reactive Oxygen Species; Retina; Tight Junctions

Vision loss affects 37 million Americans older than 50 years and one in four who are older than 80 years. The U.S. Preventive Services Task Force concludes that current evidence is insufficient to assess the balance of benefits and harms of screening for impaired visual acuity in adults older than 65 years. However, family physicians play a critical role in identifying persons who are at risk of vision loss, counseling patients, and referring patients for disease-specific treatment. The conditions that cause most cases of vision loss in older patients are age-related macular degeneration, glaucoma, ocular complications of diabetes mellitus, and age-related cataracts. Vitamin supplements can delay the progression of age-related macular degeneration. Intravitreal injection of a vascular endothelial growth factor inhibitor can preserve vision in the neovascular form of macular degeneration. Medicated eye drops reduce intraocular pressure and can delay the progression of vision loss in patients with glaucoma, but adherence to treatment is poor. Laser trabeculoplasty also lowers intraocular pressure and preserves vision in patients with primary open-angle glaucoma, but long-term studies are needed to identify who is most likely to benefit from surgery. Tight glycemic control in adults with diabetes slows the progression of diabetic retinopathy, but must be balanced against the risks of hypoglycemia and death in older adults. Fenofibrate also slows progression of diabetic retinopathy. Panretinal photocoagulation is the mainstay of treatment for diabetic retinopathy, whereas vascular endothelial growth factor inhibitors slow vision loss resulting from diabetic macular edema. Preoperative testing before cataract surgery does not improve outcomes and is not recommended.

Topics: Aged; Aged, 80 and over; Angiogenesis Inhibitors; Antihypertensive Agents; Ascorbic Acid; Bevacizumab; Blindness; Cataract; Cataract Extraction; Diabetic Retinopathy; Fenofibrate; Glaucoma; Humans; Hypolipidemic Agents; Intravitreal Injections; Light Coagulation; Macular Degeneration; Mass Screening; Practice Guidelines as Topic; Ranibizumab; Vision Disorders; Vision, Low; Vitamin E; Vitamins

Topics: Animals; Antioxidants; Ascorbic Acid; Cells, Cultured; Cornea; Corneal Injuries; Eye Injuries; Fibroblasts; Filtering Surgery; Glaucoma; Humans; Wound Healing

Topics: Adult; Aged; Amino Acids; Animals; Aqueous Humor; Ascorbic Acid; Blood Glucose; Child; Cyclic AMP; Drug Interactions; Drug Synergism; Endophthalmitis; Eye; Eye Diseases; Glaucoma; Humans; Intraocular Pressure; Kinetics; Middle Aged; Moxisylyte; Pharmacogenetics; Prostaglandins; Rabbits; Toxicology

Topics: Adrenergic beta-Antagonists; Animals; Anterior Chamber; Aqueous Humor; Ascorbic Acid; Calcium Chloride; Carbonic Anhydrase Inhibitors; Glaucoma; Glucose; Glycosaminoglycans; Gonioscopy; Hypertonic Solutions; Hypotonic Solutions; Injections, Intravenous; Intraocular Pressure; Isotonic Solutions; Osmolar Concentration; Propylene Glycols; Rabbits; Sodium Chloride; Tonometry, Ocular

Topics: Administration, Oral; Aerospace Medicine; Altitude; Animals; Aqueous Humor; Ascorbic Acid; Calcium; Glaucoma; Humans; Injections, Intravenous; Intraocular Pressure; Rabbits

Topics: Animals; Anterior Chamber; Aqueous Humor; Ascorbic Acid; Blood Pressure; Cataract; Child; Cryosurgery; Diabetes Complications; Glaucoma; Gonioscopy; Humans; Intraocular Pressure; Microsurgery; Miotics; Ophthalmodynamometry; Sclera; Thrombosis; Tonometry, Ocular; Uveitis, Anterior; Visual Field Tests

Topics: Ascorbic Acid; Clinical Trials as Topic; Female; Glaucoma; Humans; Male; Ophthalmic Solutions; Placebos

Pathophysiology of pseudoexfoliation syndrome (XFS) can be influenced by environmental factors such as solar exposure/occupational factors and genetic factors.. The study aims to assess the association of lifetime ocular UV exposure and its impact on the risk of development of XFS.. All eligible subjects underwent a comprehensive ocular examination. XFS was defined as precipitates on the pupillary border, cornea, and angle of anterior chamber or lens in at least one eye without any clinical signs of glaucoma. A standardised questionnaire was administered to assess the lifetime UV exposure. Conjunctival ultraviolet autofluorescence (CUVAF) photography was taken to detect the conjunctival changes with exposure to UV radiation. Ascorbic acid concentration in the aqueous humour was measured.. A total of 404 subjects of which 274 (controls) and 130 (XFS cases) were studied. There were 204 males (50.5%) and 200 females (49.5%).Lifetime UV exposure (OR: 1.14, 95% CI: 1.02-1.30, p: 0.032), CUVAF damage (OR: 1.03, 95% CI: 1.01-1.06, p: 0.008) and outdoor worker (OR: 1.87, 95% CI: 1.18-3.00, p: 0.008) were positively associated with XFS. Usage of spectacles (OR: 0.63, 95% CI: 0.39-0.95, p: 0.030) and ascorbic acid concentration in aqueous (OR: 0.47, 95% CI: 0.23-0.99, p: 0.038) were found to be protective against XFS.. Besides genetic factors, environmental factors such as lifetime ocular UV exposure and outdoor work are significantly associated with the risk of XFS. CUVAF can be used as a non-invasive tool to detect preclinical sun damage in outdoor workers.

Topics: Ascorbic Acid; Conjunctiva; Exfoliation Syndrome; Female; Glaucoma; Humans; Male; Ultraviolet Rays

Glaucoma is a common neurodegenerative disorder characterized by retinal ganglion cell death, astrocyte reactivity in the optic nerve, and vision loss. Currently, lowering the intraocular pressure (IOP) is the first-line treatment, but adjuvant neuroprotective approaches would be welcome. Vitamin C possesses neuroprotective activities that are thought to be related to its properties as a co-factor of enzymes and its antioxidant effects. Here, we show that vitamin C promotes a neuroprotective phenotype and increases gene expression related to neurotropic factors, phagocytosis, and mitochondrial ATP production. This effect is dependent on the up-regulation of secreted phosphoprotein 1 (SPP1) in reactive astrocytes via the transcription factor E2F1. SPP1

Topics: Animals; Ascorbic Acid; Glaucoma; Mice; Optic Nerve; Osteopontin; Retinal Ganglion Cells

Previous studies regarding antioxidant consumption and glaucoma have shown contradictory results. The aim of this study was to analyze the combined effect of the consumption of three vitamins (A, C and E) on the incidence of glaucoma in the SUN Project.. For this study, 18,669 participants were included. The mean follow-up was 11.5 years. An index including vitamins A, C and E (ACE-Vitamin Index) was calculated. Vitamin intake was extracted from participants' dietary data and vitamin supplements, if taken. Information on glaucoma incidence was collected by previously validated self-reported questionnaires. The association between glaucoma and vitamin intake was assessed by repeated-measures Cox regression using multi-adjusted hazard ratios.. A total of 251 (1.3%) cases of glaucoma were detected. Participants with a higher ACE-Vitamin Index presented a reduced risk of glaucoma compared to participants with lower consumption (adjusted HR = 0.73; 95% CI, (0.55-0.98)). When each vitamin was analyzed individually, none of them had a significant protective effect. The protective effect of the ACE-Vitamin Index was higher in men and older participants (≥55 year).. The consumption of vitamins A, C and E considered separately do not seem to exert a protective effect against glaucoma, but when these vitamins are considered together, they are associated with a lower risk of glaucoma.

Topics: Antioxidants; Ascorbic Acid; Dietary Supplements; Glaucoma; Humans; Male; Vitamin A; Vitamin E; Vitamins

The development of advanced drug delivery systems with extensively sustained release and multiple functions is highly imperative for effective attenuation of the degradation of ocular extracellular matrix that is associated with inflammatory glaucoma. Here, the generation of amine-terminated polyamidoamine dendrimers in an injectable biodegradable thermogel is demonstrated to be important for achieving prolonged drug release profiles and potent anti-inflammatory effects. Among various generations (Gx, x = 0, 1, 3, 5), third-generation G3 is proved as the most effective material for optimizing the synergistic effects of gelatin and poly(N-isopropylacrylamide) and generating a thermogel with the highest biodegradation resistance, the best drug encapsulation/extended-release performance, and the best ability to reduce the elevated expression of inflammatory molecules. A pharmacotherapy based on intracameral injection of thermogels coloaded with pilocarpine and ascorbic acid results in effective alleviation of progressive glaucoma owing to the anti-inflammatory activity and long-acting drug release (above a therapeutic level of 10 µg mL

Topics: Animals; Ascorbic Acid; Biocompatible Materials; Cattle; Collagen; Drug Carriers; Drug Delivery Systems; Extracellular Matrix; Gelatin; Gels; Glaucoma; Pilocarpine

Elevated intraocular pressure (IOP) is an important risk factor for glaucoma. Mechanisms involved in its homeostasis are not well understood, but associations between metabolic factors and IOP have been reported. To investigate the relationship between levels of circulating metabolites and IOP, we performed a metabolome-wide association using a machine learning algorithm, and then employing Mendelian Randomization models to further explore the strength and directionality of effect of the metabolites on IOP. We show that O-methylascorbate, a circulating Vitamin C metabolite, has a significant IOP-lowering effect, consistent with previous knowledge of the anti-hypertensive and anti-oxidative role of ascorbate compounds. These results enhance understanding of IOP control and may potentially benefit future IOP treatment and reduce vision loss from glaucoma.

Topics: Adult; Aged; Ascorbic Acid; Female; Glaucoma; Humans; Intraocular Pressure; Male; Metabolome; Metabolomics; Middle Aged; Public Health Surveillance

Topics: Animals; Antihypertensive Agents; Benzimidazoles; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Design; Female; Glaucoma; Humans; Molecular Docking Simulation; Molecular Structure; Protein Kinase Inhibitors; Rats; Recombinant Proteins; rho-Associated Kinases; Structure-Activity Relationship

To investigate the potential association between glaucoma prevalence and supplemental intake, as well as serum levels of vitamins A, C and E.. This cross-sectional study included 2912 participants in the 2005-2006 National Health and Nutrition Examination Survey, age ≥40 years, who self-reported a presence or absence of glaucoma. Participants were interviewed regarding the use of dietary supplements during the preceding 30-day period. Participants also underwent serum measurements of vitamins A, C, and E (both alpha- and gamma-tocopherol). Information on the primary outcome measure, presence or absence of glaucoma, as well as demographic information, comorbidities and health-related behaviors, was assessed via interview.. Multivariate odds ratios for self-reported glaucoma, comparing the highest quartile of consumption to no consumption, and adjusted for potential confounding variables were 0.48 (95% confidence interval (CI) 0.13-1.82) for vitamin A, 0.47 (95% CI 0.23-0.97) for vitamin C, and 2.59 (95% CI 0.89-7.56) for vitamin E. Adjusted odds ratios for self-reported glaucoma comparing the highest vs lowest quintiles of vitamin serum levels were 1.44 (95% CI 0.79-2.62) for vitamin A, 0.94 (95% CI 0.42-2.11) for vitamin C, 1.40 (95% CI 0.70-2.81) for alpha-tocopherol, and 0.64 (95% CI 0.24-1.70) for gamma-tocopherol.. Neither supplementary consumption with nor serum levels of vitamins A and E were found to be associated with glaucoma prevalence. While low- and high-dose supplementary consumption of vitamin C was found to be associated with decreased odds of glaucoma, serum levels of vitamin C did not correlate with glaucoma prevalence.

Topics: Adult; Aged; Antioxidants; Ascorbic Acid; Cross-Sectional Studies; Dietary Supplements; Female; Glaucoma; Humans; Male; Middle Aged; Odds Ratio; United States; Vitamin A; Vitamin E; Vitamins

To establish the antioxidant status of the aqueous humour in glaucoma associated with exfoliation syndrome (XFG) and to compare it to primary open-angle glaucoma (POAG) and cataract patients.. Patients were diagnosed with POAG, XFG, or cataract (n=25 for each group). Total reactive antioxidant potential (TRAP) was measured by chemiluminescence. Ascorbic acid levels and the activities of catalase, glutathione peroxidase (GPx), and superoxide dismutase (SOD) were measured spectrophotometrically.ResultsTRAP value was lower in XFG (28+/-2 microM Trolox) than in POAG (55+/-8 microM Trolox; P<0.001). TRAP values in both glaucomas were lower than the cataract value (124+/-5 microM Trolox; P<0.001). A decrease in ascorbic acid was measured in XFG (230+/-20 microM) compared with POAG (415+/-17 microM; P<0.001). Ascorbic acid in both glaucomas was lower than in cataract (720+/-30 microM; P<0.001). A significant increase in GPx was found in XFG (30+/-2 U/ml) compared with POAG (16+/-3 U/ml). GPx activity in both glaucomas was increased when compared with cataracts (6+/-2 U/ml; P<0.001). A significant increase of 67% in SOD activity was observed in the glaucoma group vscataract group (27+/-3 U/ml; P<0.001), but no changes were found between both glaucomas.. The antioxidant status of the aqueous humour may play a role in the pathophysiology of both glaucomas.

Topics: Aged; Aged, 80 and over; Antioxidants; Aqueous Humor; Ascorbic Acid; Catalase; Cataract; Exfoliation Syndrome; Female; Glaucoma; Glaucoma, Open-Angle; Glutathione Peroxidase; Humans; Luminescence; Male; Superoxide Dismutase

To evaluate changes in the reducing power of aqueous humor (AH) with cyclic voltammetry (CV) and HPLC-EC.. NZW Rabbits exhibiting a sporadic mutation causing bilaterally buphthalmus eyes were set for intra ocular pressure (IOP) and eye size measurements. AH was obtained under anesthesia, from congenital glaucomatic rabbits (CGR, n=6) and age-matched controls (CON; n=6). The AH samples were analysed by CV and HPLC-EC.. CGR IOP was found to be significantly higher than in CON (33.5+/-1.1 and 14.2+/-1.0 mmHg, respectively), eye size was 18.25 and 13.9 cm, respectively. CV analysis revealed two anodic currents representing two groups of low molecular weight antioxidant (LMWA). The two anodic potentials were equal for the two tested groups, indicating the same components of LMWA. The first anodic current of CGR was only 30% of the CON rabbits (2.11 vs7.17 microA/mg protein, t-test: P<0.05). As the main hydrophilic components of the first anodic current are known to be uric acid (UA) and ascorbic acid (AA), they were analysed for exact content by HPLC-EC. UA and AA levels were significantly lower in the CGR group (UA: 17.1+/-3.2 and 189.1+/-75.70 microM/mg, AA: 1.1+/-0.3 and 4.8+/-2.0 microM/mg protein respectively).. Changes in the reducing power, as indicated by CV analysis, of CGR AH, is probably a result of chronic oxidative stress caused by the pathology. The differences in the first anodic wave are mainly due to a fall in the concentration of UA and AA.

Topics: Animals; Aqueous Humor; Ascorbic Acid; Chromatography, High Pressure Liquid; Disease Models, Animal; Eye; Female; Glaucoma; Intraocular Pressure; Male; Oxidation-Reduction; Rabbits; Uric Acid

Topics: Antioxidants; Ascorbic Acid; Cataract; Clinical Trials as Topic; Dietary Supplements; Eye Diseases; Glaucoma; Humans; Macular Degeneration; Risk Factors; Smoking; Vitamin E; Vitamins

This study was performed to better understand the differences between patients in specific components of wound healing as it may pertain to glaucoma filtration surgery, including the use of antimetabolites.. Human Tenon's capsule fibroblasts were obtained at the time of glaucoma filtering surgery and established in individual cell cultures from 35 glaucoma patients. The dose-response to 5-fluorouracil (5FU) and mitomycin C (MMC) was determined. The individual cell lines were exposed to the antimetabolites and ascorbic acid with measurement of collagen type I and III production by an ELISA-type dot blot assay. These results were then statistically compared to the individual patient characteristics including age, race, previous surgery and medications, and type of glaucoma.. 5-FU had little effect on collagen type I and III production or protein synthesis. MMC had an inhibitory effect on collagen secretion and total protein synthesis with increasing concentration. Photomicrographs of the cells after each treatment condition revealed characteristic morphologic changes when compared to controls. There was a large range of collagen type I and III production with correlation between the amounts of each collagen type secreted in response to the antimetabolites. However, there was no correlation with accepted risk factors for filtration failure.. These antimetabolites act similarly on different cell lines in a nonspecific manner. The results suggest that the increased risk of filtration failure due to age, race, diagnosis, and previous conjunctival surgery is not due to differences in secretion of collagen types I and III by Tenon's capsule fibroblasts.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Antimetabolites; Ascorbic Acid; Cells, Cultured; Child; Collagen; Conjunctiva; Enzyme-Linked Immunosorbent Assay; Fibroblasts; Filtering Surgery; Fluorouracil; Glaucoma; Humans; Infant; Middle Aged; Mitomycin; Retrospective Studies; Sclera; Wound Healing

To determine if there is an association between the surgical outcome of trabeculectomy and uric acid and ascorbic acid concentrations in the aqueous humor at the time of the procedure.. Aqueous humor samples were collected from the eyes of 169 of 249 adult patients who underwent trabeculectomy alone for any type of glaucoma between April 1989 and July 1995. Postoperatively, all medical records were reviewed and outcomes were classified as successful, unsuccessful, or indeterminate. The ascorbic acid and uric acid concentrations were determined in masked fashion by high-pressure liquid chromatography. Factors associated with surgical outcome were determined.. Uric acid concentration was higher in unsuccessful eyes (mean+/-SD, 0.21+/-0.08 mmol/L, n=26) than in successful eyes (0.15+/-0.09 mmol/L, n=91, 95% confidence interval for difference, 0.02-0.10 mmol/L). Ascorbic acid levels were not significantly different in the eyes with unsuccessful (1129.9+/-601.9 micromol/L) and successful (1334.3+/-511.0 micromol/L) surgery (95% confidence interval for difference, -475.2 to 66.4 micromol/L, P=.13) surgery. Other factors associated with failure were previous surgery and surgery performed at the inferior limbus. A multiple polytomous logistic regression analysis was performed, after excluding the small number of operations performed at the inferior limbus. The odds ratio for failure increased by a factor of 1.68 for every 1-mmol/L increase in uric acid (95% confidence interval, 1.16-2.43, P=.006).. Uric acid levels were higher at the time of surgery in eyes that had unsuccessful outcomes than in those with successful outcomes. No significant difference in ascorbic acid levels was detectable. A higher uric acid level in the aqueous humor is a risk factor for trabeculectomy failure and might be tested as a prognostic indicator [corrected].

Topics: Aged; Aqueous Humor; Ascorbic Acid; Chromatography, High Pressure Liquid; Female; Glaucoma; Humans; Male; Middle Aged; Regression Analysis; Risk Factors; Trabeculectomy; Treatment Outcome; Uric Acid

Topics: Ascorbic Acid; Cell Division; Fibroblasts; Glaucoma; Humans; Prognosis; Tendons; Trabeculectomy

Successful glaucoma filtration surgery depends on the incomplete healing of the surgical wound, with formation of a filtration bleb. In most other tissues, however, complete healing is the rule. I have explored the possibility that the high concentration of ascorbic acid normally present in aqueous humor inhibits wound healing after filtration surgery. At the concentration normally present in aqueous humor (1.1 mmol/L), ascorbic acid decreased the plating efficiency of cell suspensions of human Tenon's capsule fibroblasts by a mean (+/- SD) of 40% +/- 10%. When added to low-density monolayer cultures of fibroblasts, ascorbic acid decreased the cell number by 90% +/- 5%, an effect that was completely prevented by catalase. When added to confluent cultures, the cell number was decreased by only 14% +/- 2%. If ascorbic acid has similar effects on fibroblasts in vivo, it may contribute to the incomplete wound healing that characterizes successful glaucoma surgery.

Topics: Ascorbic Acid; Catalase; Cell Division; Cells, Cultured; Fibroblasts; Glaucoma; Humans; Sclera; Trabeculectomy

Topics: Ascorbic Acid; Glaucoma; Humans

Aqueous humor from human glaucomatous eyes was divided into two groups. Group I aqueous humor contains a negligible amount of ascorbate, while group II contains ascorbate. Group I aqueous humor stimulates ascorbate oxidation. This oxidative effect is inhibited by the addition of EDTA, indicating the presence of metallic ions. The amount of copper determined by atomic spectrophotometry in these samples was 1.54 micrograms/ml. On the contrary, group II aqueous humor protects against ascorbate oxidation. The small amount of albumin present in these samples accounts for part of this protective effect.

Topics: Aqueous Humor; Ascorbic Acid; Copper; Edetic Acid; Eye Proteins; Glaucoma; Humans; Osmolar Concentration; Oxidation-Reduction; Serum Albumin

Serum, aqueous humour, and lens ascorbic acid levels were determined by high-performance liquid chromatography in cataract-, closed-angle glaucoma-, and aphakic patients. The total number of 108 patients were subdivided into different groups. In several groups the pre-operative serum and aqueous amounts were tested, whereafter patients in some groups were loaded with ascorbic acid orally. Finally, a second test was performed on samples taken during operation. It turned out that the ascorbic acid concentration mechanism in cataractous eyes needed more than 12 h for maximum reaction on the loading stimulus. The slow reaction is surprising compared to other species, and it may reflect an affection of the secretory process itself in this disease.

Topics: Aged; Aphakia, Postcataract; Aqueous Humor; Ascorbic Acid; Cataract; Cataract Extraction; Chromatography, High Pressure Liquid; Female; Glaucoma; Humans; Lens, Crystalline; Male; Middle Aged; Time Factors

It has been postulated that glycosaminoglycans in the trabeculum have an influence on aqueous humor drainage. Ascorbate reduces the viscosity of hyaluronic acid, and also increases outflow facility. Our recent observation of high urate concentrations in some glaucomatous eyes led us to study the influence of urate on oxidative degradation of hyaluronic acid by ascorbate. The viscosity of rooster comb hyaluronic acid was reduced slowly by ascorbate. Cupric sulfate accelerated ascorbate oxidation and also enhanced hyaluronic acid degradation. Urate inhibited ascorbate oxidation and prevented the copper catalyzed oxidative degradation of rooster comb hyaluronic acid. The range of urate concentrations used in this study was within the range of urate concentrations observed in glaucomatous eyes. The partially purified umbilical cord hyaluronic acid had lower viscosity than rooster comb hyaluronic acid, and rapidly degraded in the presence of ascorbate. The ascorbate effect on umbilical cord hyaluronic acid was partially prevented by urate.

Topics: Animals; Aqueous Humor; Ascorbic Acid; Chickens; Copper; Copper Sulfate; Drug Interactions; Female; Glaucoma; Humans; Hyaluronic Acid; In Vitro Techniques; Male; Oxidation-Reduction; Pregnancy; Trabecular Meshwork; Umbilical Cord; Uric Acid; Viscosity

Topics: Aged; Ascorbic Acid; Female; Glaucoma; Glycerol; Humans; Intraocular Pressure; Optic Disk; Time Factors; Vision Tests; Visual Fields

In vivo incubations of Hgb SC erythrocytes showed significantly more sickling in anterior chambers characterized by high concentrations of ascorbic acid than in anterior chambers with low concentrations of ascorbic acid (normal guinea pigs compared with scorbutic guinea pigs and normal guinea pigs compared with normal rats). Low concentrations of ascorbic acid, however, did not completely eliminate intracameral sickling. Because acetazolamide raises the concentration of aqueous humor ascorbate, it should be used with considerable discretion when treating hyphema and secondary glaucoma caused by sickle cells. Methazolamide may be more desirable.

Topics: Acetazolamide; Anemia, Sickle Cell; Animals; Anterior Chamber; Aqueous Humor; Ascorbic Acid; Erythrocytes, Abnormal; Glaucoma; Guinea Pigs; Hemoglobin, Sickle; Humans; Hyphema; Injections; Male; Rats; Sickle Cell Trait

Blood levels of thiamine and ascorbic acid in chronic open-angle glaucoma are determined in this study. Dietary vitamin intake was compared with thiamine and ascorbic acid blood levels in a sample of 38 patients with glaucoma and 12 controls. These patients had a statistically significant lower thiamine blood level than controls (P less than 0.001), but no significant difference was found for ascorbic acid blood levels. Poor absorption of thiamine occurred in the glaucomatous patients in this study.

Topics: Adult; Aged; Ascorbic Acid; Black People; Diet; Evaluation Studies as Topic; Female; Glaucoma; Guyana; Humans; Male; Middle Aged; Thiamine; Thiamine Deficiency

Standard values of the intraocular pressure, as an average result of mass examinations, need not be valid in the actual case. So the upper limit of the intraocular pressure for a hypertonic patient may be higher than in persons with arterial hypotonia. In order to achieve an individual approach A. M. Vodovozov introduced in 1975 the notion of tolerable intraocular pressure (Ptl) which may be determined by means of campimetry and perimetry, or using hemodynamic and electrophysiological methods. Here the campimetric method of determining the individually tolerable intraocular pressure (Ptl) is described. The size of the blind spot (namely the vertical diameter) and the pertinent intraocular pressure are measured several times (every half an hour), in the course of which the effect of an oral dose of glycerol combined with ascorbic acid is observed. That tonometric value which coincides with the minimal size of the blind spot is considered as the individually tolerable level of intraocular pressure. The campimetric investigation of 98 eyes in 52 glaucomatous patients showed that the tolerable intraocular pressure may be above as well as below the standard. This aids in ordering the appropriate treatment and in preventing the loss of ocular function in glaucomatous patients.

Topics: Ascorbic Acid; Glaucoma; Glycerol; Humans; Intraocular Pressure; Optic Disk; Reference Values; Tonometry, Ocular; Visual Field Tests; Visual Fields

Blood pH, aqueous pH, and intraocular tension were noted in 20 albino rabbits before and after administration of vitamin C in oral dosage of 7.5 gm/kg/day (in 4 equal divided doses for one week). A significant difference was noted in changes of blood pH and fall in intraocular tension but aqueous pH did not show any change. In 20 glaucoma patients there was no significant change in pH of blood of glaucoma after administration of vitamin C in 3.5 gm/kg body weight per day by oral route for one week (in 4 equal divided doses).

Topics: Acid-Base Equilibrium; Animals; Aqueous Humor; Ascorbic Acid; Blood; Drug Administration Schedule; Glaucoma; Humans; Hydrogen-Ion Concentration; Intraocular Pressure; Male; Rabbits

Topics: Aerospace Medicine; Altitude; Animals; Aqueous Humor; Ascorbic Acid; Calcium; Glaucoma; Humans; Intraocular Pressure; Potassium; Sodium; Water-Electrolyte Balance

Topics: Ascorbic Acid; Drug Combinations; Female; Glaucoma; Glycerol; Humans; Injections, Intravenous; Male; Middle Aged

The mean value for aqueous concentration in 35 patients with open-angle glaucoma was 22.4 +/- 12.9 mg/100 ml. The mean value for aqueous ascorbate in four patients with uncomplicated senile cataract was 11.55 +/- 3.01 mg/100 ml. The results indicate that the majority of open-angle glaucomatous eyes do not involve a deficiency of ascorbate, and suggest that ascorbate has no therapeutic value in the management of primary open-angle glaucoma. The magnitude of aqueous ascorbate variation among glaucoma eyes is probably related to the factors that influence the patency of trabecular meshwork, not the metabolic activity of the ciliary processes.

Topics: Animals; Aqueous Humor; Ascorbic Acid; Glaucoma; Humans; Rabbits

Topics: Animals; Anterior Chamber; Aqueous Humor; Ascorbic Acid; Glaucoma; Rabbits; Steroids

Some aqueous humor constituents, including ascorbate, protein, and sodium, potassium, and calcium ions, were analyzed in three groups of adult buphthalmic (bu/bu) rabbits from strain AXBU/J and in control rabbits of the closely related strain AX/J. Aqueous humor ascorbate concentration of the normal strain was 22.5/"2.3mg/100ml. The buphthalmic rabbits that had no meaningful clinical signs of glaucoma at the time of sample collection had lower values (11.7/"1.7mg/100ml). Much lower values were observed in the bu/bu mutant rabbits that showed mild to severe glaucoma: 8.9/"3.8mg/100 ml and 1.9"/0.4mg/100ml, respectively. It was concluded that reduction of aqueous ascorbate is a biochemical change associated with the pathological development of buphthalmia in rabbits of the AXBU/J strain. However, the exact mechanism is still unclear.

Topics: Animals; Aqueous Humor; Ascorbic Acid; Calcium; Disease Models, Animal; Eye Proteins; Genotype; Glaucoma; Hydrophthalmos; Intraocular Pressure; Potassium; Rabbits; Sodium

Topics: Ascorbic Acid; Drug Evaluation; Glaucoma; Glycerol; Humans; Intraocular Pressure; Sodium; Solutions

In order to investigate whether or not there is a causal relationship between the metabolic acidosis and the ocular hypotension induced by acetazolamide, we undertook to correlate over a period of time the blood-acidifying and ocular-hypotonizing effects of administering the lowest intravenous effective dose of acetazolamide; to treat the metabolic acidosis induced by acetazolamide by means of the intravenous introduction of bases, and pulmonary hyperventilation (respiratory alkalosis); to evaluate the effects on the intraocular pressure (IOP) by neutralizing the acetazolamide-induced metabolic acidosis by means of a continuous infusion of sodium bicarbonate; to determine the relationship between the metabolic acidosis induced by blood-acidifying agents, which do not inhibit carbonic anhydrase, and the IOP; and to determine the changes in the acid-base status of the aqueous humor induced by acetazolamide and other blood-acidifying drugs. We found that the hypertonic buffering solution of sodium bicarbonate could reduce the IOP by itself through an osmotic mechanism. On the basis of our results, we believe that a causal relationship exists between the metabolic acidosis induced by acetazolamide, and by other drugs that have a blood-acidifying effect as the result of other mechanisms, and ocular hypotension, bothin the animal and in the glaucomatous patient.

Topics: Acetazolamide; Acid-Base Equilibrium; Acidosis; Alkalosis, Respiratory; Animals; Ascorbic Acid; Buffers; Calcium Chloride; Dose-Response Relationship, Drug; Glaucoma; Humans; Hydrochlorothiazide; Intraocular Pressure; Osmolar Concentration; Rabbits

A high-pressure liquid chromatography instrument has been used to establish a method for the analyses of ascorbate concentration in aqueous humor. The method detects only the reduced form of ascorbate. The values obtained by this method are very similar to those of the colorimetric method. The ascorbate value in a group of random samples obtained from human glaucoma eyes varied between 3.5 to 31 mg. per cent, independent to blood ascorbate concentration.

Topics: Aqueous Humor; Ascorbic Acid; Chromatography, High Pressure Liquid; Colorimetry; Glaucoma; Humans

Topics: Aged; Ascorbic Acid; Female; Glaucoma; Glycerol; Humans; Intraocular Pressure; Male; Middle Aged; Sodium; Solutions

Topics: Acid-Base Equilibrium; Alkalies; Alkalosis; Animals; Aqueous Humor; Ascorbic Acid; Epinephrine; Glaucoma; Humans; Hydrogen-Ion Concentration; Intraocular Pressure; Methylprednisolone; Phenylephrine; Pilocarpine; Propranolol; Rabbits

Topics: Acetazolamide; Acid-Base Equilibrium; Acidosis; Animals; Aqueous Humor; Ascorbic Acid; Bicarbonates; Calcium Chloride; Carbonic Anhydrase Inhibitors; Dichlorphenamide; Glaucoma; Humans; Hydrogen-Ion Concentration; Intraocular Pressure; Rabbits; Time Factors

Topics: Adult; Aged; Ascorbic Acid; Female; Glaucoma; Humans; Intraocular Pressure; Male; Time Factors

Topics: Acidosis; Animals; Ascorbic Acid; Calcium Chloride; Carbonic Anhydrase Inhibitors; Diabetic Ketoacidosis; Glaucoma; Humans; Intraocular Pressure; Methods; Rabbits

Topics: Animals; Aqueous Humor; Ascorbic Acid; Biological Transport; Glaucoma; Hydrophthalmos; Injections; Intraocular Pressure; Mathematics; Rabbits; Tonometry, Ocular

Topics: Ascorbic Acid; Drug Synergism; Glaucoma; Glycerol; Humans; Injections, Intravenous; Intraocular Pressure; Ocular Physiological Phenomena; Sodium; Time Factors; Tonometry, Ocular

Topics: Acid-Base Equilibrium; Acidosis; Administration, Oral; Animals; Aqueous Humor; Ascorbic Acid; Bicarbonates; Chronic Disease; Glaucoma; Humans; Hydrogen-Ion Concentration; Hypotension; Intraocular Pressure; Osmosis; Rabbits

Topics: Adolescent; Anterior Chamber; Aqueous Humor; Ascorbic Acid; Epinephrine; Glaucoma; Humans; Kinetics; Male; Ouabain

Topics: Ascorbic Acid; Cataract; Glaucoma; Humans; Injections, Intravenous; Intraocular Pressure; Male; Mannitol; Middle Aged; Time Factors

Topics: Acute Disease; Adrenal Cortex Hormones; Ascorbic Acid; Burns, Chemical; Chronic Disease; Contact Lenses; Cornea; Corneal Injuries; Edema; Eye Diseases; Glaucoma; Glucose; Glycerol; Humans; Hypertonic Solutions; Idoxuridine; Intraocular Pressure; Keratitis, Dendritic; Keratoconus; Ophthalmic Solutions; Povidone; Silicones; Sodium Chloride; Surface-Active Agents; Tears

Topics: Adult; Aged; Ascorbic Acid; Blood; Glaucoma; Humans; Injections, Intravenous; Intraocular Pressure; Middle Aged; Osmotic Pressure

Topics: Animals; Ascorbic Acid; Dosage Forms; Glaucoma; Humans; Injections, Intravenous; Intraocular Pressure; Rabbits

Topics: Aqueous Humor; Ascorbic Acid; Glaucoma; Humans; Ophthalmic Solutions; Tonometry, Ocular

Topics: Ascorbic Acid; Cataract; Glaucoma; Glycerol; Humans; Injections, Intravenous; Intraocular Pressure; Mannitol; Urea

Topics: Ascorbic Acid; Glaucoma; Humans; Injections, Intravenous; Intraocular Pressure; Postoperative Care; Preoperative Care

Topics: Ascorbic Acid; Glaucoma; Glycerol; Humans

Topics: Animals; Ascorbic Acid; Glaucoma; Humans; Hydrogen-Ion Concentration; Intraocular Pressure; Osmolar Concentration; Rabbits

Topics: Acetazolamide; Animals; Ascorbic Acid; Glaucoma; Humans; Intraocular Pressure; Pilocarpine; Rabbits

Topics: Adult; Aged; Ascorbic Acid; Cataract Extraction; Female; Glaucoma; Glycerol; Humans; Injections, Intravenous; Intraocular Pressure; Male; Middle Aged

Topics: Adolescent; Adult; Aged; Animals; Ascorbic Acid; Female; Glaucoma; Humans; Injections, Intravenous; Intraocular Pressure; Male; Middle Aged; Rabbits

Topics: Ascorbic Acid; Glaucoma; Humans; Parasympathomimetics; Sympathomimetics

Topics: Ascorbic Acid; Echothiophate Iodide; Epinephrine; Glaucoma; Humans; Iris; Pilocarpine; Propranolol; Quaternary Ammonium Compounds; Uveitis, Anterior

Topics: Ascorbic Acid; Glaucoma; Glycerol; Humans; Hypertonic Solutions; Intraocular Pressure; Mannitol; Urea

Topics: Animals; Ascorbic Acid; Female; Glaucoma; Glycerol; Humans; Injections, Intravenous; Intraocular Pressure; Male; Middle Aged; Rabbits; Sodium; Tonometry, Ocular

Topics: Ascorbic Acid; Cataract Extraction; Eye Diseases; Glaucoma; Glycerol; Humans; Intraocular Pressure; Mannitol; Osmosis; Sodium; Urea

Topics: Animals; Ascorbic Acid; Glaucoma; Humans; Rabbits

Topics: Anterior Chamber; Aqueous Humor; Ascorbic Acid; Cataract Extraction; Glaucoma; Humans; Lens, Crystalline