ascorbic-acid and Myopia

Topics: Adolescent; Ascorbic Acid; Child; Connective Tissue; Copper; Female; Glycosaminoglycans; Humans; Iron; Male; Myopia; Phosphorus

To analyze remote clinical and functional outcomes of correcting high myopia in patients with thin cornea by the method of femtosecond laser-assisted implantation of intracorneal implant MyoRing.. The study included 22 patients (22 eyes; the mean age of study patients was 30.2±5.37 years). Mean spherical equivalent (SE) of refraction was -11.52±1.96 D, cylindrical component (cyl) of refraction was -2.04±1.64 D, minimal pachymetry index in the center was 491.6±20 µm, corneal hysteresis (CH) amounted to 8.6±1.19 mm Hg. The average pupil diameter in mesopic conditions was 5.6±0.23 mm. All patients had a history of mild amblyopia. The follow-up period lasted 2 years.. Анализ отдаленных клинико-функциональных результатов коррекции миопии высокой степени у пациентов с тонкой роговицей методом интрастромальной имплантации кольца MyoRing с фемтолазерным сопровождением.. В исследование включены 22 пациента (22 глаза; средний возраст пациентов 30,2±5,37 года). До операции среднее значение сфероэквивалента рефракции (СЭ) составило (–)11,52±1,96 дптр, цилиндрического компонента (cyl) — (–)2,04±1,64 дптр, минимальное значение пахиметрии в центре — 491,6±20 мкм, корнеальный гистерезис (КГ) — 8,6±1,19 мм рт.ст. Средний диаметр зрачка в мезопических условиях 5,6±0,23 мм. У всех пациентов в анамнезе имелась амблиопия слабой степени. Срок наблюдения — 2 года.

Topics: Adult; Ascorbic Acid; Astigmatism; Cathartics; Colonoscopy; Corneal Stroma; Corneal Topography; Follow-Up Studies; Humans; Lasers; Middle Aged; Myopia; Patient Satisfaction; Polyethylene Glycols; Prospective Studies; Refraction, Ocular; Treatment Outcome; Young Adult

lntravitreal injection of substances dissolved in a vehicle solution is a common tool used to assess retinal function. We examined the effect of injection procedures (three groups) and vehicle solutions (four groups) on the development of form deprivation myopia (FDM) in juvenile tree shrews, mammals closely related to primates, starting at 24 days of visual experience (about 45 days of age). In seven groups (n = 7 per group), the myopia produced by monocular form deprivation (FD) was measured daily for 12 days during an 11-day treatment period. The FD eye was randomly selected; the contralateral eye served as an untreated control. The refractive state of both eyes was measured daily, starting just before FD began (day 1); axial component dimensions were measured on day 1 and after eleven days of treatment (day 12). Procedure groups: the myopia (treated eye - control eye refraction) in the FD group was the reference. The sham group only underwent brief daily anesthesia and opening of the conjunctiva to expose the sclera. The puncture group, in addition, had a pipette inserted daily into the vitreous. In four vehicle groups, 5 μL of vehicle was injected daily. The NaCl group received 0.85% NaCl. In the NaCl + ascorbic acid group, 1 mg/mL of ascorbic acid was added. The water group received sterile water. The water + ascorbic acid group received water with ascorbic acid (1 mg/mL). We found that the procedures associated with intravitreal injections (anesthesia, opening of the conjunctiva, and puncture of the sclera) did not significantly affect the development of FDM. However, injecting 5 μL of any of the four vehicle solutions slowed the development of FDM. NaCl had a small effect; myopia development in the last 6 days (-0.15 ± 0.08 D/day) was significantly less than in the FD group (-0.55 ± 0.06 D/day). NaCl + Ascorbic acid further slowed the development of FDM on several treatment days. H2O (-0.09 ± 0.05 D/day) and H2O + ascorbic acid (-0.08 ± 0.05 D/day) both almost completely blocked myopia development. The treated eye vitreous chamber elongation, compared with the control eye, in all groups was consistent with the amount of myopia. When FD continued (days 12-16) without injections in the water and water + ascorbic acid groups, the rate of myopia development quickly increased. Thus, it appears the vehicles affected retinal signaling rather than causing damage. The effect of water and water + ascorbic acid may be due to reduced osmolality or ionic conce

Topics: Animals; Antioxidants; Ascorbic Acid; Axial Length, Eye; Disease Models, Animal; Intravitreal Injections; Myopia; Ophthalmic Solutions; Pharmaceutical Vehicles; Refraction, Ocular; Sensory Deprivation; Sodium Chloride; Tupaiidae

To investigate the level of ascorbic acid in human tear fluid after photorefractive keratectomy (PRK), transepithelial PRK, and laser in situ keratomileusis (LASIK).. Departments of Ophthalmology and Biochemistry, School of Medicine, Gazi University, Ankara, Turkey.. Twenty patients (7 women and 13 men) were included in this study. Traditional PRK with epithelial scraping by a blunt spatula followed by surface ablation (7 eyes), transepithelial PRK (7 eyes), or LASIK (6 eyes) was performed. Tears were collected preoperatively and 1 and 5 days postoperatively. Ascorbic acid levels were measured using 2-4 dinitrophenylhydrazine.. Ascorbic acid levels in the tear fluid were decreased significantly 1 day after PRK, transepithelial PRK, and LASIK (P <.05). On the fifth day, the ascorbic acid levels were significantly lower than preoperatively in all groups.. After PRK, transepithelial PRK, and LASIK, the ascorbic acid levels of the tear fluid decreased significantly. Because ascorbic acid is the major scavenger of superoxide radicals in tears, topical ascorbic acid therapy may help eliminate the harmful effect of free radicals from excimer laser surgery.

Topics: Adult; Ascorbic Acid; Cornea; Female; Humans; Keratomileusis, Laser In Situ; Lasers, Excimer; Male; Myopia; Photorefractive Keratectomy; Tears

Topics: Adolescent; Adult; Ascorbic Acid; Blood Transfusion; Calcium; Conjunctiva; Evaluation Studies as Topic; Female; Glucose; Humans; Male; Middle Aged; Myopia; Niacinamide; Retinal Vessels; Thiamine; Transfusion Reaction; Visual Acuity; Visual Fields; Vitreous Body