ascorbic-acid and Corneal-Opacity

Corneal haze is a significant complication of photorefractive keratectomy (PRK) and laser-assisted subepithelial keratectomy (LASEK).. To evaluate the effect of ascorbic acid supplementation in addition to perioperative topical mitomycin-C for the prevention of haze after LASEK.. We performed a retrospective, non-randomized case series study of two groups of 48 consecutive patients (96 myopic eyes) who had LASEK surgery. The treatment group was given ascorbic acid (vitamin C) orally, 500 mg, twice daily from 1 week before to 2 weeks after surgery. The control group was not offered any additional treatment. Ascorbate supplementation was the only difference in the postoperative treatment protocol between the treatment and control groups. Haze was assessed on a scale from 0 to 4 at the 1 year visit.. Overall, 33.3% and 37.5% of the patients in the treatment and control groups respectively developed corneal haze. The trend of increased haze severity in the control group did not reach statistical significance.. Our results showed that systemic ascorbate supplementation does not have an additional effect on the prevention of haze after LASEK compared to the effect of topical mitomycin-C alone.

Topics: Adolescent; Adult; Antioxidants; Ascorbic Acid; Astigmatism; Cornea; Corneal Opacity; Drug Therapy, Combination; Female; Humans; Keratectomy, Subepithelial, Laser-Assisted; Male; Mitomycin; Postoperative Complications; Retrospective Studies; Young Adult

A superfusion apparatus (SA) was developed to maintain isolated human corneas ex vivo under conditions which mimic the natural eye environment in vivo, including controlled temperature, tear flow and intraocular pressure. The SA was designed, developed and tested for use in ophthalmic pre-clinical research and to test new pharmaceutical formulations. Corneas undergo an equilibration process in the new physiological environment for one day. The test was then initiated by the application of the test substance, incubation, and temporal assessment of corneal damage using various parameters. The effects of mild and severe irritant concentrations of NaOH (2% and 8%, respectively) on corneal opacity, swelling and epithelial integrity were studied, and the inflammatory status assessed using F4/80 and MPO as macrophages and neutrophils markers, respectively. The SA was then used to test new artificial tear formulations supplemented with silver ions as an active constituent, showing different degrees of inflammatory responses as indicated by the migration of MPO and F4/80 positive cells towards the epithelium. The human cornea superfusion apparatus was proposed as a model for acute eye irritation research.

Topics: Animal Testing Alternatives; Antigens, Differentiation; Ascorbic Acid; Caustics; Cornea; Corneal Opacity; Humans; In Vitro Techniques; Irritants; Lubricant Eye Drops; Ophthalmic Solutions; Peroxidase; Silver Nitrate; Sodium Hydroxide

The objective of this study was to determine the effect of vitamin C supplementation on reducing the size of corneal opacity resulting from infectious keratitis.The study included 82 patients (82 affected eyes), admitted for infectious keratitis from January 2009 to August 2013, who were followed for more than 3 months. Patients were divided into control, oral vitamin C (3 g/d), and intravenous vitamin C (20 g/d) groups during hospitalization. Corneal opacity sizes were measured using anterior segment photographs and Image J program (version 1.27; National Institutes of Health, Jinju, South Korea) at admission, discharge, and final follow-up. The corneal opacity size used for analysis was the measured opacity size divided by the size of the whole cornea.The corneal opacity size decreased by 0.03 ± 0.10 in the oral vitamin C group, 0.07 ± 0.22 in the intravenous vitamin C group, and 0.02 ± 0.15 in the control group. Intravenous vitamin C reduced the corneal opacity size more than oral vitamin C (P = 0.043). Intravenous vitamin C produced greater reduction in corneal opacity size in younger patients (P = 0.015) and those with a hypopyon (P = 0.036).Systemic vitamin C supplementation reduced the size of corneal opacity resulting from infectious keratitis. Intravenous vitamin C was more beneficial than oral supplementation, especially in younger patients and those with hypopyon.

Topics: Antioxidants; Ascorbic Acid; Corneal Opacity; Dietary Supplements; Female; Humans; Keratitis; Male; Middle Aged; Retrospective Studies; Treatment Outcome

A 53-year-old contact lens wearer on renal dialysis developed visual impairment due to corneal opacity. The opacity was of a crystalline type and diffusely scattered in the anterior cornea. As oxalosis was suspected ascorbic acid was immediately omitted from the dialysis treatment schedule. Within a few weeks the visual acuity recovered and the corneas became nearly clear. The cornea is an uncommon manifestation site for oxalosis. Nevertheless, one should be aware of this possible sign for oxalosis, which can be a life-threatening complication of treatment with high dose ascorbic acid.

Topics: Adult; Ascorbic Acid; Corneal Opacity; Humans; Hyperoxaluria; Male; Renal Dialysis; Renal Insufficiency; Treatment Outcome; Vision Disorders

To establish an experimental model for sulfur mustard-induced acute and delayed ocular lesions in rabbits.. Rabbit eyes were exposed to sulfur mustard (HD) vapor (370, 420 microg/l) for a period of two minutes. A three months follow-up study was carried out, based on the evaluation of clinical, biochemical and histological parameters.. HD exposure initiated typical clinical symptoms within 2-6 hrs, characterized by eye closure, eyelid swelling, conjunctival hyperemia, corneal erosions and inflammation. The clinical signs were significantly dose-dependent and reached a peak at 24--72 hrs post exposure. Biochemical evaluation of the aqueous humor exhibited an inflammatory reaction and oxidative stress at 4 hrs after exposure, subsiding at 28 hrs after exposure. Histological examination of corneas at 48 hrs revealed epithelial denudation and marked stromal edema, accompanied by cellular infiltration. Epithelial regeneration started after 72 hrs, and recovery was almost completed within 1--2 weeks, depending on the HD dose. A second phase of pathological processes started as early as two weeks post exposure and was characterized by corneal edema, opacity, recurrent erosions and neovascularization. The delayed injuries were found in 25 and 40% of the eyes respectively, and when appearing, were more severe than the initial ones.. The development of HD-induced ocular lesions in rabbits is similar to the lesions described in human casualties. Quantitative analysis of the various clinical parameters emphasizes the contribution of each tissue to the overall toxic picture. Our experimental model is useful for studying the pathological mechanisms of HD-ocular lesions, and may serve for testing potential therapies.

Topics: Acute Disease; Animals; Ascorbic Acid; Cornea; Corneal Edema; Corneal Neovascularization; Corneal Opacity; Dermatologic Agents; Dose-Response Relationship, Drug; Eye Proteins; Female; Glutathione; Models, Animal; Mustard Gas; Rabbits; Time Factors

Topics: Animals; Ascorbic Acid; Cornea; Corneal Opacity; Edema; Glucose; Glycerol; Mannitol; Methylcellulose; Osmosis; Photography; Propylene Glycols; Rabbits; Semiconductors; Sodium Chloride; Sorbitol; Urea