sodium-bicarbonate and Retinal-Diseases

Topics: Acetazolamide; Electrooculography; Fructose; Humans; Mannitol; Osmotic Pressure; Pigment Epithelium of Eye; Retinal Diseases; Sodium Bicarbonate

To evaluate the retinal pigment epithelial damage induced by light exposure.. One eye of 20 rabbits was exposed to xenon light for 2 hours at an irradiance of 140 mW/cm2 at the surface of the cornea. The contralateral eye served as a control. Forty-eight hours after the light exposure, corneal direct-coupled electroretinograms and the 7% NaHCO3 (bicarbonate) responses of the standing potential were recorded.. The amplitudes of the a-, b-, and c-waves of the electroretinograms were significantly reduced in the light-exposed eyes, with the c-waves more reduced than the a- and b-waves. The bicarbonate response was also significantly reduced in the irradiated eyes.. The decrease of the bicarbonate response of the standing potential indicated that significant functional damage of the retinal pigment epithelium was induced by the light exposure.

Topics: Animals; Electroretinography; Injections, Intravenous; Light; Membrane Potentials; Pigment Epithelium of Eye; Rabbits; Radiation Injuries, Experimental; Retinal Diseases; Sodium Bicarbonate; Xenon

The changes of vitreous pH values under acute glaucoma status have never been reported. In this study, we measured the changes of vitreous pH values in an acute glaucoma rabbit model. Under ketamine and xylazine anesthesia, the anterior chamber of the right eye of New Zealand white rabbits was cannulated and connected to a polygraph for continuous intraocular pressure (IOP) monitoring and a mini-pump for persistent injection of viscoelastic substance, Healon GV. The measurement of vitreous pH was done by inserting a pH probe via a third opening through the sclera into the vitreous. Different IOP levels were maintained by varied amounts of Healon GV injections into the anterior chamber. The changes of vitreous pH values following the intracameral injections were recorded and evaluated. The changes of vitreous pH values were minimal when IOPs were maintained at lower than 35 mmHg. Vitreous pH values decreased significantly from 7.32 to less than 7.03, when the IOPs were kept at 70 mmHg or higher. However, the decrease of pH values was reversible if IOP was held at 70 mmHg for less than 10 minutes and then reduced to normal level at once. In addition, with MTT viability assay, it was noted that the decrease in vitreous pH was associated with a higher percentage of retinal cell death.

Topics: Acidosis; Acute Disease; Animals; Cell Death; Disease Models, Animal; Glaucoma; Hyaluronic Acid; Hydrogen-Ion Concentration; Intraocular Pressure; Male; Ocular Hypertension; Rabbits; Retina; Retinal Diseases; Sodium Bicarbonate; Vitreous Body

We report a case of methanol poisoning exhibiting complete recovery from severe visual impairment following treatment with ethanol, fomepizole, and hemodialysis. An adult male presented with central blindness after ingesting methanol. Initial visual acuity was <20/800 (finger counting at 1-2 feet) with retinal edema on fundoscopy, arterial pH 7.19, methanol 97 mg/dL (30 mmol/L), formate 14.3 mmol/L, and ethanol undetectable. The patient was treated with ethanol, then fomepizole intravenously (15, 10, then 5 mg/kg), and hemodialysis. Methanol metabolism was effectively blocked by fomepizole even after ethanol had been eliminated, and the patient recovered 20/20 vision by day 14 with normal fundoscopy. This case report confirms highly efficient inhibition of alcohol dehydrogenase by fomepizole, as well as demonstrate the safety of fomepizole in a patient already exhibiting end-organ retinal toxicity. The potential for fomepizole to inhibit retinol dehydrogenase, an isoenzyme of alcohol dehydrogenase essential to vision, did not appear to be clinically significant in this symptomatic methanol-poisoned patient.

Topics: Adult; Antidotes; Buffers; Central Nervous System Depressants; Ethanol; Fomepizole; Humans; Male; Methanol; Pyrazoles; Retinal Diseases; Sodium Bicarbonate; Solvents; Vision Disorders