ABSTRACT
A double-masked, randomized clinical trial was conducted to determine if subcutaneous eyelid injections of a bicarbonate-buffered lidocaine-epinephrine-hyaluronidase mixture were less painful than unbuffered injections. Twenty-one patients received both buffered (pH = 7.4) and unbuffered (pH = 4.6) injections. After each injection, patients recorded pain on a scale of 0, "no pain," to 10, "severe pain." Mean pain score for buffered injections was 2.0 versus 4.1 for unbuffered injections (P = 0.0003). Seventeen (81%) of 21 patients ranked the buffered injection less painful. Use of a bicarbonate-buffered lidocaine-epinephrine-hyaluronidase mixture is effective in making ophthalmic anesthesia less painful.
Subject(s)
Anesthetics, Local/administration & dosage , Bicarbonates/administration & dosage , Epinephrine/administration & dosage , Eyelids/drug effects , Hyaluronoglucosaminidase/administration & dosage , Lidocaine/administration & dosage , Adult , Aged , Aged, 80 and over , Bicarbonates/pharmacology , Buffers , Cataract Extraction , Double-Blind Method , Epinephrine/pharmacology , Female , Humans , Hyaluronoglucosaminidase/pharmacology , Hydrogen-Ion Concentration , Lidocaine/pharmacology , Male , Middle Aged , Pain/prevention & controlABSTRACT
Collagen shields made of porcine collagen were placed in a solution containing tobramycin sulfate (40 or 200 mg/ml) for five minutes, then applied to rabbit eyes. One, four, or eight hours after application, the corneas, aqueous humor samples, and shields were assayed for antibiotic. At all intervals, the concentration of antibiotic in the corneas and aqueous humor samples exceeded the mean inhibitory concentration for tobramycin, as determined for most strains of Pseudomonas. Shields immersed in 200 mg/ml tobramycin produced significantly higher concentrations of antibiotic in the cornea at one hour than subconjunctival injections of tobramycin (20 mg) (P = .0001). Shields immersed in 40 mg/ml tobramycin produced higher, although not significantly higher, concentrations of antibiotic in the cornea at one hour than subconjunctival injections of tobramycin (20 mg) (P = .318). Shields immersed in commercially available tobramycin drops or injectable tobramycin solution (40 mg/ml) caused no epithelial damage visible by slitlamp examination. Collagen shields containing antibiotics can serve as a vehicle for drug delivery and may prove superior to current methods for preoperative and postoperative antibiotic prophylaxis and the initial treatment of bacterial keratitis.
Subject(s)
Aqueous Humor/metabolism , Collagen , Cornea/metabolism , Occlusive Dressings , Tobramycin/administration & dosage , Animals , Conjunctiva , Cornea/pathology , Drug Carriers , Injections , Ophthalmic Solutions , Osmolar Concentration , Propoxycaine/administration & dosage , Propoxycaine/adverse effects , Rabbits , Swine , Time Factors , Tobramycin/adverse effects , Tobramycin/pharmacokineticsABSTRACT
The hypothesis that a direct neural pathway exists between the midbrain and the intrinsic musculature was investigated. Wheat germ agglutinin labeled with HRP and WG-HRP were injected intraocularly into the ciliary muscle of rabbits and cynomolgus monkeys, and their retrograde movement was monitored. Sparse, but definite labeling was found in the AM nuclei, the EW nuclei, and Perlia's nucleus of the monkey, confirming the existence of a nonsynapsing pathway between intraocular structures and the midbrain in the primate.
