Biomedical subjects
A N Kohn
Publications and source records attributed to A N Kohn.
Piggyback contact lenses for reducing postkeratoplasty astigmatism.
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Relative afferent pupillary defects in glaucoma without characteristic field loss.
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Clinical comparison of dipivalyl epinephrine and epinephrine in the treatment of glaucoma.
Dipivalyl epinephrine, 0.1%, though slightly less effective in decreasing intraocular pressure, showed significantly fewer side effects than epinephrine hydrochloride, 2%. Seventeen patients with symmetrically increased intraocular pressures who completed a six-month double-masked crossover study showed a significant decrease in intraocular pressure averaging 23.7% for dipivalyl epinephrine over the entire study and 27.4% for epinephrine. In the first treatment period, dipivalyl epinephrine was slightly less effective than epinephrine. In the second treatment period, dipivalyl epinephrine was statistically less effective than epinephrine. Two of the original 25 patients were dropped from the study because of epinephrine allergy or intolerance, one had uncontrolled pressures with either drug, and five failed to maintain adequate follow-up. Complaints of side effects such as burning and irritation occurred much more frequently in eyes receiving epinephrine (24%) than dipivalyl epinephrine (3%). Mild mydriasis occurred with each drug, averaging +0.65 mm with dipivalyl epinephrine and +0.55 mm Hg with epinephrine. No effect on blood pressure or pulse rate was found for the two drugs.
A comparison of the effects of timolol and epinephrine on intraocular pressure.
We conducted a double-masked, six-week crossover study comparing bilateral twice-a-day therapy with timolol maleate (0.1%, 0.25%, and 0.5%) and epinephrine hydrochloride (0.5%, 1.0%, 2.0%) in 36 otherwise untreated patients. Increasing concentrations of each drug were administered until an arbitrary level of control was achieved before each of the six-week follow-up periods. Seventeen patients were controlled by both drugs and four patients were controlled by neither drug. Timolol, but not epinephrine, was effective in ten patients, whereas epinephrine, but not timolol, was effective in two patients. Three patients did not complete the study. The mean decrease in intraocular pressure from baseline was significantly greater with timolol than with epinephrine both before crossover and overall at both the lowest and highest concentrations of drug used. Significantly toxicity was produced in four patients during treatment with epinephrine, but in no patients during treatment with timolol.
Ocular toxicity of styrene.
We completed histories and ocular examinations of 345 workers in a styrene plant in order to determine the ocular toxicity of styrene. Despite previous case reports of retrobulbar neuritis and central retinal vein occlusion (associated with a toxic hematopoietic disorder), no such conditions were found in these workers. Conjunctival irritation from styrene was found in 22% of the workers and correlated with intensity of exposure, thus confirming previous reports.
Bacterial cultures of lenses removed during cataract surgery.
Lenses removed in 408 cataract operations were cultured for bacteria. Most (78%) lenses were sterile. Of the positive cultures, 48% were positive for Staphylococcus epidermidis and 15.4% for S. aureus. These findings reflect the flora of the normal preoperative conjunctiva, and the organisms most commonly implicated in postoperative endophthalmitis. One case of endophthalmitis occurred in this series, and S. aureus was cultured from the lens and later from the postoperative wound and a wound suture, but no intraocular paracentesis was performed to confirm the causative organism.