Category Archives: Ophthalmologist

Simple Techniques Aid Eye Drop Penetration (part 6)

Systemic administration works, but because the medication must hurdle the blood-aqueous barrier, the dose needed is high and systemic toxicity is a real concern. Direct injection is possible, but because it makes a wound, it carries the risks of injury and/or infection. Corneal iontophoresis has not been used because studies done in the 1940s, when the practice was common, showed that the lens-iris barrier effectively blocked the movement of the drug into the posterior chamber. Continue reading

Simple Techniques Aid Eye Drop Penetration (part 5)

Aid Eye Drop Penetration (part 5)

In another presentation, Jules Baum, MD, professor, Department of Ophthalmology, Tufts University School of Medicine/New England Medical Center, Boston, described a method of getting medication into the vitreous that he believes is a vast improvement over common intravitreal injection.Baum’s collaborator, David Maurice, PhD, conceived of the idea of using iontophoresis to get antibiotics into the vitreous while he was riding a number-64 bus through the streets of London, in 1965. However, it wasn’t until recently that Maurice, professor of ophthalmology and physiology at Stanford University School of Medicine, working in collaboration with Baum, actually began designing the apparatus and experimenting on rabbits.
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Simple Techniques Aid Eye Drop Penetration (part 4)

Aid Eye Drop Penetration (part 4)

In the second experiment, fluorescein was applied topically to eight subjects to determine if each of the procedures had any effect on the amount of medication absorbed by the eye. The researchers used fluorophotometry to establish the magnitude and duration of fluorescein concentration in the anterior chamber of the eye.“Both [techniques] also show a 50% increase in maximal concentration of the drug in the eye and a 50% increase in the duration of significant concentrations of drug in the eye [in comparison with no attempt to enhance drug delivery],” Zimmerman says.
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Simple Techniques Aid Eye Drop Penetration (part 3)

At the conference, Zimmerman presented the results of a study designed to find out if the finger-pressure procedure (nasolacrimal occlusion) and the eyes-closed procedure increased the amount of drug that was absorbed by the eye (Arch Ophthalmol 1984;102:551-553). The study also measured the effects of nasolacrimal occlusion and eyelid closure on systemic absorption. He found that these simple procedures increase the amount of drug that gets into the eye, while at the same time, decrease the likelihood that the patient will experience systemic side effects.
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Simple Techniques Aid Eye Drop Penetration (part 2)

One woman cut her eye with her fingernail. “So much for science,” he said.
So he has decided it is better to advise people to simply close their eyes for three minutes after applying eye drops. Since the nasolacrimal drainage system relies on the pumping action of the eyelids to remove fluids from the eye, gently closing the eyes stops the pump and keeps the medication on the eye longer, he explains.
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Simple Techniques Aid Eye Drop Penetration (part 1)

Aid Eye Drop Penetration (part 1)

OPHTHALMOLOGISTS ARE eye-balling a couple of techniques that may help drugs penetrate behind the cornea and sclera.Two techniques described at a Research to Prevent Blindness (RPB) Science Writers Seminar (in Bethesda, Md) may prove to be better ways to get more medication into the poorly-vascularized eye. What’s more, the researchers say, their methods will reduce the side effects that patients often experience when treated with ophthalmic drugs.
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Ophthalmologists Discuss Methods to Help Physicians See What Patients Can’t See: Glaucoma Detection (part 5)

Quigley says he has found that the optic disk shows evidence of cupping early, a condition long suspected but never demonstrated. As the cells die, they no longer support the meshwork of collagen and astrocytes that makes up the disk. Hence, the disk begins to fall back behind the eye, cupping. Quigley says he hopes it will be possible for trained ophthalmologists to recognize cupping with an ophthalmoscope examination.

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Ophthalmologists Discuss Methods to Help Physicians See What Patients Can’t See: Glaucoma Detection (part 4)

The large ganglion cells may be most sensitive to flashing patterns and dim-cefazolin, ticarcillin, and gentamicin in the vitreous. “It has been suggested that gentamicin and fluorescein [which Maurice has used] are less lipid-soluble than penicillins or sulfadiazine and, therefore, may show more benefit from iontophoresis,” Baum writes in his study.
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Ophthalmologists Discuss Methods to Help Physicians See What Patients Can’t See: Glaucoma Detection (part 3)

Applying 2 mA for ten minutes, Baum was able to achieve significant concentrations of three antibiotics — buy antibiotics online, Quigley says this is not reasonable. While he was a resident, he and a colleague, Alfred Sommer, MD, now also a faculty member at Hopkins, began grappling with the question of how to detect glaucoma earlier. Building on the work of William F. Hoyt, MD, out at the University of California, San Francisco, School of Medicine, those two began using red-free light to examine the retina. Hoyt had found that using red-free light and a common ophthalmoscope he could detect nerve damage in the retina (Invest Ophthalmol Vis Sci 1973;12: 814-829).

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Ophthalmologists Discuss Methods to Help Physicians See What Patients Can’t See: Glaucoma Detection (part 2)

Assuming therefore that most persons with ocular hypertension would not go on to develop glaucomatous visual deficits, most ophthalmologists decided that rather than subject all patients with elevated intraocular pressure to the side effects of medications, it was better to treat only those who had actual detectable visual deficits. But, Quigley writes in a recent editorial (Surv Ophthalmol 1985;30:111-126), “To accept this concept, we must assume that it is reasonable to allow an eye to go to the stage of visual field loss on Gold-mann perimeter testing [which measures different areas of the field of vision separately] before attempting to halt the process with therapy.” solution, which is charged through a platinum electrode inserted into the solution in the syringe barrel. That syringe is attached to a nipple that protrudes into the cup such that, when suction is applied, the tip rests against the sclera.
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