This study investigates the use of magnetic microspheres to induce a glaucoma-like condition in anesthetized rats. By blocking aqueous humor outflow, the research aims to understand the mechanical stress on the retina and optic nerve degeneration.
Start with an anesthetized rat with a sterilized eye, and place a magnetic ring covering the eyeball.
Pierce the eye tangentially with a syringe containing magnetic beads.
Inject the beads into the anterior chamber of the eye, holding the syringe in position.
The magnet pulls the beads to the iridocorneal angle and begins to block the outflow of aqueous humor fluid from the eye through the trabecular meshwork.
Angle the needle slightly when removing the syringe to avoid a sudden increase in eye pressure.
Remove the magnet and reposition it to direct beads into areas with incomplete coverage.
Then, place the magnet back around the eyeball.
As the beads settle, they completely block aqueous humor outflow, causing fluid buildup in the anterior chamber and increased eye pressure.
The elevated pressure induces mechanical stress on the retina, promoting optic nerve degeneration and developing a glaucoma-like condition.
After anesthetizing the rats, apply ocular ointment to the unoperated contralateral eye to keep it moist during anesthesia. Apply 0.5% pro procaine hydrochloride local anesthetic to the operative eye. Next, wash this eye with 5% povidone iodine in water. After 5 minutes, wick off the povidone iodine and wash the eye with 0.9% sterile saline solution.
Keep the eye moist during anesthesia with regular application of sterile saline. Now, place a toroidal magnet around the eye. To minimize the risk of iris trauma and minimize bead loss, orient the needle tangential to the corneal surface as parallel to the iris as possible. Proceed to inject 25 microliters of 30 milligrams per millimeter gamma irradiated magnetic microspheres into the anterior chamber.
Leave the needle in place for one minute post-injection, to ensure that beads settle into the iridocorneal angle to impede aqueous drainage from the trabecular meshwork. Slightly angle the needle a few seconds after the beads have initially settled to allow some leakage of aqueous, and to minimize transient increases in intraocular pressure.
To ensure continued use of the needle in separate procedures, flush the needle with PBS, then 70% ethanol, followed by distilled water. At this stage, if necessary, remove the magnet and use it to draw beads into areas of incomplete coverage. Leave the magnet in place around the eye for a further 10 minutes post-injection, to ensure beads settle well into the iridocorneal angle.
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