Ultrasound-Guided Concanavalin A Injection Into Inferior Lacrimal Gland: A Technique to Inoculate Inferior Lacrimal Gland With Concanavalin A to Induce Dry Eye Disease in Rabbit Model

For ILG injection, view the animal from the side to locate the prominence of the ILG along the lower anterior portion of the orbit. Use a surgical marking pen to draw a vertical line onto the skin, where the superficial part of the ILG gland transitions from its superficial resting place on the zygomatic bone to its more medial location in the orbit.

Sweep a vertically-held ultrasound probe across the line on the skin to identify the end of the zygomatic bone. The ILG transition occurs where the image of the gland changes from a circumscribed hyperechoic line to one without a recognizable medial border. The relative position of the hand-piece to the line drawn on the skin when this change is observed will be the injection site.

To place ConA into a gland at a point just medial to the zygomatic arch bone, set the desired depth of injection as the depth of the zygomatic bone (hyperechoic signal) plus 1 millimeter, minus the known length of the needle. Insert the needle about 12 millimeters into the gland at the injection site, before slowly withdrawing until the length of the exposed needle outside of the body is equal to the calculated difference.

Then, inject 0.2 milliliters of a 1000-microgram of ConA solution, and confirm the success of the injection by ultrasound. The ILG should exhibit a characteristic hypoechoic space.