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New anesthetic formulation alleviates discomfort of intraductal probing
Compounding jojoba with the anesthetic molecule enables the anesthetic to be accepted into the meibomian gland more readily.
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A topical formulation of lidocaine 8% and jojoba oil 25% provides consistently good anesthetic block, enabling overall well-tolerated and comfortable intraductal probing, according to the originator of the Maskin meibomian gland intraductal probe procedure.
The unique formulation is stronger than commercially available anesthetics, but it can be compounded for any ophthalmologist in the United States or overseas, Steven L. Maskin, MD, said.
Topical ointment best
Dr. Maskin said that he decided to create a stronger anesthetic to make the Maskin meibomian gland intraductal probe (Rhein Medical) a more comfortable procedure. He experimented with lidocaine liquid 4%, transdermal medications and injected anesthetics before deciding to add a topical ointment on the lid margin in order to avoid complications associated with other methods of applying anesthetic.
“In transdermal [application], relying on medication to penetrate through intact skin to get to the tarsal plate where the meibomian glands are is difficult, and even though infiltrative [application] works, there are potential complications. Some patients dislike needles, and sometimes there is a partial result so you need to re-inject. There is risk of bruising and lid swelling, and the possibility that the pressure from the needle or injected anesthetic solution will distort the duct that you are probing,” Dr. Maskin told Ocular Surgery News.
Role of jojoba
Jojoba, derived from a desert shrub indigenous to Arizona, California and Northern Mexico, is a wax ester whose oil lacks triglycerides. Rather than the typical molecule of glycerol and fatty acids, jojoba combines fatty alcohols with fatty acids to produce a vegetable oil reminiscent of a liquid wax, which is of the same chemical class as the wax esters that make up 45% of the meibum secreted from the meibomian glands.
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Image: Maskin SL |
Compounding jojoba with the anesthetic molecule helps the anesthetic be more readily accepted into the gland. “Like dissolves in like, so the jojoba — being wax esters — appears to be able to chaperone these molecules into the glands and create a good anesthetic effect, which makes the procedure more comfortable for both the patient and the physician,” Dr. Maskin said.
The jojoba anesthetic ointment should be kept refrigerated until use.
Positive response
Dr. Maskin’s protocol for using the ointment is to place a drop of traditional topical anesthetic solution in the conjunctival sac and then apply the jojoba anesthetic ointment on the lash line of the lower lid using a sterile tipped applicator. There is initially a 30-second period of mild to moderate burning, which soon dissipates. Dr. Maskin instructs patients to keep their eyes closed for no less than 15 minutes before the probing. Another drop of the topical anesthetic solution is placed in the conjunctival sac to eliminate mild burning from the ointment.
“The procedure itself continues to be highly successful. We are seeing two categories of responses. One is the response to lid tenderness; those patients have a 75% improvement immediately, which increases to 83% over 12 months. The second category of patients with symptoms other than lid tenderness, such as burning and stinging, improve 32% immediately after probing, and their improvement continues up to 82% at 6 months before tapering off,” Dr. Maskin said. The first peer-reviewed paper on meibomian gland probing was published in the October issue of Cornea.
After probing, Dr. Maskin rinses any residual ointment that might have gotten into the eye with preservative-free saline and directs his patients to use preservative-free artificial tears every hour until bedtime. – by Stephanie Vasta
- Steven L. Maskin, MD, can be reached at the Dry Eye and Cornea Treatment Center, 3001 W. Swann Ave., Tampa, FL 33609; 813-875-0000; e-mail: drmaskin@tampabay.rr.com. Dr. Maskin has a direct financial interest in Maskin meibomian gland intraductal probes and tubes. He also has a pending patent on the use of jojoba for the treatment of meibomian gland dysfunction or obstruction.