Why Cautery:
The use of cautery dates back to prehistoric times when hot stones were used to stop bleeding. Still, in modern days, cautery is paramount, and an absolutely essential item to have in the majority of ophthalmic procedures.
Hemostasis remains the most important role of cautery. Without hemostasis, we run the risk of bleeds leading to the worst case scenario of a retrobulbar hematoma and blindness. Hemostasis allows for a safer and more favorable outcome. But besides hemostasis, cautery can be used for other purposes. We use it commonly in ophthalmology to induce punctal stenosis for patients with dry eyes. We use it to close conjunctival incisions. We use it as a surgical marker.
What You Need to Know:
Heat is generated through an electrical current and flows to a metal tip to coagulate blood vessels and stop bleeding. Electrocautery comes in the form of monopolar or bipolar. With monopolar electrocautery, the current is applied through a handheld active electrode and travels back to the generator through an inactive electrode attached to the patient (the grounding pad), so the patient is part of the electrical circuit. The inactive electrode is typically placed on a large area of the body to avoid heat conduction.
With bipolar electrocautery, the current is passed between one forceps tip to the other, and a limited amount of tissue is cauterized in between. The current is spread more with monopolar electrocautery, there is more tissue damage, and recovery of the tissue takes a bit longer. Bipolar cautery allows for more precise delivery of the heat. Lateral thermal damage is greater with unipolar cautery than bipolar cautery.
For these reasons, I use bipolar cautery more often, but many use monopolar cautery because this method tends to decrease surgical time with the capability to cut and coagulate with the same instrument.