Preoperative Preparation of the Patient
Many surgeons administer topical antibiotic prophylaxis preoperatively. The patient’s skin is prepared with povidone-iodine, 5%–10%, or alcohol wipes before or after the patient enters the laser suite, and povidone-iodine solution, 5%, is sometimes applied as drops to the ocular surface and then irrigated out for further antisepsis. There is no consensus about the utility of these measures. When preparing the patient, the surgeon should take care to avoid irritation of the conjunctiva, which could lead to swelling of the conjunctiva and difficulties with suction.
In addition, before laser treatment, patients should be informed about the sounds and smells they will experience during the laser treatment. They may receive an oral antianxiety medication, such as diazepam.
If substantial astigmatism is being treated, some surgeons mark the cornea at the horizontal or vertical axis while the patient is sitting up to ensure accurate alignment under the laser. This step is done to compensate for the cyclotorsion that commonly occurs when the patient changes from a sitting to a lying position. A 15° offset in the axis of treatment can decrease the effective cylinder change by 35% and can result in a significant axis shift. There are multiple methods for marking the cornea or limbus.
After the patient is positioned under the laser, a sterile drape may be placed over the skin and eyelashes according to the surgeon’s preference. Before doing so, a “time-out” should be performed during which the correct patient is identified, and the treatment and eye(s) to which treatment will be performed are confirmed. Topical anesthetic drops are placed in the eye; for LASIK patients, care should be taken to ensure that the drops are not instilled too early, as doing so may loosen the epithelium substantially. An eyelid speculum is placed in the eye to be treated, and an opaque patch is placed over the fellow eye to avoid cross-fixation. A gauze pad may be taped over the temple between the eye to be treated and the ear to absorb any excess fluid. The patient is asked to fixate on the laser centration light while the surgeon reduces ambient illumination from the microscope, focuses on the cornea, and centers the laser. It is important for the plane of the eye to remain parallel to the plane of the laser, for the patient to maintain fixation, and for the surgeon to control centration even when using lasers with tracking systems. For most patients, voluntary fixation during photoablation produces more accurate centration than globe immobilization by the surgeon.
Excerpted from BCSC 2020-2021 series: Section 13 - Refractive Surgery. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.