Head positioning and exposure of the surgical field is important for success in phacoemulsification. The patient should be supine with the head positioned so that the iris is parallel to the floor. Then the eyelashes should be draped out of the way and a speculum placed to spread the eyelids. The palpebral fissure between the eyelids is determined by patient anatomy but also by the level of patient cooperation. If the patient is uncooperative and is actively squeezing the eyelids then the palpebral fissure will narrow and the Bell’s phenomenon will cause the globe to move to upgaze.
The solution is for the anesthesiologist to give the patient additional intra-venous sedation in the form of a short-acting benzodiazepine like midazolam. Calming the patient with reassurance can also be helpful, as can turning down the intensity of the microscope lights.
Click below to where we highlight the importance of surgical exposure: