Eclipse Method For Corneal Vertex Centration In Small Incision Lenticule Extraction Using Visumax 800

To describe a novel method for corneal vertex centration in small incision lenticule extraction (SMILE) using the VisuMax 800 femtosecond laser.

Single-center study conducted at GS Eye Clinic, Seoul, Korea, involving patients with myopia and astigmatism undergoing small incision lenticule extraction (SMILE) using the VisuMax 800 femtosecond laser.

The patient is positioned supine on the operating table, with the eye to be treated aligned directly beneath the VisuMax 800 femtosecond laser delivery system. The patient is instructed to fixate on the green internal fixation light. The surgeon assesses the Kappa angle by analyzing the relative position of the pupil and the Purkinje-Sanson image (green dot P image), which appears as a faint green dot on the monitor. The green dot P image is then aligned with the bright green light reflected on the contact lens, achieving what is referred to as the 'eclipse state’. Suction is then applied while simultaneously pressing the cornea, ensuring precise centration centered on the corneal vertex (CV).

A total of 528 patients with myopia or astigmatism underwent the eclipse method for centration during SMILE using VisuMax 800. Postoperatively, all patients achieved an uncorrected visual acuity (UCVA) of 20/20, and no cases of significant decentration were observed.

Optimal centration can be achieved by aligning the faint green dot P image on the patient's cornea with the bright, distinct green light at the center of the contact lens (eclipse state). When combined with the Centralign® function, which utilizes the pupil offset data from the IOL Master 700, this method enhances the verification and reliability of centration.