Smile Pro With The Visumax 800: The Impact Of Centration

Published 2023 - 41st Congress of the ESCRS

Reference: PO0882 | Type: Free paper | DOI: 10.82333/pmnk-8h17

Authors: Michael Lawless* ¹ , Chris Hodge ¹ , Gerard Sutton ¹ , Colin Chan ²

¹Vision Eye Institute,Sydney,Australia;University of Sydney,Sydney,Australia, ²Vision Eye Institute,Sydney,Australia;University of Sydney,Sydney,Australia;University of Canberra,Canberra,Australia

Purpose

To understand the potential impact of centration on the refractive outcome for patients undergoing SMILE pro refractive procedure on the Visumax 800 laser.

Setting

Private ophthalmic refractive clinic (Sydney, Australia)

Methods

The outcomes of patients undergoing the initial SMILE pro procedures from 3 surgeons were assessed and collated. Centration and postoperative refractive data were available for 83 eyes (58 patients) from a total cohort of 445 eyes. Centration target was at the surgeon discretion and was based on either 50% or 75% of the Px and Py values (“50% cohort” n = 52, “75% cohort” n = 31). Basic demographic, refractive and centration variables were assessed. The Purkinje vector reflected the distance from final centration to the Purkinje image 1 (Px, Py).

Results

Overall mean age 33.9 +/- 6.4 years and mean preoperative spherical equivalent (SE) was -4.84 +/- 1.96D (range -10.0Ds to -1.75Ds). Following surgery, overall decentration from target xy value was 0.145 +/- 0.067 mm (range 0 to 0.32mm). There was no difference in mean decentration values between surgeons. The mean vector distance from achieved centration to Purkinje image 1 was 0.128 +/- 0.090mm. This vector was smaller in the 75% target group (mean 0.107 +/- 0.732 vs. 0.134 +/- 0.091) however the difference was not statistically significant (p = 0.078). Overall, the Purkinje vector was positively correlated with the absolute difference from target SE (r = 0.232, p = 0.039). This remained significant for the 50% target group only.

Conclusions

Centration over the visual axis is thought to provide the optimal refractive and visual quality outcome in refractive surgery. The Visumax 800 allows for centration to be optimised and thereby more accurate placement of the laser pattern. In this small cohort, the final decentration correlated with the target refractive outcome suggesting a tangible impact. Further, this early data suggests that using a centration target closer to the visual axis (Px Py) may result in more accurate visual outcomes.