Influence of Tomographic and Biomechanical Corneal Indexes on Refractive Surgery Indications: A Cross-sectional and Multicenter Study

Abstract

Purpose: To evaluate the influence of corneal tomographic and biomechanical indexes on the refractive technique indication. Methods: 251 eyes from 251 patients interested in refractive surgery were enrolled in this cross-sectional and multicenter study. Previous to surgeon decision, a preoperative protocol was performed by refractive optometrists, containing four sections: refraction, biometry, corneal tomography and biomechanics. The refractive surgeons made a first decision based only on refraction, biometric and tomographic information. Biomechanical indexes were revealed, and refractive surgeons made a second indication. Additionally, for LASIK cases the percent tissue altered (PTA) were calculated. Possible indications were no refractive surgery, photorefractive keratectomy (PRK), Laser Assisted in-situ Keratomileusis (LASIK) or intraocular collamer lens (ICL). Results: After the first surgery indication, the distribution were PRK (47.4%), LASIK (48.2%) while ICL achieved 2.8%. This proportion changed significantly after second indication regarding corneal biomechanics and PRK and LASIK decreased in a 24% while ICL increased 19%. 69 eyes changed the indication (27.5%) and 182 eyes (72.5%) remained unchanged. All indications changes were from PRK or LASIK to ICL or no surgery. Indication changes to ICL were observed in 49 eyes (71%). Tomographic, biomechanical indexes, ablation depth and PTA achieved statistically significant differences between eyes without and with indication changes (all, P < .01). Conclusion: New corneal biomechanical indexes could change the indication decision regarding biometric and tomographic data alone. ICL was the preferred indication for eyes at risk of ectasia or with subclinical keratoconus due to corneal biomechanical parameters.