Customized Surface Ablation After Additive Keratoplasty Techniques

To verify the visual outcomes and complications of the customized Surface ablation after additive keratoplasty. Despite the safety, stability, and efficacy of the implantation of myopic Small Incision Lenticules, the method does not have predictability in the correction of refractive errors to an adequate degree. So this study aimed to evaluate customized ablation in these patients.

All procedures from patient selection to evaluation were conducted in Negah Eye Hospital.

In this comparative study the visual, refractive, keratometric outcomes, aberrometry, and Epithelial Thickness maps were compared. Customized surgery based on the patient's corneal surface information performed from the SIRIUS topographic device. The laser profile was Aspheric, the Q value was considered constant – 0. 25 D, and all Spherical Aberration was corrected based on the eye model with Q=-25.0. Also, the mentioned eye model Q=-25.0 was used to correct the remaining HOA. The plan was according to four steps: Demonstration of corneal wavefront surgical method; Display maps of Ablation, Wavefront and High order; Display numerical values of Zernike coefficients (High orders); Display values in RMS High order, RMS total, and Aberrations.

Customized surface ablation as a safe ablative procedure could give us an acceptable result; in reducing postoperative regression or residual refraction after additive procedures. This method is suitable for patients whose visual quality is impaired due to HOAs on the surface of the cornea that are not compensated from within. Altogether, depending on actual preoperative refraction and aberrometry, using a simple and reversible technique called “CW” (corneal wavefront surgical method), might offer predictable results.

In general, 2 important points should be considered in corneal wavefront methods: First, the amount of ablation should not differ from the amount of ablation in AF mode by 12 to 15 microns, which in itself causes more ablation and unwanted hyperopia. Second: The final ablation shape should be consistent with the patient's anterior elevation or anterior keratometric power.