Correspondence
Manoj Motwani
Motwani LASIK Institute, 4520 Executive Dr., Suite 230, San Diego, CA 92121, USA
Tel +1 858 554-0008
Email drmmlj@gmail.com
Purpose: To demonstrate how Wavelight Contoura can be used to repair corneas damaged by trauma and prior poor surgical outcomes.
Methods: Four representative eyes are presented that show different scenarios in which highly irregular corneas can be corrected with Wavelight Contoura using a protocol (named the San Diego Protocol) designed to use the information in Contoura processing. Both laser-assisted in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) were used.
Results: Highly aberrant corneas with large amounts of warpage can be corrected safely with the Wavelight Contoura system. The San Diego Protocol requires individual analysis of each case with decisions based on the level of warpage and the level of epithelial hyperplastic compensation. The need for a second refractive power equalization procedure should be planned for.
Conclusion: Contoura measured refraction can be integrally used as part of the San Diego Protocol to safely repair highly warped corneas. The refractive outcomes show dramatic improvement in vision, best-corrected visual acuity (BCVA), refraction, and topographic uniformity.
Keywords: corneal ablation, laser-assisted in situ keratomileusis, photorefractive keratectomy, refractive surgery, corneal irregularity, corneal trauma, decentered excimer laser ablations, radial keratotomy, higher order aberrations
Introduction
The repair of highly irregular corneas using topographic-guided ablation has been available for some years outside of the US, and development of the Wavelight system led to the US Food and Drug Administration (FDA) approval for primary eyes.1–3 In the FDA approval, the correction of prior distortions and corneal warpage (not to be confused with corneal warpage syndrome from contact lens wear; corneal warpage is used in the labeling to denote extreme corneal irregularity) is listed as a precaution, and not a contraindication, and hence procedures repairing past surgery, trauma, or corneal disease are not expressly off label with Wavelight topographic-guided ablation but are actually under the FDA labeling only with a precaution.4
The repair of corneal issues is an area that is fraught with lack of full understanding even outside the US and has been virtually non-existent in the US until 2016. Furthermore, there has also been a lack of full understanding thus far as to the use of the measured astigmatism and axis from the Wavelight topography-guided software. The market name has been Contoura, but the repair function is often referred to as topography-guided custom ablation treatment (T-CAT). Much of the current literature with T-CAT internationally has dealt with the treatment of keratoconus combined with corneal cross-linking.5,6 There has been less information concerning other forms of corneal reconstructive repair such as corneal trauma, past laser ablation decentration, and radial keratotomy (RK) irregularity correction and precious little in the way of a protocol that can be used to make decisions on how to proceed with such cases.
This study was undertaken to show four examples of corneal repairs stemming from both surgical and traumatic causes. Although each repair must be undertaken as a case unto itself and must be evaluated individually, we have developed a protocol that allows for an understanding of how to make decisions concerning corneal repair. It is this protocol that has been named the San Diego Protocol.
The fundamental problem with repairs is the extent of irregularity of the cornea and how much it affects the pre-operative (pre-op) correction. The decisions on this must be made on a case-by-case basis by understanding where the visual axis lies in the distortion. Treatment with topographic-guided ablation can be affected by corneal epithelial compensation, as epithelial hyperplasia will change the thickness of the epithelium to thin over “high” spots and thicken in “low” spots. Although instruments such as optical coherence tomography (OCT) and the Artemis very high frequency (VHF) scanner can show the extent of epithelial compensation, many clinics (including ours) do not have these devices, thus making it difficult to tell how much epithelial compensation is affecting the Contoura measured astigmatism, and even the spherical power. Even if epithelial hyperplasia information is available, this information cannot be integrated into Contoura to change the treatment, and it is only useful for diagnostic purposes.
The use of Contoura measured astigmatism in repairs derives directly from previous work done by the author demonstrating the superiority of using Contoura measured correction in primary eyes to create a uniform cornea (Motwani and Lemonis, unpublished data, 2017). To make matters more complicated, the presence of several corneal irregularity may significantly effect the ability to properly measure the manifest refraction. All of these factors must be taken into consideration when undertaking a corneal repair with topographic-guided ablation.
