Complex Therapeutic Laser Refractive Corneal Surgery Guided By Prognostic Topographic Algorithm

Complications from corneal refractive surgery are rare. However, when they occur, they are devastating. The cornea is thinner, scarred, irregular while, the refractive error is negligible, making therapeutic corneal refractive surgery extremely difficult. Patients are emotionally scarred and risk-averse. These are the first reports on complex therapeutic laser refractive corneal surgery cases guided by a prognostic topographic algorithm. Being able to accurately foresee the final topography and refraction after repair surgery would be a boon to all corneal refractive surgeons. This preview may help correct many hundreds of corneal refractive surgery cases with complications.

Private practice, Jerry Tan Eye Surgery, Singapore

A series of complex corneal refractive surgery treatments for complications were planned and previewed by a foresight topographic algorithm. Corneal tomography, topography, epithelial and stromal thickness were measured using a Spectral domain optical coherence tomographer and topographer. The pre-operative topographies from this system were input into the preview algorithm. Various parameters like the optical zone size, the type of wavefront-driven treatment (Ocular and Topography), refraction - SPH, CYL, Axis, and type of ablation - e.g. PRK, TransPRK, LASIK,  could be chosen, to alter the final result.  The actual postoperative topography and refraction after complex correction were compared to the preview.

The final results of the preview versus the actual corneal topography post-operation were compared. In addition, the expected refraction result and the post-operation refraction were also compared. The results show that there is a close correlation between the preview and actual post-operation results. The post-operative topographies were also in general accurately depicted by the algorithm. The estimated postoperative refraction from the preview was consistent with the trend observed in actual postoperative refraction.

This preview algorithm shows great potential. Despite its early stage of development, the preview algorithm showed promising accuracy and great potential in complex cases. The possibility of adding artificial intelligence into future versions of this algorithm, may make complex cases accessible to everyone (using this tool), and be no longer in the purview of only a few expert corneal therapeutic surgeons. This preview algorithm aims to educate surgeons and patients alike in the correction of complex corneal refractive surgery cases.