Combined Artemis very high-frequency digital ultrasound-assisted transepithelial phototherapeutic keratectomy and wavefront-guided treatment following multiple corneal refractive procedures

Abstract

We present a patient with severe visual symptoms following multiple corneal refractive procedures including automated lamellar keratoplasty, arcuate keratotomy, laser in situ keratomileusis (LASIK), LASIK enhancement by cutting another flap, followed by a further LASIK enhancement by flap lifting. Topography was irregularly irregular, and the best spectacle-corrected visual acuity (BSCVA) was 20/25. Artemis very high-frequency digital ultrasound (US) analysis of the anatomical irregularities of the epithelium and stroma was used in conjunction with the topography to determine the cause of the visual symptoms. Very high-frequency digital US-assisted transepithelial phototherapeutic keratectomy together with a wavefront-guided treatment was used to reduce the stromal surface irregularities and the higher-order aberrations (HOAs), respectively. The treatment successfully regularized the stromal surface, dramatically reduced the HOAs, improved the contrast sensitivity to the high normal range, and improved the BSCVA to 20/20.

Epithelial Thickness After Hyperopic LASIK: Three-Dimensional Display with Artemis Very High-Frequency Digital Ultrasound

“…1 Numerous reports have been published describing central epithelial thickening following central tissue removal by myopic excimer laser ablations, which has been related to myopic regression. 2-12 Epithelial thickness changes have also been described after radial keratotomy, 13 intracorneal ring segments, 14,15 and orthokeratology contact lens wear.…”

“…16-20 The epithelium has also been reported to compensate for stromal irregularities in cases of asymmetric resection in automated lamellar keratoplasty, 4 asymmetric LASIK flaps, 4,21,22 microfolds, 21,22 flap malposition and short flap, 21-23 free cap malrotation, 24 and irregular stromal surface following multiple refractive procedures. 1 …”

Guiding flying-spot laser transepithelial phototherapeutic keratectomy with optical coherence tomography

“…Reinstein and Archer 21 and Reinstein et al 22 first described the phenomenon that the epithelial masking effect could shift the refractive outcome of the transepithelial PTK procedure. In a 2012 case report, 22 they predicted that the transepithelial ablation in an eye with superior and inferior epithelial thinning would effectively result in a hyperopic astigmatic ablation of 3.5 D. In our 2014 study, 8 we modeled the epithelial refractive masking effect using the difference between the central and peripheral epithelial thicknesses.…”

Repeatability of Layered Corneal Pachymetry with the Artemis Very High-Frequency Digital Ultrasound Arc-Scanner

“…Repeatable epithelial thickness measurements are useful for a wide variety of applications including measuring epithelial thickness profile changes after refractive surgery, 27 diagnosing optical complications due to an irregular stromal surface, 4,15,24 and determining the minimum possible flap thickness to use for thin-flap LASIK to avoid a buttonhole. This is particularly useful when considering the possibility of creating a flap in an eye that has previously had PRK where the epithelium might have thickened to compensate for the tissue removed.…”

“…The Artemis 1 has been used to measure flap thickness reproducibility 22,23 ; provide diagnoses for optical complications after corneal refractive surgery 24-26 ; demonstrate epithelial changes after myopic LASIK, 27 hyperopic LASIK, 28 and orthokeratology 29 ; investigate the sizing issues related to phakic intraocular lenses (IOLs) 30-33 ; measurement of stromal change to evaluate excimer laser ablation depth 34 ; describe the epithelial thickness 35 and stromal thickness 36 in a normal population; describe corneal, epithelial, and stromal thickness in a keratoconic population 37 ; and using epithelial thickness profiles to screen for keratoconus. 38,39 The Artemis 1 prototype was used for the present study.…”