Ray-Tracing Transepithelial Excimer Laser Central Corneal Remodeling Plus Pachymetry-Guided Accelerated Corneal Crosslinking for Keratoconus

Abstract

Purpose: The aim of this study was to report the 12 to 96 months results of a tissue-preservation algorithm based on ray-tracing-guided transepithelial excimer laser central corneal ablation (RT t-PRK) combined with individualized pachymetry-guided accelerated crosslinking (M nomogram ACXL) in young adult patients with stable keratoconus (KC). Methods: This was a prospective interventional study including 38 eyes of 38 young adult patients (stage II KC) with a mean age of 35 years (range 26–46 years) who underwent simultaneous RT with t-PRK plus pachymetry-based ACXL in the worst eye. The treatments were performed using the iViS Suite iRES Excimer Laser (Ligi, Taranto, Italy). Ray-tracing–guided treatments were planned using the customized interactive programmed transepithelial ablation (CIPTA) 2 web software and diagnostic data were assessed by the Precisio 2 tomographer (Ligi, Taranto, Italy) and Sirius tomographer (C.S.O., Florence, Italy). The main outcome measures included uncorrected distance visual acuity, best spectacle–corrected visual acuity, Kmax, high-order aberrations, minimum corneal thickness, and posterior elevation, with a mean follow-up of 52 months (range 12–96 m). Results: The mean UDVA improved + 3.5 ±1.28 Snellen lines (SL); 38% gained ≥ 4 ±1.34 SLs, 35% ≥ 3 ±1.21 SLs, 22% ≥ 2 ±1.12 SLs, and 5% ≥ 1 ±0.75 SLs. The mean best spectacle–corrected visual acuity increased by + 4.3 ±1.3 SL. Sixty-eight percent gained ≥ 4 ±0.88 SLs and 30% ≥ 3 ±0.78 SL. No SLs were lost. Conclusions: RT t-PRK plus ACXL significantly improved the quality of vision in patients with KC, preventing overcorrection and minimizing tissue consumption.

Utility of artificial intelligence in the diagnosis and management of keratoconus: a systematic review

“…Additionally, AI can be used in the surgical planning of some therapeutic options for keratoconus that are growing in popularity, such as ray-tracing-guided transepithelial photorefractive keratectomy with accelerated crosslinking, which may help reduce refractive overcorrection and stromal tissue ablation ( 151 ). Mazzotta et al.…”

“…Mazzotta et al. used a tissue-preservation algorithm involving ray tracing among 38 patients with stable keratoconus undergoing this procedure ( 151 ). They reported that the algorithm and surgical treatment significantly improved visual outcomes in their cohort ( 151 ).…”

It is time for a Turning Point in Keratoconus

“…3 I cannot hide a certain emotion, because it was precisely in this Journal that the M nomogram 4,5 for the standardized treatment of individualized crosslinking of ectatic corneas of all thicknesses was born, as awarded in the ESCRS Congress in 2019 in Paris with the "Joseph Colin Prize" for innovating therapies in the field of Keratoconus. 4,5 The "M nomogram" allows safe and effective setting of CXL parameters based on thickness minimum preoperative corneal membrane, also allowing the standardized treatment of thin and ultrathin ectatic corneas with a minimum thickness between 250 and 400 µm, keeping the fluence standardized in the Dresden Protocol constant (5.4 J/cm 2 ). 4,5 Actually, the preliminary results on new epithelium-on accelerated CXL protocols with progressively higher fluence and pulsed light show that a new pachymetry-based PFPL M Epi-on ACXL nomogram stabilizes ectasia progression.…”

“…4,5 The "M nomogram" allows safe and effective setting of CXL parameters based on thickness minimum preoperative corneal membrane, also allowing the standardized treatment of thin and ultrathin ectatic corneas with a minimum thickness between 250 and 400 µm, keeping the fluence standardized in the Dresden Protocol constant (5.4 J/cm 2 ). 4,5 Actually, the preliminary results on new epithelium-on accelerated CXL protocols with progressively higher fluence and pulsed light show that a new pachymetry-based PFPL M Epi-on ACXL nomogram stabilizes ectasia progression. 6 Higher fluence Epi-on ACXL increases CXL penetration, with better functional outcomes in the absence of complications, thus paving the way to a replacement of epithelium-off crosslinking treatments.…”

“…2 Selective ray-tracing-guided sequential and simultaneous excimer laser transepithelial photorefractive or phototherapeutic keratectomy combined with conventional and accelerated CXL is another way in selected cases to improve spectacles-corrected distance visual acuity (CDVA) of keratoconic eyes. 5…”